Wednesday 13 June 2012

Animal Behaviour

INNATE BEHAVIOUR = a pattern of inherited behaviours that do not require learning or practice

Taxis = a directional movement towards or away from a stimulus
e.g maggots move away from light as they have photoreceptors on their anterior end = negative phototropism

Kineses = a change in an animal's rate of response or rate of turning. Affected by intensity of a stimulus but not its direction
e.g woodlice tend to move into darker areas rather than lighter ones so turn more in favourable conditions
---> has adaptive value as means organisms spend more time in favourable conditions, increasing chance of survival by reducing exposure from predators and sticks to damp areas so less chance of drying out

Escape Reflex = a fast response in which organisms move away from potential danger
e.g escape reflec in earthworms: in response to light touch and ground vibrations an earthworm will retreat into its undergroung burrow
---> organisms with alleles for faster especape are more likely to survive to breed and pass on the advantageous alleles to the next generation

Fixed Action Potentials (FAP) = a stimulus is required to initiate an instinctive behavioural response. Stimuli lead to release of mechanisms within the brain (essentially brain activity that leads to fixed pattern of neuronal output which, in turn, produces FAP)
e.g Female stickleback follows red objects to nest (males belly). Once in nest male touches females tail and she releases her eggs. Male then pushes female out of nest and deposits sperm

LEARNED BEHAVIOUR = behaviour that has been modified by experience
--> influenced by environment so allows organism to responf to changing conditions, and adapt to them as a result of experience
- Evident only in more complex organisms:-
               - with a larger lifespan, young have time to learn
               - improves survival of organism and species

Latent = learnt information only gives rise to a useful response much later
e.g mice may explore the surroundings of their burrow so that in the future they may more easily be able to escape from a predator

Imprinting = organism learns to stay close to a larger organism
- learned during 'critical period'
- is fixed and irreversible
e.g chicks follow mother or first thing they see when they hatch

Habituation = a type of learning in which an animal learns not to respond to a stimulus
e.g ragworm learns to ignore shadows and not use escape reflex. This is good as no energy wastage from continual retreat and more time for breeding and feeding

Insight = animal appears to integrate memories arising from two or more pieces of behaviour in order to produce a new response that achieves a reward
e.g problem-solving chimps stacking boxes to reach food

Operant Conditioning = animal learns to carry out a particular action to obtain a reward or avoid an unpleasant effect
e.g Skinner box using pigeons to show ability to learn which lever to press to get reward. Pigeons learns by trail and error and food acts as reinforcer

Classical Conditioning = two unrelated stimuli are applied to an animal, one a 'normal response' another unrelated. After repeated exposure to both stimuli together the animal will eventually respond with the normal response to the unrelated stimulus
e.g food = unconditioned stimulus causing salivation as natural response = unconditioned response, conditioned stimulus = bell, conditioned reflex = salivation when the bell is rung

Primate Behaviour
- Primates are social animals
--> They pay a great deal of attention to each other and an individuals behaviour is influenced by those around them, with each chimp having a rank in society

- Social behaviour benefits primates (=increases chance of survival)

- Social behaviour in insects is innate whereas in mammals it is learnt

Human Behaviour and D4
- D4 gene locus on chromosome 11
- Insertion mutation repeats 48 base pair section of gene, creating variations of DRD4
- Repeat in primary structure creates different tertiary structure
- Impacts on human include alchoholism, hyperactivity, durg abuse and schizophrenia

- Brain has many neurotransmitters which moderate behaviour of neurones
- Dopamine is involved in voluntary movements - muscle contractions
- 5 types of dopamine receptor on the postsynaptic membrane at the synapse and they are all proteins
- Dopamine receptors affect cAMP

Well that is practically the entire Animal Responses module - I hope it is helpful and the revision is going well, not long left now!!!

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