Behavioural ecology

behavioural

the internally coordinated responses of whole living organisms to internal or external stimuli

• varies within and between species

adaptive behaviour

a behaviour that increases the fitness of an organism and will be selected for over multiple generations

• depend on both genese and environment

hamiltons four classes of social interaction

• cooperation

• altruism

• selfishness

• spite

cooperation

both donor and recipient benefit

altruism

recipient gets benefits, donor doesn’t

selfishness

donor benefits, recipient doesn’t

spite

neither donor or recipient benefits

Inclusive fitness

an individuals overall fitness is determined by its survival and reproduction, plus the survival and reproduction of its relatives

• natural selection favours behaviours that increase inclusive fitness

reasons for altruism

• group selection

• manipulation 

• reciprocal altruism

• kin selection

group selection

reason for altruism due to neglecting individual needs to increase fitness of entire group

manipulation

reason for altruism due to not recognizing they are being parasitized

reciprocal altruism

reasons for altruism due to recipient paying back in the future

kin selection

reason for altruism due to increasing their inclusive fitness by increasing survival and reproduction of kin

coefficient of relationship

Rg → the probability that the alleles at a given locus will be identical by descent among two individuals in the population- influences whether a behaviour will be maintained

what determines continuation of altruism

high genetic relatedness or reproductive benefit gained and low reproductive cost

sociality

consists of a group of individuals living together, involving some degree of cooperation between individuals

evolution of sociality

• cooperative feeding

• defense of the social group

• decreased by restricted reproductive opportunities

cooperative breeders

live in groups with several adults to help with offspring

• high level of relatedness promotes altruistic behaviour due to high kin selection

why does cooperative breeding work

inclusive fitness is increased and reciprocal altruism promotes helping the group

eusociality

highly complex social behaviour that evolved independently across multiple organismal groups

• individuals of more than one generation live together

• cooperative care of young

• division of individuals into non reproductive and reproductive group

two examples of eusocial animals

leafcutter ants and naked mole rat