3rd Post – CHANGES IN DISTRIBUTION

 

Australia climate was once much cooler and wetter and much of the land were covered in temperate rainforest.

From about 25 million years ago, as Australia continued to drift north, conditions began to dry out (Ahmad Shah Idil, 2006). The dry, poor soil conditions favoured the sclerophyll plants rather than the Antarctic beech forest. There were also frequent fires and sclerophyll plants can survive water loss. The rainforests in central Australia were unable to survive without permanent water (Kendall, 2006).

Fossils of Antarctic beech in central Australia indicate it was once forested.

  • Climate Change: Mega fauna were mainly suited to glacial conditions. Their large bodies enabled them to live in extreme conditions. In Eurasia and North America, when permafrost was replaced with forest, the mega fauna died out and animals more adapted to forest began to thrive. In Australia, the temperature changed from cold-dry to warm-dry. As a result, water sources began to dry up, and many animals lost their habitat and died out.

 

  • Climate: Increase in climate and decline in water availability is shown in the contraction of rainforests and in the expansion of open woodland. The rise and fall of Australian mammals and the radiation of marsupials is also related to climate

                                                                       

  • Human Impact: Humans arrived as an exotic species in Australia. Their actions may have contributed to the mega fauna’s extinction and use of fire changed the environment. Arrival of Europeans drastically changed the environment, due to unsustainable agricultural methods

 (Kendall, 2006)

 

The knowledge we gain from palaeontology (fossils) and the study of past environments can help us to understand present-day ecosystems. We can use this knowledge to predict and to determine the future for Australia’s plants and animals (kate mudie,2000).

Palaeobiologists gain knowledge about the long term changes that have occurred in ecosystems over millions of years. At Riversleigh, fossils are being used to see how Australia’s biota evolved (Ahmad Shah Idil, 2006).

One concept I predict is that there has been a loss of biodiversity over time. Over the last 200 years we know that the area covered by forest has been reduced because of timber harvesting and clearing for agriculture. Most of our rainforest is now found only in small, isolated pockets near the coast of eastern Australia, and much is now in national parks. The one thing that comes to my mind is ‘Are these pockets large enough for long term sustainability of rainforest ecosystem?’

Evidence from other parts of the world suggests that the areas currently protected are not big enough. Plants and small animals may survive, but the larger mammals probably will not.   

 

The main findings of palaeontology in Australia are:

1.    Loss of biodiversity over time – reduction in rainforest

2.    Thylacine – numbers were already declining, Europeans finally killed them all

3.    Analysis of plant and animal fossils can allow palaeontologists to create a picture of the ecosystems at the time.

 

­ Annotated bibliography

Source 1

Montanari, Shaena. 2013. PLOS blogs. “Climate Change and Paleontology: Back to the Future” http://blogs.plos.org/paleo/2013/08/02/climate-change-and-paleontology-back-to-the-future/ (accessed 13/8/13)

  • The website is most likely to be accurate as the use of language is scientific and unbiased.
  • Repetitive search shows that other websites have similar information as this website which makes this website mostly credible
  • Information is gathered from many different sources proving to be a valid source which is relevant to the area of study and provides evidence.
  • The website was last updated August 2, 2013 which emphasises that this website is most likely accurate.
    • This website summarises information about Climate Change and Paleontology

 

Source 2

Wikipedia contributors (Author Unknown) (2013) “Paleontology” http://en.wikipedia.org/wiki/Paleontology (accessed 13/8/13)

  • Repetitive search shows that other websites have alike information as this website which makes this website mostly credible
  • Although it is written by an anonymous author it provides sufficient material on Paleontology and is written in a formal manner which shows that an older person or educated person could’ve written it.
  • This source was last modified on 7th of August 2013 at 10:27 ensuring information is updated recently.
  • This website summarises information about Paleontology including information about its fossils, natural history, evolution and the branches.

 

 

 

 

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