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Geologic Time
Chapter Vocabulary for Geologic Time
| Term | Definition |
|---|---|
| eon | longest unit of geologic time |
| epoch | subdivision of a period |
| era | subdivision of an eon |
| extinct | dying out |
| geographic isolation | separation of a population of organisms from the rest of its species due to a physical barrier |
| land bridge | stretch of land that connects two continents that were previously separated by water |
| mass extinction | dying out of many species on Earth within a short period of time |
| period | subdivision of an era |
| scale | series of marks or points at known intervals |
| coal swamp | oxygen-poor environment where, over time, plant material changes into coal |
| inland sea | body of water formed when open water flood continents |
| supercontinent | ancient landmass that separated into present-day continents (Pangaea) |
| dinosaur | dominant Mesozoic vertebrate that walked with legs positioned directly below its hips |
| evaporated | changed from liquid to gas |
| plesiosaur | Mesozoic marine reptile with a small head, long neck, and flippers |
| pterosaur | Mesozoic flying reptile with large, bat-like wings |
| glacial groove | gouge made by rocks carried in glaciers |
| hypothesize | to make an assumption about something that is not positively known |
| ice age | time when much of Earth's surface is covered by glaciers |
| mega-mammal | large mammal of the Cenozoic era |