| A | B |
|---|
| ecosystem | all the living and nonliving things that interact in an area |
| habitat | the place where an organism lives and that provides the things it needs |
| biotic factor | a living part of a ecosystem |
| abiotic factor | a nonliving part of an ecosystem |
| photosynthesis | the process in which organisms use water along with sunlight and carbon dioxide to make food |
| species | a group of organisms that are similar and reproduce to produce fertile offspring |
| population | all the members of one species in a particular area |
| community | all the different populations that live together in an area |
| ecology | the study of how living things interact with each other and their environment |
| population dnsity | the number of individuals in a specific area |
| estimate | an approzimation of a number based on reasonable assumptions |
| birth rate | the number of births in a population in a certain amount of time |
| death rate | the number of deaths in a population in a certain amount of time |
| immigration | moving into a population |
| emigration | leaving a population |
| limiting factor | an environmental factor that prevents a population from increasing |
| carrying capacity | the largest population that an area can support |
| natural selection | process by which individuals that are better adapted to the environment are more likely to survive and reproduce that others |
| adaptation | the behaviors and physical characteristics of species that allow them to live successfully in their environments |
| niche | an organism's particular role in an ecosystem, or how it makes its living |
| predator | the organism that does the killing in predation |
| prey | an organism that is killed in predation |
| symbiosis | a close relationship between species that benefits at least one of the species |
| mutualism | a relationship between two species in which both species benefit |
| commensalism | a relationship between two species in which one species benefits and the other is neither helped nor harmed |
| parasitism | a relationship in which one organism lives on or inside another and harms it |
| parasite | the organism that benefits by living on or in a host in parasitism |
| host | the organism that a parasite lives in or on in parasitism |
