SIGN-283 Lecture 16:
27 Jul 2020
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Task 1: once upon a time (brysbaert; chapter 1) Generally accepted age of 4,6 billion years. Georges-louis leclerc: one of the first scientific attempts to establish the earth"s age; based on the degree of heat lost by the earth estimated between 75000 and 168000 years. Lord kelvin: increased the estimate to some 100 million years (1862) but later corrected to 24 million years (1897) Charles darwin: estimate of some 300 million years; based on the geological and evolutionary processes. Cambrian explosion: sudden appearance of animals that resemble those in current life; some 542 million years ago; often presented as the beginning of real . Palaeozoic era (540 250 million): animals of the. Cambrian explosion thrived and were accompanied by other life forms: emergence of fish, land plants, insects, amphibians and reptiles respectively, then suddenly 95 per cent of marine species and 70 per cent of terrestrial species vanished.
