Anthropology 1Honors Transfer Level

Fundamental Concepts in Sociobiology

Kin SelectionConcept formalized by W.D.

Hamilton in 1963-4. Reconciles altruism with Darwinian selection by pointing to the fact that close relatives share large numbers of genes in common. The theory predicts therefore that you would more likely try to pull a full sibling from a hungry polar bear than a second cousin or mother-in-law.

Kin RecognitionA necessary prerequisite of kin

selection. For kin recognition to exist, animals must possess the means to distinguish kin from non-kin. Mechanisms include imprinting and phenotype matching.

Reciprocal AltruismProposed by Robert Trivers in

1971. Explains that cooperative behavior may have evolved from an organism realizing that if it temporarly lowers its fitness by helping another organism, its fitness will be raised when that organism reciprocates.

Preconditions for Reciprocal Altruism

For reciprocal altruism to have come into existence, there are two necessary preconditions:

1. There has to be way of identifying cheaters/deception.

2. Opportunities for altruistic behavior must be frequent.

Inclusive FitnessAnother mechanism proposed by W.D.

Hamilton to explain altruism. He predicted that organisms would behave in ways that would maximize their inclusive fitness.

If an organism displays an altruistic behavior, one that causes the organism to be protective of close relatives and their offspring, then the gene underlying this behavior will increase in the population as it would be shared with these relatives.

The theory of inclusive fitness also proposes that there will be ways for one organism to recognize the altruistic acts of another non-related organism, and to support that behavior.