envs lecture 12 Flashcards
1
Q
what is found at all levels of all biological organization
A
cooperation and conflict
2
Q
examples of cooperation
A
seemingly altruistic behavior to gather food, raise offspring, defend resources like food/nest
3
Q
example of conflict
A
infanticide, siblicide
4
Q
what’s a useful way to think about social interactions among individuals
A
start w/ a table of the effects on actor and recipient
5
Q
how are the effects on the actor and recipient classified
A
w/ respect to how they effect the fitnesses of the two individuals (increase in fitness or decrease in fitness)
6
Q
what does mutualistic behavior do (in terms of fitness)
A
increases fitness for both actor and recipient
7
Q
what is mutualistic behavior a form of
A
cooperation
8
Q
what is altruistic behavior
A
negative/costly effect on actor but benefits the recipient by increasing fitness
9
Q
what is altruistic behavior a form of
A
cooperation
10
Q
what is selfish behavior
A
benefits actor by increasing fitness, but negative effect on recipient by decreasing fitness
11
Q
what is selfish behavior a form of
A
conflict
12
Q
what is spiteful behavior
A
both a negative effect on actor and recipient; fitness decreases for both of them
13
Q
what is spiteful behavior a form of
A
conflict
14
Q
what is cheating
A
individuals cheat when they can benefit from actions of others without providing reciprocal benefits in return
15
Q
describe cheating vs. cooperation
A
if cheating has high fitness in population of cooperators, then mutation that causes cheating will spread and cooperation will collapse
16
Q
so what is big question/puzzle
A
how does natural selection favor cooperative behavior when cheating is a possibility
17
Q
give example of cheating in unicellular slime mold
A
when food is scarce, individual cells aggregate intoo a slug that can move around, slug –> mushroom like structure cells form spores that disperse while those in stalk die w/o reproducing
18
Q
basically what happens to cells in stalk in unicellular slime mold
A
sacrifice themselves for benefit of cells that make spore
19
Q
what gene allows slime mold cells to cheat
A
chtA mutation
20
Q
what does chtA mutation cause
A
them to behave selfishly and avoid contributing to the stalk
21
Q
what happens in a mix of wild-type cells and chtA cells
A
mutant cells become concentrated in cap and are more likely to form reproductive spores
22
Q
what happened to frequency of selfish mutant allele over 11 cycles
A
frequency increase
23
Q
what happens to cheating mutation, and what is question
A
cheating mutation doesn’t go to fixation, why don’t we see end of cooperative behavior and fixation of cheating mutation in population?
24
Q
what did biologists think until 1960s
A
evolution favored traits for group selection (that benefited population or species)
25
but what do we know about group selection
group selection is uncommon
26
why is group selection uncommon
b/c of strong fitness advantage of cheating
27
so why hasn't cheating mutation spread to fixation?
colonies that have high relatedness evolve resistance to cheaters
28
describe competition experiment w/ slime mold
compared evolved cheaters (non-fruiters) and both their ancestors and evolved fruiters (wild-type) which are both cooperative.
evolved fruiters are fruiters that have evolved in presence of cheaters
if nonfruiters cheat the ancestor as expected, resistance to cheating will be established. if they cheat the evolved fruiters less or not at all, shows that resistance to cheating has evolved in experiment.
if nonfruiters cheat ancestor and evolved fruiters equally, we would expect to see same number of nonfruiters in study for both mixtures
29
describe results of competition experiment
evolved fruiter evolves resistance to cheating before cheating sweeps thru population and multicellularity is lost
colonies are able to evolve resistance against cheating.
when colonies closely related, stronger resistance
30
what conditions can cooperation or altruism evolve
mutualism, reciprocity (form of mutualism), kin selection
31
what is mutualism
cooperation among unrelated individuals where both actor and recipient benefit
32
what is reciprocity
another form of mutualism; individuals reciprocally increase each other's fitness
33
what is kin selection
altruism among related individuals
34
give example of cooperation among non-kin (unrelated individuals)
flocking behavior
35
what does flocking behavior do
lowers risk of predation among individuals in a group --> less likely predator will focus on individual
36
what is flocking behavior
selfish herd effect
37
what does selfish herd effect do
lowers risk of predation among individuals in groups
38
what is shared vigilance
groups lookout for predators together; more time can be devoted to grazing in larger herd
39
give another example of cooperation among non-kin
starlings flock in response to predator --> selfish herd effect
40
what is the point of selfish herd effect
safety in numbers
41
another example of cooperation among non-kin
wolves & cooperative predators (lions, hyenas) hunt cooperatively in packs to take down prey a single individual couldn't take down
42
what does hunting large prey require
cooperative behavior
43
what do some systems have
delayed benefits
44
what are delayed benefits
helping at the nest where more than a pair takes care of young at a nest; sometimes helpers are kin, sometimes they aren't
45
what do manakin leks do
cooperation among non-kin; delayed benefits
46
describe delayed benefits in manakin leks
two males court female. female goes w/ dominant males. when dominant male dies, subordinate male takes over
47
what do baboons do
reciprocity
48
what did robert trivers suggest
reciprocity; cooperation can involve when one individual provides fitness benefit to another, as long as 2nd individual returns favor
49
what is reciprocity
individuals provide reciprocal favors to one another that both provide fitness benefits
50
when can cooperation evolve
when individuals provide reciprocal favors to one another that both provide fitness benefits
51
what can favor cooperative behavior
repeated interaction
52
what does cooperation/reciprocity require
requires repeated interactions and ability to recognize individuals
53
describe reciprocity in yellow baboons
offspring of female yellow baboons that have strong bond w/ females other than mom have better survival
54
when can cooperation be enhanced
when selfish individuals are punished
55
where is reciprocity common
mammals, including humans
56
what can mathematical models predict
conditions under which reciprocity is favored by natural selection
57
what are evolutionary stable strategies (ESS)
mathematical models can predict conditions under which reciprocity is favored by nat selection
58
what did john maynard smith do
evo biologist; introduced game theory from econ to study evolution of social behavior
59
what is famous scenario
prisoner's dilemma
60
prisoner's dilemma
two individuals do better by acting selfishly, but if they both act selfishly they do worse than if they cooperate
61
what does game theory show about selfishness
selfish behavior is favored if individuals interact only once, but repeated interactions can favor cooperation
62
when is selfish behavior favored
if individuals interact only once
63
when is cooperation favored
repeated interactions
64
describe prisoner's dilemma
2 thieve commit crime, caught and isolated.
if they both defect & incriminate the other, each get 2 years in prison.
if both remain silent/cooperate, each get one year
if one defects and other doesn't, one goes free other gets 3 years.
65
what is best strategy in prisoner's dilemma
only one defects
66
what is worst strategy in prisoner's dilemma
both defect
67
what happens if these individuals interact repeatedly
strategy changes; gang members don't rat each other out
68
what is one kind of behavior w/ high fitness in interactions w/ other individuals
tit for tat
69
describe this 'tit for tat' behavior
cooperate on first interaction, do whatever the other did on the previous round
70
what is this 'tit for tat' behavior an example of
situation where individuals interact repeatedly
71
what is cooperation
activity/behavior that provides a benefit to other individuals and to the actor
72
what is altruism
involves behavior that enhances fitness of other individuals, but LOWERS fitness of the actor
73
how can we explain altruism (in terms of what)
kin selection
74
what is kin selection
helping out close relatives to increase their fitness
75
when does kin selection favor altruism
only if individuals more likely to help kin than non-kin
76
how do species recognize kin
cues, like distinctive calls or odors
77
what is Hamilton's rule
rB > C
78
what is r
relatedness
79
what is B
fitness benefit to recipient
80
what is C
fitness cost to actor
81
what does Hamilton's rule say
relatedness times fitness benefit to the recipient MUST be greater than the fitness cost to the actor
82
when is Hamilton's rule met
when altruistic behavior can evolve
83
what did JBS Haldane say
when asked if he would give his life to save a drowning brother, he said "no, but I would to save two brothers or eight cousins"
84
why did JBS Haldane say that
relatedness; we share 50% genes w/ siblings and 25% w/ cousins
85
what is better than us reproducing ourselves
saving two siblings or 8 cousins, cuz our offspring are only related to us by 50%
86
what was Haldane referring to
inclusive fitness
87
how much of genes do parents and offspring share
50%
88
how much of genes do cousins share
25%
89
who came up w/ idea of inclusive fitness
JBS Haldane
90
what is inclusive fitness
the relative number of an individual's alleles that are passed onto future generations, both directly AND indirectly
91
how are individual's alleles passed on to future generations directly
as a result of an individual's own reproductive success
92
how are an individual's alleles passed on to future gens indirectly
when the individual helps relatives who also carry a proportion of their alleles
93
what is this component due to indirect called
kin selection
94
what was the idea behind inclusive fitness
relative # of someone's alleles passed down are a combo of direct fitness and indirect fitness
95
what does W.D. Hamilton's rule say
selection favors genes for altruism if rB-C>0; ( relatedness of actor to the beneficiary * benefit in fraction of additional offspring resulting from helping - minus cost (in loss of offspring) to the actor from helping is greater than 0)
96
what is W.D. Hamilton's rule
rB-C > 0
97
what does W.D. Hamilton's rule say
altruism favored by natural selection IF
relatedness of actor to beneficiary x benefit to recipient (in fraction of additional offspring resulting from helping) - cost to altruist (cost in loss of offspring) is greater than 0
98
what can we simplify this equation to
r > C/B
99
what does r > C/B mean
genes for altruism more likely to spread when there's genetic basis for behavior, benefits to recipient are great, cost to actor is low, and participants closely related
100
when are genes for altruism more likely to spread
genetic basis for behavior, benefits to recipient are great, cost to actor is low, participants closely related
101
talk about test of hamilton's rule in pied-kingfishers
communal breeders that tunnel into mud banks. sex ratio biased towards males. have helpers at the nest; 2 types, primary and secondary helpers
primary helpers forgo mating for the first year, stay at natal nest to help raise siblings.
secondary helpers help unrelated pairs
delayers do nothing and wait until next year
60% of primary helpers breed the following year
91% of secondary helpers breed the following year
33% of delayers breed the following year
males do more helping
related individuals do more helping
secondary helpers do better than all the others the following year
102
what are primary helpers
forego mating for first year and stay at natal nest to help raise siblings
103
what are secondary helpers
help unrelated pairs
104
what are delayers
do nothing and wait until next year
105
what are results of kingfisher test
inclusive fitness is highest for a primary helper, high secondary helper, low for a delayer
106
does it pay for secondary helper to assist non-relatives
yup
107
another example of altruism in wild turkeys
wild turkeys display in pairs of dominant and subordinate brothers. dominant male has higher fitness.
presence of subordinate increases reproductive success of dominant male.
subordinate doesn't mate, so cost of helping brother is cost of not displaying solo
108
what was finding in turkey experiment
there is an inclusive fitness advantage to going solo; or advantage to this altruistic behavior of subordinate male
109
what is most extreme cause of altruism
eusociality
110
what is eusociality
colonies of individuals where most colony members do not reproduce and a few do
111
what animals are in eusociality
naked mole rats, termites, ants, wasps
112
what is eusociality
living in a cooperative group where one female and several males are reproductively active, nonbreeding individuals care for young, protect, provide for group
113
what's up w/ naked mole rats
only known eusocial mammals
114
what are naked mole rats
diploid
115
why are naked mole rats in a eusocial structure
cuz of harsh environment they live in
116
what are famous examples of eusociality in insects
ants, bees, wasps, termites
117
describe eusociality in termites
queen termite is attended by small, sterile workers and large-headed sterile soldiers
118
what do ants do
engorged w/ nectar, hang from roof of nest's ladder. they regurgitate nectar to worker nestmates
119
what do wasps do
colonial nests
120
what is involved in evolution of eusocial insects
kin selection likely involved
121
what explains cooperation and conflict and why some individuals forgo reproduction and help their relatives in the haplodiploid system of relatedness
kin selection
122
what does kin selection explain
in haplodiploid system of relatedness, kin selection explains cooperation and conflict and why some individuals forgo reproduction and help their relatives
123
how are organisms related in diploids
offspring and parents are 50% related, siblings are 50% related
124
what happens in haplodiploid systems
fertilized eggs are diploid, develop into females. unfertilized eggs are haploid, develop into males
125
what happen to fertilized eggs in haplodiploid system
develop into females
126
what happens to unfertilized eggs in haplodiploid system
develop into males
127
so is the coefficient of relatedness the same in diploid system as it is in haplodiploid system
nope
128
describe coefficient of relatedness in haplodiploid system
females are more closely related to sisters, r = 75%, than she is to offspring, 50%, and less closely related to brothers, r = 25%
129
who are females most closely related to in haplodiploid system
her sisters, then offspring, then brothers
130
what do social interactions often involve
conflict
131
what must males and females do in order to produce offspring
cooperate
132
but what else is pervasive between mates
conflict
133
what is present between mates
conflict and cooperation
134
what happens as effort by one parent increases
the other's decreases
135
what happens if you plot effort of male and female
intersection shows ESS; will evolve to ESS no mater what initial conditions are
136
can conditions occur where optimal curves for sexes don't intersect
yup; ESS is care only by female (scorpion) or male (poison dart frog)
137
what else can conflict include
siblicide and infanticide
138
who does siblicide
brown booby, owls, hawks, herons, pelicans
139
when does siblicide happen
when food is limited
140
does siblicide happen when food is plentiful
no, young don't compete and parents raise a full nest
141
who does infanticide
hyenas and lions
142
when does infanticide occur
social cooperative mammals; males take over a harem/group of females, kill young so females can go into heat and reproduce
143
what does infanticide do
eliminates alleles of competitors, allows females to become fertile and sexually receptive
144
where does infanticide occur
social groups w/ more females than males
145
can some species kill their own offspring
yup
146
when do some species kill their own offspring
social situations where offspring survival would decrease even more if all offspring were allowed to compete w/ each other
147
what is one last major form of conflict
cannibalism
148
who does cannibalism
tiger salamanders
149
when do tiger salamanders do cannibalism
when at high population density
150
what kind of balance occurs in many biological systems
balance b/w conflict and cooperation
151
what can males and females and parents and offspring have
aligned or conflicting interests
152
what do ESS do
can predict which phenotype or balance of phenotypes is optimal
153
what does altruism do
benefits other individuals, reduces individual fitness of the actor
154
what does cooperative behavior do
increase individual fitness of both donor and recipient
155
what does inclusive fitness explain
evolution of altruism
156
what does individual selection explain
situations; behaviors
157
what does kin selection explain
evolution of altruistic behaviors
