Bio 265 Lecture 11

Evolutionary stable strategy (ESS)

A phenotype that cannot be replaced by any other phenotype under specified conditions; 'A strategy that, if all the members of a population adopt it, then no mutant strategy could invade under the influence of natural selection.'

Game theory

A branch of mathematics concerned with the analysis of strategies for dealing with competitive situations where the outcome of a participant's choice of action depends critically on the actions of other participants; often explained using the hawks vs doves metaphor.

Assessor strategy

Escalates a conflict if opponent is judged to be smaller or weaker; retreats if opponent is larger or stronger.

Honest signal

Information that is a true indicator of the underlying quality of the sender and is useful to the receiver.

Altruism

An activity that enhances the fitness of other individuals, but lowers the fitness of the actor.

Reciprocation

A behavior whereby an 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.

Manipulation

Donor dispenses aid because the donor is being manipulated by the recipient.

Individual advantage

Cooperative behavior may evolve because it is advantageous to the individual.

Reciprocal altruism

A behaviour whereby an 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.

Prisoner's dilemma

A thought experiment that challenges two completely rational agents to a dilemma: they can cooperate with their partner for mutual benefit or betray their partner (i.e., defect) for individual reward.

Direct fitness

The effect of fitness of an allele on the individual that has it.

Indirect fitness

The effect of fitness of an allele on other individuals that share the allele.

Inclusive fitness

The effect of fitness of an allele on both the individual that has it and the fitness of other individuals that share the allele; includes both direct and indirect fitness.

Hamilton's Rule

An altruistic trait can increase in frequency if the benefit (b) received by the donor's relatives, weighted by their relationship (r) to the donor, exceeds the cost (c) of the trait to the donor's fitness; altruism spreads if rb > c.

Eusociality

The highest level of organization of animal sociality, is defined by the following characteristics: (1) Cooperative brood care, (2) overlapping generations within a colony of adults, and (3) a division of labor into reproductive and non-reproductive groups.

Coevolution

When two or more species reciprocally affect each other's evolution through the process of natural selection.

Red Queen hypothesis

States that species must continually evolve and adapt in order to survive because other associated species are also ever-evolving.