After Skelton: Evolution (1993)

Geneticists have long opposed the principle of natural selection. One of the causes was the fact that the Dutchman Hugo de Vries stated that evolution was powered by saltations. These are very large mutations abruptly giving  raise to a new species. Some of these saltations are known, but in by far the most cases such a large mutation is lethal. Hugo de Vries is the discoverer of mutations, but he overestimated the effect. Only in the thirties of the last century the geneticists, the paleontologists and the field biologists found each other in the so-called Modern synthesis. In this version of the evolution theory natural selection was accepted as the driving force. Founder was Julian Huxley, the grandson of Thomas Huxley, 'Darwin's Buldog'. After the Second World War, Ernst Mayer (photo) gave important contributions to what is called the Neo-Darwinism. Know more? The Modern Synthesis

In the eighties and the nineties of the last century the discussion on evolution was given a boost by Stephen J. Gould, Niles Eldredge and David Raup. The last one pointed at the great importance of extinctions in the process of evolution. Without these tragedies life on Earth wouldn't have developed so extremely varied as we know it now. After every extinction there was room for new adaptations. If the dinosaurs hadn't died out at the end of the Cretaceous, it is likely that the mammals couldn't have developed as they have done now (see the ultimate consequence?). The most extreme extinction was at the end of the Permian, about 250 million years ago. During this period 95% of all plants and animals became extinct . It took as many as 10 million years before the biodiversity had reached the old level. Raup stated that the great extinctions occur with interval of 26 million of years . This is illustrated in the diagram on top. But nowadays this is believed not to be true. Know more? The role of extinction in evolution

Evolution 14

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