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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 |