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 the Diprotodon optatum, it does not belong to the same family as the modern wombat, but they are relatives which can be observed in their similar characteristics. Their structural similarities include their skull structure, body covering, structure of limbs, ears and snout. However, the Diprotodon was huge; 3 metres long and 2 metres high, comparable to a hippoptamus. They also had pigeon toed feet, a longer nose, possibly a small trunk, a very dense coat and sharp claws. The Diprotodon flourished in the late Tertiary and declined in the Pleistocene, becoming extinct at the time humans arrived, 50 000 years ago. The Diprotodon is mentioned in some dreamtime stories, supporting the idea that human hunting and Aboriginal fire stick burning (burning vegetation for easier hunting) altering the ecosystem both contributed to the extinction of the Diprotodon.
Current research into extinct megafauna and extant Australian species revoles heavily around the finding off fossils. Fossils provide Palentologists with information about the similarities and differences between species, deducing certain evolutionary relationships. Other research includes radiometric dating, providing dates for when fauna died and the possible cause. Ideas...
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