14 terms

Gr 8 Unit 3b Geologic Time

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eon
the longest division of geological time
era
a major division of geological time that is usually divided into periods
period
unit of geologic time into which eras are subdivided, they are divided into epochs
epoch
the shortest division of geologic time marked by distinctive features, events, and organisms.
mass extinction
event during which many species become extinct during a relatively short period of time
land bridge
a landform that connects two continents that were previously separated
geologic isolation
occurs when a population, separated by geologic barriers, adapt differently than similar populations in a different environment
Precambrian Eon
the part of geologic time from the formation of the Earth through the rise of simple life forms
Paleozoic Era
the part of geologic time when invertebrates, fishes, amphibians, reptiles and ferns were dominant
Mesozoic Era
the part of geologic time when dinosaurs flourished and then became extinct
Cenozoic Era
the current era of geologic time that began about 66 million years ago; it is known as the "Age of Mammals"
inland sea
body of water formed when ocean water floods continents
coal swamp
an oxygen-poor environment where, over a period of time, decaying plant material changes into coal
supercontinent
single landmass once formed by all of Earth's continents