Nobody Was Trying

You'll learnhow allele frequencies shift across generations while the individuals themselves never change.

A beetle population goes from mostly light to mostly dark in six generations, and not one beetle changes colour. The dark variants were already there, thrown up at random by mutation, and they simply left more offspring. Twelve short steps; press Next for each one.

AP BIOLOGY · 12 STEPS · 6 QUICK CHECKS · VARIATION FIRST, AT RANDOM · POPULATIONS EVOLVE, INDIVIDUALS ARE SELECTED · v6

a beetle census · the frequency moves · no beetle changes colour

Before you start

What you're looking at

About twenty beetles on tree bark, some light and some dark, with a two-morph key in the right margin.

The question

What is actually changing when a population evolves — the individuals, or something else?

Step 1 / 12