Text Book: 
Georgia Life Science, Pearson- Prentice Hall 
 
Supplies needed: 
1. Loose-leaf paper 
2. #2 pencils 
3. 3-ring notebook specifically for Science 
 
** pens will be allowed with the condition that there are to be absolutely no scribbles, etc. to correct mistakes. Only neat and proper work will be accepted. Students who turn in sloppy work in pen will be asked to re-do the work in a neat and orderly manner. I advise that students use a pencil the first time to keep from having to re-do assignments.  
 
AGENDA 
Always bring your agenda to class. Record the daily information and homework in your agenda. No bathroom passes during class except during extreme emergencies, and YOU MUST have an Agenda pass for a visit to the restroom. 
 
Goals: (taken directly from the GPS website) 
Seventh grade students keep records of their observations and use those records to analyze the data they collect. They observe and use observations to explain diversity of living organisms and how the organisms are classified. They use different models to represent systems such as cells, tissues, and organs. They use what they know about ecosystems to explain the cycling of matter and energy. The students use the concepts of natural selection and fossil evidence in explanations. Seventh graders write instructions, describe observations, and show information in graphical form. When analyzing the data they collect, seventh graders can recognize relationships in simple charts and graphs and find more than one way to interpret their findings. The students replicate investigations and compare results to find similarities and differences. The middle school life science course is designed to give students the necessary skills for a smooth transition from elementary life science standards to high school biology standards. The purpose is to give all students an overview of common strands in life science including, but not limited to, diversity of living organisms, structure and function of cells, heredity, ecosystems, and biological evolution.  
 
Course Outline: 
A. Structure and Function of Cells 
B. Organization of Life 
C. Heredity- Genetics 
D. Evidence of Evolution 
E. Interdependence of Life: Ecology 
F. Energy Flow & Nutrient of Cycling 
G. Scientific Process Skills 
 
Labs: 
During the year some of the labs in class involve food. If your child has a food allergy please make me aware so I can substitute ingredients if possible. Also, I may ask for volunteers to bring things in for lab. Please do not feel that you have to send these items, but anything that you can send is greatly appreciated.  
 
Projects: 
Throughout the year we will work on various projects. Some will be done in class, and some will be worked on outside of class. All projects count as a major assignment grade. Most projects will be done with partners or in groups. 
 
Grading: 
Daily Science Trivia 1x 
Classwork 1x 
Homework 1x 
Quizes 1x 
Projects 2x-3x 
Tests 2x 
 
Weblogs and Powerschool: 
Your student’s grade will be updated weekly (Tuesday by the latest) and available on Powerschool. Parents can keep up with your child’s assignments and grades. Teachers post assignment information on their weblogs, and students should be writing it in their agendas. Grades can be checked on Powerschool and are updated every Tuesday. Stop by the office to get your login information. Both of these tools can be accessed on the LMS website: www.walkerschools.org/lms 
 
Homework: 
Homework will be assigned on a regular basis. Students are expected to complete these assignments. Homework will include reading notes, written work, projects, printing out materials from Mrs. Semtner’s weblog, and other work related to science. 
 
**Assignments are due on the day set by the teacher. NO LATE WORK WILL BE ACCEPTED! 
 
Class Rules: 
1. Do your best 
2. Be prepared 
3. Be honest 
4. Be respectful 
5. Always learn 
 
Consequences: 
1. Warning 
2. Loss of stamps 
3. Parent Contact and Silent Lunch 
4. Office Referral 
5. Teacher discretion  
 
Procedures: 
Beginning Class 
1. Walk quietly into class with all your materials on time. 
2. Place your books on your desk appropriately. 
3. Read the board for essential information and write down and answer daily  
science trivia, record homework into your agenda, prepare for daily  
lesson. 
4. Look over and do today’s assignment. 
 
Ending Class 
1. If you complete all of your class work you may read. 
2. You must work until the teacher tells you to prepare to leave, the teacher  
dismisses you not the bell. 
3. Double check to make sure your assignment and information is written in  
your agenda. 
4. Clean up your space. 
5. Exit when the teacher tells you, in an orderly fashion. 
 
Policy Regarding Cheating 
**When a student is given an assignment (daily activity, quiz, test, etc.) that is to be completed independently; independent behavior is what is expected. Any other behavior will be considered cheating, and the student will receive a grade of zero for the assignment. 
 
Expectations: 
MRS. SEMTNER’S CLASS EXPECTATIONS 
 
1. Students will have homework in this class. The completion of homework is expected. When written homework is assigned it will be taken up by the teacher at the beginning of class the following day. 
2. Students are expected to be active learners in this class. This includes bringing necessary supplies to class everyday, participating in class discussions, taking thorough notes, reading, and studying. 
3. If a student is absent, the student will have five days in which to complete missing assignments. These assignments are expected to be turned in at the end of the five-day period. 
4. If a student is having trouble in science, after school help is available. The student is expected to make arrangements with the teacher in advance. Please do not wait until the last week of the grading period to ask for help. 
5. Supplies needed for this class are loose-leaf notebook paper, a Science notebook, an agenda, and #2 pencils. Students are expected to have these supplies in class everyday. 
6. Students are expected to have all supplies at their desks when they are needed. 
7. Good behavior and good manners are always expected in this classroom. Students will be treated with courtesy and respect. Students are expected to treat others in the same manner.  
8. Students are expected to do their best at all times. This includes academically and behaviorally.  
9. Students are expected to show respect to themselves, their peers, and all adults. Guests, who include substitutes, will be treated with the highest respect.  
10. Students are expected to be truthful and trustworthy. 
11. Students are expected to be active listeners. Active listeners look at the speaker. Active  
listeners are not engaged in other activities while someone is speaking. Active listeners  
are silent when someone is speaking to them. Active listeners can answer questions  
about what was said by the speaker. Active listeners are respectful. 
12. Students are expected to be positive. Put downs and negative comments will not be tolerated. 
 
Communication is a key factor in your child’s education. Feel free to contact me at KARASEMTNER@WALKERSCHOOLS.ORG I look forward to an awesome year! 
 
Kara Semtner 

Posted by: Team 7-2 Science

The Scientific Method 
 
Georgia Professional Standards Addressed in this Lesson: 
S7CS4: Students will use tools and instruments for observing, measuring and manipulating equipment and materials in scientific activities. 
S7CS6: Students will communicate scientific ideas and activities clearly. 
 
Science is basically the process of observing things, asking questions about the observation and conducting experiments to find answers to the questions. 
 
Life Science - the study of living things. Life scientists conduct research or experiments that help in finding cures for diseases, conduct research to understand the components of cells, understanding how the living organisms in the environment effect each other as well as the forces or occurrences that impact living organisms. 
 
In order to do the work of scientists, the scientific method has been designed to break the process into stages. The scientific method is often described as a series of steps that is used to answer a question or solve a problem. 
 
There are six steps to the scientific method: 1) Ask a Question 2) Form a Hypothesis 3) Test the Hypothesis (Conduct Experiment) 4) Analyze the Results of the Experiment 5) Draw Conclusions and 6) Communicate the Results. 
 
Ask a Question 
When you observe something you do not fully understand you often ask yourself a question about what may have caused what you observed. Once you ask yourself a question, you must often do more observations while searching for the answer. 
 
Form a Hypothesis 
The hypothesis is a logical explanation for what you have observed. In other words you make a possible explanation to the phenomenon you observed. The hypothesis is usually written in the form of an If…,then statement. Example: If I take a balloon and fill it with air I can poke it with a sharp needle and then it will deflate very fast. This can be easily tested with a blown up balloon and a sewing needle. 
 
Test the Hypothesis 
When you test your hypothesis you are conducting experiments that may help you explain the phenomenon or observation. Many of the experiments scientists use are designed by the scientist working on solving the problem or phenomenon observed. This means that many scientists must be somewhat creative and often think “outside the box” to set up their experiments. 
 
When scientists test their hypothesis, they utilize controlled experiments. A controlled experiment is an experiment that tests only one factor at a time. The one factor being tested is known as the variable. Scientists only test one variable at a time to be more certain that it is the variable causing the effect. 
 
 
 
Analyze the Results 
After the experiments have been completed, the scientist must carefully analyze the results and determine if the results help in solving the problem or answer the hypothesis. 
 
 
 
Draw Conclusions 
The scientist must look at the data gathered from the experiments and draw a conclusion based on the results from the experiment. In other words, does my data support or not support the hypothesis that was formed. 
 
 
Communicate the Results 
This step involves telling others in the scientific field about your experiment and your findings. At this point other scientists may want to see if they can replicate you experiment or maybe modify your experiment to see if they come up with the same conclusion(s). 
 
Sometimes a problem may be tested over and over with scientists getting the same results. When this occurs, we call the explanation of why something occurs in a particular way a theory. 
 
Tools that Scientists Use 
Many of the tools scientists work with are often new and have been developed to work on specific research experiments. We often call this technology. Technology is the use of knowledge, tools, and materials to solve problems and accomplish tasks. 
 
One of the most common pieces of equipment for scientists to use is a microscope. Scientists use microscopes to see things in more or greater detail. There are two main types of microscopes scientists use: 1) Compound Light microscope and 2) Electron microscope. 
 
Compound Light Microscope – has three main parts (a tube with lenses, a stage and a light source). Specimens are often viewed with compound light microscopes that have been dyed (stained) in order to see the object better. The specimen or object is placed on the stage in order for the light to pass through it and as the image passes through the lenses, it becomes magnified. 
 
Electron Microscope – this is where tiny particles of matter (called electrons) are passed through (with a transmission electron microscope) or bounced off of the specimen (scanning electron microscope). A flat image is produced with the transmission electron microscope and a three dimensional image is produced with a scanning electron microscope. All organisms viewed with the electron microscopes must be dead because the electrons passing through them or bombarding them will cause death or mutations. 
 
Other Tools 
X Rays allow us to detect internal structures (broken bones) or living organisms. 
 
CT (Computed Tomography) Scans and MRI (Magnetic Resonance Imaging) these tools provide clearer images of internal tissues than X rays. These tools create images that experts can interpret. 
 
Computers are very prevalent in science. Computers now allow scientists to model different problems and modify the influences to see what results occur. You are probably familiar with computer generated weather forecasts if you watch the weather on nightly news. Computers are also one of the fastest methods for communicating, writing research articles for journals, calculating numerical data, and organize information to name a few uses. 
 
 
Systems of Measurement 
Scientists are constantly measuring things (temperature, mass, velocity, volume, and length to mention several). Scientists use the metric system to take measurements. For length we use the meter as the standard, for mass we use the gram as the standard, and for temperature we use Celsius, and for volumes of solids we use cubic units and for liquid volume we use liters. 
 
We must realize that each major unit has subunits based on the value of 10. Look at the following prefixes and know what they represent: (we will be using the prefixes with the standard length unit in this example) 
 
Kilo = 1,000 Kilometer = 1,000 meters 
Hecto = 100 Hectometer = 100 meters 
Deci = 1/10th Decimeter = 1/10th of a meter 
Centi = 1/100th Centimeter = 1/100th of a meter 
Milli = 1/1,000th Millimeter = 1/ 1,000th of a meter 
 
Most of these prefixes are also used with other measuring units. Example: Many times scientists need a liquid in small amounts so we measure it in milliliters (1/1,000th of a liter). We will practice with these in our homework/class work worksheets throughout the year. Remember to use the best suited unit for your measurements. We would not measure the length of a soccer field in millimeters normally, we would want it in meters. Small objects like algae or bacteria would not be measured with meters, but some subunit of meters like micrometers (1/100,000th of a meter). 
 
Measuring Area - area is the measurement of how much surface something has. We measure area with the following formula: 
Area = Length X Width or (L)(W) 
Notice that this will give us SQUARE UNITS. Example: If we have a rectangle that measures 3 meters in length and 2 meters in width, we can calculate the area of the rectangle by using our formula Area (A) = (L)(W) or (3)(2) which equals 6 SQUARE meters. 
 
Practice: Measure a regular sheet of notebook paper and calculate the square inches in centimeters. Answer: _________________ square centimeters (sq. cm.) 
 
Measuring Volume – volume is the amount of space something occupies or as in the case of a box, the amount of space it contains. We can calculate volume by using the formula as follows: 
Volume (V) = Length (L) X Width (W) X Height (H) 
Notice this will require a cubic unit on the answer. Example: If I have a plastic container that measures 4 meters wide, 6 meters in length and 2 meters in height, we can calculate the volume of water the container will hold. 
V = 4 meters X 6 meters X 2 meters which equals 48 Cubic meters 
 
Scientists often have specific tools to measure liquids. The most accurate tool is the graduated cylinder. It is a cylinder with marks (often in milliliters) that we will use in lab. When in class you can see one of the graduated cylinders on page 25 of your text book. 
 
Measuring Mass – mass is the amount of matter that makes up an object. The basic unit of mass is the kilogram. When we measure the mass of small items or organisms we may use milligrams, or in the case of our labs we usually measure in grams. The tool used to measure mass is the triple beam balance scale. We will use one of these in lab and you must know how to use it and read the scale. 
 
Measuring Temperature – temperature is the measure of how hot or cold something is. Temperature is really a measure of how fast or slow molecules are moving. The higher the temperature, the faster those molecules are moving. We measure temperature with a thermometer and in degrees Celsius. Celsius is the metric system’s unit of scale, while Fahrenheit is the unit we use in the United States. 
 
You should know that water boils at 212 degrees Fahrenheit, which is 100 degrees Celsius. Normal human body temperature is 98.6 degrees Fahrenheit, which is 37 degrees Celsius. Water freezes at 32 degrees Fahrenheit, which is 0 degrees Celsius. 
 
Safety – during science class this year we must observe safety rules. No horseplay will be allowed in the science room, no eating or drinking should occur. Always follow directions your teacher outlines and discusses. If you do not understand something, ask the teacher instead of “trying” something that could result in an accident. 
 
 
 

Posted by: Team 7-2 Science

NOTES 
GPS: S7L2: Students will describe the structure and function of cells. 
GPS: S7L3(b) – compare and contrast sexual and asexual reproduction. 
 
Most organisms must eat other organisms in order to obtain energy for survival, but we have found some organisms that obtain their energy from hydrogen sulfide. These organisms are bacteria. Other organisms then feed on the bacteria. Not only are these bacteria found in deep ocean trenches and in Movile Cave that was discussed in your reading. 
 
PART 1 NOTES 
Every living thing has cells. Humans are composed of about 80 trillion cells. A cell is a membrane-covered structure that contains all of the materials necessary for life. 
 
Most cells are too small to be seen with the naked eye. Organisms with many cells have cells that carry out special functions. Example: Your nerve cells carry impulses to your brain. These impulses may be signals to walk, laugh, talk or be silent. 
 
All organisms have the ability to sense change in their environment and respond to that change. (Getting more cloths if you are cold, taking a sweater off if you are hot). 
 
Living organisms respond to change. 
 
A change in the organism’s environment that affects the activity of the organism is called a stimulus. (Plural - stimuli). 
 
Stimuli can be chemicals, gravity, darkness, pain, light, sounds, tastes, or anything that causes an organism to respond. 
 
Homeostasis 
 
The maintenance of a stable internal environment is called homeostasis. 
 
Even though an organism’s external environment changes, their internal environment must remain fairly constant. Example: the human body must remain at 37o Celsius. If it falls below this, we could go into hypothermia (hypo – below, thermia – temperature) or if it rises much above we could go into hyperthermia (hyper – above, thermia – temperature). Both of these conditions may result in death. 
 
**The maintenance of a stable internal environment is called homeostasis. 
 
If you are too hot, your body sweats. This is your body’s method to cool itself off and maintain homeostasis. If you are cold, your body shivers. This creates heat from the muscles and raises your body temperature to maintain homeostasis. 
 
Living Things Reproduce 
 
Organisms make other organisms like themselves. They can do this in one of two ways: asexual reproduction, or sexual reproduction. 
In asexual reproduction a parent produces offspring that are identical to the parent. (Hydra producing buds on page 38). 
 
In sexual reproduction, it requires two organisms to serve as parents to produce offspring, which will have traits from both parents. (Bears). 
 
Can you think of other asexual and sexual organisms? 
 
Living Things Have DNA 
 
The cells of all living things contain a special molecule called DNA (deoxyribonucleic acid). DNA provides the instructions to build the proper proteins in the organism. These proteins take part in the organism’s cells activities. 
 
The transmission of the characteristics from one generation to the next is called heredity. What are some traits you received due to heredity? 
 
Living Things Use Energy 
 
All living organisms must have energy in order to carry out daily activities. An organism’s metabolism is the total of all of the chemical activities that it performs. 
 
The cells in your body must transport materials into and out of them in order to remain alive. All of this requires energy and the total energy needs is your metabolism. 
 
Living Things Grow and Develop 
 
All living things, whether they are made up of one cell or many cells, grow during periods of their lives. (Single celled organisms have their cell get larger. Multi-cellular organisms add cells to become larger.) 
 
Organisms also go through different stages of development. Humans go through different stages as we develop. (Embryo, fetus, baby, child, adolescent, young adult, middle aged, senior citizen.) (An oak tree begins as an acorn, seedling, sapling, and then a tree)  
 
 
Review 
 
1. What characteristics of living things does a river have? Is a river alive? 
 
A river has energy (it moves – kinetic energy), and can grow larger (flooding). But it is not alive because it is not made of cells, cannot respond to stimuli, has no DNA, and cannot reproduce. 
 
2. What does a fur coat on a bear have to do with homeostasis? 
 
Homeostasis is the maintenance of a stable internal environment. The fur coat of a bear helps it keep a stable body temperature. 
 
 
3. How is reproduction related to heredity? 
 
Heredity is the passing of characteristics from parents to offspring. When organisms reproduce, offspring inherit copies of their parents DNA. 
 
4. What are some of the stimuli that you respond to in your environment? 
 

Posted by: Team 7-2 Science

NOTES: Copy and Paste these into a word document if you want to print them! 
 
Section 1 
Cells are similar to factories in that they must obtain materials form outside the cell membrane and remove material within the cell membrane. Food and liquids must be brought into the cell and wastes must be removes from the cell. All of this exchanging must be carried out across the cell membrane. 
 
Diffusion 
 
Particles are always moving whether they be in the form of a liquid, solid or gas. Particles naturally move from areas that are crowded to areas not as crowded. Stated scientifically we would say particles move from areas of greater concentration to areas of lower concentration. We call this process diffusion. Diffusion can occur across cell membranes or outside of the cell. Diffusion does not require any energy expended on the cell’s part. 
 
Diffusion of Water 
 
All living things require water. Recall that humans cannot survive except for about three days without water. Water is diffused through a cell membrane, but we call this process osmosis. Osmosis is the process by which water disperses from an area of high concentration to an area of low concentration. 
 
If we place a semi-permeable membrane between pure water and food coloring, what would happen? 
 
Semi-permeable membrane 
| 
Pure Water (100%) | Water (80%) 
| Food Coloring (20%) 
| 
 
In this situation we would have pure water “100%” in a higher concentration and it would flow to the area of lesser concentration (80%) until equilibrium were reached. 
 
Osmosis will occur across cell membranes also. This is why a wilted plant will become firm and erect when watered. The water will enter into the plant cell (area of lower concentration). 
 
Moving Small Particles 
 
Many substances can cross the cell membrane by diffusion and osmosis, but some may be too large to pass through the cell membrane. Recall that the cell membrane is a double layer of phospholipids. Embedded within the cell membrane, you will find some proteins that act as passageways into and out of the cell. Objects that are too large to directly pass into and out of the cell must enter or leave by way of these proteins. This can occur by passive or active transport. 
 
Passive Transport 
 
This occurs where the substance or particle entering or leaving the cell is too large to directly pass into or out of the cell. In passive transport, the particles travel from an area of higher concentration to an area of lower concentration by way of the embedded protein. The cell does not use any energy for this to occur. 
 
Active Transport 
 
In active transport, the particles flow in the opposite direction of diffusion. In other words, the embedded proteins transport the particles from lower concentration to areas of higher concentration. This process requires energy expended by the cell. This energy is ATP. An example of active transport could include sugar molecules needing to get inside a cell where the concentration is higher than the outside of the cell. 
 
Summing it up: Diffusion, Active Transport and Passive Transport are good methods to move small particles into and out of the cell. 
 
Moving Large Particles 
 
At times, large particles will need to enter and exit the cell. This can be done in two ways: endocytosis and exocytosis. 
 
Endocytosis – the cell membrane surrounds the large particle and encloses it to form a vesicle. The vesicle is “pinched off” inside the cell to be used. Remember: endo - into 
 
Exocytosis – This is carried out when a large particle must be removed from the cell. In exocytosis, the vesicles are formed at the endoplasmic reticulum or the golgi complex to carry the particles out of the cell. Remember: exo – exit. 
 
Review on your own: 
1). what is diffusion? 2). what is Osmosis? 3) How do cells take in large materials into the cell? 4). How do cells remove large particles from the cell? 5). Explain passive and active transport. 
 
Section 2 
 
Cell Energy 
 
All cells must have food in order to survive. When you feel hungry, your cells are telling you they need something to eat. 
 
Nearly all the energy for all life comes from the sun. Plants and some algae are able to capture this light energy and convert it into food through the process of photosynthesis. If we did not have plants and other producers, there would not be any consumers. 
 
Photosynthesis 
 
As we discussed in class, plants have molecules that are able to capture the energy of sunlight. These special molecules are called pigments. Most people have heard of the term chlorophyll, this is the molecule that can capture the sun’s energy and use the energy in the production of ATP. The chlorophyll is located in structures called chloroplasts. The chlorophyll is responsible for the colors we see in plant leaves/stems in most cases. 
Plants use carbon dioxide + water + sunlight to yield glucose and oxygen. 
The chemical formula will look like this: 
6CO2 + 6H2O + light energy -à C6H12O6 + 6O2 Glucose is a carbohydrate; this is a form of energy the plant can store. If a consumer eats a producer, the consumer can use the glucose as a source to be used for the production of ATP. Notice that photosynthesis also produces oxygen. We need oxygen to carry out our respiration processes. 
 
 
 
Getting Energy From Food 
 
Consumers must eat other organisms (plant or animal) in order to obtain food. This material can be broken down into a form of energy our cells can use. There are basically two methods to this: 1) cellular respiration and 2) fermentation. 
 
Cellular Respiration 
 
When we respire, we breathe. This means we take in a breath of air into our lungs and we exhale the waste gas carbon dioxide. This is respiration, but not cellular respiration. Cellular respiration is occurring at the cellular level. In general terms, our cells are taking the food in the form of glucose and breaking it down into carbon dioxide and water and releasing energy. This energy being released is in the form of heat. Most of this heat is used to maintain homeostasis (37 degrees Celsius). Some of the energy is stored in the form of ATP. The ATP can be used to carry out biological functions of the cell (we will discuss this in detail later). All of this cellular respiration is occurring in the organelle called the mitochondria. 
 
Summarizing: Glucose + Oxygen à Water + Energy (ATP) 
This is the reverse of what? That’s correct, photosynthesis. 
 
Fermentation 
 
This is essentially the partial breakdown of glucose in the absence of oxygen. When you run and your muscles begin to ache, you are experiencing a type of fermentation. The aching is lactic acid building up within your muscles. Another type of fermentation occurs when yeast cells are mixed with flour and water (making dough). The yeast cells will begin to break down the glucose and give off carbon dioxide gas. This is what causes bread dough to rise. 
 
Fermentation is also used to produce alcohol products. Yeast is added to some form of sugar and as the yeast break down the glucose they give off carbon dioxide and produce ethanol. The percent of ethanol being formed is what finally kills the yeast cells. (Example – winemakers press the sugars out of the grapes and the yeast cells will begin to ferment the juice into wine. Once the wine gets to a certain percent alcohol it becomes toxic for the yeast and they die. 
Section 3 
 
Cell Information 
 
The cell goes through a cycle during its life. The cycle begins when a new cell is made and that new cell goes through specific stages or phases and divides to form new cells. 
 
Before cells can divide to produce new cells, they must make copies of their DNA. Recall that DNA is the hereditary information or genetic information that contains all the information to produce proteins. The DNA is in the form of structures called chromosomes. We can recognize the phase that a cell is in during cell division by looking at the chromosomes and where they are located during the division process. We will look at these phases shortly. 
 
Division of Prokaryotic Cells 
 
Recall that bacteria do not have a nucleus and the DNA is in an oval pattern and is not complex. The bacteria also do not have organelles that are enclosed by a membrane. These are the main reasons that bacteria or prokaryotic cell division is simple compared to eukaryotic cells. Essentially the DNA is copied and the bacteria cell divides with each new cell receiving one copy of the DNA. This division process is known as binary fission, of prokaryotic cells. 
 
Division of Eukaryotic Cells 
 
Recall: Eukaryotic cells are much larger than prokaryotic cells and they are more complex. They have a nucleus and organelles that are enclosed within membranes. The nucleus is where the DNA is “housed”. 
 
The number of chromosomes in organisms has nothing to do with the complexity of the organism in eukaryotic cells. Example: Fruit flies have 8 chromosomes, humans have 46, and potatoes have 48. So is a potato more complex than a human? Don’t answer that! (Joke). If the number of chromosomes determined the complexity, the potato would be more complex. Chromosomes are lined up into pairs. Each chromosome in each pair is similar to each other. 
 
 
 
 
General Eukaryotic Cell Division 
 
The eukaryotic cell cycle has three main stages. The first stage involves the cell growing and copying organelles and chromosomes. The duplicated chromosomes are called chromatids. The chromatids are held together in the center by a centromere (disk shaped structure). Imagine two pieces of wire the same length and same diameter laying beside each other. Then picture the wires joined in the center with a disk of glue. This is essentially what the chromatids look like. 
 
The second stage of eukaryotic cell division involves the chromatids separating. When the chromosomes separate, the process is known as mitosis. This separation stage or mitosis ensures the new cells each get a copy of each chromosome. 
 
During the third stage of the cell cycle, the cell divides and two identical cells, called daughter cells, are formed. 
 
Specifics of Eukaryotic Cell Division 
 
Interphase – this is the phase before mitosis begins. During this phase, all of the DNA and organelles are copied and the cell is preparing itself to enter the mitosis phases. 
 
Mitosis Phase 1 called prophase. During prophase, the DNA begins to “twist” together and darken within the cell. (Imagine tiny, thin fibers twisting. These fibers will become thicker, shorter and more visible. This is similar to what the DNA or chromosomes are doing during prophase). The nuclear membrane breaks apart and organelles known as centrioles move to opposite ends of the cell. A “spindle” made of protein fibers is formed between the two centrioles. 
 
Mitosis Phase 2 called metaphase. During metaphase, the chromosomes line up on the spindle of the cell and are located at the equator of the cell. 
 
Mitosis Phase 3 called anaphase. During anaphase the spindle fibers begin to shorten and the chromosomes attached to the spindle begin to move away from the equator with one pair of chromosomes moving toward the poles or to the centriole location. 
 
Mitosis Phase 4 called telophase. During telophase the cell begins to divide into two cells. Close to the equator of the cell, the cell begins to “pinch inward. This area is called the cleavage furrow. This is the location where new cell membranes will be forming for each cell. Now mitosis has completed and we must discuss the last phase of cell division. 
 
The last phase of cell division is called cytokinesis. During cytokinesis, the cytoplasm divides and the new cell membranes completely form and the result is two identical cells called daughter cells. These cells are genetically the same as the original cell that we started with. At this point the new cells are starting their life cycle or cell cycle. 
 
Plant versus Animal Cell Division 
 
Recall: Plant cells have a cell wall and a cell membrane. During telophase in plant cells, instead of a new cell membrane forming at the cleavage furrow, a cell plate is formed. The cell plate will form the cell membrane of the two new plant cells. After this, a cell wall will form between the two membranes to complete cell division of the plant cell. 
 
Notes adapted from Robert Littlejohn 

Posted by: Team 7-2 Science

Section 1: Body Organization 
 
Recall: The maintenance of a stable internal environment is called homeostasis. If homeostasis is not maintained, cells are often damaged and can die from the damage. These cells make up tissues, so in effect the tissues can die and as the organization levels occur, the organism can ultimately die. 
 
Tissue Types 
 
There are four types of tissue: 1) Epithelial Tissue – this tissue covers and protects underlying tissue 2) Nervous Tissue – this tissue sends electrical signals from the point of a stimulus to the brain in order to react to the stimulus if necessary 3) Skeletal Muscle Tissue – this tissue is made of cells capable of contracting and relaxing that can produce movement within or of our body 4) Connective Tissue – this tissue joins, supports, protects, insulates, nourishes, and cushions organs and keeps organs from falling apart. 
 
Recall that two or more tissues working together will form an organ. Our stomach has all four types of tissues that make it up (the stomach therefore is an organ). The stomach has blood vessels which is connective tissue, it contains epithelial tissue to cover the lining, it has nervous tissue (tell us when we are hungry or full), and it contains muscle tissue that expands and contracts to break up the food we ingest (eat). 
 
Recall organs make up organ systems. When any organ fails, the body’s organ systems can fail. We have 11 organ systems. 
 
The 11 Organ Systems (We will look at these in great detail) 
 
1: Integumentary System – made up of our skin, hair and nails. This system helps protect underlying tissue(s). 
 
2: Muscular System – Your skeletal muscles move your bones and this allows us to move from one place to another if our body is functioning properly. 
 
3: Skeletal System – this is made up of your bones. Our bones provide support. If we didn’t have bones we would be one ugly blob with no shape. 
4: Cardiovascular System – composed of our heart, and blood vessels (arteries and veins). Transports blood with nutrients and wastes. 
 
5: Nervous System – this system sends electrical impulses throughout our body (nerves, spinal cord, and brain). 
 
6: Lymphatic System – this system includes lymph nodes and lymph vessels and helps us with immunity and getting rid of germs. 
 
7: Digestive System – Breaks down food we eat into nutrients that our body can use. 
 
8: Endocrine System – Composed of glands that secrete hormones (chemical messages) for specific actions in our body (pituitary gland, thyroid gland and testies for males, and ovaries for females to name a few of the glands in our body). 
 
9: Respiratory System – our lungs absorb oxygen and release carbon dioxide. 
 
10: Urinary System – removes wastes from our blood and regulates fluids in our body. 
 
11: Reproductive System: In males it produces and releases sperm. In females it produces eggs and provides a development site for an unborn baby. 
 
Review 
 
1. Explain the organization level and relationship between cells, tissues, organs, and organ systems. 
 
2. Compare the four types of tissues and their function. 
 
3. Without looking at your notes, make yourself a chart listing all of the major organ systems and their function. 
 
Answers to Review 
1. Cells make up tissues, tissues make up organs, organs make up organ systems and organ systems is what make up an organism. Cells work together to make tissues. Tissues work together to make organs. Organs work together to make organ systems. Organ systems make up organisms. 
2. Nervous Tissue – sends electrical signals (impulses) for stimuli, Epithelial – covers and lines in order to protect underlying tissue, Muscle – cells contract and expand to produce movement, Connective Tissue – joins, supports, protects, insulates, nourishes, cushions, and keeps organs from falling apart. 
3. Compare your chart to the notes you have learned. 
 
Applying what you learned 
Think of a time when homeostasis in your body was disrupted. Which body system(s) were affected? Explain your reasoning. 
 
IMPORTANT: As we learn details about each system always make yourself learn the NAME, LOCATION, and FUNCTION. Example: Name: nervous system, Location: spinal cord, nerves, brain, Function: to send electrical impulses for reactions to stimuli or other needed reactions (walking, talking, etc.). 
 
Section 2 
 
The Skeletal System 
 
Our bones and cartilage and the special structures that connect them make up our skeletal system. If we did not have our skeleton for support we would be a mass or blob so to speak. Our skeleton or bones are living cells. They must be nourished because they are made up of cells. These special cells are called osteocytes and they mage up our bone tissue. 
 
Functions of Our Bones 
 
1) Protection - the vital organs in our chest (heart and lungs) are protected with our ribs, our spinal cord is protected by our vertebrae, and our brain is protected by our skull. 
2) Storage - bones store minerals that help the nerves and muscles function properly. Your arm and leg bones store fat that can be used for energy. 
3) Movement – Muscles pull on the skeleton in specific locations to produce movement. Without the bones we also could not sit, stand, walk, or run. 
4) Blood Cell Formation – Some of our bones are filled with marrow that produces blood cells. 
 
Bone is composed of connective tissue and minerals that are deposited by living cells called osteoblasts. If we looked at a section of our longest bone (the femur) in our thigh, we would find spongy bone and compact bone. These are found in all of our long bones. Compact bone is dense and has no visible openings. Spongy bone appears to look like a real fine sponge with air spaces. Spongy bone is where we get most of the strength for our bones. The “spongy” configuration acts as a truss structure analogous to what we would see in a building made of steel. 
 
Marrow 
The soft tissue in the bone is called marrow and red marrow produces red blood cells.Yellow marrow found in the center of the bone (central canal) of long bones stores fat. The canals in the compact bone contain small blood vessels. 
 
Bone Information 
 
Most bones start out as soft, flexible tissue called cartilage. As a new born baby, we had very little bone. We were mostly cartilage. As we became older, the cartilage was replaced by bone. 
 
The location where two or more bones connect is called a joint. These joints have unique designs that will allow movement from some joints and little or no movement from others. Joints that are freely moving are more susceptible to injury than those that are less flexible. 
 
Joints are held together by ligaments that are connecting bone to bone. A strained ligament will heal if given time, but a torn ligament must be repaired surgically. Most bones also have cartilage on the ends to help cushion the area where two bones meet. When this cartilage is worn away, the joint becomes arthritic. This can create discomfort for the individual with arthritis. 
 
 
Types of Joints 
 
1. Sliding Joint – this type of joint allows some movement of flexibility. The bones in this type of joint glide over each other. Example: the bones in your wrist. 
2. Ball and Socket – this operates like a joystick on a computer game, the joint is free to move in all directions. Example: your shoulder joint. 
3. Hinge Joint – this operates like a hinge on a door. Example: Knee joint, knuckles, toes, jaw and elbow joint. 
 
 
How Bones Function to Help Movement 
 
Bones function like a simple machine called a lever. The lever has three parts: fulcrum, effort, and the load. The effort is the force applied to the lever, the fulcrum is the pivot point and the load is the resistance.  
 
Review 
1. What are the important functions of bones? 
2. Draw a long bone like a femur that has a section removed and label the parts (spongy bone, compact bone, areas for blood vessels, marrow cavity, and cartilage). 
3. List three hinge joints in your body. 
4. Are bones living? What do bones begin as? What do we call the cells that deposit bones? Where are red blood cells produced? Some bones store fat, what is it used for? 
5. What is a function of cartilage on the ends of bones? 
 
Answers 
 
1. Bones provide support, store and release minerals, enables us to move our bodies, and make blood cells. 
2. Compare your drawing to the bone on page 527 in our classroom text. 
3. Hinge joints can include the elbow, knee, jaw, knuckles and toes. 
4. Bones are living, they require nourishment like other tissues in our body. Bones start out as cartilage. The cells that deposit bones are called osteoblasts. Red blood cells are produced in the red marrow. The fat can be used as a source for energy. 
5. Cartilage can serve as a cushioning source when it is located at the end of long bones. 
 
Section 3 
 
The Muscular System 
 
Muscles attach to bones and the connective tissue that attaches them make up the muscular system. Remember: Muscles ALWAYS contract to do work. In other words, for muscles to do work, the muscle fiber must contract (get shorter). 
 
Types of Muscle Tissues 
 
1) Smooth Muscle – this is found in the digestive tract and your blood vessels. 2) Cardiac Muscle – this is heart muscle (found only in the muscle tissues of your heart). 3) Skeletal Muscles – these are the muscles attached to your bones for movement and protecting inner organs. 
 
Voluntary or Involuntary Muscle 
Muscles that are under your control are voluntary muscles. The muscles used to pick up a pencil when you want to write are voluntary muscles (you are controlling their actions). Muscles that digest food, move food through your digestive system (smooth) and cardiac muscles are examples of involuntary muscles (you do not have to think about making these muscles take action). 
Some may fall into voluntary and involuntary (example: eyelids – sometimes you control your blinking, other times you blink and do not realize you have blinked). 
 
Working Muscles 
When you want your muscles to contract and make you walk you must have electrical signals traveling from your brain to your muscle cells. The muscle cells respond by contracting (shortening). Remember, muscles only do work when their fibers are contracting. 
 
Muscles to Bones 
Your skeletal muscles are attached to your bones by a connective tissue called tendons. When the muscles contract, they get shorter and bring the bones closer to each other, hence producing movement. 
 
Muscles always work in Pairs 
Muscles work in pairs, resulting in smooth controlled movements. Example: Your Biceps (upper arm muscle in the front) can contract and cause our arm to bend at our elbow. The triceps (back of upper arm) can contract to straighten our arm back out. The muscle that is causing the bending movement is called the flexor, and the muscle that straightens out a part of the body is called the extensor. So in the above example, the biceps is the flexor and the triceps is the extensor. 
Use It or Lose It 
If you do not use your muscles, the muscle tissue will deteriorate. We must use our muscles in order to keep them “tone” and in order to build them up and become stronger. If you know someone with a broken bone and they wear a cast, the muscles not being used will become weaker and will have to be strengthened when the cast is removed. 
Muscles also aid in the circulation of blood and lymphatic fluid. When muscles contract, the action constricts the vessels and “pushes” blood and lymph in their respected vessels. This helps blood flow without extra effort from the heart. 
 
Exercise 
In order to maintain muscle or build muscle, we have to be active and exercise. The most effective exercise is resistance exercise. This is where the muscle contracts to move an object and the object offers resistance. The process of lifting our bodies vertically offers one method of resistance. An example of this type of exercise would include climbing steps, push-ups, sit-ups, pull-ups and other motions that use our own weight as the resistance weight. Resistance exercises are often hard to maintain long periods of time, but they offer one of the best methods of building muscle. 
 
Aerobic Exercise 
Aerobic – with oxygen. Aerobic exercise is great for our cardiovascular system. This strengthens the heart muscle and will increase the lung capacity and the effectiveness of our lungs. Aerobic exercises do not necessarily strengthen skeletal muscles, but increases our endurance. 
 
Damaging Muscle Tissue 
Before taking part in any physical exercise program, our muscles need to be warmed and stretched. Stretching can do this. Taking in deep breaths while stretching also increases the oxygen content in our bodies. After stretching and giving our muscles a warm-up reduces the chance for a muscle injury. When we “pull a muscle” we may be straining it or the muscle fibers can actually tear. We can also damage tendons. The tendons can become inflamed (irritated) and the area may feel warmer than the surrounding tissue. This type of tendon injury is called tendonitis. 
 
Anabolic Steroid Use 
This has become all too common in the area of sports. Taking the anabolic steroids can make our muscles larger and stronger and gives many athletes an unfair advantage. We are now seeing the effects of using anabolic steroids. Many athletes have died from having an enlarged heart as well as other complications from using anabolic steroids. If a person has not fully developed it may also cause bones to stop growing, high blood pressure, kidney failure and liver and heart problems. Anyone taking these steroids are at risk for an early death or a very unhealthy life due to the negative affects. 
 
Review 
1: What are the three types of muscle tissue and give a few locations you can find each type. Give the main functions of each type of muscle tissue. 
2: What are the differences and similarities between resistance and aerobic exercising and give a few examples of each. Can they both be the same in certain instances? 
3: Describe or explain how the muscles in your arm allow you to pick up a glass from a table to your mouth for a drink. 
 
Answers: 
1: Smooth muscle tissue helps move materials through the digestive tract and blood vessels; cardiac muscles cause the heart to beat; and skeletal muscles enables bones to move. 
2: Resistance exercises increase our strength of skeletal muscles. Resistance exercises involve overcoming weight of some type. Aerobic exercises improve the condition of heart muscle and increase our endurance. 
3: Our biceps contract in order for our arm to bend and bring the glass up to our mouth to drink. Our triceps contract in order to straighten our arm back out and set the drink back onto the table. 
 
Section 4 
 
The Integumentary System 
 
The integumentary system is for protection and includes our hair, nails, and skin. Our skin is the largest organ of all the organs our bodies have. Integumentary means covering. The integumentary system also helps your body to maintain homeostasis. Remember from chapter 1: homeostasis is a stable internal environment. 
 
 
 
 
Functions of the Skin 
1) Protects our bodies from evaporation and helps keep foreign particles out of the body. 
2) Keeps us in “touch” with our environment. The nerve endings in our skin allow us to fell what is around us. 
3) Our skin helps to maintain our body temperature. We have sweat glands in our skin that will sweat and when the sweat evaporates, it cools our body. 
4) Our skin also helps rid our bodies of waste products from the blood stream by way of the sweat. 
 
Skin Color 
A pigment in our skin called melanin determines the color of our skin. If we have a lot of melanin, our skin is very dark. If a small amount of melanin is produced, our skin will be very light. Melanin in the upper layer of the skin protects us by absorbing much of the ultraviolet radiation from the sun, which reduces the DNA damage that can lead to cancer. All of our skin is susceptible to cancer so protection should be taken when we spend time outside. Proper skin suntan lotion should be used and the lotion should contain a SPF protection of at least 30. 
 
Layers of Skin 
The skin is the largest organ of our body and it has two layers. The epidermis is the upper layer and is thinner than the second layer. “Epi” means above or top. The deeper layer is called the dermis. It is thicker than the epidermis. 
 
Epidermis 
Composed of epithelial tissue. It is about as thick as two pieces of notebook paper over the most of our body. Our palms of our hands and soles of our feet have thicker layers of epidermal cells. Most epidermal cells are dead and filled with keratin which helps the skin be tough and water-proof. 
 
Dermis 
Found beneath the epidermis. It contains many connective tissue fibers called collagen. This provides strength and allows the skin to bend without tearing. 
 
 
 
Hair and Nails 
Hair is grown from the hair follicle and the portion we see is actually dead cells. As hair grows from the follicle, cells are pushed up and form the portion we see. 
 
Hair protects us from ultraviolet radiation and also helps keep dust and other particles out of our eyes and nose. Hair also helps maintain internal body temperature. Many mammals rely on their hair to keep them warm in very cold climates. Humans form “goose bumps” on our skin when we get cold. This occurs when a muscle connected close to the hair follicle contracts and the hair stands up in an erect position. The erected hairs act like a sweater to trap heat which warms the body. 
 
Our nails protect the ends of our toes and fingers so they can remain sensitive to touch. Our nails grow from nail roots. The nails we see are dead cells. As cells grow from the root, the nail gets longer. 
 
Skin Cancer and other Problems 
Sometimes skin cells become damaged and the cells rapidly multiply out of control. When cells go through the cell cycle at a rate faster than normal we call that cancer. This can also invade other tissues and result in cancer spreading. 
 
A common problem many individuals face is having hormones cause too much oil being produced by the skin cell oil glands and creating a situation for infections. The oil may cause skin cells and bacteria to clog up the follicle and when the bacteria multiply you have an infection. Washing our skin well each day can usually prevent this type of infection. 
 
REVIEW 
 
1: Why does skin color vary from person to person? 
2: List as many structures as you can that are found in the skin and give the function of each one. 
 
ANSWERS 
1: The amount of melanin produced regulated the skin color. 
2: Hair follicle, blood vessels, nerves, oil glands, sweat glands, keratin for water proofing and flexibility, fat cells to help conserve temperature and can be used as energy sources if needed. 

Posted by: Team 7-2 Science

 
Chapter 6 Genes and Gene Technology 
 
Section 1 
 
We now know that genes can be passed on from one generation to another. Genes are located on chromosomes. Chromosomes are made of protein and DNA eoxyribonucleic acid). 
 
What must Genes be able to do? 
 
Genes must be able to do two things: 1) supply instructions for cell processes and for building cell structures, and 2) must be able to be copied each time a cell divides, so that each cell contains an identical set of genes. 
 
What are Nucleotides? 
 
Nucleotides are the subunits that make up DNA. There are four subunits that make up these nucleotides. Each nucleotide consists of three different types of material; a sugar, a phosphate, and a base. All nucleotides are identical except for their base. The four bases are: adenine, thymine, guanine, and cytosine. Each of these has a slightly different shape. The bases are usually referred to by the first letter in their name. Example: Cytosine = C, Guanine = G, Thymine = T and Adenine = A. 
 
Chargaff’s Rule 
 
Erwin Chargaff discovered that the amount of adenine is always equal to thymine and the amount of guanine is always equal to that of cytosine. When Chargaff released his finding, no one knew what to think about them, but as we later learned he was correct. 
 
 
 
Rosalind Franklin (Women in Science) 
 
Rosalind Franklin was studying DNA molecules and used X-rays to get an “image” of what DNA looked like. She reported that DNA looked like a coil or spiral shaped (like a twisted ladder). 
 
Watson and Crick 
 
James Watson and Fredrick Crick were two scientists also studying DNA molecules and trying to determine what DNA also looked like. James Watson did not give much attention to Rosalind Franklin’s idea about the shape of a DNA molecule, but Fredrick Crick respected her work and continued to look into Rosalind Franklin’s findings. Guess What!? Rosalind Franklin was correct. As Watson and Crick soon found out, DNA did look like a twisted ladder. Watson and Crick called their model a double helix. 
 
What is the Structure of DNA? 
 
Picture in your mind a ladder. The “handrails” contain the sugar and phosphate components of the nucleotide and the “rungs” (places where you would position your feet to climb a ladder) is where the bases are located. Remember that the bases are of a specific shape and adenine and thymine always pair up and cytosine and guanine always pair up. So if we have GGATC on one side of the ladder composing half the rung, the other side must contain CCTAG to compliment or match up to the bases on the other side of the ladder. 
 
Why is Making Copies of DNA Important? 
 
It is important to make copies of DNA because DNA is used to make proteins. We call this coping process replication. DNA replicates by splitting down the middle (imagine cutting a ladder in half at the rungs, or a zipper being unzipped down the middle). As the DNA strand is “unzipped”, one half of the strand must be used for copying or act as a template or pattern for a new complimentary side. Try your skill: What is the complimentary copy for the bases GCGGTCCAAAT? If you chose CGCCAGGTTTA, then you are correct. 
 
What order can the bases occur? The bases can occur in any sequence depending on the protein that needs to be produced. The order of the bases supplies the information on how to make each protein and/or trait the cell needs. 
 
DNA has the same bases in all organisms, the difference is how the bases are arranged in their order. So, all organisms have DNA that consists of the same bases (from bacteria to dogs, snakes, alligators, fish or what ever organism you want to name). Remember though that the order makes all organisms different from each other. All organisms are similar in that they have DNA, but all are different in the order the bases occur or the sequence the bases are arranged. 
 
 
 
Recall: Gregor Mendel conducted research that identified how genes are passed from parents to offspring or one generation to the next. We only discussed the possibility of having dominant or recessive traits, but there are always a few exceptions to the rule. 
 
Incomplete Dominance 
 
During Mendel’s research, he did not find any traits that “blended” together, but there are occasions where two or more genes affect the trait being looked at. In other words, one trait is not dominant over another, but they both have influences. This is known as incomplete dominance. 
 
Example: There is a flower called the snapdragon. In the Red flower form, the alleles are R1R1. In another form the flower is white and the alleles are represented as R2R2. Try crossing R1R1 X R2R2. If you did your Punnett Square correctly, you should know that all four of the possibilities for the cross are R1R2. When you have these alleles in the snapdragon, the result is a pink flower (both the white alleles and the red alleles have an affect and the result is pink). This is a good example of incomplete dominance  
 
Weird Gene Expression 
 
Sometimes some genes may affect more than one trait. Our book discussed a white tiger. The gene that influences the white fur color also influences eye color and white tigers have blue eyes. 
 
 
 
In humans, eye color is often affected by more that one gene. Different shades of blue or green eyes are two examples. With this example, the different colors are due to different amounts of pigment present. 
 
Can the Environment have an Influence on your Traits? 
 
Oddly enough, the environment can have an effect. Let’s find out how. Suppose you have the traits to be tall. If you do not get the proper nutrition or nutrients, you may not reach your full height potential that your genes are programmed for. Another example, you may have inherited specific genes for a talent, but if you do not practice your talent will not develop to the potential you have inherited. 
 
 
 
Review Section One 
 
 
 
1. What are the subunits that make up DNA? 
 
2. What are the components that make up nucleotides? 
 
3. What shape did Rosalind Franklin say the DNA molecule was in? 
 
4. What did James Watson and Fredrick Crick confirm? (shape) 
 
5. What makes all organisms have something in common? 
 
6. I have extracted the DNA from a cell and determined there was 43 percent guanine in the DNA. What percent of cytosine must be present? 
 
Answers to Review Section One 
 
 
 
1. The subunits of DNA are nucleotides. 
 
2. The compounds that make up nucleotides are phosphate, a sugar and the base (cytosine, guanine, adenine, thymine). 
 
3. Rosalind Franklin determined the shape was a coiled or a spiral shape. 
 
4. Watson and Crick confirmed that the shape of the DNA molecule was a double helix (looks like a twisted ladder). 
 
5. All organisms have DNA and this makes them have something in common, but the bases are not in the same sequence and this causes them to be different. 
 
6. There has to be 43 percent of cytosine because the amount of cytosine must equal the amount of guanine and the amount of adenine must equal the amount of thymine. 
 
 
 
Practice, More from reading! 
 
1. Why did scientists think that proteins instead of DNA carried genetic information? Answer: Because proteins are much more complex than DNA. 
 
2. What is incomplete dominance? Answer: In incomplete dominance, each of the two alleles that determine a trait has it’s own degree of influence. 
 
3. True/False: Tigers with white fur are probably going to have blue eyes. If you said true, you are correct! 
 
4. If a person inherits a gene to be tall, that person will be tall no matter what. Is this statement true or false? 
 
5. If we found the bases AATACGTTC, what would be the complementary base chain? If you said TTATGCAAG you are correct. 
 
6. We can relate to the shape of DNA if we can picture a twisted ladder (True or False). True, it is also called a double helix. 
 
7. Food for thought: If we took the entire DNA in your body and stretched it out, it would stretch from the Earth to the Sun and back two times…. Wow, that is some length!! 
 
 
 
Funny Time: Why did the mutant chromosome go to the tailor? 
 
 
 
Because it had a hole in its genes! 
 
 
 
Section 2 
 
How does DNA Work? 
 
Scientists knew that the DNA held some sort of code that told the cell what to do, but they wanted to “break the code” in order to understand the instructions better. 
 
 
 
Genes and Proteins 
 
Scientists discovered that the sequences of the bases in the DNA strand read like a book. Each set of three bases made up the “word” that coded for a specific amino acid. RECALL: Amino acids are the building blocks of proteins. So DNA tells our cells what proteins to make. Let’s find out how. 
 
 
 
The order of the bases determines the order of the amino acids in a protein. Each gene is a set of instructions for making a protein. Why are proteins so important? Because proteins are found throughout the cell and serve as chemical messengers. They also help determine how tall you will grow, what color your eyes are, if you are colored-blind or not, if your hair is curly or straight. These are a few examples of the importance of proteins. 
 
 
 
The three bases that code for a particular protein is called a codon. A messenger carries the DNA half of strand with the codons out into the cytoplasm from the nucleus and into a ribosome. At the ribosome site the ribosome attaches the amino acids into the proper sequence to form the appropriate protein. Essentially, the ribosome is the “factory” where the proteins are made. 
 
Changes in Genes 
 
Genes are specific in the proteins they produce and the codons must occur in the proper order or a problem may result. Sometimes extra bases can be added, subtracted, or substituted and problems may occur. These problems are called mutations. 
 
Mutation Types 
 
If a base is left out, the mutation is called a deletion mutation. If a base is added (where we now have an extra base) it is called an insertion mutation. If there is a base substituted for another base we call it a substitution mutation. 
 
Example: 
 
 
 
Normal Base Pair Sequence: AACCTTGGA 
 
TTGGAACCT 
 
 
 
Base has been removed: ACCTTGGAA 
 
TGGAACCTT 
 
 
 
Base is added: AAACCTTGGA 
 
TTTGGAACCT 
 
 
 
Base is substituted: AACATTGGA 
 
TTGTAACCT  
 
If any of the changes occur, a mutation results. The mutation may not have any affect on the organism, or it could cause harm to the organism to the point that death results. Mutations do happen, but we are very fortunate that many of these mistakes are repaired in the cell, but sometimes the mistakes may not be repairable or they are not 100% repaired. A third situation that can occur if a mutation happens in sex cells is the mutation can be passed on to the next generation. 
 
What can damage DNA? 
 
Anything that can damage DNA is called a mutagen (capable of causing a mutation). Some examples that you may have heard of before are high energy radiation, ultraviolet radiation, chemicals (asbestos and benzene are two), and cigarette smoke to name some common mutagens. Can you think of others? 
 
Specific example of a substitution Mutation 
 
The bases GAA are the code for an amino acid called glutamic acid. If GTA occurs, it codes for an amino acid called valine. When valine is substituted in the wrong place for glutamic acid it can cause a blood disease known as sickle cell anemia. This effects the red blood cells. Normally the red blood cells are round and have a concave side on each side. When an individual has sickle cell anemia, the red blood cell is the shape of a crescent moon (or a sickle used to harvest grain). This causes trouble for the red blood cell to pass through the blood vessels. The sickle shape can cause the vessels to become blocked and is very painful. 
 
 
 
What is a Pedigree? 
 
A pedigree is a tool that can be used to map out a family’s genetic traits and determine the probability of the trait being passed on through generations. If a dangerous mutation has occurred in a family, the scientists and doctors may want to see if the mutation has occurred before and determine the probability of it occurring again if the couple wants to have more offspring. 
 
Selecting Genes for Specific Reasons 
 
Some genes may be selected for during crossing some plants or breeding some organisms. Scientists may want a type of agricultural grain to be resistant to certain fungi and if they can cross specific resistant grains, they can create a variety that will withstand becoming infected with the fungus. 
 
Creating Specific Traits by Inserting Genes on Purpose 
 
 
 
Scientists have also learned how to insert specific traits into a DNA strand. This can be controversial. Do we want to allow scientists to create organisms with specific traits that normally would not occur in nature? An example we read about in the book included scientists inserting a tobacco plant with some DNA from a lightening bug (firefly) and the result is a tobacco plant that grows. 
 
 
 
This is known as genetic engineering. Do you think genetic engineering is okay to carry out? Why or why not? 
 
 
 
What is we can identify a gene that will cure certain diseases if we allow scientists insert the gene into a strand of human DNA. Is this morally correct? Is it humanities duty to carry this type of research out? 
 
 
 
Review Section 2 
 
1. List and explain all three types of mutations. 
 
2. What type of mutation did we discuss that causes a disease in the blood of humans, what is the disease called? 
 
3. How is genetic engineering different from selective breeding? 
 
4. What is the function of ribosomes (this should be a review)? 
 
5. What are some examples from the environment that can cause mutations? 
 
Answers: 
 
 
 
1. Insertion – an extra base is added, Deletion – a base is deleted, Substitution – a base is substituted for another base. 
 
2. Substitution mutation is responsible for sickle cell anemia. 
 
3. Selective breeding involves selecting specific traits and breeding organisms that have those traits. Genetic engineering involves changing the DNA in the DNA strand of an organism. 
 
4. Ribosomes are the “factories” to make proteins. 
 
5. Ultra-violet radiation can cause skin cancer and this is because the cells DNA become mutated and the cell begins to divide faster than it normally would. Cigarette smoke is another example. The chemicals, asbestos and benzene can cause certain types of cancers due to the mutations they cause. 
 
 
 
Study/Review Sheet for Chapter 6 Section 1 
 
1. Chromosomes are made up of proteins and __________. 
A. DNA C. Ribosomes 
B. Nucleus E. Lipids 
 
2. DNA is made up of units called ________________. 
A. Genetic Tablets C. Nucleotides 
B. Identical Partners D. Double Nitrogens 
 
3. Adenine, Thymine, Cytosine, and Guanine are found on ________________. 
A. The surface of our cells. 
B. The nucleus cells in the nervous system 
C. The nucleotides that make up our genes. 
D. There are not such things as adenine, thymine, cytosine, and guanine. 
 
4. Each nucleotide consists of three different types of material. What are they? 
_________________, ________________, and _________________. 
 
5. There are four possible bases in a nucleotide, what are the names of each of the bases? 
____________________, _________________, __________________ and _______________________________. 
 
6. The bases found in nucleotides are always paired up. Adenine is always paired with _____________________ in DNA and Cytosine is always paired up with _____________________________. 
 
7. Our textbook gives an artists rendition of the shapes the nucleotides may occur. Draw the examples given from page 128. Do you notice how these could fit together? 
 
 
 
 
 
 
8. ____________________ _____________________ is the lady who used X-rays to create images of DNA molecules. 
 
9. James ________________ and Francis _______________ modeled DNA and determined the shape must be a _________________ _________________. 
 
10. Describe and draw a double helix DNA molecule. 
 
11. Draw the DNA molecule with at least 10 base pairs correctly matched (your drawing on this portion can be as if the DNA molecule appeared exactly like a ladder). 
 
11. Make sure you understand that one side of the DNA molecule is complimentary to the other side regarding the bases that pair up. 
 
12. When a DNA molecule makes a copy of itself it “unzips” resembling a zipper or an upside down Y. When DNA makes a copy of itself we say it ________________ or has undergone replication. 
 
13. The DNA molecule splits down the middle where the _______________ meet when it replicates. One side is used as a template or pattern to form a new complimentary side. 
 
14. When DNA replicates itself and no mutations have occurred, the two new DNA molecules are _________________ to each other. 
 
15. Remember: DNA functions in the same way for all organisms. The same bases are found in all organisms, but it is the __________________ in which the bases occur that makes all organisms different from each other. 
 
16. Sometimes one allele may not be completely dominant over another allele and the result is that both alleles play a role in the phenotype (recall phenotype: what the organism looks like or the appearance of an organism). When two or more alleles have their own degree of influence, we say the alleles exhibit ____________________ dominance. 
 
17. What are two examples given to demonstrate incomplete dominance in organisms that we read and discussed? Explain this concept in terms of the white tiger and snapdragon flower. 
 
18. We have discussed how alleles/genes can influence your development. Explain how our environment can influence our development. 
 
Chapter 6 Section 2 Review/Study Questions 
 
1. The bases adenine, thymine, cytosine, and guanine make up the _________________ of the code in DNA. 
2. Each __________ bases code for a specific amino acid. 
3. __________________ are made up of amino acids linked together (we have had this before). 
4. The ____________ of the bases determines the order of the amino acids in a protein. 
5. Scientists thought or DNA was found in proteins at one time because proteins are so ________________. 
6. The first step in making a protein is copying the _______ strand that contains the code for the gene (protein) wanting to be made. 
7. The “factory” where proteins are assembled is the _______________ (this is a review from cell organelles). 
8. Sometimes there are mistakes that occur during the gene making process. These mistakes are known as ________________________. 
9. The cause for a mutation is a change in the sequence of _________________ in the DNA. 
10. If a base has been mistakenly left out, this type of mutation is known as a _______________. 
11. If an extra base has been included into the code, this mutation is called a ________________ mutation. 
12. If a base has been replaced by a different base in the code, this type of mutation is known as a _________________. 
13. There are three possible outcomes to a mutation. One is it has no effect at all on the organism. The second possible outcome could result in a harmful change, and the last possibility is the mutation occurs in the sex cells and is passed from one ____________________ to the next generation. 
 
14. DNA can be damaged by several means. Anything that can damage DNA is known as a _______________. 
 
15. High-energy radiation, X-rays, and ultraviolet radiation can all cause ______________ and are classified as _____________________. 
 
16. Notes to know: Many chemicals are mutagens and have been placed on lists giving specific warning to avoid direct contact with these chemicals. It is very important to read the manufacturers labels on chemicals because you will find the important directions and warnings located here. 
 
17. A specific example of a substitution mutation is when valine is substituted for glutamic acid. The resulting substitution results in a red blood cell problem called _________________ cell anemia. Draw what a sickle cell would look like and explain some of the problems associated with sickle cell anemia. 
 
18. A tool used for tracing a trait through generations of a family is called a _________________. 
 
19. Most disorders resulting from mutations are recessive, therefore they only show up when both alleles for the trait are _________________. 
 
20. The process that scientist use to transfer genes from one organism to another is called __________________ engineering. 
 
21. When scientists breed (mate) organisms for desirable characteristics or to create a new breed, they often use ________________ breeding. 
 
Adapted from Robert Littlejohn 

Posted by: Team 7-2 Science

Introduction: 
 
For many years we have been breeding dogs, cats, horses and other animals and plants to produce offspring with desired traits. (Example: horses that can run fast, flowers that are prettier than others, dogs that have better mannerisms, etc.) We also try to breed plants that produce offspring that will produce a greater harvest, or resistant to specific diseases. 
 
Can you think of other plants and animals that are bred or crossed for specific traits? Write a few down. 
 
Mendel and his pea plants 
 
If you look at yourself and try to compare yourself to others, most likely there is no one person exactly like you. Even if you have a twin, you are not exactly alike. You may resemble each other or your parents, but there is no one else exactly like you. That is what makes us all special and unique. 
 
We will find out in this chapter, why we are not all exactly alike and how we get the traits we have that cause us to look, act, and behave different from other humans. We will focus on plants and animal traits to study this. 
 
Gregor Mendel also wanted to know why organisms differed and what caused the differences to show up in offspring. 
 
Why Don’t You Look Like A (Rhinoceros or any other Organism?) 
 
Well, what do you think the answer to this topic is? If you said because your parents are not a rhinoceros or some other organism, then you are correct! You are who and what you are due to your parents. Heredity is the passing of traits, also called genes, from parents to offspring. 
 
The person given credit for discovering this was Gregor Mendel. He worked with pea plants and bred pea plants to determine how traits are passed from one generation to another (parents to offspring). Mendel noticed some pea plants were always tall, some always short, and some always produced purple flowers, while others always produced white. Mendel questioned why this happened. 
Mendel lived in a monastery during the time he studied the pea plant characteristics. Pea plants are self-pollinators. In other words, one pea plant flower has both male and female parts. The male parts produce pollen and the female part produces the egg. In this situation, pollen from one flower can fertilize the eggs of the same flower or the eggs of another flower on the same plant. With the help of an insect, wind, or other organism, the pollen can also be carried to a totally different pea plant where fertilization can occur. 
 
When genes or traits are passed from the parent to the offspring, we say the offspring has inherited the genes from the parents. Mendel noticed, from his breeding of pea plants, that sometimes a trait from one generation would not show up in the second, but if he crossed (bred or mated) pea plants of the second generation, the traits would show back up in the third generation. Mendel noticed the same occurrences in other plants and animals also. To simplify all of his observations and try to learn what was occurring, he decided to work exclusively with the garden pea plant. 
 
To make his research easier, he decided to study one trait at a time. He worked with one group of pea plants regarding the height of the plant from one generation to the next and in a separate experiment with different pea plants he worked with the color of flower the plants produced. 
 
Recall from Chapter 1 (Scientific Method): When doing experiments it is best to test one variable at a time. This was what Mendel was doing by looking at height in one group of peas and flower color in a different group. 
 
True-Breeding Plants 
 
When a true-breeding plant pollinates itself, it always produces offspring with the same trait as the parent plant. Example: a true-breeding plant for the tall characteristic always produces tall offspring, a true-breeding plant for purple flowers always produces offspring with purple flowers. 
 
Traits Mendel Looked at with the Pea Plants 
 
Mendel noticed some of the pea plants produced wrinkled peas and some produced round peas. Mendel crossed a plant that produced wrinkled peas with a plant that produced round peas (these are the parent generation). The offspring from this cross is called the first generation. Mendel noticed the first generation plants produced all round peas. So Mendel concluded that the round trait must hide the wrinkled trait. Mendel called the trait that appeared; the dominant trait and the one that did not show up he called the recessive trait. Mendel then allowed the first generation to self-pollinate and the second-generation plants produced round and wrinkled seed, but he noticed for every round seed there was only one wrinkled seed. 
 
In other words, the recessive trait showed up again in the second generation. 
 
Mendel tested seven traits he found the pea plants to have and the following shows his results. 
 
Characteristic Dominant Recessive 
Flower color purple white 
Seed color yellow green 
Seed shape round wrinkled 
Pod color green yellow 
Pod shape smooth bumpy 
Flower position along stem tip of stem 
Plant Height tall short 
 
Out of all of these traits Mendel conducted research on he noticed the result of the second-generation always had the dominant trait about three times more often than the recessive trait. So for every time a dominant trait showed up, the recessive trait showed up one time. This produces a “ratio” of 3:1. 
 
Mendel’s Brilliant Idea 
 
Mendel realized that the only way this could happen, was if each plant had two sets of instructions (now known as genes) for each characteristic. Mendel reasoned that each parent must contribute one gene each and the offspring would end up with two. The offspring therefore would have two forms of instruction (genes) for the same trait. Each individual form of a gene is known as alleles. 
 
Proving His Idea was up to the Punnett Square 
 
Mendel did not invent the Punnett Square, it was invented by a man with the last name of Punnett. A Punnett Square is a visual tool to see all the possible combinations of alleles that offspring can receive from their parents. When using a Punnett Square the dominant alleles are given a capital letter and the recessive alleles are assigned a lower case letter. Example: For flower color, Mendel noted that purple was dominant over the white recessive gene, therefore in a Punnett square purple would be assigned a “P” and white would be assigned a “p”. 
 
How is a Punnett Square Set Up? 
 
First, you draw a square that is large enough to divide into equal quarters and the quarters should be large enough to write the letter of the alleles into. 
Try to follow this example on your own paper. We want to breed or cross a true-breeding purple pea plant “PP” with a true-breeding white pea plant “pp”. So, we would write “PP x pp”. Now for the square: 
 
Draw a square large enough, maybe 2 inches by 2 inches and the divide it into equal units of four 1 inch by 1 inch squares.  
 
 
 
 
 
Now we place our parents alleles on the outside of the square. One parent’s alleles will go across the top and the other will go down the side. Remember we are crossing PP x pp.  
 
Next we bring one parents alleles down and place them into the square and bring the other parents alleles across and place then into the square. 
 
Now we have all the possible genotypes of the offspring. In this situation all of the offspring will have Pp which is one alleles for the dominant purple and one allele for the recessive white. All of the pea plants will produce purple flowers, but carry the recessive gene for the white flower. This situation is called heterozygous (one allele for a different form of the same characteristic). This is the same type of work Mendel completed. 
 
Now let’s see what happens if we take these offspring (first generation) and cross them together (Pp x Pp). 
 
 
Now, we see the genotype possibilities are PP, Pp, Pp, and pp. For the genotypes, one is homozygous dominant “PP”, two are heterozygous “Pp”, and one has the possibility of being homozygous recessive “pp”. for the phenotypes, three have the possibility of being purple and one has a possibility of being white. So now we have Mendel’s 3:1 ratio. So in this cross, there is a 75% probability that the pea will produce purple flowers and 25% probability the offspring plant will be white flowered. 
 
All of these probabilities are random, in other words it is entirely random as to which alleles the offspring gets and each time we breed organisms with this possibility, there is the same chance to get the same outcome. Each fertilization or cross we conduct is independently random each time. Just because we cross a pea plant three times and get offspring that has purple flowers, does not guarantee we will get a white flowered pea plant on the fourth cross we complete. 
 
What is probability? Probability is the mathematical chance that an event will happen or occur. Probability is usually expressed as a fraction or percentage (3/4 or 75%) or a ratio can be used sometimes (3:1). 
 
Gregor Mendel published his findings in 1865, but his ideas were not given much attention until after his death about 30 years later. We now often referr to him as the “father of modern genetics”. Genetics is the study of passing of traits from one generation to another. 
 
 
Cross the Following: 
 
1. A true- breeding purple flowered pea plant with a heterozygous pea plant. You should have visualized or determined the true-breeding plant as “PP” and the heterozygous as “Pp”, so you have PP x Pp. 
2. Cross a heterozygous purple pea plant with a white pea plant. 
3. Use “T” for the tall trait, and “t” for the short trait. Cross a homozygous tall plant with a homozygous short plant. 
4. Cross a heterozygous tall pea plant with a homozygous tall pea plant. 
5. “R” is dominant for seed shape in peas, it means round. Wrinkled is the recessive trait. Cross a homozygous round pea plant with a homozygous wrinkled pea plant. 
6. Cross a heterozygous round pea plant with a homozygous round pea plant. 
7. Cross a heterozygous round pea plant with a homozygous wrinkled pea plant. 
8. Cross a homozygous smooth pod (smooth is dominant, bumpy is recessive) pea plant with a heterozygous smooth pod pea plant. 
9. Cross a homozygous smooth pod pea plant with a homozygous bumpy pea plant, then cross the first generation and show your second generation results. Tell me what the original parents (parent generation) genotype is in this scenario. 
10. Now, brown hair is dominant over blonde hair in humans. What would the genotype of a homozygous brown haired person be? What about a heterozygous brown? What about a homozygous recessive blonde? Now cross a homozygous brown haired individual with a blonde haired individual. Cross two heterozygous brown haired individuals. Make sure you show all of your work clearly. 
 
 
With this information you should be able to cross organisms with different forms of the same gene at this time. This is referred to a mono-cross. Mono means one. We will learn how to cross organisms with different forms of the same gene for two different genes, which are called a di-hybrid cross. Di meaning two. 
 
 
Chapter 5 Section 2 Notes 
 
Meiosis 
 
Recall: there are two kinds of reproduction, 1) asexual and 2) sexual reproduction. 
 
In asexual reproduction, only one parent is needed for reproduction to occur. This is how bacteria or prokaryotic cells reproduce. They copy their genetic information and then divide (binary fission). 
 
In sexual reproduction, you must have two parent cells known as sex cells. In males, the sex cell is the sperm. In females, the sex cell is the egg. Remember that humans have 23 pairs of chromosomes. When we look at sex cells, each one will have only 23 chromosomes so when an egg and sperm unite, we end up with 23 pairs of chromosomes again (one from the mother and one from the father). In other words, human sex cells have half the usual number of chromosomes. 
 
For sex cells to have 23 chromosomes, they must go through a process called meiosis. Meiosis produces new cells with half the usual number of chromosomes. Simply put, when sex cells are made, the chromosomes are copied and then the nucleus divides two times. The resulting cells (egg and sperm) have half the number of chromosomes found in a normal body cell. 
 
Location, Location, Location 
 
What does location have to do with genes? Well, a man by the name of Walter Sutton discovered that genes are located on chromosomes. Scientists have actually located specific genes and their locations on the chromosomes. 
 
RECALL, RECALL, RECALL the steps of mitosis because meiosis is very similar. Review mitosis for a better understanding (Interphase, Prophase, Metaphase, Anaphase, and Telophase) know what happens in each phase that we have discussed in the past. 
 
 
 
 
 
The Process of Meiosis (remember: meiosis is for sex cells). 
 
The following is the phases of meiosis and the major event that happens in each phase. 
 
Interphase: during this phase the chromosomes copy themselves. 
 
Prophase 1: the nuclear membrane disappears and the chromosomes begin to pool into the center of the cell. 
 
Metaphase 1: the chromosomes line up on the equator or middle of the cell. 
 
Anaphase 1: the copied pairs of chromosomes pull away from each other toward the “poles” of the cell. 
 
Telophase 1: the nuclear membrane reforms and the cell divide taking one complete pair of chromosomes into each new cell. (Now we have two cells with 23 pairs of chromosomes). 
 
Prophase 2: the nuclear membrane disappears and the pairs of chromosomes in each cell pool in the cell. 
 
Metaphase 2: the pair of chromosomes line up on the equator of each cell. 
 
Anaphase 2: the pairs of chromosomes pull apart and move to the poles of each cell. (23 chromosomes move one direction and 23 move the other direction). 
 
Telophase 2: the two cells form cleavage furrows, nuclear membranes reform and each cell divides to end up with four cells total and each cell has 23 chromosomes. Each new cell has half the number of chromosomes present in the original cell. 
 
 
QUESTION: Does this process resemble anything we studied before? What does it resemble? 
 
 
 
 
Meiosis review: 
 
1. In a human, how many chromosomes are in the original single cell before meiosis? 
 
2. In a human, how many times do chromosomes make copies of themselves in meiosis? 
 
3. In a human, how many times do cells divide in meiosis? 
 
4. In a human, how many chromosomes are in the cells at the end of meiosis? 
 
5. In a human, how many chromosomes are in the cells at the end of mitosis? 
 
 
Meiosis Review Answers 
 
1. In a human, there are 23 pairs of chromosomes or 46 chromosomes in the original single cell before Interphase begins. At the end of Interphase, there are 46 pairs of chromosomes or 92 chromosomes. At the end of Telophase 1 there are 23 pairs or 46 chromosomes in each cell. At the end of Telophase 2, there are 23 chromosomes in each cell and we have four cells total. 
 
2. In a human, chromosomes copy themselves only one time in meiosis. 
 
3. In a human, cells divide in meiosis two times. (Once in Telophase 1 and once in Telophase 2). 
 
4. In a human, there are 23 chromosomes in each of the four cells after the completion of meiosis. 
 
5. In a human, there are 23 pairs (46 chromosomes) in each cell at the end of mitosis. 
 
 
Male or Female? 
 
In humans we have 23 pairs of chromosomes. Twenty-two of those pairs are called autosomes, but one pair is called sex chromosomes. The reason they are called sex chromosomes is because these chromosomes determine if you are a male or female. 
 
The sex chromosomes resemble an “X” or a “Y”. Remember we get one from our father and one from our mother, so we have two sex chromosomes. If a person has two X’s (XX), then the person is a female. If the person has an X and a Y (XY), then the person is a male. 
 
In simple terms, the female can contribute an X sex chromosome and the male may contribute an X or a Y to the offspring. Experiment: Cross a male and female in a Punnett square to see the probability of having a male or female offspring. What did you get? Remember, it is random as to which sex chromosomes become fertilized together so we can only give probabilities that an offspring will be male or female by using Punnett squares. 
 
We have become so technologically advanced that we can remove some of the cells from an embryo prior to birth and look at the sex chromosomes to determine if a male or female has been conceived. We also have ultrasound tests that can give us a picture of the fetus and knowing what to look for, we can tell if the child will be a male or female. 
 
 

Posted by: Team 7-2 Science

 
Virus Notes 
Many people think viruses are one of the dangerous agents for the survival of humans. A virus is a microscopic particle that invades a cell and takes over the cell and has the cell make copies if the virus, which eventually destroys the cell and when the cell ruptures all of the copies of the virus are released to invade more cells. Viruses are not living, but the do contain protein and nucleic acids (they are not considered living because they cannot reproduce themselves without controlling a cell, they must use a different cell to do this, they cannot live on their own, they do not eat, grow or breathe. 
 
The only way in which viruses are like organisms is that the can multiply. 
 
Again, viruses invade a cell and instruct the cell to produce viruses instead of new healthy cells. The virus must have a host cell to invade and make new viruses. A host is an organism that supports a parasite. Viruses are not cells; they do not have cytoplasm or organelles. 
 
Classifying Viruses 
 
Viruses can be grouped into the type of disease they cause, their life cycle, or the type of genetic material they contain. Viruses can also be classified by their basic shape. Some are cylinders, some are crystals, some are spheres, and some look like spacecraft. 
 
How Viruses Work 
 
Viruses find a host cell and inject their nucleic acids and proteins into the cell. The virus then takes control of the cell and makes copies of it. As the host cell is destroyed and breaks open, new viruses are released to invade more host cells. Now the cycle can start again to produce even more viruses. This cycle is called the lytic cycle. When viruses first enter the host cell they allow the cell to copy itself and then the virus end up in two different cells and as this occurs, the virus is utilizing the host cell to make more. The cycle of allowing the host cell to copy itself is known as the lysogenic cycle. 
 
Active vs Hidden viruses 
Active viruses enter cells and immediately begin to multiply, leading to the quick death of the invaded cells. Hidden viruses "hide" for a while inside host cells before coming active. 
 
Tuesday:  
Answer questions over viruses and worksheet. 
Bacteria notes, graphic organizer, foldable.  
Students need to make sure they are updating their table of contents for their Kingdoms folder. All information given from last Friday on should be kept in their Kingdoms Folder. Students may bring it home to study or keep it in my room. 
 
Bacteria are one of the smallest and are the simplest organism on the planet. They are also the most abundant. Many bacteria cause illnesses, but scientists have discovered that many bacteria are beneficial to humans and our way of life (from medicine production to food production). We will explore how bacteria are classified and some uses of bacteria as well as unique cell structure. Some of the material should be a review because we have already learned it in previous lessons. 
 
Classifying Bacteria: All organisms on Earth fall into six kingdoms: Protista, Plantae, Fungi, Animalia, Eubacteria, and Archaebacteria. As you can easily tell, bacteria make up the kingdoms Eubacteria and Archaebacteria. These two kingdoms contain the oldest forms of life on earth. 
 
RECALL: Bacteria are single celled organisms that do not have nuclei (nucleus). A cell with no nucleus is called a prokaryote. A prokaryote is capable of cellular respiration, move around, and reproduce. Since the prokaryotes have these features, they can function as an independent organism. 
 
RECALL: Bacteria Reproduction 
 
Most bacteria reproduce by a type of simple cell division known as binary fission. During binary fission the DNS is copied (replicated) and one copy ends up in each new cell. RECALL: Binary fission is NOT mitosis or meiosis, the DNA is replicated and then the cell gets longer and then divides in the middle with one copy of the DNA in each cell. 
 
Bacteria when Conditions are Unfavorable 
 
When the conditions become unfavorable for bacteria, some species will produce thick protective membranes and then they are called endospores. Many endospores can survive freezing, drying out, and even boiling. After the conditions become favorable for the bacteria, the endospores will break open and the bacteria become active again. Some endospores have been estimated to be millions of years old and when scientists improved the conditions the bacteria inside became active again. Ethical Question: Should we try to get bacteria from endospores to become active again after being enclosed for millions of years? Could the bacteria be of such dangerous proportion that we may not be able to stop a disease that it introduces? These are things we have to think about. 
 
Shapes of Bacteria 
 
There are three shapes of bacteria, 1). Bacilla, 2). Cocci, and 3) Spirilla. Bacilla shaped bacteria appear as short rods. Cocci bacteria are spherical shaped. The Spirilla are spiral shaped (like a cork screw). 
 
Locomotion of some Bacteria 
 
Some bacteria have flagella that serve as their source of locomotion (movement). The flagella are whip like structures that spin like a cork screw to move the bacteria through the liquid they are in. 
 
Kingdom Eubacteria 
 
Most bacteria are eubacteria. These bacteria are classified by the way they get their food. Some are consumers, others are decomposers and some are producers. The consumers get their nutrients from other organisms. The decomposers get their nutrients from dead organic matter. The producers are capable of making the nutrients they need through photosynthesis (using the sunlight to produce sugars). The producers, like plants contain chlorophyll that captures the energy from the sunlight. 
 
Some bacteria producers are called cyanobacteria, and they live in many different types of water environments. Cyanobacteria have chlorophyll that enables them to carry out photosynthesis. Some scientists have thought that millions of years ago some of the cyanobacteria became adapted to living within cells that had nuclei and as millions of years passed; the adaptations resulted in the first plants being formed. 
 
Kingdom Archaebacteria 
 
Achaebacteria are believed to be ancient bacteria and they are able to survive in environments other organisms living today cannot survive. The environments we find archaebacteria living in are the hot springs and some species survive deep below the ice of Antarctica. Archaebacteria are genetically different from eubacteria. Some archaebacteria do not have cell walls and those that do, the cell walls are chemically different from other organisms. 
 
There are three types of archaebacteria; 1). Heat lovers, 2). Salt lovers, and 3). Methane gas producers. Some heat lovers can survive in temperatures as hot as 360 degrees Celsius (almost 700 degrees F) . Salt lovers live in environments like the Dead Sea, where other forms of life are inexistent. The methane producers give off methane gas where things are decomposing (one place you may find them is in swamps). 
 
SECTION 2 What Do Bacteria Do? 
 
The majority of bacteria are microscopic, in other words we cannot see them without a microscope. Some bacteria are bad for us and some are very beneficial. We often only hear about the bacteria that cause illness and death, so we think all bacteria are bad. 
 
Nitrogen Fixation: RECALL: A species of bacteria is capable of taking atmospheric nitrogen and converting it into a form of nitrogen that plants can use. All organisms must have nitrogen for making proteins and DNA. RECALL: Living organisms that are not producers must get their nitrogen from eating plants and other organisms. Nitrogen enters organisms as they feed on plants and other organisms and when the living organism dies and decomposes, the nitrogen is released back into the soil. Some plants may take this in or a different species of bacteria may consume it and convert it back into atmospheric nitrogen. This is the nitrogen cycle. RECALL: Everything is cycled or recycled through nature. 
 
Some bacteria help humans clean up messes that we make. Bioremediation is the use of bacteria and other microorganisms to change pollutants into harmless chemicals. Bacteria are used to clean up certain types of agricultural, industrial and municipal wastes. We have also used species of bacteria to clean up oil spills. 
 
People and Bacteria: The Benefits 
 
Scientists have used bacteria to produce types of medicines, insecticides, cleaners, adhesives, foods and other products we use. Some bacteria have been used to make antibiotics, which are used to kill harmful bacteria and other harmful microorganisms. Scientists have used a species of bacteria to make insulin that diabetics can use. Diabetes is a disease in which a person’s pancreas does not produce enough or good quality insulin. Scientists have learned how to make insulin and the diabetics can inject the insulin into their body to control the level of blood sugar. A too high or low of a blood sugar level can lead to death of organisms. 
 
Scientists have also learned that bacteria can be used to make yogurt, buttermilk, cheese, and sour cream. Scientists have learned how to use lactic acid bacteria to convert the milk sugar into lactic acid, which acts as a preservative and adds flavor to the food. Examples of other foods made by using bacteria in specific ways include: sour dough bread, cheeses, pickles, some sausages, and some vinegars. 
 
HARMFUL BACTERIA 
 
Bacteria that cause diseases are called pathogenic bacteria. Some diseases you may have heard of are dental cavities, ulcers, strept throat, food poisoning, bacterial pneumonia, lyme disease, tuberculosis, leprosy, typhoid fever, and bubonic plague. 
 
Other organisms are also affected by pathogenic bacteria. Plants, animals, protists, fungi and even certain types of bacteria can be harmed by pathogenic bacteria. Some grains, fruits, and vegetables can be damaged by pathogenic bacteria. 
 
 
Some protists are so small they must be seen with a microscope, while others can easily be seen without magnification. Some are like plants, some are like animals, and some are like neither. All protists are eukaryotic. That means they all have a nucleus in each of their cells. Most protists are single-celled, but there are some that are multi-cellular. 
 
Some protists have chlorophyll and are producers. (RECALL: photosynthesis). Other protists are consumers; they cannot obtain their energy from the sun and must get their food from the environment. Protists are classified by the way they obtain their energy. This process groups them into fungus-like protists, plant-like protists, or animal-like protists. 
 
FUNGUS-LIKE PROTISTS 
 
A fungus is an organism that obtains its food from dead organic matter or from the body of another organism. The protists that obtain their food in this way are fungus-like protists. Fungus-like protists are consumers that secrete digestive juices into the food source and then absorb the digested nutrients. These protists also reproduce like fungi. We will look at slime molds and water molds. 
 
Slime Molds 
 
Slime molds are thin masses of living matter. They look like colorful, shapeless blobs of slime. They live in cool, moist, shady places. You can find them in woods and in freshwater. Slime molds feed on bacteria, yeasts, and small bits of decaying plant and animal matter. They surround their food and digest it. As long as it has water and food, it will grow. When conditions become unfavorable for a slime mold to grow, they form stalk like structures that are rounded on the tops. These rounded knobs contain spores and the knob like structures are called sporangia. When conditions improve, the sporangia open and release the spores and new slime molds will grow from the spores. 
 
Water Molds 
 
These are also fungus-like protests. They are usually small, single-celled organisms. They survive in water, moist soil, and other organisms. Some are decomposers and eat dead organic material, but many are parasites (must have a host). Parasites invade the body of another organism to obtain the nutrients they need to survive. Some parasitic water molds cause diseases. An example of a water mold causing a disease is the “late blight” with the potato serves as the host. Other water molds use fruit as their host and this almost caused the collapse of the French wine industry in the 1800’s. 
 
 
 
Plant-Like Protists 
 
These protists are producers and like plants have chlorophyll in their cell(s) that captures sunlight to make the sugars they need for survival (they carry out photosynthesis). The plant-like protists are known as algae. Even though they have chlorophyll for photosynthesis, some algae have other pigments that cause them to have other colors than green. There are species that will look brown, red, and reddish brown. Some of the algae are multi-cellular and are several meters in length. If you have heard of kelp and know it grows several meters in length, it is one example of algae (protist). 
 
The single celled algae cannot be seen without a microscope (very small). They also contain chlorophyll and live near the surface of the water to capture sunlight for photosynthesis. We call these phytoplankton, and they make up the base of most aquatic food chains. They also produce most of the world’s oxygen. 
 
Red Algae: Most of the seaweeds are red algae. They contain chlorophyll and a red pigment that gives them their red coloration. The red algae live mainly in the warm tropical seawaters of the tropics. The red pigment gives them a special property. It allows the red algae to capture light down to 260 meters below the surface. The red wavelength of light penetrates the deepest into water, so it is the last wavelength of light filtered out naturally by the water. 
 
Brown Algae: Most of the seaweeds found in cool climates are brown algae. They attach to rocks or other algae and form large floating beds. Brown algae have chlorophyll and a yellow brown pigment. Many brown algae are very large and rapid growers (some grow up to 60 meters in one growing season). The tops of the brown algae are exposed to sunlight and the sugars made here are transported to the lower parts of the algae where light does not reach. 
 
Green Algae: The green algae are the most diverse group of plant-like protists. They are green because of chlorophyll. The chlorophyll is the main pigment so the color is green. Most live in water or moist soil, but you can find some in melting snow, on tree trunks, and even inside other organisms. Many green algae are single celled, microscopic organisms, others are multi-cellular. The green algae have a few members that may grow up to 8 meters in length. Some of the green algae that are single celled are found living in colonies. One example of colonial algae is Volvox. 
 
Diatoms: Diatoms are single celled organisms. They are found in both saltwater and freshwater environments. They also get their energy from photosynthesis and they make up a large percentage of phytoplankton. The diatoms are composed of cell walls made of cellulose and silica (glass like substance). The diatoms that die will settle to the floor of the body of water they are in. They are then gathered for use as abrasives in silver polish, toothpastes, filters, and insulation. 
 
Dinoflagellates: Most dinoflagellates are single-celled algae. They are primarily in saltwater. With a few found in freshwater and snow. Dinoflagellates have two whip-like strands called flagella, which serve as a locomotion device. The flagella cause the dinoflagellates to spin through the water. Most of the dinoflagellates get their energy from the sun, but some are consumers, decomposers, or parasites. Some of the dinoflagellates are red and if the population gets very large, the water they live within will actually look red. This is known as a red tide and red tides are poisonous to shellfish. If an organism like the shrimp eats the dinoflagellates of a red tide they become toxic as the poison builds in their body. If humans and other organisms consume the poisoned shellfish, they may get sick. 
 
Euglenoids: Euglenoids are single-celled protists that live primarily in freshwater. Most euglenoids have characteristics of both plant and animals. Like plants, they use photosynthesis, but when light is too low for photosynthesis, they become consumers like animals. Euglenoids can also move like animals. They have flagella that propel the organisms through the water. Some euglenoids do not have chloroplasts for photosynthesis. These species either consumes other small protists of absorb nutrients that are dissolved in their environment. 
 
ANIMAL-LIKE PROTISTS: PROTOZOA 
 
The animal-like protists are single celled consumers. These protists are also known as protozoa. /some protozoa are parasites. Many can move. Scientists are not real sure on how to group or classify protozoa, but many agree on four phyla. The four phyla are: 1). Amoeba-like protists, 2). flagellates, 3). ciliates, and 4).spore forming protists. 
 
AMOEBA-LIKE PROTISTS 
 
An amoeba is a jelly or slime like organism. They are found in freshwater, saltwater, in soil, or as parasites in animals. Amoebas have a structure called a contractile vacuole that pumps out excess water. Amoebas move with the aid of pseudopodia (false feet). The amoeba will extend a projection (pseudopod) and then the remainder of the Amoeba will “flow” into the area the pseudopod is located. 
 
Amoebas feed like slime molds do; they surround their food source by engulfing it. This process forms a food vacuole. Enzymes move into the vacuole and digest the food item and the digested food moves into the cytoplasm of the amoeba. In order to rid it from the wastes, the amoeba simply reverses the process. A vacuole filled with waste is moved to the outer edge of the amoeba and then released from the amoeba. 
 
Some amoebas are parasitic. Some species live in the human intestine and cause amebic dysentery, which is painful and often has bleeding ulcers involved along with frequent vomiting. 
 
 
 
 
 
PROTOZOA WITH SHELLS 
 
Some protozoa have shells and are called radiolarians. The shells are made of silica and look very glassy looking. Another example of protozoa with a shell is foraminiferans. Foraminifera have snail like shells made of calcium carbonate. 
 
FLAGELLATES 
 
These are protozoa that use flagella to move. The flagella wave back and forth to propel the organism forward. Some flagellates live in water. Others are parasites that cause disease. The flagellate Giardia lambia lives in the digestive tract of humans and other vertebrates. These also survive in streams. If hikers or any other outdoor enthusiast drinks from one of these streams and takes in one of the protozoa, he/she can get diarrhea and severe stomach cramps, but it usually does not kill the individual. 
 
Some flagellates live in symbiosis. In symbiosis, one organism lives closely with another organism, and each organism helps the other survive. One example is a flagellate that lives in the gut of termites and they digest the cellulose the termites consume. Without the protozoa, the termite could not completely digest the cellulose. 
 
CILIATES 
 
Ciliates are the most complex protozoa. Ciliates have hundreds of tiny hair-like structures known as cilia. The cilia serve as a locomotion device; they propel the ciliate forward when they beat back and forth. Some ciliates use the cilia to push food in the water toward them. The most widely known ciliate is the paramecium. Ciliates have two kinds of nuclei, macro-nuclei, and micro-nuclei. The macronucleus controls the functions of the cell and the micro-nucleus passes genetic material to another individual during sexual reproduction. 
 
SPORE FORMING PROTISTS 
 
These are all parasites that absorb nutrients from their hosts. They have no cilia or flagella and they cannot move on their own. Spore forming protozoa have life cycles that involve two or more different hosts. 
 
Plasmodium vivax is a spore-forming protist that causes malaria. Malaria is a disease that is carried by mosquitoes in tropical areas. Malaria can be treated with drugs, but even today there are over 2 million people that die form the disease each year. If a mosquito has the Plasmodium vivax and bites a human and transfers some of the protist to the human, it will infect the human’s liver and multiply inside red blood cells. The red blood cells will burst and release more of the protist and if the human gets bitten by another mosquito, the protist can be transferred to another human host. 
 
 
 
REPRODUCTION of PROTISTS 
 
Some protists reproduce asexually. RECALL: Asexual reproduction involves only one parent. They reproduce by dividing in half in a process called fission. 
 
Some protists reproduce sexually. Sexual reproduction requires two parents. Example: the paramecia often reproduce sexually by a process called conjugation. During conjugation, two Paramecia join together and exchange genetic material using their micro-nuclei. Then they divide to form four organisms with new combinations of genetic material. 
 
Some protists reproduce sexually and asexually. In some algae, asexual and sexual reproduction alternate between generations. 
 
 
 
You are probably more aware of fungi than you were of protists. Some examples of fungi are mushrooms, bread mold, yeast, and athlete’s foot is caused by a fungus. Fungi are used to make certain cheeses, antibiotics, and soy sauce. So fungi can and are beneficial if they are of the correct species, if they are not, they may cause death in a worse case scenario. 
 
Characteristics of Fungi 
 
Fungi are eukaryotic consumers. They are so different from other organisms though, that scientists place them in a classification kingdom of their own. Fungi come in many shapes and colors, but they all have similar ways of obtaining food and reproducing. 
 
How Do Fungi Get Their Food? 
 
Fungi are consumers, but they do not eat their food or engulf it. Fungi must live near or on their food supply. They get their nutrients by secreting digestive juices onto the food source and as the food source decomposes, the fungi absorb the nutrients that have dissolved. Many fungi are decomposers and they feed on dead plant and animal matter. Some other fungi are parasites, and some are involved in symbiotic relationships with other organisms. 
 
Some fungi grow on the roots of plants and release acid that changes minerals in the soil into forms the plants can use. The fungi also protect the plant from disease causing organisms. 
 
Fungi are eukaryotic and have a nucleus. Some are single-celled, others are multi-cellular. Multi-cellular fungi are made up of chains of cells called hyphae. The hyphae are unique in that they have pores in the cell wall that allows cytoplasm to transfer from one cell to another. The hyphae grow in a mass that is called a mycelium. The mycelium is the major part of the fungus. The mycelium is under the surface of the soil and out of sight. 
 
How Do Fungi Reproduce? 
 
Reproduction of fungi can be sexual or asexual. If a hyphae breaks away from the mycelium, it can begin growing a new fungus. This is an asexual reproductive process (one parent). Another asexual reproductive process involves the production of spores. Spores are small reproductive cells protected by a thick cell wall. Spores are light and are easily dispersed by the wind. If the spore lands in a area where the growing condition is good, it will produce a new fungus. 
 
Sexual reproduction of fungi involves forming special structures to make sex cells. The sex cells join together to produce sexual spores that grow into a new fungus. 
 
Fungi Groups 
 
Fungi are grouped into four forms 1). Thread-like, 2). Sac fungi, 3). Club fungi, and 4). Imperfect fungi. These are based on the shape and the way it reproduces. 
 
Thread-like fungi: Molds are an example here, especially bread mold. Molds are shapeless fuzzy looking fungi. The thread-like fungi can reproduce asexually. Extensions of the hyphae grow into the air and have round ball looking structures on the tips. These round structures are called sporangia. When the sporangia burst open, many thousands of spores are dispersed into the air. 
 
Thread-like fungi also reproduce sexually. Two hyphae from different individuals can join and form specialized sporangia. These sporangia can survive unfavorable conditions like heat, cold, and drought. Once the conditions improve to “growing conditions” the sporangia release the spores and new fungi grow. 
 
Sac Fungi: This is the largest group of fungi. The sac fungi include yeasts, powdery mildews, truffles, and morels. Sexual reproduction in this group involves the formation of a sac called the ascus. These sacs give the sac fungi their name. Sexually produced spores develop in the ascus. They also reproduce asexually. Example: Yeasts produce asexually by budding. Budding involves a new cell pinching off from an existing cell. Some sac fungi are very useful to humans. Yeasts are added to flour to cause it to rise when baking breads. The yeast breaks down the sugars and gives off the carbon dioxide that causes the bread to rise. 
 
Some sac fungi are used to make antibiotics and vitamins. Truffles and morels are sac fungi and are prized for their flavors they can add to foods. 
 
Some sac fungi are parasites that cause damage to plants. One example id the Dutch Elm Disease that kills elm trees and the Chestnut Blight that killed the American Chestnut trees. 
Club Fungi: The shape you think of as a mushroom or toadstool is characteristic of club fungi. During sexual reproduction the hyphae produce special club like structures called basidia and the sex spores develop inside the basidia. 
 
When we see a “mushroom” we are only seeing a small portion of the fungus. The majority is under the surface of the ground and the structure “mushroom” we see is located at the ends of the hyphae. That is why it appears mushrooms often grow in halo shapes or circles. 
 
The most well known mushrooms are the gill mushrooms. If you look under the “cap” of the mushroom you will see slits or gills that house the spores. Only touch mushrooms if you can positively identify them as a safe to handle species. Many are poisonous to the point that ingesting them can cause death. 
 
The club fungi also include shelf fungi, which are often seen growing on the sides of trees and resemble half-moon shaped shelves. You may have stepped on a puffball and seen the spores float away in the air. The puffball is an example of club fungi. There are also club fungi that are called smuts, or rusts, which often infect crops and ruin or decrease their yield. 
 
Imperfect Fungi: this group has all the other fungi that do not fit into the other fungi groups. The imperfect fungi do not reproduce sexually. Most of the members of this group are parasites that cause diseases in plants and animals. One common disease many humans get is athlete’s foot. Another fungus in this group produces a poison called aflatoxin, which can cause cancer. 
 
Do not make the mistake of thinking all imperfect fungi are disease causing. The fungus Penicillium is the source for the antibiotic penicillin, which has been used for years against bacterial infections. Also, some imperfect fungi are used to make cheeses, soy sauce, and the citric acid in cola drinks. 
 
LICHENS 
 
A lichen is a combination of an fungus and a algae that grow intertwined in a symbiotic relationship. The lichen is different from either of the two that are in the symbiotic relationship if they were growing alone. 
 
Lichens are producers, and get their food by carrying out photosynthesis. The lichen can withstand drying out because the walls of the fungus protect the algae from drying. 
 
Lichens need water, air and light to grow. This is why they are most often the pioneer species in primary succession. As the lichens grow and die, they fill the cracks on the rock(s) with organic material that allows other organisms to begin growing. Lichens absorb water and minerals from the air and they can serve as a “pollution detector” because if lichens are not present in an environment they would normally be found, there may be a high level of air pollution. 
 
Notes adapted from Robert Littlejohn 
 

Posted by: Team 7-2 Science

6 Kingdoms Introduction 
 
As scientists began classifying organisms, they have arranged all living things into six kingdoms. The kingdoms are 1) Archaebacteria, 2) Eubacteria, 3) Protista, 4) Plantae, 5) Fungi, and 6) Animalia. We will look at each of these in this chapter and in later chapters we will look more closely at the phyla in the kingdoms, as well as some looking at some organisms at the species level. 
 
 
 
Kingdom: Archaebacteria 
 
 
 
Scientists believe this group of bacteria has been on Earth for 3 billion years. The prefix Archae comes from the Greek word meaning “ancient”. Archae bacteria live in places that most organisms cannot currently survive. One example is very hot springs coming out of the Earth like you would find in Yellowstone National Park. 
 
 
 
Kingdom: Eubacteria 
 
 
 
These bacteria are found in soil, water, and other living things and include most of the species of bacteria living presently. An example of a Eubacteria is Escherichia coli which can be found in the human intestines. It get the nutrients from the decomposing foods we eat and produces vitamin K that our body takes up to use. Other bacteria are used to make yogurts and cheeses. Most people only think about bacteria causing sinus infections or other illnesses, but as you have just read, there are some species humans use to benefit ourselves. Bacteria also decompose dead organisms. If this did not happen, we would have dead carcasses laying everywhere. 
 
 
 
Kingdom: Protista 
 
 
 
Members of this kingdom are commonly called Protists. These are single celled or simple multi-cellular organisms. The protests are eukaryotes (RECALL), which means they have membrane bound organelles. Protists are not plants or animals or fungi. Scientists think that protists evolved from ancient bacteria. Scientists also believe that much later, the protests gave rise to plants, fungi, animals, and modern protests. 
 
 
 
Protists include protozoa, which are animal like protests; algae, which are plant like protests; and slime molds and water molds, which are fungus like protests. Most protests are single celled, but there is some multi-cellular like giant kelp. 
 
 
 
Kingdom: Plantae 
 
 
 
Plants are complex multi-cellular organisms that are usually green and use the sun’s energy to make sugar by a process called photosynthesis. RECALL: Photosynthesis, revisit the formula we learned during the photosynthesis chapter. 
 
 
 
Plants are in various sizes and colors. The Giant Sequoia trees are the largest and a small plant called duckweed is about the size of an eraser tip on a pencil. 
 
 
 
Kingdom: Fungi 
 
 
 
Examples of fungi you may have seen before includes mushrooms and bread mold. Fungi (singular is fungus) were originally classified as plants, but fungi do not get their nutrients through photosynthesis. Fungi do not have any animal characteristics. Fungi absorb nutrients from their surroundings after breaking the organic material around them down with digestive juices. 
 
 
 
 
 
 
 
 
 
Kingdom: Animalia 
 
 
 
Animals are complex multi-cellular organisms that belong to the kingdom Animalia. Most animals can move from one place to another on their own and have a nervous system that helps them sense and react to their surroundings, If we looked at animal cells under a microscope, we would notice that they are different from plant cells, fungi cells and are also different from most protest cells, and bacteria cells because animals do not have a cell wall. 

Posted by: Team 7-2 Science

Interactions of living Things 
SECTION 1 
 
When we look closely at our surrounding environment, we find that everything (all organisms and object) is connected in one or more ways. If one of the connections is broken, the impact is often detected by observing many different organisms and what happens to organisms when a “connection” is manipulated. Most of the time we look at organisms in our environment and only “see” only organisms that eat other organisms. We seldom pay much attention to some of the other factors we will learn about during our study of the environment. 
 
The living organisms in the environment are dependent on other living organisms for food sources and survival. We are going to learn that these interactions form what is known as a food web(s). Scientist that study these interactions within the environment and we call these scientists ecologists. We must ask ourselves “what is ecology?” and we will find out that ecology is the study of the interactions between organisms and their environment. 
 
The Environment 
 
The environment is made of two things, nonliving things and living things. We have special terms for these. Nonliving things are referred to as abiotic; these include rocks, weather factors, the type of soil, the amount of light, and the temperature. The living part is referred to as biotic. Biotic factors include all the living organisms that live together and interact with each other. 
 
Practice: Consider a pond, list as many biotic and abiotic factors that someone may find at a pond. Did you say: biotic may include the fish in the pond, birds around the pond, maybe a beaver or muskrat, the small organism’s fish feed on, aquatic (water) plants, maybe algae? What about abiotic: you may have listed the mud on the bottom of the pond, the rocks in and around the pond, the water, the temperature of the water, the amount of sunlight the pond gets, the shade if there are trees bordering the pond? You may have other biotic and abiotic factors listed, but the main idea is to learn what the terms biotic and abiotic means and give examples of the terms. 
 
The Organization of an Environment 
 
RECALL: remember the organizational levels of organisms? Cells make up tissues, tissues make up organs, organs make up organ systems and organ systems make up organisms. 
 
The environment also has levels of organization we can discuss. The first level contains individual organisms. The second level is similar organisms that form populations. The third level is different populations forming a community. The fourth level is the community and its abiotic factors forming an ecosystem. And finally, all of the different ecosystems make up the biosphere. Bio means life. 
 
We must understand the definition of each level in order to understand how they are all connected. 
 
Populations – A population is a group of individuals of the same species that live together in the same area at the same time. Example: All of the white-tailed deer in Walker County. These deer compete with each other for resources (food, water, space, etc). 
 
Communities - A community consists of all of the populations of different species that live and interact in an area. The different populations will be depending on each other for food, shelter and other things. All of the various animals and plants in an area make up the community in a given area. 
 
Ecosystems – An ecosystem is made up of all the communities found there as well as the abiotic factors in the area. Ecologists that study ecosystems must look at the interaction between living organisms and the nonliving objects in order to get a good understanding of how the ecosystem functions. 
 
Biosphere – The biosphere is the portion of the Earth where we find life. The biosphere extends to the deepest parts of the ocean to very high in the atmosphere, where tiny insects and plant spores drift. The biosphere includes all ecosystems. 
 
Section 2 – Living Things Need Energy 
 
In order for living things to survive, they must all have energy available to them. Organisms use energy to carry out daily activities, heal themselves if they become hurt, and reproduce offspring. Organisms can be grouped into three categories based on how they obtain their food. These three categories are producers, consumers and decomposers. 
 
Producers – These organisms are capable of producing their own food, most often by carrying out photosynthesis (plants and algae). In the last 15 years scientists discovered that there are organisms producing their own food from deep ocean vents where the element sulfur is released from the Earth. There are bacteria that capture the sulfur and make their own food from it and the bacteria serve as food for other organisms that survive at these great depths. On land, (terrestrial environment) plants carry out photosynthesis and are the main producers. In our oceans, algae that carry out photosynthesis are the main producers. 
 
Consumers – Consumers are organisms that cannot produce their own food. Consumers must eat other organisms in order to get food. We will look at several types of consumers. These include herbivores, carnivores, omnivores and scavengers. 
 
Herbivores – these consumers eat plants for their food source. Examples: cows, bison or buffalo, grasshoppers, muskrats, and some rodents (groundhogs). Carnivores – these consumers feed upon other animals, so they eat meat. Omnivores – these consumers feed upon both plant and animals as their food source. Scavengers – scavengers are animals that feed on bodies of dead animals. Example: Turkey vultures (some people call them buzzards) feed on dead animals. In aquatic ecosystems, crayfish (crawdads), snails, worms and crabs can be considered scavengers. 
 
Decomposers 
 
Decomposers are the organisms that obtain their energy by breaking down the remains of dead organisms. Bacteria and many fungi can be considered decomposers. Decomposers are very important to an ecosystem because they return the dead organism’s nutrients back into the ecosystem so other organisms can benefit from the nutrients. You could think of decomposers as natures “recyclers”. 
 
Food Chains and Food Webs 
 
A food chain is a “flow chart” that shows how energy flows from one organism to another and through the ecosystem. A food chain shows what organism another organism consumes. Example: Imagine there is some clover growing on the ground and a mouse is eating the clover. A snake slithers from the nearby tall grass and catches the mouse and eats the mouse, but before the snake gets back into the tall grass to hide a hawk swoops from the sky and captures the snake and eats the snake. The food chain would be represented by: clover > mouse > snake > hawk. 
 
Most food chains can overlap because many organisms feed on several different foods. When food chains overlap, we say there is a food web. A food web shows us many pathways that energy can flow through an ecosystem. The energy always flows in a one-way direction in the ecosystem. Energy an organism does not immediately use is stored in the organism’s tissue(s). Only the energy that is stored in an organism’s tissue(s) can be used by the next consumer. This leads us to the question of “how much energy can be passed from one consumer to the next consumer?” We must look at food pyramids to understand this concept. Some people refer to these as energy pyramids. 
 
Energy Pyramids 
 
Imagine the shape of a pyramid. The base is very wide compared to the pointed tip. Now imagine the lowest area near the base is where producers are located. The next level up the pyramid you will find a consumer that feeds on the producer represented at the pyramids base. This consumer is called the primary consumer (meaning the first consumer of the food chain the pyramid is representing). The next level would be the secondary consumer meaning the second consumer on the chain, the following level is the tertiary (meaning third) consumer. With our previous example, the clover is the producer and the base level of the pyramid. The mouse is the primary consumer, the snake is the secondary consumer, and the hawk is the tertiary consumer. Most energy pyramids only have four or five levels. REMEMBER: only the energy stored in the tissues of an organism can be transferred to the next level. 
 
As you proceed from one level to the next higher level, the energy that can be transferred becomes less and less. As a rule, only about 10% of the energy can be transferred from one energy level (pyramid level) to the next higher level. 
 
Example: if the clover provided the mouse with 1,000 calories, the snake could only gain about 10% of these when it consumed the mouse (100 calories), when the hawk consumed the snake, it could gain about 10 calories. In other words only 10% of the energy is available from one consumer to the next higher consumer. 
 
The energy pyramid also gives us some other information. The wide base represents a larger number of organisms than the next level. So there must be more clover plants than mice and more mice than snakes and more snakes than hawks as we go up the pyramid. If it were the opposite, there would not be enough organisms to support the next level with sufficient calories (food) so the food chain would collapse. 
 
Habitat and Niche 
 
These are two terms that are important to an ecologist because it gives an indication of the food types available for an organism and what the function of the organism is in the environment. An organism’s habitat is the environment in which the organism lives (forest, desert, swamp, marsh, etc.) An organism’s “role” or way of life is the organism’s niche. An organism’s niche includes its habitat, its food, its predators, the organisms it competes with for survival. The niche can also include the abiotic factors like temperature, light, and moisture. 
 
 
SECTION 3 
 
Types of Interactions 
 
Within nature the interactions between populations of different species affect the population sizes. (Some organisms regulate the population of others by feeding “preying” on other organisms). Example: in the arctic tundra, there are small rodents (similar to hamsters) called lemmings. The lemmings are eaten (preyed upon) by arctic foxes and other animals. The animals that prey on lemmings help control the lemming population size. 
 
 
Having Offspring 
 
In nature, most organisms have more offspring than can survive. Example: A fish may lay hundreds of thousands of eggs, but all of the eggs will not hatch. Some of the eggs may be preyed upon before they hatch. In most situations, the population of organisms remains fairly constant in nature unless rare conditions occur that supplies more food for a larger population than normal.  
 
Limiting Factors 
 
Populations of organisms cannot continue to get larger and larger (grow) due to limited food, space, water, and other resources the organism needs. These resources (biotic and abiotic) serve as limiting factors. (Limiting factor – a resource that is needed, but is in limited supply). Any needed resource can become a limiting factor if the organism cannot get enough of the resource to survive. 
 
Carrying Capacity 
 
The largest population that an environment can support over a long period of time is known as carrying capacity. When populations grow larger than the carrying capacity, limiting factors occur and some of the population will die due to limited resources. 
 
If the limiting factors continue to decline, the population must decline also. As soon as the environment “improves” and the limiting factors return to “normal”, the population size will also increase and return to “normal. 
 
Interactions Among Organisms 
 
Populations have interactions between their own species and other species in the environment. Example: Grey squirrels interact when they feed in the same area, so this is an example of the same species interacting together. Grey squirrels may also interact with different species. Example: an Great Horned Owl may see a Grey Squirrel as food and capture and eat the squirrel. Many interactions such as this occurs everyday in the environment(s) that are on Earth. These interactions are necessary for life to continue. Interactions may take the form of competition for food, space, mating partners, water, and living space for example. Interactions may also take the form of predator prey relationships (one organism capturing and eating another organism). 
 
Competition 
 
Again populations in a community can have competition among the same species, or you can also find competition between different species. An example of competition between different species could be Grey squirrels and White-tailed deer competing for the available acorns for the main food source at times of the year. Remember competition can be in the form of organisms competing for the same space, food, shelter, and even sunlight (especially plants). So we must remember that competition can be within the same species as well as between different species. 
 
Predators and Prey 
 
An organism that is eaten by another organism is called prey. The organism that is eating is called the predator. When a fish eats a worm, the fish is the predator and the worm is the prey. 
 
Predator Adaptations 
 
In order for predators to survive, they must be able to capture prey. Some predators run fast in order to accomplish this, others may be excellent at hiding, others may be excellent stalkers to capture prey. Different predators have different methods and adaptations to capture their prey. 
 
Prey Adaptations 
 
Prey organisms have also adapted to keep from being eaten. Methods prey have to avoid capture is to run fast, stay in groups, and some have adapted camouflage methods. Some prey are poisonous to predators and so they are not eaten. Some preys have bright colors that warn prey that they should stay away. Examples: fish often stay in small schools which give the illusion that they are one large organism and this can scare predators away. Antelopes and buffalo remain in herds for protection. When you have many organisms, they all serve as lookouts because each organism will be using sight, hearing, and smell to avoid being eaten. Some prey hide by using camouflage, some look like leaves, some may resemble sticks, and some may look like tree bark. 
 
Symbiosis 
 
Symbiosis is a close, long term association between two or more species. The individuals in a symbiotic can benefit from, be unaffected by, or be harmed by the relationship. Often one species lives on or in another species when a symbiotic relationship occurs. There are three specific types of symbiotic relationships in nature. These are 1) mutualism, 2) commensalisms, and 3) parasitism. 
 
Mutualism 
 
A symbiotic relationship in which both organisms benefit is called mutualism. Example: we have a species of bacteria that live in our intestines that produce certain vitamins for us and the bacteria get nutrients form the food we eat. Humans and the bacteria benefit from the relationship. 
 
 
 
Commensalism 
 
Commensalism occurs when there is an symbiotic relationship in which one organism benefits and the other is unaffected by the relationship. An example is a fish that rides under a shark waiting on the shark to eat something and get the “tidbits” the shark loses. These fish are called remora fish. The shark is not harmed in the relationship. 
 
Parasitism 
 
In this symbiotic relationship, one organism benefits and the other organism is harmed. The organism that benefits is called the parasite and the organism that is harmed is called the host. The parasite gets nourishment from its host and the host will become weak over time and often so weak the host dies. Examples of parasites are ticks, tapeworms, leeches, and many organisms called roundworms.  
Most parasites do not kill their host or they would have to find another host to survive within. If the parasite killed the host organism it may not be able to find another host to live in or on and the parasite itself may die. 
 
Coevolution 
 
Coevolution is a long term change that takes place in two species because of their close interactions with one another. Coevolution sometimes occurs with herbivores and the plants they feed on. The acacia tree and a species of ant have evolved together. The tree produces a form of food for the ant and provides a place for the ants to live and the ants protect the tree by attacking herbivores that try to feed on the tree. 
 
Coevolution and Flowers 
 
Some of the most amazing examples of coevolution are between their pollinators. A pollinator is an organism that carries pollen from flower to flower. Examples of pollinators: hummingbirds, butterflies, and bees. These organisms gather nectar from flowers and in the process they get pollen on themselves and when they visit the next flower, they leave some pollen on the flower and this helps fertilize the flower to produce fruit. The pollinators are attracted to the flowers by color, scent, and the nectar. When the pollinator places its head into the flower for the nectar, some of the pollen there attaches to the pollinator and is transferred to the next flower the pollinator visits. 

Posted by: Team 7-2 Science

 
Cycles in Our Ecosystems 
 
Anything that has mass and occupies space is matter. This matter must be used over and over again in our closed ecosystem, we call this recycling. We will discuss a few of the very important cycles life depends on. 
 
The Water Cycle 
 
The movement of water among the oceans and our atmosphere, and the movement of fresh water (lakes, rivers, and streams) and our atmosphere make up the water cycle. There are several parts we will consider of the water cycle. 
 
Precipitation 
 
Water moves from the atmosphere to the land or bodies of water as precipitation (rain, snow, sleet, and hail). About 91 % of the water falls into our oceans, the rest falls on lakes, rivers, ponds, streams and the land as fresh water. Remember: fresh water does not necessarily mean it is clean water, it simply means it is low in salt content. Think of ocean water as salt-water. 
 
Evaporation 
 
When water goes from the bodies of water on the Earth back into the atmosphere, evaporation has occurred. This cycle is driven by the energy from the sun. When water vapor cools as it undergoes the process of condensation. Condensation is the process of water going from the gas phase into the liquid phase. In order for water to condensate, the moisture must have some form of particulate to attach to. This particulate can be in the form of dust, smoke, or other forms of pollution as well as solid surfaces. When condensation occurs in the atmosphere and falls back to Earth we again have precipitation. This is why it is called the water cycle. 
 
Ground Water 
 
As the water falls to the Earth, some of it falls onto the land. Some of the water seeps into the ground and enters underground caves, rocks with small pores and is often stored there. This water in under ground is called ground water. Ground water may stay in the Earth for hundreds to thousands of years. It can also slowly flow through the passages underground. Some ground water may drain into rivers, streams, form springs, or enter into the ocean. 
 
Water and Life 
 
All organisms require water to survive. Humans are about 70% water. RECALL: water transports wastes from our tissues and cells. Water also regulates our body temperature when we sweat and the sweat evaporates (this cools our body). Plants also need water in order to survive (they are living organisms). When water is returned from organisms back into the environment or atmosphere, the process is called transpiration. If there was not any water on Earth, there would not be any life. 
 
The Carbon Cycle 
 
Carbon is in all living organisms. The movement of carbon from the environment into living things and back into the environment again is called the carbon cycle. 
 
Photosynthesis (This should be a review) 
 
Photosynthesis is the process by which carbon cycles from the environment into living organisms. During photosynthesis, plants use carbon dioxide from the air to make sugars. Most animals get the carbon they need by eating the plants (when they eat the plants they are taking carbon into their body to make molecules that will contain carbon. 
 
Respiration (This should be a review). 
 
Carbon returns to the environment during respiration. RECALL: Respiration occurs in both plants and animals. When respiration occurs, sugar molecules are broken down to release energy. Carbon dioxide and water are released as by-products. Remember: we exhale carbon dioxide and water. 
 
Decomposition 
 
The breakdown of dead materials into carbon dioxide and water is called decomposition. Recall: Bacteria and some fungi decompose dead materials. When these organisms decompose the dead material, they are returning the carbon to the environment. 
 
Combustion 
 
The carbon in coal, oils and natural gas returns to the atmosphere when we burn the fuels. They release carbon dioxide into the environment when they are burned. The process of burning fuel is called combustion. We use combustion to heat our houses, run our vehicles, and make electricity. 
 
The Nitrogen Cycle 
 
The movement of nitrogen from the environment to living things and back is called the nitrogen cycle. About 78% of the Earth’s atmosphere is nitrogen gas. Most organisms cannot use the atmospheric nitrogen (nitrogen in our atmosphere), but there are specific types of bacteria that convert atmospheric nitrogen into a form of nitrogen plants can take in and use. These bacteria are carrying out nitrogen fixation. After the plants get the nitrogen into their tissues, other organisms consume the plants and take the nitrogen into their body to be used. 
 
Bacteria in the soil perform the final step of the nitrogen cycle. These bacteria are of a different species than those that carry out nitrogen fixation. These bacteria break down dead organisms and animal wastes. This process produces nitrogen gas, which is returned to the atmosphere. 
 
 
SECTION 2 
 
Ecological Succession 
 
Succession is defined as the gradual development of a community over time. There are two types of succession. The first type we will discuss is primary succession and the second type is called secondary succession. 
 
 
Primary Succession 
 
Primary succession occurs when a community develops on an area where living organisms did not live before. A bare rock can be an example of a location where living organisms had not grown in the past. We will use this as our example of primary succession. 
 
If we observed a bare rock over many years, we would have noticed that the first life forms to begin growing on the rock are lichens. The acids produced by the lichens begin to weather or break down the rock. These first organisms are called pioneer species. The lichens that die over time and small fragments of rock that begins to break away from the larger rock become soil. The next organism that becomes established are mosses, which may be dropped from an animals paw, hoof, or other part of their body or the moss may have spores that are blown onto the area by the wind. Once some of the mosses and lichen begin to die off, the soil become deeper and small species of grasses and flowers can begin to grow. 
 
The grasses and flowers may get to the area by wind blowing them onto the site or animals that have eaten the seeds of the grasses and flowers may deposit them on the site. As time passes and more plant material accumulates from plants, mosses and lichens dieing, the soil continues to get deeper. This deeper soil provides a “root bed” for larger plants like small trees and shrubs. 
 
After many more years of soil formation, larger trees can become established onto the site and the area ends up being a forest. Remember that new plants arrive on an area by the wind blowing the seeds or spores and animals can carry the seeds onto the site. Many seeds that are eaten by birds are spread to new areas after the seed has passed through the digestive system of the bird. Many seeds actually cannot germinate unless they pass through the digestive system of an organism. 
 
Secondary Succession 
 
This is very similar to primary succession, but the area has once had an existing community on it. The community or ecosystem may have been destroyed by fire, other natural disasters or by the interference of humans. A good example would be an area that once had a forest on it, but the forest was removed to make farmland and the farmer stops farming. Secondary succession begins the first year the farmer stops farming. During the first year, many weeds like crabgrass and broom sedge (a form of grass) grows on the field. During the second year, new plants begin to grow from the seeds that have blown into the field or have been carried into the field by an animal. In five to fifteen years (depending on the location) small trees like pines begin to grow. After many years of the pines growing, hardwood trees begin to grow under the pines and as the pines die and fall to the ground, the hardwoods receive more sunlight in which to grow. After 80 to 100 years you will end up with a mature hardwood forest (oaks, hickories, some maples, sweetgum, and other hardwoods) and a few pines on the drier ridges in the area. 
 
 
Does succession end? Well, the answer is yes. What type of ecosystem is the end result? It depends on the climate (how much precipitation and the temperatures the area has over time). In the southeast United States, we end up with a mature hardwood forest. In the northern United States and southern Canada, you would find the Coniferous Forest (Pines, Spruces and Fir Trees). If you had an area with relatively high temperatures on average and low precipitation, you would end up with a desert. If the area had relatively low temperatures and low precipitation, you may have Tundra.  

Posted by: Team 7-2 Science