Why the Flora and Fauna of Australia so Unique

2158 Words Dec 16th, 2012 9 Pages
Why is the flora and fauna of Australia so unique?
Evolution is ultimately an unpredictable process. Although it can be predicted in the short term through knowledge of natural selection and inheritance, long term evolution is randomly altered by the interaction of highly variable factors. Such factors include the randomness of genetic diversity within a species and the process of natural selection acting upon this. Also significantly altering evolution is the unpredictable movement of tectonic plates which often leads to the isolation of large areas of land, such as Australia. Stemming from this arises various other substantial factors such as a lack of competition and predation and considerable changes in climate and ecosystems. The
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Some have considered these animals to be reptiles and others classify them into a subclass with extinct lineages and separate from all other living mammals today. Consisting of only five different species, including T. aculeatus, the Monotremes are the epitome of unique Australian fauna.
Australian organisms have become so adapted to the environment that they have lost the genetic diversity to deal with change. For example, Australia’s isolation protected its species from the threat of disease. Today the Tasmanian devil is threatened by a single virus, Devil facial tumour disease, due to its inability to adapt-stemming back to Australia’s isolation. It is estimated that since 1996, it has caused a 20-50% decrease in the devil population, spreading across over 65% of Tasmania. Thus it can be argued that Australia’s unique flora and fauna is in fact an evolutionary anomaly and a disadvantage for the future survival of Australian species.
This unique evolutionary pathway can also be traced back to changes in Australia’s environment as it floated over the southern regions of Earth. As Australia’s climate changed, the environment underwent a dramatic transformation. As Australia drifted northwards, the closed rainforests that once dominated the continent began to shrink as large areas of the continent started to die. By 2 million years ago, more than half of the continent was arid desert or
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