4.2 Changes in Australian flora and fauna – Questions and answers

4.2 Changes in Australian flora and fauna – Questions and answers
Bk Ch4 S4.2 Q1
Use examples of an Australian animal and plant to illustrate that variation exists within populations of
a species.
Bk Ch4 S4.2 A1
Variation exists between members of the same species. For example, different populations of the
white-naped honeyeater that occur in Western Australia vary in the colour of eye-patch—some
populations have a white eye-patch and others are characterised by a green eye-patch. Victoria’s
common heath, Epacris impressa, can be found with crimson or white flowers or with intermediate
varieties of pink.
Bk Ch4 S4.2 Q2
Describe the changes that have occurred in the Australian climate over the last 65 million years.
Explain why these climatic changes have occurred.
Assess the impact of these climatic changes on plant communities, in terms of both distribution
and vegetation type.
Bk Ch4 S4.2 A2
When Australia was still joined to Antarctica around 65 million years ago the climate was cooler
and wetter than it is now. Temperate rainforest covered much of the land. Once Australia became
separated from Antarctica it began to move northward and as it did so its climate became warmer
and drier. As the northern part of Australia moved into the Tropic of Capricorn the climate in this
part of the continent became tropical.
As Australian climate became warmer and drier the temperate rainforests that once covered much
of the land contracted to coastal regions. The vegetation type also changed with species
developing that were more tolerant of higher temperatures and reduced water availability. These
included more woody sclerophyll forests and grasslands.
Bk Ch4 S4.2 Q3
Describe the evidence from Riversleigh in Queensland and Naracoorte in South Australia that
demonstrate change in Australian ecosystems.
Bk Ch4 S4.2 A3
The kinds of organisms found at Riversleigh in Queensland suggest that the environment has changed
from predominantly rainforest to a much drier habitat over the period from about 24 to 2 million years
ago. At Naracoorte in South Australia the fossil evidence is a testimony to a change from an ecosystem
of forests and inland lake ecosystems to one including open woodland over the last two million years.
Bk Ch4 S4.2 Q4
Outline how Charles Darwin interpreted his observations of Australian flora and fauna in terms of his
theory of evolution. Use specific examples to clarify your answer.
Bk Ch4 S4.2 A4
Darwin observed similarities between Australian species of organisms and more familiar organisms in
Europe; for example, he likened the crow to an English jackdaw, a potoroo to a rabbit. He interpreted
the likenesses as suggesting that the organisms were related. Of his observations that different kinds of
organisms living in similar environments showed similar adaptations he suggested that such organisms
must have become adapted to their particular habitats.
4.2 Changes flora and fauna QA
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© Pearson Australia (a division of Pearson Australia Group Pty Ltd)
Bk Ch4 S4.2 Q5
Describe Australian environmental conditions, identifying those areas that experience wide
fluctuations in temperature and water availability.
Relate the distribution of vegetation to temperature and rainfall patterns.
Bk Ch4 S4.2 A5
Australia is the driest of the world’s continents. While much of the northern and eastern sea
borders experience average rainfall the interior of the land is largely desert. Seventy-five per cent
of the Australian continent receives less than 800 mm of rainfall each year and that is often
unreliable, especially in the interior and along the west coast. Extreme patterns of drought and
flood are common. Australia is a mainly hot continent with cooler temperatures experienced only
in the south-east and south-west. Dramatic temperature fluctuations are most pronounced in the
interior where daytime temperatures reach over 40C and the heat escapes rapidly at night, and
temperatures plummet.
Vegetation types vary across the continent with the changing climatic conditions. The richest and
most abundant vegetation can be seen along the east coast where conditions are temperate with
reliable year-round rainfall. This includes rainforests in the north, and forests and woodlands
further south and inland. As temperatures increase and rainfall declines towards the interior,
shrubland becomes more prominent. Only plants adapted to the arid conditions survive in the
4.2 Changes flora and fauna QA
© Pearson Australia (a division of Pearson Australia Group Pty Ltd)
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