Behavioral Ecology and the Evolution of Altruism & Social Behavior Flashcards
Darwin Puzzle
Give 2 examples
A trait that appears to reduce the fitness of
individuals that posses it; these traits attract the attention of evolutionary biologists.
ex. Peacock, or Sterile Weaver Ants
Altruism
– Self-sacrifice-individual acting in a way
that reduces their own fitness while increasing the fitness of another
Kin Selection
a form of natural selection favoring behaviors that increase the survival or
reproduction of close relatives.
equation: use r(coefficient of relatedness) to calculate value
Indirect Fitness
measure of genetic success of an
altruistic individual
Cooperation
Reciprocity
the individual that are helped generally returns the favor eventually. Tit for Tat cooperation.
ex. grooming
problem: there are takers
By- Product Hypothesis
A non-adaptive trait that occurs as a byproduct of a mechanism that has adaptive consequences in other scenarios.
ex. Mexican Jays will care for non-related offspring that they are near because it still triggers a parental response
Direct Fitness
measure of reproductive success based on
individuals and their offspring
Inclusive Fitness Theory
Both direct and indirect fitness
Hamilton’s Rule
Brb > Crc
(B number of offspring gained due to donors’ help, rb relatedness of donor to offspring, C number of offspring not had due to helping, donors relation to their own offspring (0.5)
Why Eusocial works, Queen makes millions of copies of genes (large B)
Theory of descent with modification
Identify a distant ancestor state and then see what modifications have occurred over time
example:
* Hughes created phylogeny of bees, ants, and wasps
for 267 species
* ancestral species at the base were monogamous
* polyandry evolved independently among
different lineages
Why work with those you are not related to?
Living in groups you are more obvious to predators but you have more individuals watching out for predators.
Decreased chance of individually being targeted by predators.
Brown-necked Raven example of Cooperation
Hunt lizards in teams and share the food
Yearlings
Want to be a 10 or a 5, not an 8. They are unrelated helpers. Dominant yearlings have territory and have a dull male as a helper increasing both fitness. But a male that is not dominant but too blue (an 8) is not used as a helper and they have less success.
long-tailed manakin
unrelated males work together as wingmen. The beta wingman doesn’t reproduce that season but becomes the next in line.
Game Theory with Reciprocity
According to the prisoner dilemma
cooperation should not occur in non
relatives but cooperation does occur
because of tit-for-tat
Vampire Bats
show reciprocity. A bat needs blood every 3 days and they will share a blood meal with those who need it.
Pied Kingfishers 3 types of helper
Primary: help raise their brothers and sisters (deliver more food than secondary, lower chance of survival, 60% reproduction next year)
Secondary: assist at another unrelated
nest (91% reproduction next year)
Tertiary: not help and delay breeding until
next year
Seychelles warblers: Is fledging a function of the territory quality?
Young birds help only when they have little chance of making direct fitness gains by dispersing
