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BIOL359 Study Guide - Final Guide: Hadean, Assortative Mating, Phyletic Gradualism

Course Code
Jonathan Witt
Study Guide

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Kin Selection:
Direct Fitness: an individual’s contribution to the next generation directly through reproduction
Indirect Fitness: additional reproduction caused by relatives to the species resulting from actions
(assistance). The additional reproduction would not have been made without the assistance.
Kin Selection: is the selection for and spread of alleles that cause increased indirect fitness
Altruism is paradox to Darwin’s theory – it is highly unlikely that a species would undergo an action that
would in turn decrease its own fitness for the increase of another individuals fitness.
However selection would favour traits that decrease an individual’s personal fitness if it
increased the survival traits and fitness of close relatives
Co-efficient of relatedness (r) the probability that two homologous alleles are identical by decent;
involves an allele in the actor and allele in the recipient at the same locus
HAMILTONS RULE: the spread of an allele for altruistic behavior will occur if B r C > 0
The benefit to the recipient minus the cost to the actor is greater than 0
The benefits and costs are measured in terms of surviving offspring
Prairie Dogs:
Prairie dogs reside in coteries and were observed to have altruistic behavior
When both males and females spotted prey they would made a call to warn others in the
coteries that there was danger although it meant self sacrifice
At first they were unsure whether these calls were selfish (the action was done to increase their
own chance of survival or fitness) or whether they were altruistic (although the action reduced
their own survival rate and fitness decreased it increased the fitness of the recipient)
Studies showed that the proximity to kin related members affected the ways in which they
The closer the individual was to relatives, the more likely they were to call
White Fronted Bee Eaters
They are responsible for kin selection
It is very hard for all birds to find their own territories, raise offspring etc. so when young birds
are of age to rear offspring they will mostly stay in their own nest and assist other members in
raising their offspring instead
The birds will choose relatives that have the closest relation to them and help them raise their
own offspring (help parents raise siblings etc)
Most of the young birds die of starvation before leaving the nest but they have huge benefits to
their kin, by increasing the additional reproduction offspring.

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Wood Mice
Female wood mice are highly promiscuous and mate with multiple males
The males are in competition for their sperm to reach and fertilize the egg the fastest
Males with large testes is an adaptive trait for sperm competition
The sperm show their competitiveness they have hooks that hook onto other sperm heads or
flagella and form a train of thousands of individual cells that increase the speed of travel in
comparison to single sperm
When the sperm reaches the cell they must release from one another via an enzyme and a lot of
the sperm are destroyed in this process
This altruistic behavior is a form of kin selection as siblings are helping one another to reach the
Cannibalistic Tadpoles:
2 forms of tadpoles: omnivorous and cannibalistic
Omnivorous are plant eating however their morphs are capable of eating other tadpoles
Did a study to see whether cannibalistic toads would eat their omniviorous kin and found out
that 6/8 times they would not
These tadpoles display kin selection by choosing to eat non kin members over relatives
Did not affect their own fitness levels by eating other non kin members the cost of missing a
meal was less than the benefit
Conspecific: individuals belonging to the same species
Heterospecific: individuals belonging to different species
Congeneric: individuals from different species belonging to the same genus
Conspecific Nest Parasitism: Mal Altruistic behavior
Avoid paying the costs on behalf of non-kin individuals
American coots may sometimes place their own eggs in the nests of other coots (conspecific) so
that they can rear them
This will decrease the fitness of their own offspring because for every parasitic egg in their nest,
their own offspring have less chance of survival
Coots have ways of avoiding mal-altruism through noticing the specific color of their own eggs in
comparison to the parasitic one and also counting, they can see if there is an extra egg
The survival of a parasitic egg with increase the fitness of the parasitic kin

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Kin Selection and Eusociality:
Eusociality: individuals that have no direct contribution to the next generation (non reproducing) but
instead provide additional reproduction by means of assistance
Involves: cooperative family (brood) care
Individuals who do not reproduce
Overlap of generations between parents and offspring
Eusociality and Hymenoptra
Special species of insects that are haplodiploid
The males are haploid but the females are diploid
The genetic code is different and causes a special coefficient of relatedness the sisters are more
related to each other than they are to their offspring
Sister sister = ¾
Sister brother = ¼
Sister offspring = ½
The sisters will assist in helping the queen with child rearing rather than making their own
The queen has equal relatedness with both male and female; and wants to keep a 1:1 ratio
But the sisters want to make more sisters 3:1 ratio and will deliberately destroy male eggs
Many males will develop into soldiers to protect the colony and others are reproductive and will
mate with the queen
Hamilton’s rule may not be the reason behind eusociality but instead be caused by nesting
Parent Offspring Conflict
The more parental care given will increase the fitness of the offspring and their contribution to
the next generation
The relation of coefficient between:
o the parent and offspring is ½
o Siblings = ½
o Half siblings = ¼
o Yourself = 1
Offspring compete for the most parental care between their siblings
The cost benefit ratio is very low when offspring is small
When they get bigger the weaning conflict begins where parents will try to kick offspring out of
nest but they will attack and try to continue parental care
The cost increases because they now use more nutrients and it is expensive
Sublicide also occurs siblings attack/kill others to fight for more parental care
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