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.
See also the rhetoric of Darwinism.
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link | Feedback | Contributed by: Dr. Christopher Southgate and Dr. Michael Robert Negus
Source: God, Humanity and the Cosmos (T&T Clark, 1999)
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