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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 |