Showing posts from March, 2012

A changing Australian landscape

There was a time – yesterday, geologically speaking – when kangaroos 3 metres tall hopped about Australia, elephants roamed North America and 2-metre high birds strutted around in New Zealand. Since the end of the nineteenth century, many different writers have noticed that the world doesn’t have an abundant number of creatures over 40 kilograms. Collectively, these large beasts are known as ‘megafauna’. Alfred Wallace, who wrote the first paper on evolution by natural selection with Charles Darwin, noted that ‘we live in a zoologically impoverished world, from which all the hugest, and fiercest, and strangest forms have recently disappeared’. We now know that the extinction of many of these creatures was global and that they died out quite recently. Their bones, when explorers and researchers found them, were not fossilized, suggesting their death was a matter of thousands of years ago. But the extinction seems to have happened at different times in different places. Some regions eve…