Animal Behaviour. AP Campbell Chapter 51. Explaining animal behaviours. What stimulus elicits the behaviour, and what physiological mechanisms mediate the response? How does the animal’s experience during growth and development influence the response?
Campbell Chapter 51
Many behaviours have a geneticbasis.
Selection for individual survival and reproductive success can explain most behaviours.
All behaviours can be analyzed by cost-benefit analysis.
Behaviours that are favourable should maximize benefitswhile minimizing costs.
Two types of behaviours directly related to the fitness of an organism:
Foraging includes any activities an organism undertakes to search for and procure food.
Optimal foraging theory:
Natural selection should favour foraging behaviours that maximize nutritional benefits while minimizing costs.
Case study: Drosophila larva foraging behaviour
How are both alleles maintained in natural populations? Why doesn’t the rover allele become fixed in the population?
Selection favours different alleles depending on the conditions.
The propagation of genetically-based behaviours is dependent on maximizing reproductive success.
Types of mating systems
Male monogamy and parental care are an evolutionary mystery.
Males have the potential to produce many offspring by mating with multiple females.
Factors promoting male paternal care
The mate-assistance hypothesis:
Males will help rear offspring in environments where male parental care can greatly promote offspring survival.
The male will produce more viable offspring if he stays and helps, than if he mates with more females.
When is paternal certainty high?
In internally-fertilizing species, males will engage in behaviours that tend to increase certainty of paternity.
These behaviours make up an aspect of male-male competition termed “spermcompetition”.
The mate-guarding hypothesis:
Males will stay with a single female partner in environments where receptive female mates are scarce.
Multiple matings with the same female will produce more offspring than mating with more than one.
Polygamous species are often sexually dimorphic: