1. Food Chains and Webs
-producers (plants and photosynthetic microorganisms): produce organic matter
-primary consumers (herbivores like cows, horses, and rabbits): eat plant matter

2. Food Chains and Webs
-secondary consumers (omnivores and carnivores): consumers that eat primary consumers/herbivores
-tertiary consumer (top consumers like humans): have no natural predators

3. Food Chains and Webs
-scavengers (coyotes and vultures): prey on dead things
-decomposers (fungi and microorganisms): recycle organic matter

4. Food Chains and Webs
-Conditions that threaten the stability of producers and decomposers in an ecosystem jeopardize the availability of energy and the capability of matter to recycle for the biological community

5. Food Chains and Webs
-The energy pyramid illustrates how stored energy is passed from one organism to another.

6. Food Chains and Webs
-All organisms use energy to survive and grow, but much is released as heat, usually about 90 percent
-Energy is transferred from one level to the next, but typically only 10 percent of the energy from the previous level is passed on to the consumer

7. The Importance of Trophic Levels
Consider this argument: Even before humans entered the scene, many species of plants and animals were extinct and new ones had developed. Why are we even concerned about endangered species, given the fact that species have always come and gone?
How would you respond to this argument? Write a paragraph in response to question. Your response can be for or against the statement.