No Two Alike
Look closely at any wild population and no two individuals are identical. These small differences are the raw material natural selection acts on.
Every measurable feature — size, colour, beak, bone, behaviour — varies from individual to individual. The variation is everywhere.
Some of that variation is inherited. The heritable differences are the ones that matter for evolution.
“These individual differences are of the highest importance for us, for they afford materials for natural selection to accumulate.”
Learn to see variation
See the spread, not the type
A “species” is not one fixed form but a cloud of slightly different individuals. Train your eye on the differences, not the average.
Ask which differences are heritable
Only variation that offspring inherit can drive change. Separate the passed-on from the merely acquired.
- Would this difference show up in the offspring?
Treat variation as opportunity
Where others see noise, see the raw material. Every heritable difference is a possibility that selection can seize.
Individual differences afford the materials for natural selection to accumulate.
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