Difference between revisions of "Haldane 1937"
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"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." | "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 | + | 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 student's ''t''-test comparison of two populations of equal size with equal variance and a mean difference of 0.001 is | |
| − | 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}} | + | <math>t = \frac{0.001}{\sqrt{2}\sqrt{2/1.6\times10^7}} =2</math>. |
| + | |||
| + | However, this is the size of each group being compared. Detecting this difference would require a comparison of the number of offspring of 32 million individuals, half with the genotype and half without. | ||
==Terms== | ==Terms== | ||
Revision as of 12:26, 9 September 2018
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 student's t-test comparison of two populations of equal size with equal variance and a mean difference of 0.001 is
[math]t = \frac{0.001}{\sqrt{2}\sqrt{2/1.6\times10^7}} =2[/math].
However, this is the size of each group being compared. Detecting this difference would require a comparison of the number of offspring of 32 million individuals, half with the genotype and half without.
Terms
Facies - appearance. https://en.wiktionary.org/wiki/facies
