Causes, evidence and effects of the Cretaceous extinction event on biodiversityThe most significant event of the Cretaceous era came to its end. Nearly 65 million years ago, the second most severe mass extinction in the earth's history occurred. This resulted in the loss of approximately 80% of the species then alive. While nowhere near as severe as the End-Permian mass extinction, the End-Cretaceous extinction is the best-known mass extinction event. This is due to the violent event that caused its extinction, as well as the chapter in the history of the earth that it closed: the Dinosaurs. The Cretaceous event (often shortened to the KT event) Among the animals that were killed were the flying reptiles (pterosaurs) and the later mosasaurs and plesiosaurs, both early marine reptiles. Many molluscs and microscopic plankton species were killed. Land plants also suffered a mass extinction. Nearly 60% of land plants were lost. This led to high rates of extinction among insect populations, with insects highly specialized in feeding on only a few types of plants the worst off. It took about 9 million years for global insect populations to recover from the Cretaceous extinction. Immediately following the extinction, the earth saw a short-term explosion of species that respond well to fire or other external disturbances. Evidence of the catastrophe comes from a thin layer of rock deposited around the world soon after the impact. It is dominated by fossil plants whose descendants recover quickly after fires from other disturbances, such as Fire Weed in Alaska. The causes of the Cretaceous extinction are still a matter of debate among paleontologists. Scientists agree that the main cause of the extinction was a... medium of paper... that lasted about a million years. The eruption was not violent compared to others, but it was able to send ash up to the stratosphere. So another theory is that shifting tectonic plates caused the Deccan traps to erupt, causing huge amounts of carbon dioxide to be released from the Earth's crust. This went on to create a global greenhouse effect that cooked the planet. This, along with climate change due to continental drift, may have caused the KT event. Paleontologist Richard Cowen believes that the evidence for an asteroid impact is so strong that it makes no sense to explain such evidence as solely volcanic effects. We should focus on the fact that the KT border coincides with two different, but very dramatic events. Works Cited Cowen, Richard. A life story. 2nd ed. vol. 1. Massachusetts: Cambridge, 1999. Print.