BIOL2110- Vertebrate Zoology
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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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Indeed, what is known of the pattern of extinctions approximates this hypothesis (Alvarez et al. 1980). The research of the Alvarez team is the most widely known and accepted theory/mechanism of how this extinction came to be: A single but destructive asteroid impact has done its job. The extinction of the KT boundary organisms is still a mind boggling puzzle piece that needs to be solved, but until then, theories will always surround as to how this event happened. Whatever theory it is, the damage it had done during the Cretaceous is beyond human capacity, and it serves as a reminder that nothing is ever permanent. Whether they disappeared due to a combo of disasters or just a single and destructive asteroid impact, it still does not change the fact that these large organisms once ruled the Earth are now gone. The ramifications of massive impacts are poorly understood- an asteroid impact with that kind of magnitude is not within human experience: allowing some calculation and/or estimation mistakes to occur. The fossil records are incomplete, and the survival of the organisms can also have some dependence on luck. Further evaluation of all possible theories, mechanisms and hypotheses is needed. One thing is for sure, this extinction changed the course of evolution forever: it paved way for the adaptive radiations of mammals, including humans.