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Darwinian Evolution Explains Lamarckism

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Extremely interesting article by Pradeep Mutalik in Quanta:

Our May Insights puzzle was inspired by recent discoveries of some rare, intriguing patterns of inheritance that hark back to Jean-Baptiste Lamarck’s theory of evolution and its emphasis on the “inheritance of acquired characteristics.” Elementary textbooks often present Lamarck’s theory as a failed 19th-century rival to Charles Darwin’s theory of evolution by natural selection. But reality, as usual, is far more complicated. There is indeed a great deal of evidence that most acquired characteristics are not inherited, but as the new findings have shown, this proscription is not absolute. The famous Överkalix study, for example, showed that men who were exposed to a poor food supply between the ages of 9 and 12 were found, two generations later, to have conferred a measurably lower risk of diabetes and cardiovascular death to their grandchildren. Adaptive Lamarckian inheritance does seem to be possible, and epigenetic mechanisms for it have been found. These mechanisms modify DNA in ways that differ from those of heredity.

But at a deeper level this kind of inheritance can be naturally selected for in the traditional Darwinian way, provided certain environmental conditions are satisfied. So Darwinian natural selection remains the fundamental basis of evolution and can produce Lamarckian inheritance: The theories are not rivals after all! Using simple models, our puzzles show how natural selection can sustain Lamarckian inheritance. The requirement is that environmental conditions, such as famines, follow patterns that persist across several generations and are repeated over long stretches of evolutionary time.

Question 1:

Imagine there exists an animal that has a new generation every year. Every normal individual has . . .

Continue reading.

Written by LeisureGuy

2 June 2017 at 7:21 pm

Posted in Evolution, Science

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