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ch 7.1
Term | Definition |
---|---|
eon | largest units of of geologic time |
era | eons are subdivided into smaller units of time |
periods | eras are subdivided into this |
epochs | periods are subdivided into this |
mass extinction | the extinction of many species on earth within a short period of time |
land bridge | connects the two continents that were previously seperated |
geographic isolation | the separation of a population of organisms from the rest of its species due to some physical border |