Earth's history through the periods and space's impact

by GabrielaMaduro
Last updated 7 years ago

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Discipline:
Science
Subject:
Planets & Astronomy
Grade:
6,7,8,5

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Earth's history through the periods and space's impact

In the later part(s) of the Devonian Period, a prolonged series of extinctions eliminated about 19% of all families, 50% of all gener and 70% of all species. This extinction event lasted perhaps as long as 20 Ma, and there is evidence for a series of extinction pulses within this period.

CRETACEOUSin the cretatous period, mass extinction of 50% of life, mostly dinosaurs because of what is thought to have been a meteorite or comet, hitting the yucatan penninsula in Mexico. mammls an birds were the only ones to survive on a large scale. This lead to the beginning of a new period

Triassic Particularly affected the ammonoids and conodonts, important index fossils for assigning relative ages to various strata in the Triassic System of rocks.Many scientists think that this event was caused by climate change and rising sea levels resulting from the sudden release of large amounts of carbon dioxide. The release of carbon dioxide from widespread volcanic activity associated with the rifting of the supercontinent Pangea, is thought to have strengthened the global greenhouse effect, which raised average air temperatures around the globe and acidified the oceans.

PERMIANAbout 23% of all families, 48% of all genera (20% of marine families, 55% of marine genera) and 70% - 75% of all species went extinct. Most non-dinosaurian archosaurs, therapsids, and most of the large amphibians were eliminated, leaving dinosaurs with little terrestrial competition. Non-dinosaurian archosaurs continued to dominate the aquatic environments, while non-archosaurian diapsids continued to dominate marine environments. 95 percent of marine species and more than 70 percent

Two events occurred that killed off 27% of all families, 57% of all genera and 60% to 70% of all species. Together they are ranked by many scientists as the second largest of the five major extinctions in Earth's history in terms of percentage of genera that went extinct.

Earth's history through it's periods and Space's impact

ORDOVICIAN

Devonian


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