EXAM 1 CRAM

But aren't lemmings altruistic in committing suicide for the good of the species? Explain why this theory may be false and how it does not support the idea of altruism in lemmings to reduce overpopulation

-,If altruistic individuals jump and die, then their genes for altruism die, too. These altruistic genes would be overrepresented in a pile of dead lemmings at the bottom of the cliff. • Because selfish individuals do not jump and die, the proportion of selfish genes in the surviving population should increase. • Thus, at the individual level, altruistic behavior is selected against, and genes for reproductive selfishness are favored.

Cooperative breeding is rare in bird species. Which U.S bird species display cooperative breeding and how do they help?

-Acorn woodpeckers (ACWP)- (Koenig, Mumme, Stacy) communal breeders-polyandrous female mating w/ brothers -Florida Scrub Jay (FSJ)- helpers are sons that remain on territory & often take over father's or adjacent territory. -Red-cockaded woodpeckers (RCWEP)- Jeff Walters - nest holes a limiting resource Types of Help: Types of helping: • 1) feed young and incubating female • 2) nest defense against predators/nest parasites • 3) territory defense against conspecifics and others • 4) help takeover new territory • 5) food storage (Acorn Woodpeckers)

Colony-specific emergent properties

1) division of labor/task specialization with life histories that favor extreme behaviors (workers not limited by interest in direct reproduction) 2) group defense of colony (larvae), resources 3) increased foraging efficiency due to information transfer 4) dominance over competitors and prey due to numbers and aggressiveness 5) food sharing and gardening 6) alloparenting of offspring (the queen can focus on her job as an egg layer - high relatedness)

How do animals identify kin?

1. Association at critical periods (e.g. in nest) 2. Phenotype recognition (chemical, vocal and visual cues) 3. Association with known relatives 4. Taught by parents

Evidence for Kin Selection Theory

1. Florida Scrub Jays show a significant preference for close family members in helper relationships. 2. Black-tailed prairie dogs give more alarm calls when kin are nearby. 3. Cooperative breeding -White-fronted bee eater Emlen and Wege Under poor conditions individuals help close relatives (e.g. parents) even after they have previously successfully reproduced. 4. Kinship affects morphogenesis in cannibalistic salamanders (Groups with nonkin developed cannibalistic morphs at an earlier age than those with sibs only or sibs and cousins) 5. Paul Sherman found that Belding's ground squirrels have two call types: in trills and whistles trills are given in response to ground predators and are dangerous to give and are given predominantly when kiln are present. whistle calls are given in response to aerial predators and function to indicate to the predator that they have been seen and thus its not wort attacking. These "I see you calls" are selfish and not affected by the presence of kin. 6. cooperative courtship in wild turkeys 7. Kinship and bower destruction in satin bowerbirds (destruction done by males and more destructions present when in proximity to unrelated members of the species) 8. Argentine ant super colonies - colonies may be because there is a breakdown in the kin recognition system

How can eusociality evolve? (non-exclusively)

1. Hamilton's haplodiploidy hypothesis with female biased production of reproductive 2. Ecological hypothesis - environmental conditions favor offspring staying and helping rather than dispersing and attempting reproduction - termites living in logs 3. Parental manipulation

What other models play into kin helping/how?

1. Inbreeding - creates high r when close relatives mate potentially favoring helping behavior2. Green beard - Preferring to help others who share a particular phenotypic trait

Why is Inclusive fitness important? (4)

1. It explains widespread and sometimes extreme helping behavior and other kin- affecting adaptations. 2. It identifies direct and indirect reproduction as alternative pathways to increase genetic fitness. 3. It identifies more precisely the level of selection and adaptation. 4. There are shared interests across the genome about the decision rule.

Eusociality

1. Reproductive division of labor - reproductive specialists - "queens" and less/non reproductive workers 2. Overlap of generations - long-lived queens 3. Cooperative care of young - helpers aid nondefendant kin

Why is selection at the individual/gene level accepted as the mechanism for producing adaptation?

1. The greater numbers, high turnover rate and high heritability of phenotype makes individual level selection a more precise and powerful force for shaping adaptations. 2. Adaptations function primarily to benefit individuals (there are NO known adaptations that benefit species at the expense of individuals) - consider Lack's experiment. 3. There are some biologists who call selection in groups "group selection," but all realistic cases involve individuals maximizing personal reproduction.

Key Points of Kin selection:

1. There are many examples of kin selection operating in natural populations. 2. Generally, Individuals helping others prefer helping closer relatives over more distantly related individuals. 3. Ken helping can involve not harming closer relatives relative to more distant relatives. 4. Individuals can reform groups with helpers under poor conditions when they had previously reproduced independently.

What is the value of Honeybee dance

Adaptive Value of the Dance 1) Bees can quickly and efficiently communicate location of resources, with little wasted effort. 2) By comparing foragers' dances, it directs bee recruits to the best food sources. 3) Allows recruits to efficiently monopolize rewarding food sources before their discovery by competitors

What is an Evolutionarily Stable Strategy (ESS) and how does kin selection play into the strategy?

An Evolutionarily Stable Strategy (ESS) invades and increases in a population against competing other alleles specifying alternative helping strategies. (Hamilton's Kin Selection are winners) Hamiltonian rule wins as an ESS because due to its behavior it invades and is stable against invasion by other competing genotypes.Indirect reproduction when r relative to B/C is too low loses because direct reproduction is a better reproductive strategy. Helping descendant kin only when relatedness relative to B/C is high misses opportunities to gain high payoffs from indirect reproduction.

What can we consider altruistic traits? list an exmaple:

Any evolved trait that benefits the group but comes at a meaningful net cost to the individual actor can be considered altruistic. Ex. restrained reproduction to avoid overpopulation, restrained feeding not to over-exploit food supply, etc.

Hamilton's inclusive fitness model: A rule for when to choose direct vs. indirect reproduction Determine the relatedness needed to be a discreet y full sibling, cousins and grandparents.

Br/Cd > 1/r Br = benefit to the recipient Cd = cost to the donor r = coefficient of relatedness between recipient and donor through identity by descent (full sibs, parents = 1/2, grandparents, grandchildren = 1/4, cousins = 1/8, 1/16 etc.)

V.C Wynee-Edwards (proposed that there were many instances in animal behavior that involved self-sacrifice for the good of the population/species) Give examples and counterarguments:

Breeding leks Clutch size in birds --> withhold eggs to prevent overpopulation, whereas lack hypothesized that: Females limit clutch size to the number of chicks they can feed, and this maximizes their reproduction.

Describe the Developmental plasticity in social insects

Castes take on different functions in the colony even though they share the same genes (except males). • Different genes are turned on and affect development leading to caste-specific morphological and behavioral traits. • Within castes there may be age-related behavioral and even morphological (mushroom body) differences. • Phenotypic changes result for different environmental cues (e.g. pheromones, food, social dominance).

Are selfish/out-law genes always favored by selection?

Dawkins argued that genes have evolved to behave selfishly. However, in order for genes to effectively reprocure offspring, they must cooperate with other genes in the genome. If Dawkins is correct about focusing on selfish genes as the appropriate level of selection, these outlaw genes should be common and should lower fitness at the individual level.

who supports the theory of species selection?

Eldridge and Gould

Different degrees of sociality - Eusociality - (sterile workers and reproductive division of labor)

Groups that have eusocial species: ants, termites, bees, wasps, aphids, trips, mites, beetles, shrimp, flatworms and naked mole rats (vertebrate)Eusocial helpers evolve to specialize in helping a (related) queen reproduce (indirect reproduction).

What does Eusociality look like it in diplopod termites?

High relatedness in termite colonies (r=1/2) • Termites are monogamous • Queen and king are long-lived (Secondary queen clones!!!) • Large colonies in complex air-conditioned mud nests • Use symbionts - fungus (external gardens) or in gut to digest cellulose. • Extreme cast specialization and weaponry • Workers take on dangerous tasks - nest guarding

How do you test the Kin Selection hypothesis?

How do you test the Kin Selection hypothesis?We can measure r, but B and C are difficult to measure.Solution: make and test predictions expected from KS theory.a. Help relatives only.b. Help closer relatives over more distant relatives, all things being equal.c. Helping should be based on payoff.d. Age and ability to help should affect giving.

How did Darwin solve the problem with the helping behavior pythosesis?

Inclusive fitness theory: "... in each distinct behavior-evoking situation the individual will seem to value his neighbors' fitness against his own according to the coefficients of relationship appropriate to that situation." (Hamilton, W. D. (1964) "The genetic evolution of social behavior." J Theoretical Biology 7: p. 18)

Can altruism ever evolve? (Models we can can consider altruism)

Kin selection - most robust and best supported model for helping • Selection in groups - very small group size may favor altruism/cooperation. • Green beard/trait group selection - altruists choose one another. • Selection in viscous populations - altruists stick together.

How kin selection allows flexibility in reproductive strategies

Kin selection alleles allow flexibility in expressing direct (personal) or indirect (kin- helping) reproduction depending on which has the greater payoff. Direct reproducing only alleles do not have this flexibility and cannot gain from situations where helping kin has especially high payoffs for the genes involved.

Why was the Green beard model proposed by Darwin?

It is an alternative to explain helping behavior. Why individual may help others despite unrelatedness, Model: Individuals help others that share a phenotypic trait (the green beard) when B/C > 1, even if they are unrelated. Problems: 1) We expect "cheater" green beards, individuals who take benefits but don't help, to invade unless there is policing. 2) Conflict because non-green beard genes in the genome should resist giving resources to non-relatives. Conclusion: there should be no green beards.

What is kin selection?

Kin selection involves reducing personal reproduction to help a relative reproduce.

who supports the theory of individual level election? - incomplete/does not explain kin helping

Lack, Williams

who supports the theory of Gaia hypothesis?

Lovelock and Margules

Is kin selection altruism?

No, not at the gene level. Kin selection is genetically selfish behavior. What looks like altruism among individuals can be fully understood as genetic selfishness. Confusion in the literature; you often see kin selection spoken of as altruism.

Why do queens mate with multiple males if it lowers worker relatedness to their eggs?

Queens need a lot of sperm to produce a large colony. Manipulation by queens: Queens may mate multiply to cause workers to rear her sons rather than workers sister's sons.

Explain/Describe Parental manipulation: an alternative route to eusociality.

R. D. Alexander argued that parents could manipulate offspring so that some took on reproductive and others took on helper roles. They suggested that Polistes wasp queens make female offspring of different size so that the smaller offspring would be biased toward helping their sister.

If we have selfish genes, why should one individual help another?

Separating effects of selection on genes and individuals

Describe how the Honeybee Dance tells time, length and to find food

The length of waggle dance run indicates the distance (flight time) to food source (longer = farther) For nearby food sources the bees used a round dance The frequency of wing beats in the waggle phase and the frequency of wing-beating pulses in the return phase were significantly higher in foragers collecting more concentrated honey compared with foragers collecting less-concentrated honey, whereas the duration of the return phase was significantly shorter.

Diplopod naked mole rats

The naked mole rats. - 2 castes: - "workers" - Non-reproductive adults: dig tunnels, find food - "Reproductive" - Reproductive female (queen) and several reproductive males: breed, keep young warm - Inbreeding - high relatedness - Constrained to live in colonies by ecological conditions

Who is in charge of the colony?

The queen - The queen makes chemical signals that "prevents" workers from making new queen cells • She can mate multiply or singly affecting relatedness which affects worker decisions. • The workers - affect development of other workers• Make queen cells and royal jelly • Decide in foraging and swarming • Workers police other workers - eat their eggs • The queen's interests are upheld by workers' reproductive dependence on her.

Describe Lack experiment (the design, conclusion and connection to selection adaptations):

To test the group selection hypothesis, Lack moved eggs among bird nests to create nests of different egg numbers. If the group selection hypothesis was correct and eggs were limiting reproduction (and population size), then he predicted that nests with added eggs should produce more fledged birds. Alternatively, if nests with more eggs produced fewer fledglings, that would support Lack's hypothesis. Result: Lack found that increased numbers of eggs in the nest did NOT increase the number of young fledged. Conclusion: The failure of females to make extra-large clutches does not occur for the benefit of the species, but because it lowered the female's own individual selfish reproduction.

Name/Describe other cues bees use to communicate where food is

Tropholaxis - foragers dole out food and scent to help recruits identify source. Foragers learn landmarks that they use in navigation. Sounds foragers make can indicate the height of a food source.

who supports the theory of population level selection?

V.C Wynee-Edwards (proposed that there were many instances in animal behavior that involved self-sacrifice for the good of the population/species)

How honeybee workers chemical signals affect worker maturation and task specialization.

Young worker bees work inside the colony as nurse bees and then, as they age, they become foragers. Forager bees collect ethyl oleate when foraging. Foragers feed this chemical to the young worker bees, and this delays maturation into foragers. As forager bees die, less ethyl oleate is available and nurse bees more quickly mature to replace foragers. This mechanism allows the hive to regulate caste numbers for the benefit of the colony.

Karl von Frisch

a major figure in animal behavior; most famous for his discovery that honeybees communicate through dance. First believed bees used flower scents or other odors to find food sources. • Trained honeybees, Apis mellifera, to use feeders Noticed precise but variable dances performed by returning foragers • Was able to decode the dance with experiments, e.g., moving feeders different distances and directions

What does Hamilton's haplodiploidy hypothesis state? When is the is the reasoning incorrect or correct? Overall Disclaimer: Hamilton's haplodiploid model for eusocial evolution is not sufficient to explain eusociality in nonhaplodiploid species and for other reasons.

eusociality - High sister-sister relatedness for single-mated haplodiploid females causes them to favor raising sisters (r=3/4) (mother's offspring) rather than their own offspring (r=1/2). Problems with Hamilton's HD hypothesis: -If the net relationship of all queen's offspring (sons and daughters) to sisters is considered, with an equal sex ratio, relationship of sisters to siblings is the same as diplopod The hypothesis does not explain diplopod eusocial species (termites, snapping shrimp and mole rats)-When queens mate multiple times it reduces relatedness among sisters (3/4 >1/4), below their relatedness to their own offspring (1/2).

What is wrong with the theory of gene level selection? Gene level selection - genes cause individuals to act to maximally transmit genes they carry

suppression of outlaw genes

Describe the Age-related changes in worker bees

• Phase 1 - Clean cells - 3 days • Phase 2 - Nurse bees feed brood - 1 week • Phase 3 - Nest construction/build comb, store food, guard nest entrance 10 days • Phase 4 - Forage 10 days

How are queens made in bees (and social insects)?

• Queens give off pheromones indicating they are present or not. • Workers make new queens by making large cells and feeding larvae "royal jelly." • Royal jelly contains fewer micro RNAs from plants that limit growth. • Better quality food (few micro RNAs) allows faster growth and switches on queen genes.