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The Permian Extinction Event: What Happened
The Permian Extinction Event is known as the largest mass extinction in the history of the Earth and was responsible for the devastation and literal genocide for thousands of species, from marine species, to terrestrial vertebrate and even insects.
Since the Permian Extinction Event “dwarfs all the others, it has long been the major focus of inquiry. If we could explain this greatest of all dyings, we might hold the key to understanding mass extinctions in general” (Gould, 1977, 135). The Extinction itself is best understood by taking a close look into a land known as Karoo in South Africa, known to “the world’s paleontologists…[as] a sacred place, for the flat sandstones, and shales piled into tablelands, called koppies, are one of the Earth’s great museums, a store house of ancient history, holding treasures more precious than all the gold and diamonds still to be found in Africa” (Ward, 2000, 39). This treasure trove account for more than “50 million years of land animal evolution…[and is also] a graveyard filled with the victims of one of the Earth’s great massacres: the protomammals, victims of the Permian Event” (39).
Protomammals, as many people have never heard the term, are “common ancestors of all mammals” and are often mammal-like reptiles (Scott, 1997). In all cases, the protomammals were the terrestrial creatures living during the Permian period, and nearly all were devastated by the Permian Extinction Event, though there is some record for a few of the species’ survival into the Triassic Period.
The Permian Extinction Event occurred in “the latter part of the Permian Period, about 255 million years ago, and perhaps 20 million years after the first protomammals emigrants reached South Africa, an episode of extinction occurred among the most diverse assemblage of protomammals ever to inhabit the Earth—perhaps one hundred different species in the Karoo alone—and a variety of their cold-blooded reptilian amphibian and reptilian cousins” (Ward, 56).
For its part, the Permian Extinction Event “was nevertheless unprecedented: for 100 million years, reptilian history had experienced an unbroken record of diversification…and then the darkness of extinction rolled across the land…in deadly earnest, species after species fell away, not to be replaced for a very long time…there to rest for 250 million years” (Ward, 56).
What Caused the Permian Extinction?
But what caused such an extinction event? It seems the debate has ended as many of the scientists agree that it was caused by one major Earth shifting, when “all the continents coalesced to form the single supercontinent of Pangaea” (Gould, 136). This means that, unlike the dinosaur extinction (which scientists are still debating about, but may have been caused by a super-sized asteroid), there is a pattern of events that led to the extinction itself that can be analyzed and studied. Indeed, the coalescing of the Earth’s continents would have been a “fusion of fragments [that] would produce a wide array of results, ranging from changes in weather and oceanic circulation to the interaction of previously isolated ecosystems” (136).
As the Earth is more than half ocean, the colliding of major continents to form larger continents would have had a drastic effect on the amount of water available to marine life during the Permian period. Indeed, “as shallow seas disappeared, the rich ecosystem of earlier Permian times simply lacked the space to support all its members” (138). More than that, many animals would have found their water source missing altogether—which would certainly explain how such a mass extinction could occur.
The Permian Extinction Event was the largest mass extinction in the history of the Earth. It was responsible for wiping out nearly every marine species, more than half of all terrestrial vertebrate species, and was the ultimate annihilation for insects. After a brief analysis of the Permian Extinction Event itself, the known cause can be traced to the coalescing of the continents to form Pangaea, which would certainly have caused mass extinction among the marine species. The terrestrial vertebrate species and the insects would have, as a result, fallen to extinction as well, simply because the ecosystems shifted too much in too short a span a time for their survival.
Gould, S.J. (1977). Ever since Darwin: reflections in natural history. New York: Norton.
Scott, D.J. (1997). Evolution: from reptiles to mammals. Accessed 22 July 2009 <http://genesispanthesis.tripod.com/fossils/rept_mam.html>
Ward, P.D. (2000). Rivers in time: the search for clues to the Earth’s mass extinctions. New York: Columbia UP.