Group living, altruism and Cooperation

improved foraging, decreased predation risk, conservation of heat and water, also energy used in movement

benefits of group living

improved foraging mechanism

cooperative foraging

coordinated foraging efforts among predators

cooperative hunting

an improved foraging by observing behavior of group members

information sharing

communal roost or colonies where animals can observe the foraging success of conspecifics and follow the successful ones to food sites

informational centers

behavior by an individual that increases the fitness of another individual while decreasing the fitness of the individual performing the act

altruism

altruistic behavior is costly to the altruist

but beneficial another conspecific

no alleles in common

0

identical

1

represents a full sibling

0.5

grandparent/ half-sibling shares what percentage of alleles with you

0.25

the probability that particular pair of relatives share the same alleles thru common descent can be calculated

coefficient of relatedness

first cousin shares what percentage of alleles with you?

0.125… 12.5%

how the coefficient of relatedness affected altruism- B/C >1/R

Hamilton’s Rule

the genetic relatedness of the recipient to the actor, often defined as the probability that a gene picked randomly from each at the same locus is identical by descent

R

the additional reproductive benefit gained by the recipient of the altruistic act

B

the reproductive cost to the individual of performing the act

C

refers to an animal’s poetntial ability to distinguish btwn close genetic kin and non-kin

Kin recognition

involves animals learning to recognize individuals with whom they were raised

familiarity

allows animals to identify kin even if they had never previously met

phenotype matching

involves an inherited allele or group of alleles that the individual can use to recognize others with the same allele

green beard effect

recognition alleles

mammalian example of greenbeard effect

wood mouse

organism acts in a manner that temporarily reduces its fitness while increasing another organism’s fitness, with the expectation that the other organism will act in a similar manner at a later time

reciprocal altruism

reciprocal altruism concept developed by

Trivers

reciprocal altruism requires

non-kin are involved

required for reciprocal altruism to occur

benefit of the act to the recipient must be greater than the cost of the act is to the actor

opportunity for repayment is likely to occur

altruist and recipient are able to recognize each other

species cooperation in mating- male to male

long tailed manakin

social system in which individuals contribute care to offspring that are not their own at the expense of their own reproduction

cooperative breeding

cooperative breeding is an example of

Kin Seelection

disadvantage of cooperative breeding

cost of expending energy towards raising the offspring of another individual

highest level of social organization in a hierarchical classification

eusociality

how do you qualify for reciprocal altruism?

benefit to receiver would have to be larger than the cost to donor

eusociality includes organizations with certain features

reproductive division of labor

cooperative care

overlapping generations

eusociality is what in nature?

rare

Evolution of eusociality

haplodiploidy

sharing defensible resource

according to inclusive fitness theory, euscociality may be easier for species like ants to evolve, due to their…, which facilitates the operation of kin selection

haplodiploidy