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Equation 1 · Part 3 · Darwin's Finches: The Beak the Grants Measured for Forty Years

Symbol S

R=h2SR = h^2 S
SS

What this part means

the selection differential actually measured on the population in one generation, h2h^2 is the trait’s heritability.

Its job in the formula

S is an input to the expression that computes the quantity on the left.

Where the article explains it

where S is the selection differential actually measured on the population in one generation, h2h^2 is the trait’s heritability, and R is the response: the amount the population’s mean should shift in the next generation, if the difference between survivors and non-survivors was genetic rather than purely environmental.

The passage around this formula

Heritability is what turns a measured selection differential into a testable prediction, through the simplest quantitative-genetics identity in the field, the breeder’s equation: R=h2SR = h^2 S. where S is the selection differential actually measured on the population in one generation, h2h^2 is the trait’s heritability, and R is the response: the amount the population’s mean should shift in the next generation, if the difference between survivors and non-survivors was genetic rather than purely…

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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.

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Sources cited in the surrounding passage

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