The Triassic Extinction

The Triassic Extinction - the cycads, seed ferns and the

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The Triassic Extinction At the end of the Triassic a minor mass extinction occurred. The cause of this is still in dispute, although the consensus opinion involves global cooling associated with an asteroid impact or comet showers. The victims of this event included the labyrinthodont amphibians , conodonts, and all marine reptiles except ichthyosaurs. Thecodonts , brachiopods , gastropods, and molluscs also suffered a loss of diversity as did the synapsids. As with larger mass extinctions, the Triassic die off opened ecological spaces into which the dinosaurs and other creatures moved during the Jurassic. The Jurassic The Jurassic period spanned the time interval from 208 to 146 million years ago. The major events of the Jurassic were the explosive adaptive radiation of dinosaurs and the evolution of birds (sometimes referred to as the avian dinosaurs), the diversification of
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Unformatted text preview: the cycads, seed ferns and the "cycadeoids", and the continued breakup of Pangaea. The opening of the Atlantic Ocean between Africa and North America created new shallow-water environments, as did the global rise of sea-levels that occurred during the Jurassic. As you might expect, marine life responded with a burst of adaptation and the appearance of new forms. Life in Water The separation of Pangaea caused the formation of new oceans, such as the Atlantic. It also led to a global rise in sea-level. Consequently there were many more environmental spaces open for exploitation. Since the Trissic extinction was not nearly as calamitous as the Permian one, life rebounded much quicker. Dinoflagellates and coccoliths became major elements of the oceanic phytoplankton. The bivalves, specifically the rudistids, began to play a larger role in reef formation....
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This note was uploaded on 11/29/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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