Exam 2 Flashcards
1
Q
Reciprocity
A
- Also known as reciprocal altruism
- in which a helpful action is repaid at a later date by the recipient of assistance
- An exchange of altruistic acts
2
Q
Genetic Constraints Model
A
- Monogamous species often share traits
-> High male to female associations
-> Bi-parental care offspring
-> High aggression towards strangers
-> High corticosterone and vasopressin
-> Low testosterone
Ex: Prairie voles and meadow voles
3
Q
Benefits of Group Living
A
- Increased protection
- Foraging Efficiency
- information center
- > where to find food
- better prey capture
- defending renewable resources
- > food - Energetic Efficiency
- conservation of heat
- locomotory efficiency
- > ex with lobsters walking in single file - Reproductive Efficiency
- finding a mate
- increased offspring survival
- > rearing close kin
- > reciprocal nursing
- > communal defense
ex: female lion protection offspring from males
4
Q
Asexual reproduction - GYNOGENESIS
A
- occurs in the amazon molly fish
- all female reproduction
- Female produces daughters
- daughters produce their own daughters that are genetic clones of one another
- Males are in the tree because females have to get egg stimulated by a sperm cell to have first cell division occur
- > Trick males of other species to mate with them to start their cell division of their eggs but do not incorporate the males DNA
- ALL FEMALE RACE
5
Q
H1 Female Defense Polygyny
A
- males defend multiple females by preventing access by other males
- > keep them in close proximity and in groups, then defends the entire group
- effective only if females remain together and have reproductive synchrony
- > need to be receptive at the same time
6
Q
What is the purpose of a Lek?
A
- a lek is an aggregation of males gathered to engage in competitive displays
- > involves male competition and female choice
- > formed before or during the breeding season
- males compete directly for matings by displaying for multiple females
- location can affect Lek and mating success
- > Lek’s do not stay in the same location
- -> movement of lek’s suggest that females come for the males rather than the resources they need
- the most successful male gets the majority of the matings
- > mating success decreases exponentially for remaining males
7
Q
Mutualism
A
- cooperation between species.
8
Q
Why do females invest more in offspring care than do males?
A
- Males are less certain about their paternity to an offspring, whereas females are certain the offspring is theirs
- > males do not want to expend energy on offspring that might not be theirs
- Males have more to gain by mating with multiple mates than females
- > so they will skip paternal care and resources to mate with more females
- Paternity assurance in males vs females
9
Q
Polygyny
A
- one male mating with many females
- most common method in species
- when polygyny decreases, male parental care increases
- > males could be competing for the females themselves, or resources the females need
- can also gather near a lek, where they do not defend females or the territory, but instead they gather at a place where females can view multiple males
- can occur under these circumstances:
1. Female defense Polygyny
2. Resource Defense Polygyny
3. Lek
10
Q
Why is social monogamy not a good predictor of genetic monogamy?
A
- Because of Extra Pair Copulations (EPCs)
11
Q
Kin Recognition: Environmental
A
- “Nest mate effect”
- Altruism directed toward individuals that were raised together
- Does not require any genetic similarity
Ex: Beldings ground squirrels accept nest mates regardless of relatedness
12
Q
Measuring Relatedness
A
- coefficient of relatedness
- parent to offspring is r=.5
- half siblings are r= (.5)^2 = .25
- full fiblings are r = (.5)^2 + (.5)^2 = .5
- consider each relatedness as .5 and each arrow is the exponent
- draw arrows from one sibling to another
- If take different routes to get to the sibling must add a + sign
13
Q
Spite
A
- A behavior which is costly to both the actor and to the recipient where cost and benefit are defined on the basis of the lifetime direct fitness consequences of a behavior.
- Favored by selection if you If you harm a recipient that is less related to you than others in the population
- > it benefits those that remain
- A behavior which is costly to both the actor and the recipient
14
Q
Inclusive Fitness
A
- the sum of an individual’s direct and indirect fitness
- The effect of one individual’s actions on everybody’s number of offspring weighted by the relatedness.
- inclusive fitness (individual i) = direct fitness (individual i) + fitness benefit (individual j) x relatedness of i to j
- wi= ai + S bj x rij
ai = effect of i’s behavior on i’s fitness
bj= effect of i’s behavior on the fitness of relative j
rij= coefficient of relatedness of i to j
15
Q
Sexual Conflict
A
- Sex Role Reversal
- females compete for access to males and are more choosy
- males perform parental care
- when males can not mate with many females, females compete for the best male
- females with exaggerated traits indicate the best quality to males - Extra pair copulations
- Antagonistic coevolution
- Male-male sperm competition
- males compete to fertilize eggs
- multiple mechanisms
- Coolidge effect - Cryptic female choice
16
Q
Kin selection
A
- process by which traits are favored because of their beneficial effects on the fitness of relatives
- Altruism favored when a related recipient is benefited much more than the actor pays in cost (hamilton’s rule)
- rB – C > 0
- Provisioning of siblings
17
Q
How can you distinguish whether a female is choosing a male for good resources, good genes, or attractive sons?
A
- good resources
- > males that guard good resources are chosen by females, but if a female does not require that specific resource it can be ruled out
- good genes
- > males with red coloration have fewer parasites and more body fat, therefore could be favored by females
- > if we find this is not the case with red coloration, then rule out good genes
- > same with Bright males, MHC alleles and asymmetrical body patterns
- attractive sons
- > once ruled out good resources and good genes, then find a correlation between female choosiness and sons genes
- > sons inherit the preferred trait
18
Q
PAPER: “Kin Recognition” Pfennig and Sherman 1995
A
- explores the mechanisms of how kin might recognize each other
- Extension of the kin selection model was used to explain how sterile workers in the eusocial insects might evolve even though they cannot pass on their own genes
- the traditional view held
that natural selection favored individuals that produced the greatest number of offspring - Hamilton said that natural selection must favor organisms that help any relative, because by doing so they increase their total genetic representation
-> inclusive fitness - A second explanation, optimal outbreeding theory
-> Optimal outbreeding theory
explains why many organisms prefer to mate with those to whom they are neither too closely nor too distantly related - kin recognition and cannibalism
19
Q
What resources do females need that males can defend?
A
- Some resources male will exchange for mating include
- > Defensive cavities, Nesting sites, Foraging patches, and Territories
20
Q
What are the benefits of extra-pair copulations for females? what are the costs?
A
- Benefits
- favored if the costs are low and occurs when females have the highest chance of fertilization without losing parental care
- extra pair mate has better gene indicators such as longer, brighter, or larger traits
- causes more sexual dimorphism, than if no EPC
- allows female to mate with a higher quality male if she has already mated with a low quality male - Costs
- increased chance for disease, difficult to fight off different type of sperm cells
- decreased life expectancy (Drosophila- fruit flies example)
- if the male was helping to provide parental care, the male may abandon nest and not care for the offspring if he thinks he is not the father
21
Q
Group living Predator Defense advantages and disadvantages
A
- Advantages:
- dilution effect
- selfish herd
- confusion effect
- communal defense
- many eyes effect (group detection - Disadvantages
- increased conspicuousness
22
Q
Bateman’s principle
A
- The idea that, since eggs require greater energy to produce than sperm
- females should be choosier sex and this should result in greater variance in the reproductive success of males.
23
Q
Environmental kin recognition may lead to thinking non-kin are really kin. How does this . mechanism lead to nest parasitism?
A
- this is because this type of kin recognition does not require any genetic similarity, unlike the other 3 mechanisms
- nest parasitism is laying eggs in the nests of other species
- parents will feed any found offspring in their nest because they think its their kin
- > allows for cheaters to fool females into raising an individual that is not their own
24
Q
Group living Foraging Efficiency advantages and disadvantages
A
- Advantages
- information center
- better prey capture
- defending renewable resources - Disadvantages
- interference competition
- resource limitation
25
Q
PAPER: “ The prairie vole: an emerging model organism for understanding the social
brain” McGraw and Young 2010
A
- demonstrating how monogamy may be favored by specific genes
- prairie voles will likely maintain their current trajectory becoming an unprecedented model
organism for basic and translational research focusing
on the biology of the social brain. - this model organism has exceptional potential to begin to guide us in understanding the genetic pathways and neurobiological systems that regulate aspects of sociality that are often impaired in these patients.
- a model organism for
identifying mechanisms regulating complex social behaviors, which will directly impact the understanding of our own sociality and inform future treatment of psychiatric
disorders of the social domain.
26
Q
Antagonistic Coevolution
A
- evolutionary “arms race” between male traits and female traits
- traits that increase fitness in one sex will decrease the fitness in the other sex
- Sexual antagonistic co-evolution is the relationship between males and females where sexual morphology changes over time to counteract the opposite’s sex to achieve the maximum reproductive success.
27
Q
how do animals recognize kin?
A
- three primary mechanisms
1. Recognition Alleles - Greenbeard affect
- altruism directed only towards individuals with the same altruism gene
2. Genetic - armpit effect
- altruism directed only towards individuals that share many genes
- many times, similar genes = similar smell
- > why it is called the armpit effect
3. Environmental - Nest mate effect
- altruism directed towards individuals that were raised together
- do not require any genetic similarity
28
Q
Direct Fitness
A
- the genes contributed to the next generation by personal reproduction
- The component of fitness gained through the impact of an individual’s behavior on the production of offspring.
29
Q
What is an evolutionary stable strategy(ESS) and what does it have to do with games theory?
A
- ESS is a genetically distinctive set of rules for behavior that when adopted by a certain proportion of the population cannot be replaced by any alternative strategy
- an evolutionary stable strategy is Tit-for-Tat (TFT)
- > if you are playing the game with the same person over and over
- > if play a new opponent the ESS is ALLD
- ESS is the theoretical solution to a games theory problem!
30
Q
Natural Selection
A
- deals with genetic differences
- it also deals with adaptability to the environment and chances of survival
31
Q
Prisoner’s Dilemma Model: assumptions of PAVLOV
A
- Better vs. ALLC
- Worse vs. ALLD
- Better if occasional mistakes are made
- PAVLOV does not lead to an excess in cooperation or defection like TFT does
32
Q
Altruism
A
- A behavior which is costly to the actor and beneficial to the recipient where cost and benefit are defined on the basis of the lifetime direct fitness consequences of a behavior
- Helpful behavior that raises the recipient’s direct fitness while lowering the actor’s direct fitness.
33
Q
Kin Discrimination
A
- An individual different reaction toward others based on the degree to which they are genetically related
- offspring provisioning
- avoiding cannibalism
- avoid inbreeding
34
Q
Good Genes in Female mate choice
A
- A model of sexual selection in which females choose to mate with males that possess traits that are indicative of good health and vigor
- > that is, traits that are best suited to their particular environment.
- females choose males based on superior genetic quality or superior genetic compatibility
- high quality males are:
- > resistant to parasites
- > better forager
- > higher survival
- genetic compatible males
- > decreased inbreeding cost
- > decreased autoimmune cost
- handicap principle
- females prefer symmetry in males
35
Q
Secondary sex characteristics
A
- Morphological traits that differ among the sexes that usually do not develop until sexual maturity
- Most secondary sex characteristics are assumed to have been favored by sexual selection.
36
Q
Intersexual selection
A
- Traits are selected that favor one sex’s ability to attract and mate with the other sex. - Female choice of males is much more common than male choice of females.
- > females select more agreeable partners based on the males ability to excite, or charm them
37
Q
Describe Four different routes to achieve cooperation
A
- Kin selection
- helping individuals that share the same gene copies - By-product Benefits
- cooperation arises as a by-product of an otherwise selfish act - Reciprocity
- helping another individual because that individual will then help them back - Enforcement
- rewarding cooperation and, or punishing free riding
38
Q
Alternative mating strategy
A
- Any variant of one sex that differs in morphology and/or behavior that has some reproductive success against the predominant mating strategy
39
Q
When is altruism ever favored by natural selection? When should individuals discriminate kin from non-kin?
A
- When the benefit of helping close kin is greater than the cost to one’s self
- altruism is selfish
- When performing altruistic behaviors.
40
Q
H3 More Resources/Material Benefits Hypothesis Polyandry
A
- Increased material benefits due to nuptial gifts or extensive male parental care
- offsets the cost of mating with more than one male
- An explanation for why females of some species might mate with several males per breeding cycle with benefits coming to polyandrous females because they gain access to material benefits controlled by several males
41
Q
Parental care model
A
- Mating system is determined by the distribution of parental care among the sexes
- male only parental care suggests polyandry
- biparental care suggests monogamy
- female only parental care suggest polygyny
- does not work well with mammals because there is not an opportunity for males to be a primary caregiver since they can not lactate
- > in mammals can only have monogamy or polygyny
- In fish it is the opposite, when male only parental care occurs have polygyny and when female only parental care occurs have polyandry
42
Q
Cooperation
A
- Where individuals perform activities that are adapted to increasing the fitness of others because this ultimately contributes to their own direct or indirect fitness.
43
Q
Gamete sizes in males vs females: Disruptive Selection
A
- major difference between males and females is the size of their gametes
- > Theory which underlies the driving factor that is associated with the theory of sexual selection
- Disruptive Selection favors the more extreme traits as opposed to the intermediate traits
- > larger female gametes have greater energy and thus higher success
- > smaller male gametes have greater mobility and thus higher success
- -> therefore disruptive selection should favor larger and smaller gametes
44
Q
Socially Coordinated Behaviors
A
- Where individuals adjust their actions to the presence or activities of others so as to maximize their own immediate direct fitness.
45
Q
PAPER: “The evolution and significance of male
mate choice” Edward and Chapman 2011
A
- relatively infrequent case of male choice
- we provide a synthesis of the theory on male mate choice and examine the factors that promote or constrain its evolution
- the evolutionary significance of male mate choice and the contrasts in male versus female mate choice
- They conclude that mate choice by males is potentially widespread and has a distinct role in how mating systems evolve.
- in addition to variation in female quality, a key factor in the evolution of male mate choice is the availability of females relative to the capacity of an individual male to mate with those females
- male investment in mating effort should also be considered, as this reflects the costs of mate attraction and intrasexual competition incurred by males
- future work would benefit from greater comparison of
the fitness benefits, costs of mate assessment and the
strength of selection arising from male relative to female
choice.
46
Q
Kin Recognition
A
- The capacity of an individual to react differently to others based on the degree to which they are genetically related.
- Recognition alleles
- Genetic
- Environmental
47
Q
PAPER: “One Giant Leap:
How Insects Achieved
Altruism and Colonial Life” Wilson 2008
A
- once a proponent of the kin selection hypothesis, now says that kin selection may not be the reason behind eusociality.
- successful bc organized groups beat solitaires
in competition for resources, and large organized groups
beat smaller ones of the same species - rare because it requires collateral altruism, which is behavior benefiting others at the cost of the lifetime production of offspring by the altruist
- argues that the origin of altruism leading to eusociality cannot be deduced by aprioristic reasoning based
on general models. - It can, however, be revealed by reconstructing actual histories with empirical data.
- Kin selection theory is not wrong; it is simply relatively
ineffective, even inapplicable in its present form to most empirical research. This basic weakness has a great deal to do with what its defenders also stress as its basic strength, its all- inclusiveness - Depending on definitions, group selection and individual direct selection are considered the key to the origin of eusocial evolution, with
pedigree kin selection playing a minor role at best
-> or on the opposite side, kin selection is considered the key to eusocial evolution
48
Q
Attractive Sons/ Fisher’s Runaway Sexual Selection in Female mate choice
A
- Fisher’s Runaway Sexual Selection
- A form of sexual selection that occurs when female mating preferences create a positive feedback loop favoring both males with these attributes and females that prefer them
- the connection to having good genes is lost
- genetic correlation between male trait and female preference
- differs from handicap principle because the trait is not an honest indicator of the male’s genetic quality
-> sons inherit the preferred trait and daughters inherit the preference
-> will keep developing the ridiculous trait as long as females have a preference for it
—> checked by natural selection, will gain trait until they can no longer survive
Ex: stalk eyed flies - female flies for some reason prefer males with eyes that are spread further apart on the end of stalks
- this in no way correlates to healthiness, it is just a random trait the females like
49
Q
Give an example of sexual dimorphism.
A
- Coloration in male and female lizards, mallard ducks, antlers in deer, size differences in males and females of many species.
50
Q
Evolutionary Stable Strategy (ESS)
A
- A genetically distinctive set of rules for behavior that when adopted by a certain proportion of the population cannot be replaced by any alternative strategy
51
Q
When should individuals discriminate kin from non-kin?
A
- if you can not discriminate kin from non-kin, natural selection will not favor you to be an altruist
- individuals should discriminate kin from non-kin when performing altruistic behaviors
- > for the indirect fitness
- to prevent inbreeding
- to avoid cannibalism of own relatives
52
Q
Games Theory
A
- An evolutionary approach to the study of adaptive value in which payoffs to individuals associated with one behavioral tactic are dependent upon what the other members of the group are doing
53
Q
Give an example of sexual selection
A
- Female elk will only mate with males that are big and strong and can hold their own in a showdown with an opposing male
54
Q
What male strategies reduce the reproductive skew of dominant males?
A
- “sneaker strategies”
- > these strategies work for individuals who can get to the eggs first
- can have some success without having to be the largest most dominant male in the population
- strong frequency dependent selection
- > work based on the idea that the less dominant males and the dominant males have equal reproductive success
55
Q
Ecological constraints Model
A
- transition from monogamy to polygyny
- Mating system is determined by the combined influence of female reproductive synchrony and the distribution of limiting resources
- Polygyny is favored when females are synchronized and there is high resource clumping
- > if you have a lot of resources you can defend and females have a moderate level of reproductive synchrony, it can favor you mating multiple females instead of a single female
56
Q
How do differences in the costs and benefits of group living determine the potential for cooperation?
A
- you can be in a group and benefit, but it does not mean you are cooperating
- cooperation means you perform a behavior that has been selected for and is beneficial to you and someone else
- groups form first for selfish reasons and then cooperation evolves secondarily
Ex: snapping shrimp cooperative breeding - different types of group living suggests that there are circumstances that might give rise to more complex social systems
57
Q
Which strategy is best for winning the Prisoner’s Dilemma game and does it change if you play the same opponent many times?
A
- Axelrod and Hamilton (1981) asked behavioral ecologists to send in their best strategies for a pairwise tournament of Iterated Prisoner’s Dilemma (IPD)
1. ALLD is the ESS for a single game against an opponent - if you both defect, still get a small reward
- if you defect and opponent cooperates, you yield the highest reward
- ESS when w is small
2. TFT is the ESS, if repeated games against the same opponent are played, or large possibility of future interactions - ESS when w is large
58
Q
Handicap Principle
A
- when males have an extreme trait that act as an honest indicator of health
- > males develop ridiculous characteristics that disfavor natural selection
- unhealthy males could never survive with such a large handicap, they must have very good genes
- A consequence of the good genes theory where by males with the most exaggerated traits indicate their good genes by having overcome the cost (or handicap) of such extraordinary secondary sex characteristics
- Also known as the honest indicator principle.
59
Q
Sexual Reproduction Cost
A
- increased risk for sexual disease
- slower
- dilutes perfect genes because each time you breed your genes are halved
60
Q
H2 Resource Defense Polygyny
A
- Males defend a rich patch of resources critical for female reproductive success and is visited by multiple females
- > optimal for females because choose male based on who can provide best resources for her and offspring
- effective only if nesting locations are limited and easily defended by a single male
61
Q
Different Mating Systems
A
- Monogamy
- Polygyny
- Polyandry
- Polygynandry
62
Q
Give an example of secondary sexual characteristics.
A
- Elk antlers and Bird plumage
63
Q
Why do females and males look different between certain species?
A
- When there is strong sexual selection, there is the opportunity for sexual dimorphism to arise as an evolutionary result
- Therefore, the species has a long influence of sexual selection
64
Q
Prisoner’s Dilemma Model Strategies
A
- Always Cooperate (ALLC)
- Always Defect (ALLD)
- Tit-For-Tat (TFT)
- play C on the first turn and reciprocate opponent’s strategy thereafter
- > requires that an individual must remember previous opponents and must remember the opponent’s last move - Pavlov (PAV)
- play C on the first turn, then retain same strategy if previous pay-off was T or R
- > switch strategy if previous pay-off was P or S
65
Q
Sexual reproduction benefits
A
- more genetic variation since genetic material is passed down
- broader range to survive in different environments
- increases disease resistance in offspring
- more fun
66
Q
H2 Good Genes Theory Polyandry
A
- Increased genetic benefits due to a greater chance of some offspring having a superior combination of genes
- The argument that mate choice advances individual fitness because it provides the offspring of choosy individuals with genes that promote reproductive success by advancing the offspring’s chances of survival or reproductive success
67
Q
Can the differences between egg and sperm explain why males and females behave differently? Males vs Females
A
- YES, males and females have very different reproductive mating strategies based on the differences in sperm and egg size
1. Males - Sperm is cheap and does not cost much energy for the male, so they can have sex more and release sperm more often
- fitness is limited by the number of mates
- > more mates = more kids = higher fitness
- Behavior plan is to mate with as many females as possible
2. Females - producing eggs is costly and makes females choosy when selecting a mate
- > Bateman’s principle
- eggs are expensive because females are limited to how many offspring they can produce, by their limited amount of eggs
- Fitness is limited by the quality of one’s mate
- > higher quality males = higher surviving kids = higher fitness
- Should extract the most resources from the male as possible
- > Energy, protection and parental care
68
Q
Prairie voles characteristics vs Meadow Voles characteristics
A
- occupy similar burrow systems, same environment and resources, but one provides parental care and the other does not
1. Prairie voles - monogamous
- high levels of parental care from both male and female
- elevated aggression towards strangers, but elevated mating towards partners
- prefer scents of mate over stranger
- high level of oxytocin receptors
- sensitive to vasopressin
- > reduces aggression and is released with oxytocin
- > important for male parental care
- high concentration of Avpr1a receptors in VP
2. Meadow Voles - polygyny
- moderate level of parental care by female and little to none from male
- prefer to be alone
- low level of oxytocin receptors
- lower level of vasopressin than in prairie voles
- low concentration of Avpr1a receptors in VP
- > if you add more receptors they can begin to show parental care like prairie voles
69
Q
Mutual Benefit
A
- A behavior which is beneficial to both the actor and the recipient.
70
Q
H3 Lek Polygyny
A
- Males compete directly for mating’s by displaying for multiple females in a specific territory, or lek
- > put on a performance, or display for females to judge
- > reward is mating opportunities
- males are not defending females or a territory, but instead are gathering at a place where females can view multiple males and compare the male quality
- movement of the lek between breeding seasons suggests that females come to the males, rather than some resources that are needed
71
Q
Why is kin selection no longer considered the most important route to achieve cooperation ?
A
- A lot of animal groups whose genetic relatedness in a social group is no higher than genetic relatedness of those who lived in solitude
- > no strong support that kin selection was driving evolution
- Important factors include by product mutualism, reciprocity, and enforcement
- > plays huge role in eusocial insects
- There are costs of associating with kin as well
- > must compete for resources
72
Q
How can individuals incapable of passing on their genes possibly evolve and persist?
A
- by altruistic actions to protect or help kin and make sure the genes are passed on
- Darwin’s one special difficulty was if an individual that was not capable of passing on their genes helped individuals survive that carried their genes, then their genes get passed on
- > the gene for being an altruist cant get passed on directly by those individuals who can not reproduce, but can be passed on if those individuals who reproduce share the gene for altruism
73
Q
Sexual dimorphism
A
- A morphological or behavioral difference between males and females in a species
- Most often the male is the more conspicuous sex and elaborate secondary sex characters that are often exaggerated
74
Q
By product-benefit
A
- A benefit to others for behavior that is selfishly beneficial.
-> mutualistic approach to understanding cooperation
-> rather selfish strategy - Prisoners’ DELIGHT is a game where cooperators provide by-product benefits.
Ex: lions that hunt benefit and lions that dont hunt wont (ESS is to always hunt)
75
Q
Monogamy
A
- one female and male contribute to produce a batch of offspring
- common, but only in certain species
- can occur under these circumstances:
1. Mate assistance monogamy
2. Mate guarding monogamy
3. Mate enforced monogamy
76
Q
The sociality continuum (types of group living)
A
- Asocial (No coordination)
- solitary for all activities, except mating - Gregarious (coordination)
- aggregation for some activities
- sociality coordinated behaviors only - Social (cooperation)
- stable associations for all activities - Eusocial (cooperation)
- Reproductive division of labor
- Cooperative care of offspring
- Overlapping generations
77
Q
What are the costs of polyandry or EPC (extra pair copulations) to females?
A
- time and energy costs
- need to fight off more disease, or infection
- > takes a toll on, or decreases their immune system
- more susceptible to disease
78
Q
H1 Mate assistance monogamy
A
- Males remain with one female because male parental care and protection of offspring are essential for reproductive success
- > males gain more fitness by offering parental care, rather than seeking out new partners
- male and female partners become more efficient at raising offspring with more experience
- > become better parents with each year
79
Q
Sensory Exploitation in female mate choice
A
- A theory of sexual selection that posits that females may initially prefer male traits that elicit the greatest amount of stimulation from their sensory systems.
- if trait happens to arise, males will have advantage over the other males
80
Q
Mate Guarding; Example
A
- Actions taken by males usually to prevent a sexual partner from acquiring sperm from other males
Ex: - Elephant seals will fight each other for access to females
- One big male holds all the females on the beach.
81
Q
Give an example of intersexual selection.
A
- Female mate choice of males
- Female birds preferred to have male mates with very long tail feathers as opposed to males with shorter tail feathers
82
Q
Hamilton’s Rule
A
- The argument made by W.D. Hamilton that altruism can spread through a population with r x B > 0 with r being the coefficient of relatedness between the altruist and the individual helped, B being the fitness benefit received by the helped individual, and C being the cost of the altruist in terms of the direct fitness lost by the altruism due to his/her actions.
- C = cost to actor
- B = benefit to relative
- r = relatedness
- Math Use rB-C > 0 and if greater than zero altruism pays!
83
Q
What is the only mating strategy if you can not monopolize female access?
A
- the only successful mating strategy is to try to get more mates OR more fertilizations per mate
- If you can not defend resources or females, need to be able to produce a lot of sperm
- be most successful at getting sperm in the right place at the right time
- sneaker strategies
-> males disguised as females sneak in and fertilize eggs before the alpha male can
-> males hide near the alpha male and try to intercept mates
Ex: horseshoe crab, male bullfrog, sponges and fish
84
Q
PAPER: “Breeding Together: Kin Selection and Mutualism in Cooperative Vertebrates” Clutton-Brook 2002
A
- there is strong evidence that social groups are a usually the result of selfish individuals that do better by cooperating than they could by themselves
- Although the evolution of cooperative breeding has often been attributed primarily to kin selection (whereby individuals gain “indirect” benefits to their fitness by assisting collateral relatives), there is increasing evidence that helpers can be unrelated to the young they are raising
- Recent studies also suggest that the indirect benefits of cooperative behavior may often have been overestimated while the direct benefits of helping to the helper’s own fitness have probably been
underestimated. - the evolution of specialized cooperative societies has at least four important implications.
-> First, many apparently cooperative actions may generate immediate direct benefits to individuals and any
effects on “recipients” may be negative, neutral, or coincidental.
-> Second, mutualism may play a more important role in the evolution of specialized
cooperative societies than has previously been supposed
-> Third, despite superficial similarities between cooperative societies, it seems likely that there are qualitative as well as quantitative differences in the evolutionary mechanisms maintaining cooperation in different
species.
-> Finally, if mutualism proves to be important in maintaining cooperative animal societies, the benefits of cooperation in animals may be more similar to those of cooperation in humans than has been previously supposed.
85
Q
What are the advantages of asexual reproduction (benefit)?
A
- less energy costly
- faster considering you do not have to spend time looking for a mate or trying to attract one
- keeps superior gene combinations together
- > contribute more of your genes to the next generation as opposed to just half
- protection from sexually transmitted diseases
86
Q
Why don’t more animals reproduce asexually (Cost)?
A
- There is no variability in your offspring, they are identical to the parent
- offspring will not be able to adjust to changing environments
87
Q
What is cooperation and how is it different from socially mediated coordination?
A
- socially mediated coordination is where individuals adjust their actions to the presence or activities of others to maximize their own immediate direct fitness
- cooperation is when individuals perform activities that are adapted to increasing the fitness of others because this ultimately contributes to their own direct, or indirect fitness
- Difference: is that cooperation increases the fitness of individuals AND others, while socially mediated coordination increases the fitness of ONLY the individual
88
Q
Explain how post-copulatory sexual selection mirrors the pre-mating strategies of males vs females
A
- In pre-mating strategies there is:
- male vs male competition for mating opportunities
- female choice - Post-copulatory sexual selection
- the same strategies occur
- in males there is male to male sperm competition
- there is female cryptic choice
- > sperm choice for fertilization
89
Q
Prisoner’s Dilemma Model Options/Results/Assumptions needed for the model to work
A
You play and your opponent choose to play
- Cooperate (C)
- Defect (D)
Results
- If both Cooperate = Reward (R) for mutual cooperation (3)
- If you D and they C = Temptation (T) to defect (5)
- If you C and they D = Suckers (S) Pay off (0)
- if Both Defect = Punishment (P) for mutual defection (1)
Assumptions for the model to work:
- T > R > P > S
- R > (S+T) / 2
-> if two conditions are met mathematically we have a true Prisoner’s Dilemma
- w = probability of future interaction
-> key is the probability for future interaction
—> if play once go for highest pay off, but if play for multiple times best strategy is future outcome optimization
90
Q
Enforcement
A
- Cooperation favored by punishing, policing, or sanctions against those individuals that cheat
91
Q
Why are observed groups almost always larger than the predicted optimal size?
A
- individuals that are on the fringe of society (who are by themselves) benefit from the group a lot and it is a very little cost to the group to let them in
- Cost of the group is shared and small in comparison to the benefit to the individual
- Optimal group size is realized where the benefits-cost is maximized
- Individual gain is greater than group loss which is why it is favored for the group
size to be larger - Group size will increase until the group will do better by splitting into two equal sized groups
-> fission fusion
92
Q
Reciprocity
A
- Reciprocal altruism is when the helpful actor is repaid at a latter time by the recipient
Must have: - Sufficient repeated pairwise interactions
- Benefit of aid must outweigh cost of aid
- Help should be allocated proportionally
- Cannot be explained by kin selection, by product benefit, or enforcement
Ex: vampire bats - Help will be given to those familiar non-kin individuals that have helped previously
93
Q
H2 Variable territory size
A
- larger territories favor Polygynandry
- Mate number depends on the number of overlapping territories
94
Q
When should species show flexibility in their mating system?
A
- it is environmentally determined by the resources that are available
95
Q
Costs of Group Living
A
- Increased competition
- interference competition - Disease Transmission
- Risk of Parasitism
- Restriction of suitable habitat
- Competition for mates
- Cuckoldry
- caring for, or raising an offspring that is not your own - Egg, or offspring cannibalism
- Inbreeding
96
Q
PAPER: “Social semantics: altruism, cooperation, mutualism, strong
reciprocity and group selection” West et al. 2007
A
- social groups have sometimes been argued to be the result of group selection
- address issues of semantic confusion that have arisen with research on the problem of cooperation.
- In particular, discuss confusion over the terms kin selection, mutualism, mutual benefit, cooperation, altruism,
reciprocal altruism, weak altruism, altruistic punishment, strong reciprocity, group selection and direct fitness; emphasize the need to distinguish between proximate (mechanism) and ultimate (survival value) explanations
of behaviors - terms have been redefined. Altruism has been defined relative to the local scale, analogous to weak altruism, or to mean a behavior that benefits others
- cooperation has been defined to refer to only the
specific case of public goods
it has been assumed that
proximate answers can be given to ultimate questions. - We suspect that this proximate/ultimate issue is likely to be particularly important in research on communication between bacteria (quorum sensing), where signals can be defined both proximately and ultimately
- A general point here is that the potential for semantic
confusion is greatest with interdisciplinary research. One
reason for this is that different fields may use the same
term differently - Another reason is that
different areas may focus traditionally on different
questions, such as proximate vs. ultimate. In all cases,
confusion is best avoided by clear and specific statements
that minimize jargon.
97
Q
How do females benefit from polyandry?
A
- many increased genetic benefits
- fertility insurance, or maximizing the number of eggs fertilized
- good genes
- > the offspring have a chance of having a superior combination of genes
- more resources
- > nuptial gifts and extensive male parental care
98
Q
H1 Scramble competition Polygynandry
A
- Males compete directly for fertilizations by spawning near females releasing eggs
- no way to exclude males from fertilizing eggs of multiple females
99
Q
If selection favors males to mate with many females, how can monogamy evolve?
A
- it has to do with the role the male plays in parental care
- > when the female can’t raise the offspring alone so the male will remain with the female to help
- can occur under these circumstances:
1. Mate assistance monogamy - male parental care and protection for offspring are essential for reproductive success and provides experience with raising offspring
2. Mate guarding monogamy - the females may be rate, widely dispersed, or receptive for only a short period of time
- > narrow window of opportunity for mating
3. Mate enforced monogamy - one partner if the other partner prevents him, or her from mating with others
100
Q
Indirect Fitness
A
- the genes contributed to the next generation by helping non-descendant kin’s reproduction
- The component of fitness gained from aiding the reproduction of related individuals
101
Q
Cannibalism is clearly a selfish behavior, so why is it considered to be altruistic in toads, frogs and salamanders?
A
- because they do not eat their siblings
- > choose not to eat their siblings (cost) and indirectly benefit by the survival of close kin
- cannibalism generally does not occur with siblings, as salamanders will spit the sibling out if they recognize the sibling
- > they are more likely to be cannibalistic with cousins
102
Q
Difference between the relative viability of asexual and sexual reproduction?
A
- relative viability is range of high to low survival rates
- For a sexual species, they produce offspring with a wider range of relative viability
- for an asexual species, their offspring have a reduced relative viability because they are all genetic clones of one another and can not adapt
103
Q
Polyandry
A
- Females mate with multiple males
- when resources needed by the males are defended by the females
- there is a cost when females mate with many males on their immune system to fight off infection
- rare in nature
- there is a benefit of an increase in genetic diversity and the possibility of multiple males defending the territory
- occurs for:
1. fertility insurance
2. good genes
3. more resources
104
Q
Prisoner’s Dilemma Model: assumptions of TFT
A
- Capable of both cooperate and defect
- Cooperate first, reciprocate thereafter
- Must recognize previous opponents
- Must remember previous opponent’s move
105
Q
Coolidge Effect
A
- male to male sperm competition
- Males will allocate more sperm to females they have never mated with before to get more genetic variation
- males show strategic allocation of sperm
- > more sperm allocated to novel females
- A phenomenon whereby males exhibit renewed sexual interest if introduced to new receptive partners, even after refusing sex from prior but still available partners.
106
Q
H1 Fertility Insurance Hypothesis Polyandry
A
- Increased genetic benefits due to maximizing the number of female eggs fertilized
- > An explanation for why females might mate with more than one male per breeding cycle
107
Q
Coefficient of Relatedness (r)
A
- A measure of genetic similarity.
- Proportion of genes shared with another individual due to descent from a common ancestor.
108
Q
Nash Equilibrium
A
- highest payoff depends on what the other members of the population do
109
Q
H3 Mate Enforced Monogamy
A
- Mates remain with one partner because the partner prevents him, or her from mating with others
Ex: female wolves suppress subordinate females from reproducing via intimidation - males act aggressively towards other males to prevent
- also a product of relatedness within social groups, if a new alpha comes in unrelated and will mate with all females
110
Q
How do males monopolize access to females?
A
- Males tend to try to defend the group of females themselves from other males
- male-male competition, or fighting for the female
- controlling resources
Ex: elk will roar or bugle
-> Signal of competitive dominance.
-> Honest indicator of size and strength
-> Stimulates the female reproductive system to come into estrus
111
Q
H2 Mate Guarding Monogamy
A
- may be the result of enforcement
- Males remain with one female because females are rare, or receptive for only a short period of time
- > could also be widely dispersed
- male gains more fitness by preventing, or guarding their partner from mating with the other males than by seeking out additional sexual partners
112
Q
Group living Reproductive Efficiency advantages and disadvantages
A
- Advantages
- Finding a mate
- Increased offspring survival - Disadvantages
- Competition for mates
- Cuckoldry
- Egg / offspring cannibalism
- Nest parasitism
- Inbreeding
113
Q
Kin Recognition: Genetic
A
- “Armpit effect”
- Altruism directed only toward individuals that share many genes
- Different genes may code the behavior, signal and recognition
- Ex: Slime molds cells from different lines (lag genes) aggregate before segregating cells for reproduction
Ex: Honeybees guards allow workers to pass based on their genetic relatedness
114
Q
Explain why most altruism is really selfish behavior?
A
- altruism is benefiting someone else at your own expense
- by helping someone now, you’re more likely to receive help from them later on
- Hamilton’s rule says that altruism is favored under the condition that the indirect benefit offsets the direct cost
- > if you only look at the cost and not the benefit then you would call them an altruist
- –> BUT since the indirect benefit goes up and makes up for the direct benefit going down you are not a true altruist
115
Q
Group living Energetic Efficiency advantages and disadvantages
A
- Advantages
- conservation of heat
- locomotory efficiency - Disadvantages
- risk of disease
- risk of parasitism
116
Q
What mechanism of predator defense best explains elk vigilance?
A
- Dilution effect best explains
- Elk alternate between feeding and scanning for predators.
-> vigilance decreases with increasing group size
-> female elk vigilance did not increase with decreasing group vigilance, therefore dilution effect and NOT many eyes effect - Dilution effect
-> more members in the area, less likely to be eaten - Males have a low level of vigilance when compared to mothers
-> however mothers
tend to look around less when males are around even though males do not participate as much in scanning the area.
117
Q
Selfishness
A
- A behavior which is beneficial to the actor and costly to the recipient.
118
Q
Polygyny Threshold Model
A
- Mating system is determined by the differences between the value of alternative male territories
- > whether the male is monogamous, or polygynous depends on if he already has a female in his territory by the time another arrives
- polygyny is favored when there is a large difference between resource value of male territories
- > sometimes if territory is good better to be the second choice than choose a mate with a bad territory and no pair
- An explanation for polygyny based on the premise that females will gain fitness by mating with an already paired male if the resources controlled by that male greatly exceed those under the control of unmated males
119
Q
Sexy-sons Hypothesis
A
- A hypothesis that females select among males based on genetic traits in the males what will lead to the production of sons that are attractive to the opposite sex.
120
Q
PAPER: “ Sexual selection and mate choice” Anderson and Simmons 2006
A
- female choice and male to male competition
- We identify where new techniques can help estimate the relative roles of the various selection mechanisms that might work together in the evolution of mating preferences and attractive traits, and in sperm–egg interactions.
- We also point to new possibilities for testing genetic mechanisms of sexual selection in the era of functional genomics
- However, quantitative trait locus (QTL) identification and sequencing combined with functional genomics now provide the opportunity for bottom-up approaches, based on the precise characterization of genes and their effects, from DNA sequences via protein to phenotypic expression at the level of the individual, with possible consequences at the population level and above.
- Although mate choice occurs in males and females, for
convenience we refer here to female choice of male traits. - Estimating the effects of the Fisherian sexy son mechanism might help us to decide whether it explains why male ornaments and displays are often extreme, and differ more than do other traits between closely related species, apparently evolving rapidly and perhaps being involved in speciation
121
Q
Give an example of the handicap principle.
A
- Male birds with plumage so large they have difficulty flying
- > They have survived long enough to have such elaborate plumage so they must be good.
- Male elks with their bugling. It is an energy costly bugle, yet they still do it because it sends female into estrous cycle, as well as the pitch of the call being a honest demonstration of how big they are.
- > Cant fake pitch, bitch is correlated to size
122
Q
How does genetic variation in the Avpr1a gene lead to differences in monogamy in voles?
A
- Avpr1a is a receptor for vasopressin
- it is a receptor in the brain
- > located in the ventral pallidum (VP)
- prairie voles have a high concentration of Avpr1a receptors in VP
- meadow voles have a low concentration of Avpr1a receptors in VP
- > if you add more receptors they can begin to show parental care like prairie voles
123
Q
Sexual Selection
A
- selection for traits that increase mating success
- > they operate by competition between members of the same sex
- a form of natural selection that occurs when individuals vary in their ability to compete with others for mates or to attract members of the opposite sex
- LEADS TO genetic differences in the population
124
Q
Intrasexual selection
A
- Traits are selected that favor the ability of one sex to compete directly with one another for matings
- Male vs male competition is much more common than female vs female competition
-> to drive away or kill rivals - females will mate with whoever wins
-> passive
Includes: - Competition for resources
- Competition for females
- Competition for matings
- Alternative mating strategies
Ex: male-male fighting for mates
125
Q
Female cryptic choice
A
- when sperm deposited, it can be stored in the reproductive tract and females can allocate which sperm will fertilize their eggs
- > sperm expulsion
- females can remove unwanted sperm by cloaca contraction
- > sperm choice
- females can utilize sperm selectively by sperm storage tubules
- > reproductive tract complexity
- Females reproductive tract is convoluted to reduce male fertilization success
126
Q
If all offspring are the product of one male and one female, why don’t the sexes have a similar average numbers of offspring?
A
- males can mate with multiple females, whereas females have to be more choosy because mating decreases their lifespan
-> female immune systems resist invasion of foreign cells (sperm) every time the female mates causing a decreased life span
Ex: in Drosophila flies, the chemical in male sperm actually harms the female - Bateman’s Principle
-> can not increase the offspring produced by mating with more than one male - must take into account the cost of rearing the offspring
-> males have low investment, have kids until run out of females to mate with
-> females have high investment, mating a lot does not usually increase the amount of offspring - not all males will mate, whereas if females reach the reproductive age they will almost
always reproduce
-> some males reproduce A LOT more offspring than females and some males do not reproduce at all
-> this is why there are a higher average number of offspring for males
127
Q
Kin Recognition: Recognition Alleles
A
- “Greenbeard effect”
- Altruism directed only toward individuals with the same altruism gene
- The gene must code the behavior, the signal and the recognition
Ex: Fire ants accept new queens that have the b allele at the GP-9 locus
128
Q
H3 Increased Protection
A
- extreme male harassement
- Increased protection from harassment from other males
- Females that mate with multiple males benefit from their protection
- Females that mate with multiple males obscure paternity and minimize infanticide
129
Q
Mating System Evolution Models
A
- Parental Care Model
- Polygyny Threshold Model
- Ecological Constraints Model
- Genetic Constraints Model
130
Q
PAPER: “Monogamy and the Prairie Vole” Carter and Getz 1993
A
- role of hormones in favoring monogamy in prairie voles
- understanding of the importance of two hormones, oxytocin and vasopressin, which are well known for their respective roles in reproduction and body water regulation
- > Work with voles now suggests that these hormones are involved in the development of monogamy
131
Q
When should males switch from defending females to defending territories?
A
- males should switch when resources are limited and essential to females make the females come to you
1. Female Polygyny - or, if females are coming at the same time to the resource and are receptive to mating at that point
2. Resource Polygyny - males may decide to defend a rich patch of resources visited by multiple females, rather than defend the females themselves
- > only effective if nesting locations are limited and are easily defended by one male
132
Q
Prisoner’s Dilemma Model
A
- a two player strategy from game theory
- two options each encounter
- > cooperate (C) with partner
- > defect (D) against partner
- fitness depends upon the strategy of both
- A game theory payoff matrix used to study the evolution of cooperation in which the fitness payoffs to individuals are set such that mutual cooperation between the players generates a lower return than defection, which occurs when one individual accepts assistance from the other but does not return the favor.
- > A multiple-round game is referred to as the Iterated Prisoner’s Dilemma model (IPD).
133
Q
Polygynandry
A
- When multiple males mate with multiple females
Ex: Partners are swapped between monogamous pairs - Can occur because:
1. Scramble competition
2. Variable territory size
3. Increased protection
134
Q
Four explanations of how sexual selection through female choice occurs (intersexual selection)
A
- direct benefits
- male has a trait that female likes with a direct benefit for the female
- resources, gifts, etc - good genes
- attractive sons
- sensory exploitation
