| A | B |
|---|
| limiting factor | anything that can restrict the size of a population, including living and nonliving features of an ecosystem |
| habitat | a place where an oganism lives and that provides the types of food, shelter, moisture, and temperature needed for survival |
| producers | an organism, such as a green plant or alga, that uses an outside source of energy to create energy-rich food molecules |
| decomposers | consume wastes and dead organisms |
| community | all the populations of different species that live in an ecosystem |
| population density | the number of individuals in a given area |
| ecosystem | all the living oranisms that live in an area and the nonliving features of their environment |
| ecology | the study of the interactions that take place among organisms and their environment |
| organism | a living being either plant or animal |
| energy pyramid | a model that shows the amount of energy available at each feeding level in an ecosystem |
| population | all the organisms that belong to the same species living in a community |
| food web | a model that shows the complex feeding relationships among organisms in a community |
| food chain | a simple model of feeding relationships in an ecosystem |
| biosphere | the part of the earth that supports life, including the top portion of Earth's crust, the atmosphere, and all the water on Earth's surface |
