Ben Hatchwell's lectures Flashcards
W. D. Hamilton’s … … theory:
“The social behaviour of a species evolves in such a way that in each distinct behaviour-evoking situation the individual will seem to value his neighbour’s fitness against his own according to the … of relationship appropriate to that situation” - 1964
inclusive fitness, coefficients
The essence of inclusive fitness theory is that individuals can gain fitness in two ways:
- by … themselves (direct fitness)
- by interacting with …. (indirect fitness)
reproducing, relatives (because of shared genetic interest)
Hamilton’s rule: A behaviour will be favoured if … < …
c, br
c =
cost to actor of social behaviour
b =
benefit to recipient of social behaviour
r =
(coefficient of) genetic relatedness between actor and recipient
- not simply shared genetic material, but sharing of genes that are identical by descent (probability of sharing the same allele)
Between parent and offspring r = …
Between siblings r = …
Between uncles and nephews r = …
Between half siblings r = …
Between cousins r = …
0.5, 0.5, 0.25, 0.25, 0.125
Look at slide 11:35 lecture 9
stuff about when c and b are positive/negative
Look at cannibalism slide in phone folder
nice
Tiger salamanders are more likely to develop into cannibalistic morphs if they are in groups containing:
- … conspecifics
- variation in … size
- mostly … individuals - most relevant part to Hamilton’s rule
many (as not even many individuals around to eat and more likely to be related), larval (as females lay many eggs in one go, relatedness is less likely if larvae vary a lot in size as it is likely they have come from different females), unrelated
Game theory: an individual’s behavioural response should depend on the…
behaviour of the individuals around them in the population
An e.g. of game theory is shown in … …: if others are producing sons, it’s better to produce … as this will maximise the number of …-…. If the … … is even, it’s better to produce an even ratio of sons and daughters. This is called an Evolutionary … … (ESS), as it cannot be invaded by a better strategy - Nash equilibrium
sex ratios, daughters, grand-offspring, sex ratio, stable strategy
Hymenoptera females can choose the sex of their offspring as they are …. If they lay a fertilised egg it develops into a …, if they lay an unfertilised egg it will develop into a ….
haplodiploid, female, male
At an even sex ratio sons and daughters give equal … returns. The even sex ration is an ESS. If there is an excess of females in a population then the number of grand-offspring gained per … is greater than the number of grand-offspring gained per …, so a female should over-produce …, driving the population towards…
fitness, son, daughter, sons, a 1:1 sex ratio
- and vice versa
John …-… was a mathematical biologist who was instrumental in introducing the idea of game theory into biology.
Maynard-Smith
The two pairwise contests we will look at are:
- The Hawk-Dove game
- The Hawk-Dove-Bourgeois Game
The Hawk-Dove game imagines that each individual in a population plays one of two strategies. Animals compete for resources in pairs. A Hawk never … and always …, and a dove will …, never … and … if an opponent fights.
share, fights, share, fights, retreats
In this model we must assign fitness payoffs:
v = …
c = …
the value of a resource that is being competed for
the cost of fighting to the loser
We can then put these into a payoff …
matrix
Watch lecture 9 32:00 - 33:55
about hawk-dove matrix
When a hawk comes across a hawk what is the payoff?
(v-c)/2
When a hawk comes across a dove what is the payoff?
v
When a dove comes across a hawk what is the payoff?
0
When a dove comes across a dove what is the payoff?
v/2