Biology / Unit 8 Bio 1751 short lesson, about 20 seconds
Heritability of Phenotypic Variation and Environmental Variation
Captions available
The idea
Heritability is the fraction of a population's phenotypic variation attributable to genetic differences; the remaining fraction comes from environmental factors selection cannot act on.
In practice
Skin tone shaped by sun exposure, and reptile sex set by incubation temperature, are both environmentally caused, non-heritable variation.
Where people slip
Selection acts only on the heritable fraction — environmentally caused variation, however visible, does not respond to selection.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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