Revision:Behaviour and genetics

Definitions used in behaviour

Causation: - when we seek to explain a patter of behaviour in terms of events that immediately precede it.

eg. A driver stops after seeing a red light. The man stopping is an immediate response to the red light (the stimulus).

Ontogeny: - when we seek to explain behaviour in terms of events that happened earlier in an animals life.

eg. We know not to touch sharp objects because we have learned earlier in our lives that it is dangerous.

Function: - when we seek to explain behaviour in terms of the benefits derived from it.

eg. We don't touch sharp objects because we benefit from not getting ourselves hurt.

Phylogeny: - when we seek to explain behaviour in terms of our antecedants in the past, i.e. we are studying behaviour in terms of evolution.

eg. We have characteristics from our ancestors which enable us not to touch sharp objects.

Stickleback

  • Male sticklebacks when in a full reproductive condition will attack other males, but will try to mate with females.
  • Stickleback are territorial fish and will guard their nests from other males. Males have red bellies and this is the stimulus which makes other males attack.
  • Female stickleback have silver bellies, this is the stimulus that attracts the males. The bellies of females are also swollen but it has been proven through experimentation that the stimulus that attracts the males is in fact the colour of the belly.

Courtship in Stickleback

  • The male stickleback will make a nest in his territory and get it ready for egg laying.
  • When he sees the stimulus (the red belly of the female) he will do a little dance (circular movements) and swim up to the female.
  • The female is stimulated by the dance and responds by following the male into the nest. The male continues to dance until the female pops her head into the nest.
  • As soon as she does this, the male swims around to the back of the female and prods her deeper into the nest.
  • The prodding is a stimulus for the female, and she responds by laying her eggs into the nest.
  • The male then shoves her out of the nest and he enters it. It is thought that the male doesn't require the female anymore so he attacks her until she leaves his territory.
  • If any competing males come into his territory the male will attack them.