NOTES: Copy and Paste these into a word document if you want to print them! 
 
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?  
 
 
**Notes - Credited to Kara Ammons