biology / Evolution & Ecology / free

Evolution & Natural Selection

Change variation, selection pressure, and generations to watch a population shift.

Follow the mechanism1 / 3

Heritable variation exists. Individuals differ, and some differences can be passed to offspring; selection cannot act on a trait that is absent.

population changefavored trait rises · generation 8

Focus the idea

variation65%

advantage+18

trait frequency66%

pressure70%

Variation available 65%Trait advantage 18Selection pressure 70%Generations 8

Selection does not invent the trait; it changes how common an existing heritable difference becomes.

This is a population model. Individuals do not evolve because they need to; inherited variation and differential reproductive success change the next generation.

Guided journey

Walk through the process.

Step 1 of 4: 01 / Start with variation

Individuals in a population differ, and some differences can be inherited.

What changes next: Selection has material to act on; it does not create useful traits on demand.

04 / PRACTICE

Make the biology yours.

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Answer from the model, then use the explanation to connect the visual mechanism to the biological rule.

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Evolution & Natural Selection

Walk through the process.

Individuals in a population differ, and some differences can be inherited.

Make the biology yours.

What does selection require to change a trait frequency?