THE EVOLUTION OF KIN SELECTION

By Aditya KuroodiPeriod 5

Key Vocab Fitness of an Animal: How many offspring

it has, which leads to number of genes present

Individual Fitness: Number of own offspring and genes passed on

Inclusive Fitness: Ind. Fit. + Number of identical offspring and genes passed on

Altruism: Selfless concern for the welfare of others

Kin Selection Kin selection is a theory

about the evolution(persistence) of altruism

When animal risks itself to help relatives survive

Since they’re related, some of that animal’s genes still get passed on

Altruistic animals still persist because their genes are present in the relatives they save

Kin Selection Natural selection technically

shouldn’t allow for evolution of altruistic animals

But kin selection theory proved that it could

Kin selection says that relatives also might contain the “altruistic gene”

Thus, offspring still receive gene, and altruism continues

Altruism is preferred on a group basis, not an individual one, unless it has to do with kin

Fire Ants All ants are Euosocial Have sterile workers and

Queen to reproduce Because they are

haplodiploid Normally, no one would be

sterile Sisters share 75% genes w/

each other More effective to help

Queen make sisters than have own offspring

This is kin selection at its finest

Alarm Calls in Squirrels Many squirrels have alarm

calls when they sense danger

The squirrel that makes the call puts itself in risk, but saves others around it

The closest animals around it are most probably kin

The kin survive, and the ability to make an alarm call persists

Also, scientists have discovered that some squirrels change the call if relatives aren’t around

Cool Squirrels

Cool Squirrels

Scientists The idea of kin selection

was pondered at first by Darwin

“a tribe including many members who...were always ready to give aid to each other and sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection” (p.166)

Darwin thought altruism was caused by group selection

Evidence against Group Selection

The idea of group selection was quickly discarded

Idea of “free riders” cashing in on groups of altruists (Dawkins)

They would have huge advantage and take over; altruism would be run over by selfishness

This was from works of John Maynard Smith, Richard Dawkins, W.D. Hamilton and G.C. Williams

W.D. Hamilton Main man in the world of kin

selection Used inclusive fitness to

support theory Inspired by Haldane, and

R.A. Fisher His rule RB>C explains when

altruism would continue R is how related the animals

is (brother vs cousin, etc) B is benefit to

group(Inclusive fitness) C is cost to individual ( Loss

of Individual Fitness)

Contribution of Kin Selection Theory

Kin selection puts a new spin on the classic ideas of natural selection Darwin imposed

It differs from the view that evolution and life is on a strict individual basis

Relationships in animals plays a major role in evolution

There could be an “Altruistic Gene” that is passed on or not

Timeline

Works Cited http://plato.stanford.edu/entries/altruism-

biological/

http://taumoda.com/web/PD/library/kin.html

http://es.rice.edu/projects/Bios321/eusocial.insect.html

http://www.animalbehavioronline.com/haplodiploidy.html

www.Wikipedia.com