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biological species concept
definition of a species as a population or group of populations whose members can breed with one another in nature and produce fertile offspring
condition in which a reproductive barrier keeps two species from interbreeding
separation of populations as a result of geographic change or migration to geographically isolated places
evolutionary model suggesting species often diverge in spurts of relatively rapid change, followed by long periods of little change
study of multicellular organisms as they develop from fertilized eggs to fully formed organisms
geologic time scale
Earth's history organized into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic
determination of absolute ages of rocks and fossils through calculations based on a radioactive isotope's fixed rate of decay
motion of continents about Earth's surface on plates of crust floating on the hot mantle
branching diagram, suggesting evolutionary relationships, that classifies species into groups within groups
process in which unrelated species from similar environments have adaptations that seem very similar
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