suggested answers
1) If the Australian continent had separated from Gondwana before the dinosaurs died out, Australia’s isolation may have saved its dinosaurs, & the first humans to arrive here may have discovered a real-life Jurassic Park!
2) Australian fauna developed in unique ways because of 50 million years of isolation.
3) Rainfall: Mountains boost precipitation in the form of
snow & rain. As mountains wear away precipitation declines.
Soil: Mountains generate new soil (for example, when glaciers
grind away rock). As mountains wear down, less new soil is generated. Over time,
the soil that has been deposited previously eventually blows away. (Soil is
also formed by active volcanoes which are notably absent in Australia.)
4) All of the 3 examples are at least partly products of low rainfall &
poor soil:
a) Areas of low rainfall are marginal in times of normal rain. Even a small
decline in rainfall will cause drought.
b) Bushfires are more likely in drier rather than wetter conditions, especially
where the landscape is dominated by woody plants & grasses.
c) Areas of low rainfall & poor soil cannot readily sustain large populations.
The most populous regions of the world are found in areas that have high rainfall
&/or regularly flood & fertile arable soil, for example, the Nile Delta,
the Ganges Delta & the Yangtze River Delta.
5) The first humans to leave Africa needed to be extremely bold & adaptable, & quick witted enough to recognise previously unknown dangers.
6) Animals that became extinct after contact with humans include:
additional activities
1) Ask students to research a particular Australian megafauna species. For an
exhaustive list, visit: en.wikipedia.org &
key in Australian megafauna.
2) Read chapter 6 (“Splendid isolation”) & chapter 16 (“The great megafauna extinction debate”) in The future eaters by Tim Flannery.
3) View the episode about megafauna in State of the planet by David Attenborough.
4) Take students on a short excursion by foot to a scenic location near school. Ask them what they think they would have seen at this location a) 50,000 years ago; b) 200 years ago; & c) 50 years ago.
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