| A | B |
|---|
| Herbivore | an animal the eats herbage or plants; largest animals on land today are herbivores |
| Heterotroph | an organism that cannot make its own food (animals, fungi, bacteria) |
| Host | an animal or plant that nourishes and supports a parasite |
| Insectivore | a predatory animal (such as a shrew or bat) with a diet consisting chiefly of insects |
| Life table | an age-specific death schedule |
| Limiting factors | anything that can restrict the size of a population, including living and nonliving features of an ecosystem, such as predators or drought |
| Loam | a rich soil consisting of a mixture of sand and clay and decaying organic materials |
| Mutualism | an interaction that is beneficial to both species |
| Natural selection | a natural process resulting in the evolution of organisms best adapted to the environment |
| Niche | the functional role of an organism in a community; its job or position |
| Nitrogen cycle | the transfer of nitrogen from the atmosphere to the soil, to living organisms, and back to the atmosphere |
| Nitrogen fixation | some types of soil bacteria can form the nitrogen compounds that plants need |
| Nutrient cycle | how nutrients move from the physical environment into living organisms, then recycled back into the physical environment |
| Omnivore | an animal that eats both plants and animal material |
| Organism | a living thing that has (or can develop) the ability to act or function independently |
| Parasite | an animal or plant that lives in or on a host (another animal or plant) |
| Parasitism | an interaction that benefits one species and is harmful to another |
| Pioneer community | the first organisms to occupy an area |
| Population | group of individuals of the same species occupying a common geographical area |
| Population ecology | the study of how populations interact with their environment |
