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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
major biological changes evident in the fossil record
formation of new species
condition in which a reproduction barrier keeps two species from interbreeding
separation of populations as a result of geographic change or migration to geographically isolated places
evolution from a common ancestor of many species adapted to diverse envrioments
evolutionary model suggesting species often diverge in spurts of relatively rapid change, followed by long periods of little change
study of multicellular organism as they develop from fertillized eggs to fully formed organisms
geologic time scale
Earth's history organized into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic