AltruismBy: Ashley Stiles, Kelsey Detels, and Katie

Pearce

What is Altruism?

Altruism: behavior that reduces an individual’s fitness while increasing the fitness of others in the population

•“selfless” behavior•Belding’s ground squirrel - loud

call

Altruism cont.

• Often evident in colonies

• (E.g.) workers in a honeybee hive will sting an intruder, and will die doing so

How does altruistic behavior evolve?

• How can organism pass on genes if it is killing itself?

• Inclusive fitness: the total effect an individual has on multiplying its genes by producing its own offspring and by providing aid that enables close relatives to increase the production of their offspring o Parents sacrificing for young=maximizing survival of

their own geneso Helping close relatives reproduce

Kin Selection

Definition: a phenomenon of inclusive fitness, used to explain altruistic behavior between related individuals

•Genes for altruism may be passed on if the individuals that benefit from selfless acts are themselves carrying those genes

Reciprocal Altruism

• In animal behavior, a selfless act is repaid at a later time by the beneficiary or by another member of the beneficiary’s social system