Exam 2 Flashcards
Reciprocity
- 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
Genetic Constraints Model
- 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
Benefits of Group Living
- 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
Asexual reproduction - GYNOGENESIS
- 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
H1 Female Defense Polygyny
- 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
What is the purpose of a Lek?
- 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
Mutualism
- cooperation between species.
Why do females invest more in offspring care than do males?
- 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
Polygyny
- 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
Why is social monogamy not a good predictor of genetic monogamy?
- Because of Extra Pair Copulations (EPCs)
Kin Recognition: Environmental
- “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
Measuring Relatedness
- 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
Spite
- 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
Inclusive Fitness
- 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
Sexual Conflict
- 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
Kin selection
- 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
How can you distinguish whether a female is choosing a male for good resources, good genes, or attractive sons?
- 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
PAPER: “Kin Recognition” Pfennig and Sherman 1995
- 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
What resources do females need that males can defend?
- Some resources male will exchange for mating include
- > Defensive cavities, Nesting sites, Foraging patches, and Territories
What are the benefits of extra-pair copulations for females? what are the costs?
- 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
Group living Predator Defense advantages and disadvantages
- Advantages:
- dilution effect
- selfish herd
- confusion effect
- communal defense
- many eyes effect (group detection - Disadvantages
- increased conspicuousness
Bateman’s principle
- 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.
Environmental kin recognition may lead to thinking non-kin are really kin. How does this . mechanism lead to nest parasitism?
- 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
Group living Foraging Efficiency advantages and disadvantages
- Advantages
- information center
- better prey capture
- defending renewable resources - Disadvantages
- interference competition
- resource limitation