Haldane 1937

Citation

Haldane, J. B. S. (1937). The effect of variation of fitness. The American Naturalist, 71(735), 337-349.

Links

https://www.journals.uchicago.edu/doi/abs/10.1086/280722

https://www.jstor.org/stable/2457289

Notes

Paragraph One

Haldane points out the distinction between Darwinian evolution (novel adaptation) and stabilizing selection (or purifying selection or "maintenance" selection).

Paragraph Two

The change in frequency of alleles resulting in novel adaptation can be very slow in terms of a human lifetime; however, extremely fast on a geologic timescale. Very small fitness differences in numbers of offspring could be virtually impossible to detect by direct observation yet have a very real evolutionary effect.

"In order that an observed viability difference of 0.1 per cent. should exceed twice its standard error, we should have to observe at least sixteen million individuals." If the average number of offspring per individual is two, for a population at constant size, this is expected to be Poisson distributed with a variance of two. The standard deviation would be [math]\sigma = \sqrt{\sigma^2} = \sqrt{2} \approx 2.828[/math]. The student's t-test comparison of two populations of equal size with equal variance and a mean difference of 0.001 is

[math]\frac{0.001}{\sqrt{2/1.6\times10^7} \approx 2.828[/math]

Terms

Facies - appearance. https://en.wiktionary.org/wiki/facies