Essay on Evolution of Australian Biota Assessment Answers

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a) Discuss current research into the evolutionary relationships between extinct species, including megafauna and extant Australian species.

Megafauna simply means large animals, in which most have become extinct within the last 20 000 to 50 000 years. The extinction of megafauna was, debatably, due to climate change and human expansion. Although, Africa still retains some megafauna, such as the elephant or the rhinoceros. Australia has managed to keep many examples of relict species, some from the time of the megafauna. These include the Crocodile, Wollemi Pine and Stromatolites.

Megafauna are not direct ancestors of the current animals, rather certain animals both evolved from a common ancestor. An example of this can be seen in
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Fossils of the Diprotodon have been found all over Australia, in places such as the Wellington caves, which have assisted Palentologists in discovering similarties and differences between the Diprotodon optatum and the modern wombat. Other forms of current research include techniques to do with DNA hybridisation, molecular biology techniques and DNA preserved in bones to discover information about evolutionary relationships.

b) Identify data sources and analyse information from secondary sources and use available evidence to illustrate the changing ideas of scientists in the last 200 years about individual species such as the platypus as new information and technologies became available.

The Platypus is one of Australia's most unique animals, of which its origins and classifcation is still debated today. Over the past 200 years, technology has rapidly developed, causing scientists ideas about the Platypus to change and develop.

When first discovered in 1798, a Platypus skin was sent to England which scientists thought was a hoax. As the specimen was observed more, it was considered to be a primitive species, but it was in fact a highly evolved form of an ancestor. It is unique from a mammal as it lays eggs, there is an absence of teeth, it also has a bill similar to that of a duck. It also has webbed feet and a short tail. However, it does have fur like other mammals and it secretes milk from special glands.

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