Equation 2 · Part 5 · From Origins to Frontier: A History of Evolutionary Biology and Ecology
fraction
fraction
What this part means
Divide the expression above the line by the one below it.
Its job in the formula
The expression above the fraction bar is divided by the complete expression below it. The denominator must not be zero.
Full expression→fraction→Article meaning
The passage around this formula
Sewall Wright’s 1931 paper, “Evolution in Mendelian Populations,” added the piece Fisher’s and Haldane’s more deterministic treatments lacked: a formal account of genetic drift, the random change in allele frequency from generation to generation caused by finite population size [ 3 ] . Wright showed that in a randomly mating population of effective size , the variance in allele frequency change per generation from sampling alone is . for a diploid population starting at allele frequency p . This single expression carries a real consequence: small populations can fix or lose alleles by chance alone, independent of whether those alleles are beneficial, neutral, or mildly…
Learn the underlying idea
A fraction a/b means a divided by b. The top number is the numerator; the bottom number is the denominator, and it cannot be zero.
Open the illustrated fractions: division written vertically guide →
Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.