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The story of extinction and the age of the Earth
A few hundred years ago nobody believed in extinction as a concept and no one imagined the Earth could be very old. The Bible held sway as an explanation of natural world and fossils were dismissed as objects that had been left by the devil. In the mid-1600s, Bishop James Ussher studied the Bible for evidence of the age of the Earth, concluding that it was less than 6000 years old, most probably created on Sunday October 23 4004BC. But in the late 1700s, James Hutton began to use principles of geology to extend the age of the Earth back into millions of years (still far short of the current estimate of 4.6 billion years). Around the same time a French naturalist, George Cuvier, published a controversial paper claiming that a fossil could be the remnants of a creature which had become extinct. Scientists gradually realized that extinction was an inevitable part of life on Earth, and as they began to look closer at the rocks, they noticed periods during Earth's history when life was dying out at frightening rates. They dubbed these events 'mass extinctions', the most famous of which became the meteorite that wiped out the dinosaurs. But, extinction is not just a process that has occurred in the past, scientists believe man is killing off species so rapidly that we are living through a major mass extinction at the moment. First broadcast on 'Dara O Briain's Science Club' on BBC Two in November 2012.
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