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Ch 14
Term | Definition |
---|---|
Eons | The longest units of geologic time |
Eras | Eons subdivided into smaller units of time |
Periods | Eras subdivided into smaller units of time |
Epochs | Periods subdivided into smaller units of time |
Mass extinction | The extinction of many species on earth within a short period of time |
Land bridge | Connects two continents that were previously separated |
Geographic isolation | The separation of a population of organisms from the rest of its species do to some physical barrier, such as a mountain range or oceans |
Paleozoic era | The oldest era of the Phanerozoic eon |
Mesozoic era | The middle era of the Phanerozoic eon |
Cenozoic era | The youngest era of the Phanerozoic eon |
Inland sea | A body of water formed when ocean water floods continents |
Super continent | An ancient landmass which separated into present-day continents |
Dinosaur | Dominant Mesozoic land vertebrates that walked with legs positioned directly below their hips |
Plesiosaurs | Mesozoic marine reptiles with small heads, long necks, and flippers |
pterosaurs | Mesozoic flying reptiles with large, batlike wings |
Holocene epoch | The most recent epoch |
Pleistocene epoch | The first epoch of the Quaternary period |
Ice age | A time when a large proportion of earth's surface was covered by glaciers |
Glacial grooves | grooves made by rocks carried in glaciers |
mega-mammals | The large mammals of the Cenozoic era |