News: Why didn't Darwin discover Mendel's laws?
- From: "Robert Karl Stonjek" <rstonjek@xxxxxxxxxxxxxx>
- Date: Sun, 1 Mar 2009 14:26:45 -0500 (EST)
Why didn't Darwin discover Mendel's laws?
February 27th, 2009 in General Science / Biology
Mendel solved the logic of inheritance in his monastery garden with no more
technology than Darwin had in his garden at Down House. So why couldn't
Darwin have done it too? A Journal of Biology article argues that Darwin's
background, influences and research focus gave him a viewpoint that
prevented him from interpreting the evidence that was all around him, even
in his own work.
Darwin's commitment to quantitative variation as the raw material of
evolution meant he could not see the logic of inheritance, argues Jonathan
Howard of the University of Cologne, Germany.
"Quantitative variation was at the heart of Darwin's evolution, and
quantitative variation is the last place where clean Mendelian inheritance
can be seen," says Howard. "Darwin boxed himself in, unable to see the laws
of inheritance in continuous variation, unable to see the real importance of
discontinuous variation where the laws of inheritance could be discerned."
Moravian priest and scientist Gregor Mendel (1822 - 1884) studied clear-cut,
inherited traits in pea plants, which he grew in the monastery gardens in
Brno. Mendel showed that trait inheritance follow simple laws, which were
later named after him. Mendel's work was rediscovered at the beginning of
the 20th century, and laid the foundations for genetics. Mendel had a good
understanding of biology, but his understanding of physics, statistics and
probability theory were far superior to Darwin's.
Darwin's view of biology was greatly influenced by geologist Charles Lyell
during and after the 1831-1836 Beagle voyage, leading to Darwin's focus on
infinitely tiny differences between individuals giving infinitesimal
advantages or disadvantages in survival. For Darwin, selection of these
variants over hundreds of thousands of generations was the critical process
in evolution.
Darwin's book The Different Forms of Flowers on Plants of the Same Species
details breeding experiments involving a well-defined "unit" character,
yielding clear data interpretable as 'Mendelian' ratios. But these went
unremarked by Darwin, who insisted, because of his belief that only
quantitative variation contributed to evolution, that the rules of
inheritance were too complex and not ready for definitive analysis.
Heredity and variation played central roles in Darwin's development of the
theory of evolution by natural selection. His view that variation is caused
by random, quasi-physical events outside environmental control, is much as
we believe today. But he never freed himself from the incorrect belief that
environmentally determined changes could also be inherited, another victim
of his focus on quantitative characters, height, weight and so on, which are
strongly influenced by environmental effects.
This year marks the bicentennial of Darwin's birthday, and 150 years since
his book "The Origin of Species" was first published.
More information: Why didn't Darwin discover Mendel's laws? Jonathan C
Howard, Journal of Biology 2009, 8:15 (24 February 2009),
http://jbiol.com/content/8/2/15
Source: BioMed Central
http://www.physorg.com/news154958022.html
Posted by
Robert Karl Stonjek
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