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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.
Australian Biota Essay Sample
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.
Evolution of Australian Biota Assessment Answers Evolution of Australian Biota Assessment Answers Evolution of Australian Biota Assessment Answers
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 about the ecological and environmental conditions of the time can also be found from fossils and other technology today. 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. As technology began to improve, scientists were able to understand how the Platypus reproduced. In 1826, it was found that it had mammary glands, and in 1884, scientists captured female eggs. In the 1940s, an Australia scientist invented the Platypussary. This was technology that attempted to stimulate its natural habitat, hoping to breed a pair.
In 1943, the first Platypus was bred in captivity, which gave scientists much research into lifestyle and breeding habits; gestation and pre and post natal processes.
Another scientific question was that of its body temperature, but with the development of radiotelementary scientists ideas about this changed. Radiotelementary can record body temperature and transmit this information. It has helped scientists in understanding whether the Platypus can maintain its body temperature when swimming in cold water. Scientists have contiuned to develop their ideas through the research of amino acids, which allowed them to observe trends between the sequences of placentals and marsupials. Fossils have also been an important technological development in understanding the Platypus.
As well as cell observation, allowing Scientists to discover the Platypus’ salt retaining kidneys. Another huge discovery about Platypus’ was able to come about because of new technology, the question of how the Platypus got its food. Using Electron Microscopy, scientists were able to observe the Platypus bill. The discovery was made that the bill had extremely sensitive touch receptors which helped the Platypus navigate underwater with its eyes closed, and it detected prey. They also discovered Electroreceptors on the bill, which detect tiny electrical signals, creating an image underwater for the Platypus and located the prey.
Scientists have contiuned to develop their ideas through the research of amino acids, fossils, fibre optics, radio tracking, genetic fingerprinting and cell observation, which allowed Scientists to discover the Platypus’ salt retaining kidneys. c) Gather information from secondary sources to describe some Australian fossils, where these fossils were found and use available evidence to explain how they contribute to the development of understanding about the evolution of species in Australia.
Fossils are huge scientific development which have altered and explored many scientific theories. The sequences of fossils indicates the progressive chronology of the changes in plants and animals over millions of years, the dating of rocks indicates the time periods of extinction and the type of plant and animal in the fossil depicts the environment in that past area. An example of this is within the fossil tooth from a placental mammal, about 55 million years old. This was found in Murgon.
This particular fossil changed the understanding of fossil mammalian history, as it is Australia’s oldest placental land mammal. This fossil now supports the theory that both placentals and marsupials lived in Australia around 55 million years ago. Another example of how fossils contribute to the understanding of evolution is in the Glossopteris flora. It is especially significant as it provides the first evidence of continental drift, as the leaf is dominant in America, Australia, Africa and India, supporting the theory that these continents had once been joined.
The Glossopteris developed understanding about the Australian evolution of species as the adaptation of its thick skin indicates Australia’s changing climate throughout evolution. This skin prevented a rapid loss of moisture as Australia became more arid. Some important fossil sites that have developed our understanding about the evolution of species in Australia include Lightning Ridge, Murgon, Riversleigh, Bluff Downs and Wellington Caves.