Adaptation (OCR A Level Biology)

• The term adaptation can be defined as:

A characteristics 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. mosquitos produce chemicals that stoa 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