Mass Extinction Essay

1505 Words7 Pages
Mass Extinction Part A: Mass extinction can typically be thought of as the extinction of an entire species/ rapid disappearance of a species due to environmental or human causes. Traditionally mass extinctions have been seen ass some type of catastrophe for the worlds biota. Definition however must include: • Event must be rapid • Over 50% of all life on earth became extinct • Life forms that become extinct must belonged to a different phyla, on land and in the sea. There have to date been five mass extinctions, the oldest occurred during the lower Cambrian Period some 542-488 [pic]million years ago. The Cambrian Period is the first period of the paleozia period. It is characterized by the appearance of a wide tange of complex, fossilizable multicellular organisms, meaning that it was around this time, that fossils have been indentified from this time. A wide range of species emerged from this period including trilbotes, brachiopods, arthropods and conodonts. Mass extinction ended the Cambrian period. Advancing glaciers would have lowered the temperature of the shallow seas therefore such big changes in temperature would alter the amount of oxygen in the water and meant the end for any species that couldn’t adapt. Research shows that approximately 50% of all species became extinct. The Devonian period was the second mass extinction and is known as the “Age of the fish” It is famous for the thousands of species of fish that developed in the Devonian seas. During the late Devonian period, over 408-360 million years ago, ,saw mass extinction and over a fifth of marine families and more than half of marine genera gradually died out over what may have been a ten-million-year interval. Climate and sea-level changes were the causes of the extinction of many types of corals, trilobites and fish with the sponges and coral most greatly effected.

More about Mass Extinction Essay

Open Document