Examining the Cretaceous: Paleogene Extinction Event
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Examining the Cretaceous–Paleogene extinction event
Over 98% of all organisms that have lived on Earth are now extinct. A mass extinction event occurs when a large number of species die out within a small time frame (relative to the age of Earth). Mass extinctions are intensively studied for both cause and effect, as there is usually room for debate regarding catalysts that precede the extinction and the massive influx of new biological species that follows. There have been five major mass extinctions, dubbed the “Big Five,” that have wiped out at least 50% of the species living at those times. The most well known mass extinction of the Big Five, with the decimation of every species of non-avian dinosaur, is the Cretaceous-Paleogene extinction event (K-Pg). The K-Pg extinction occurred as ongoing natural disasters followed by an asteroid collided with Earth, which affected plant life, animal life, and hydrology (Cobb).
Some paleontologists believe that the global ecosystem had already been on decline before the final blow, an asteroid, destroyed much of life on earth. Continental dr...