Adaptation (OCR AS Biology): Revision Note

Types of adaptations

• The term adaptation can be defined as:

A characteristic that aids an organism's survival in its environment

• Adaptations can be:

  • anatomical

    • Physical features of an organism

    • E.g. the white fur of a polar bear provides camouflage in the snow so it has less chance of being detected by prey

  • physiological

    • Biological processes within an organism

    • E.g., mosquitoes produce chemicals that stop the host's blood from clotting when they bite, so that they can feed more easily

  • behavioural

    • The way an organism behaves

    • E.g. reptiles bask in the sun to absorb heat

Types of adaptations table

Convergent evolution

• Organisms from different taxonomic groups may show similar adaptations even though they do not share a recent common ancestor

• Shared adaptations between unrelated organisms arise due to convergent evolution

• Convergent evolution occurs by natural selection as follows:

  • two species live in different parts of the world with similar environments

  • the species deal with the same selection pressures

  • the same characteristics are advantageous in the two environments, so individuals with these characteristics are more likely to survive and reproduce

  • over time the advantageous characteristics become widespread in both populations