Natural selection

Science

Definition

Natural selection is the process by which organisms with traits better suited to their environment are more likely to survive and reproduce, passing those advantageous traits to offspring. Over many generations, this leads to adaptation and drives evolution. It requires variation, heritability, differential reproduction, and selection pressure.

Examples

  • Peppered moths evolving darker coloring during the Industrial Revolution due to soot-darkened trees
  • Antibiotic-resistant bacteria surviving and reproducing when exposed to antibiotics
  • Darwin's finches developing different beak shapes suited to different food sources
Key Fact

Darwin's four conditions: variation exists, traits are heritable, more offspring are produced than survive, and survival depends on traits.

Related Terms

Adaptation Evolution Evidence of evolution Speciation

Study This Concept

Practice natural selection with free review games in these units:

AP Biology Unit 7: Natural Selection Biology Unit 5: Evolution and Natural Selection