Extinction Events In Aquatic Research

The Oxford dictionary defines extinction in relation to biology as a species, family or a large group having no living members (Oxford, 2016). With the estimation of the four billion species that evolved on earth during its 4 billion year existence, about 99% of them now are extinct (Novacek, 2001). This displays how natural extinction is, but it is usually stabilized by speciation (Barnosky, 2011). A major extinction event is one in which many species meet their end over a short period of time, these events are grand in scale and many species of all ecological types (i.e. animals and plants, aquatic and terrestrial) all around the world are involved (Benton, 2011). There have five major extinction events in the last 600 million years ago, the Late Ordovician, Late Devonian, Late Permian, Late Triassic and end-Cretaceous (K–T), respectively in that order (Twitchett, 2006).

The Permian-Triassic mass extinction happened in between the Palaeozoic and Mesozoic eras, about 251 million years ago (Jablonski, 1995). This mass extinction was the most devastating by a big margin, this claimed 95% of all aquatic species, which dramatically changed life in the ocean. Land plants and

More than 50% of all aquatic species were wiped out and eliminated many land animals and plants, most notably all the dinosaurs except for the birds. The causes include climate change which occurred due to volcanic floods in India as a consequence of a giant comet Collison in the Gulf of Mexico (Wake, D.B., Vredenburg, V.T. and wakelab, 2008). Evidence for this can be supported by the fact that Iridium a very rare element found on earth but commonly found in extra-terrestrial objects and a layer of iridium was found on the coast of Mexico. The crater in Mexico is similar in size to an object with a radius of 5km, which could have collided there (Reece,