← All parts of this equation

Equation 9 · Part 7 · The Peacock Problem: Darwin's Second Theory and Its Hard Tests

Symbol barp

Δtˉ=ht2 βt+B βpΔpˉ=B βt+hp2 βp\begin{aligned} \Delta \bar{t} &= h_t^{2}\,\beta_t + B\,\beta_p \\ \Delta \bar{p} &= B\,\beta_t + h_p^{2}\,\beta_p \end{aligned}
pˉ\bar{p}

What this part means

barp is one of the signed contributions combined to compute the quantity on the left.

Its job in the formula

barp is one of the signed contributions combined to compute the quantity on the left.

The passage around this formula

Russell Lande’s 1981 paper gave this verbal logic its standard quantitative-genetic form, modelling the joint evolution of a female preference trait and a male display trait under stabilising natural selection on the display and showed that, “despite stabilizing natural selection on males, various types of mating preferences may create a runaway process in which the outcome of phenotypic evolution depends critically on the genetic variation parameters and initial conditions of a population” [ 4 ] . One compact way to see why sits in the coupling itself. Let tˉ\bar t be the population mean of a male display trait and pˉ\bar p the population mean of the corresponding female preference; write…

Read this part in the article →

Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

Open the illustrated variables: a letter stands for a value guide →

See this notation across published equations →

Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.