| A | B |
|---|
| evolution | change over time |
| gene | a sequence of DNA that codes for a particular trait |
| mutation | a change in DNA |
| genetic drift | biological evolution that occurs by chance |
| natural selection | the process by which traits that improve an organism's chances for survival and reproduction are passed on more frequently to offspring than those that do not |
| fitness | the degree to which an organism can reproduce successfully in its environment |
| adaptation | a heritable trait that increases the likelihood of an individual's survival and reproduction |
| artificial selection | a human-controlled process to produce individuals with certain traits |
| speciation | the process by which new species are generated |
| extinction | the disappearance of a species from Earth |
| niche | an organism's habitat, resource use, and fundamental role in a community |
| tolerance | the ability to survive and reproduce under changing environmental conditions |
| resource partitioning | a process that allows different species to share common resources |
| predation | the process by which individuals of one species hunt, capture, and feed on individuals of another species |
| coevolution | the process by which two species evolve in response to changes in each other |
| parasitism | a relationship between two organisms from different species in which one organism depends on the other for nourishment or some other benefit |
| symbiosis | a long-term and physically close relationship between two organisms from different species in which at least one organism benefits |
| herbivory | the act of feeding on a plant |
| mutualism | a relationship between two organisms from different species in which both organisms benefit |
| commensalism | a relationship between two organisms from different species in which one benefits and the other is unaffected |
| primary producer | an organism that can capture energy from the sun or from chemicals and store it |
| photosynthesis | the process by which primary producers use sunlight to convert carbon dioxide and water into sugars, releasing oxygen |
| chemosynthesis | the process by which bacteria use energy stored in bonds of hydrogen sulfide to convert carbon dioxide and water into sugars |
| consumer | an organism that relies on other organisms for energy and nutrients |
| cellular respiration | the process by which bacteria use energy stored in bonds of hydrogen sulfide to convert carbon dioxide and water into sugars |
| herbivore | an organism that eats plants |
| carnivore | an animal that kills and eats other animals |
| omnivore | an animal that eats both plants and animals |
| detritivore | an organism that scavenges the waste products or dead bodies of other community members |
| decomposer | an organism that breaks down nonliving matter into simpler parts that can then be taken up and reused by primary producers |
| trophic level | a rank in a feeding hierarchy |
| biomass | the total amount of living tissue in a tropic level |
| food chain | a linear series of feeding relationships |
| food web | a diagram of feeding relationships and energy flow showing the paths by which nutrients and energy pass from organism to organism as one consumes another |
| keystone species | a species that has a strong or wide-ranging impact on a community |
| succession | a somewhat predictable series of changes over time in a community |
| primary succession | the somewhat predictable series of changes in a community that follows a disturbance so severe that no vegetation or soil life remains |
| pioneer species | one of the first species to colonize newly exposed land |
| secondary succession | the somewhat predictable series of changes in a community that follows a disturbance that dramatically alters the community but does not destroy all vegetation or soil life |
| invasive species | a nonnative species that spreads widely in a community |
