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Ch 21 Living Things
| Term | Definition |
|---|---|
| organism | living thing |
| biotic factors | living parts of a habitat |
| abiotic factors | non living parts of a habitat - water, sunlight, temperature, soil, oxygen |
| species | group of organisms that are physically similar and can mate with each other to produce offspring |
| population | all the members of one species in a particular area |
| community | all the different populations that live together in an area |
| ecosystem | the community of organisms that live in a particular, along with the non-living surroundings |
| ecology | the study of how living things interact with each other and with their environment |
| estimate | an approximation 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 |
| population density | the number of individuals in an area of a specific size |
| carrying capacity | the largest population that an area can support |
| limiting factor | an environmental factor that causes a population to decrease - water, food, space, weather |
| natural selection | a characteristic that makes an individual better suited to its environment is this process |
| adaptation | behaviors or physical characteristics that allow organisms to live successfully in their environments |
| niche | the role of an organism in its habitat |
| competition | struggle between organisms to survive as they attempt to use the same limited resources |
| predation | interaction in which one organism kills another for food |
| predator | the organism that does the killing |
| prey | the organism that is killed and eaten |
| symbiosis | close relationship between two species that benefits at least one of the species |
| parasite | an organism living in or on another organism and harming it |
| host | the organism affected negatively by a parasite |