| A | B |
|---|
| ecosystem | all living and nonliving things that interact in an environment |
| habitat | place where an organism lives that provides the things it needs |
| biotic factor | living part of an ecosystem |
| abiotic factor | nonliving part of an ecosystem |
| photosysnthesis | process in which organisms use water, sunlight, and carbon dioxide to make food |
| species | group of organisms that are similar and reproduce to produce offspring |
| population | all members of one species in an area |
| community | different populations that live together in a habitat |
| ecology | study of how living things interact with each other and their environment |
| population density | number of individuals in a specific area |
| estimate | an about number bases on reason |
| birth rate | number of offsprings born in a certain amount of time |
| death rate | number of deaths in a population in a certain amount of time |
| immigration | joining a population |
| emigration | leaving a population |
| limiting factor | an environmental condition that prevents a population from increasing |
| carrying capacity | the largest population that an area can support |
| natural selection | process where the more adapted individuals are likely to survive |
| adaptation | behaviors and physical characteristics of a species that allow them to live successfully in an area |
| niche | an organism's particulare role in an ecosystem, or how it makes its living |
| competition | struggle between organisms for the limited resources in a habitat |
| predation | an interaction in which one organism kills and eats another |
| predator | the organism that does the killing |
| prey | an organism that is killed by a predator |
| 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 one species benefits and the other is neither helped or harmed |
| parasitism | a relationship in which one organism lives on or in another and harms it |
| parasite | the organism that benefits by living on or in a host |
| host | an organism that a parasite lives in or on |
