Inheritance, variation and evolution

Let’s learn

Core knowledge: Inherited variation arises from genetic information, while environmental factors also affect phenotype; natural selection changes populations over generations.

Distinguish inherited and environmental variation and explain natural selection.

See it

In a bacterial population, a mutation gives one bacterium antibiotic resistance. Antibiotic treatment kills susceptible bacteria; resistant survivors reproduce, increasing the resistance allele’s frequency.

Try it together

Sequence variation → selection pressure → differential survival → reproduction → population change.

Now you try

1. Give one inherited and one environmental cause of variation. 2. Define mutation. 3. Explain antibiotic resistance using natural selection.