Dinosaur Extinction Essay

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BIOL2110- Vertebrate Zoology

Word count: 1056

Dinosaur extinction: An analysis of events and theories that possibly led to the dinosaurs' demise.

Ever since the history of Earth has been studied using fossil records, extinctions have always been the object of fascination and interest, particularly the mass extinctions that occurred throughout Earth's history. A mass extinction can be caused by disruptive global environmental changes, where large numbers of species have become extinct (Urry et al. 2008). There have been five major extinctions documented based on fossil records over the past 500 million years, but the Cretaceous (KT boundary extinction – a name that meant it began the Tertiary era) extinction caught a lot of
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According to the research made by Alvarez (1980), it was due to an asteroid impact that single-handedly destroyed dinosaurs to extinction. Advocacy of this mechanism has been aided by the availability and tangibility of supporting evidence in the form of impact craters- the Chicxulub crater in the Yucatan Peninsula's date and timing of impact (dating produced an almost exact date of 65 million years ago), location, enormous size-170 km (Hildebrand et al.1991) and its high iridium content ( a metal not commonly found at the Earth's surface) make it seem that with a theoretical asteroid 10 km big caused the crater great damage at the end of the Cretaceous (Alvarez et al. 1980).
How exactly the asteroid damaged the Earth remains unclear, but the power released by such an impact is unquestionable. Effects possibly include reduced sunlight over a period of several months which possibly led to the decline or even total halt of primary production (via photosynthesis). One of the dominant signatures of the extinction at the KT boundary was the low activity of primary production, the possibility of reduced sunlight is high (Schulte et al. 2010) . Even if the primary production proved to be on a decline when this impact occurred, there is still some uncertainties as to where exactly the impact hit. This was why asymmetries in subsurface features of the Chicxulub crater were observed via geophysical methods were analyzed and it was calculated from estimates that the
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