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Edexcel IGCSE Biology · Spec 3.38

Natural Selection

How natural selection works and how it drives evolution over many generations.

Biology revision video

Natural Selection

Spec 3.38

What you need to know

  • Explain Darwin's theory of natural selection
  • Describe how a species changes over time
  • Use an example to explain evolution

Active recall

Quick check

Answer each question before opening the answer.

Outline the steps of natural selection.

Variation exists → a selection pressure/competition acts → the best-adapted individuals survive and reproduce → their advantageous alleles are passed on.

Who proposed the theory of evolution by natural selection?

Charles Darwin.

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