God, Humanity and the Cosmos Topic: From Darwinism to Neo-Darwinism

From Darwinism to Neo-Darwinism

One of the great difficulties of Darwin’s evolutionary scheme was that, knowing nothing of the mechanisms of heredity, he thought parental characteristics were transmitted in the blood. Rare variants, however successful, would therefore be likely to be diluted out. This is no doubt why Darwin continued to admit the ‘laws of use and disuse’ - direct influence of experience on inheritance in the way that Lamarck had proposed (see important evolutionists before Darwin) - as well as natural selection. The problem was certainly a factor in the lack of acceptance of Darwinism in the late 19th Century.

The solution lay at hand in Darwin’s own lifetime. In 1866 Gregor Mendel (1822-1884), a monk in Brün, Moravia, published a paper on the inheritance of attributes (‘characters’) in the garden pea. His work remained in obscurity for more than three decades, but in it he showed that characters were transmitted as units. Each higher organism had a pair of units (which we now call ‘genes’) for each inherited character. A particular gene (for example for blue eyes) may be expressed or lie dormant, but it is not simply diluted out as Darwin feared.

The first supporters of Mendelian genetics, from about 1900, rejected Darwinian evolution, because they argued that the proposed accumulation of minute variations, suggested by Darwin, were contradicted by the much larger changes observed by Mendel. Nevertheless, with time, the science of genetics became linked inseparably with Darwin’s theory. By 1942, the date of the publication of Julian Huxley’s book Evolution: the Modern Synthesis, the developing science of genetics and a recasting of the proposals of Darwin had been combined in the theory known as neo-Darwinism.