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 |