Adaptations
Biology: AQA A Level, topic 4.4.4
Anatomical
Adaptations are traits that have been selected for because they help increase an organism's chance of survival and reproduction. Adaptations can be anatomical.
Features
- Anatomical adaptations are physical structures that have evolved to increase the chance of survival.
E.g. Giraffe's long necks
- The long necks of giraffes is an anatomical adaptation.
- Giraffes have evolved long necks to allow them to access food in the top levels of acacia trees.
- Other species cannot reach the food at this height so giraffes are more likely to survive because they do not have to compete with the other species.
E.g. Walrus blubber
- Blubber is an anatomical adaptation.
- Walruses have evolved a thick layer of fat called blubber which insulates the walruses.
- Walruses live in very cold environments (e.g. the Arctic) so the blubber helps prevent heat loss.
Physiological
Adaptations are traits that have been selected for because they help increase an organism's chance of survival and reproduction. Adaptations can be physiological.
Features
- Physiological adaptations are processes within the body that have evolved to increase the chance of survival.
E.g. Snake venom
- The venom produced by some snake species (e.g. the black mamba) is a physiological adaptation.
- Snakes have evolved venom to protect them from potential predators which increases their chance of survival.
- The venom can also be used to capture prey.
E.g. Shivering mammals
- Shivering is a physiological adaptation.
- Mammals have evolved to shiver (the rapid contraction of their muscles) in cold environments.
- Shivering helps generate heat in the body.
- Shivering is an adaptation that maintains body temperature within an optimum range.
Behavioural
Adaptations are traits that have been selected for because they help increase an organism's chance of survival and reproduction. Adaptations can be behavioural.
Features
- Behavioural adaptations are actions that have evolved to increase the chance of survival.
- Behavioural adaptations can be learnt or inherited.
E.g. Cheetah hunting
- The hunting behaviour of cheetahs is a behavioural adaptation.
- Cheetahs have evolved to 'stalk' their prey by silently creeping close to them before chasing the prey.
- The stalking behaviour increases the chance the cheetah will successfully catch a prey.
E.g. Spider's web
- A spider's web is a behavioural adaptation.
- Spiders have evolved to spin complex webs made of a sticky, silk thread.
- Spiders produce a specific shape of a web that allows them to catch flies and other insects for food.
- The web increases the chance the spiders will survive because they can catch food more easily.
Test yourself on Adaptations
Which of the following statements about anatomical adaptations are true?
What is the adaptive benefit of blubber in walruses?
Which of the following statements about physiological adaptations are true?
How is snake venom adaptative?
How do physiological adaptations differ from anatomical adaptations?