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60 Cards in this Set
- Front
- Back
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Differences between male and females in a species
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sexual dimorphism
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Are differences between males and females adaptive, i.e. to increase chance or survival?
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No
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The two main challenges of organisms are to ______ and ______.
For those that sexually reproduce, this means that? |
Survive and Reproduce
1. they have to find a member of the opposite sex 2. and they have to persuade this member to cooperate by mating, to pass their genes onto the next generation |
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Darwin discovered that individuals vary in their success at surviving and...
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their success in persuading members of the opposite sex to mate.
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In evolutionary consequences, failing to mate is equivalent to...
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dying young.
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In evolutionary consequences, failing to mate is equivalent to...
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dying young (because it makes no genetic contribution to future generations).
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Define sexual selection
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differences among individuals in success at getting mates
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If there is heritable variation in a trait that affects the ability to obtain mats, then the variants with high mating success will become more common over time. (T/F)
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True
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Why are eggs (or pregnancy) more expensive than ejaculates?
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Because females typically make a larger parental investment in their offspring than males, i.e. expenditure of energy ant time in constructing an offspring and caring for it.
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Provide an example of different selection pressures among males and females.
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Orangutans:
Females- 8 month pregnancy, give birth to a 1 kg baby; nurse it for ~1 year; and continue to protect it till it reaches 7-8 years of age Male- produces few grams of semen that can be replaced in hours or days. |
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What is the fundamental asymmetry among males and females?
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Access to females will be a limiting resource for males, but access to males will not be a limiting resource for females.
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Slince females are a limiting resource, males should be ______ when mating; as males are not a limiting resource, females should be _____ when searching for a mate.
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Males = competitive
Females = choosy/selective |
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Define: when to males fight to access females and the females mates with the winner.
(inrasexual sel. or intersexual sel.)? |
Intrasexual selection
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Define: when the males advertise for mates and the female chooses among the advertisers.
(intrasexual sel. or intersexual sel.)? |
Intersexual selection
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Optimal size for survival is..
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the maximum size at which an organism could sustain their weight.
For example, the Galapagos island iguanas, too small= net energy surplus, too large= net energy deficit. |
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Which size was ideal for male iguanas to get mates?
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Larger than average size
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In sperm competition, who wins?
What factors can sperm competition lead to? |
The larger ejaculates containing many sperm.
1. Prolonged copulation (sex time) 2. Males may deposit a copulatory plug. 3. Males may apply pheromones to make the female less attractive 4. Males may use special structures on his penis to scoop out sperm |
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Infanticide: the killing of a young within 1 year of birth.
This is seen when competition among males for females extends past conception. What animal is an example of such? |
Lions
Females of a pride remain within, whereas males of a pride are kicked out and search residence in new prides (where they're unrelated to the females). If newcomers win the fight they will immediately attempt to copulate with females. But this becomes an issue if a female is nursing her young, because she is not in breeding conditions. To overcome this issue, the male will kill the still-nursing cubs that have not been weaned to bring the females back to her breeding conditions. |
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Infanticide among lions presents an evolutionary problem to the reproductive success of female lions. What two things could she do vercome infanticide?
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1. Defend her cubs from being killed, even though they rarely survive more than two months in the presence of new coalition of males.
2. Spontaneously abort any pregnancy in progress. |
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What are the two potential benefits to a choosy female?
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1. acquisition of good genes for offspring
2. acquisition of resources offered by males |
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When choosing mates, Gray Tree Frog females preferred what type of calls?
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long and fast
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Callings can be indicators of genetic quality, Gray tree frog females believe that longer calls indicate superior genes. When researches tested the offspring of short-callers versus long-callers from the same mother. What did they find?
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That between both there was either no significant difference, or better performance by the offspring of long-callers.
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Which insect attract his mate with resources through pheromones?
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Hangingfly; if the female accepts the males prey, the pair will copulate as she eats.
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In what organism are male and female roles inverted, i.e. the male is choosy?
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Sea horses, Nephoris ophidion and Syngnathus typhle.
males carry the offspring and provide all the parental care. Females are larger, with blue strips and skin folds on belly for attraction. |
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Sexual Dimorphism in plants:
Access to pollinators limits the reproductive success of pollen donors (males) to a greater extent than it limits the reproductive success of seed parents (eggs/females). True or False? |
True
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What are the two conclusions concerning sexual selection in plants?
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1. The numb. of pollinator visits is MORE IMPORTANT to male reproductive success than female reproductive success.
2. In animal pollinated species with separate male and female flowers, the flowers should be dimorphic and the male flowers should be more attractive. |
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Social interactions create the possibility for ______ and ________ among individuals of a given species. In fitness terms, interaction may have 4 possible outcomes. What are they?
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conflict and cooperation
1. Cooperation/Mutualism: resulting in fitness gain for both participants 2. Altruism: One instigating the action pay a fitness cost (actor) and one receiving the fitness cost (recipient); e.g. helper birds that assist at parents nest. 3. Selfishness: opposite of altruism; actor gains, recipient loses. 4. Spite: fitness loss for both |
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Altruism is a CENTRAL PARADOX of Darwinism.
Selection could favor traits that result in DECREASED PERSONAL FITNESS if they INCREASE the survival and reproductive success of CLOSE RELATIVES. how can we measure this relatedness? |
coefficient of relationship (r) = the probability that the homologous alleles in two individuals are identical by descent.
Calculation: The probability that a particular allele was transmitted from parent to actor is 1/2. The probability that the same allele was transmitted from parent to recipient is 1/2 Therefore the probability (r) that this same allele was transmitted to both the actor and the recipient is the product of these two independent probabilities (1/2 x 1/2) or 1/4 |
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Hamilton's Rule states that an allele for altruistic behavior will spread if:
Br - C > 0 meaning.... |
1. the benefits (B) to the recipient are great
2. the cost (C) to the actor is low 3. the participants (actor and recipient) are closely related |
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Hamilton's Rule states that an allele for altruistic behavior will spread if:
Br - C > 0 meaning.... |
1. the benefits (B) to the recipient are great
2. the cost (C) to the actor is low 3. the participants (actor and recipient) are closely related |
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Hamilton also created the concept of INCLUSIVE FITNESS, that has two components. What are they?
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Direct fitness: acheived from personal reproduction
Indirect fitness: achieved from additional reproduction be relatives that is made possible by an individual's actions. |
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when does kin selection occur?
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When natural selection favors the spread of alleles to favor indirect fitness
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What is the difference b/w indirect kin recognition and direct kin recognition?
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Indirect kin recognition: based on cues like the timing and location of interactions.
Direct kin recognition: specific cues, like chemical, vocal, etc. |
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3 components required for a kin recognition system:
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1. production of signal
2. recognition of signal by conspecifics 3. actions based on that recognition |
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What pattern did researchers discover in the ground squirrel alarm calling?
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1. females were more likely to call than males
2. females were more likely to call when they had close relative earshot. |
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_____ selection is responsible for evolution of alarm-calling.
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Kin
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In the case with the White-fronted bee eaters, why is indirect fitness a "best-of-a-bad" strategy?
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Because they cannot gain direct fitness; i.e. breeding opportunities are extremely restricted: either habitats are too saturated with est. breeding pairs or because suitable nest sites are difficult to obtain.
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In the case with the white-fronted bee eaters, who did the helpers almost always choose to help?
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Those most closely related, with the highest r value.
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Eusociality (true sociality) describes social systems with which 3 characteristics?
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1. Overlap in generation b/w parents and their offspring
2. Cooperative brood (family of young) care 3. Specialized castes (classes) of non-reproductive individuals |
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In the hymenopetra like ants, females were more or less related to their sisters than their offspring?
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More related to their sisters; r = 3/4
w/ their offspring, r = 1/2 Therefore, daughters of the Queen ant gain inclusive (indirect) fitness through helping rear sibling rather than their own offspring. |
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Haplodiploidy is not the main explanation for eusociality because...
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1. not all females have the same father; multiple matings occur within
2. in many species, more than 1 queen is active; if neither of them father in common then the workers have an r-value of 0. 3. many eusocial species are not haplodiploid and many haplodiploid species are not eusocial |
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The Haplodiploid hypothesis suggested that eusociality was a factor of genetics. What did the pdigree of the ants show?
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That the primary agent favoring reproductive altruism in insects is ecological in nature, NOT GENETIC. That it evolved in groups that build complex nests and that cared for their larvae for extended periods.
That all hymenoptera are haplodiploid, but only a few families revealed eusociality, revealing that eusociality most likely evolved several time independently. |
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altruism involving non-kin participants
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reciprocal altruism
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What two conditions must be met for reciprocal altruism to evolve?
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1. The cost to the actor must be less than or equal to the benefit to the recipient.
2. Individuals that fail to reciprocate (cheaters) will be punished |
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When is reciprocal altruism most likely to evolve?
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1. when individuals interact with the same set of individuals
2. many opportunities for altruism occur in the lifetime 3. individuals have good memory 4. benefits = costs (symmetrical situations) |
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Blood-sharing among vampire bats were most seen between...
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Mother and child (~75%) and between individuals with a close degree of ASSOCIATION, non-relatives who are frequent roostmates, and RELATEDNESS, relatives (~25%).
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List the 3 major diversities in reproduction.
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1. mature early = reproduce quickly; mature late= reproduce slowly
2. plants live and flower for one season (poppy); plants live and flower for years (cherry) 3. bivalves produce large amount of tiny eggs (oyster); or produce small amount of large eggs (clam) |
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The branch of evolutionary biology that attempts to make sense of the diversity in reproductive strategies is...
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life history analysis
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There is a trade-off between time to ____ and time to ____.
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grow; reproduce
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Is optimal balance the same for every organism?
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NO, DIFFERENT BALANCES ARE OPTIMAL FOR DIFFERENT ENVIRONMENTS.
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In the case with the female opossum, before she matured sexually, she expended her energy on ____, ____, and _____.
After she matured, the expended her energy on ____, ____, and ____. |
Before maturity: GROWTH, metabolism , and repair of damaged tissue.
After maturity: metabolism, repair, and REPRODUCTION. |
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Differences among life histories, concern differences in allocation of ____.
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energy
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The more offspring a parent attempts to care for at once the less...
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time she can devote for caring EACH ONE
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Selections will favor the clutch size that will produce the most....
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surviving offspring.
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Numb. of surviving offspring for each particular clutch size =
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probability of survival per clutch size X clutch size
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Regarding clutch size, studies reveal that birds will lay a _____ clutch size than predicted.
Why? |
smaller
When reproduction is costly and selection favors withholding some reproductive effort for the future, the optimal clutch size may be less than the most productive clutch size. |
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There is a trade off between ____ and ____ of offspring produced. (clutch size)
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quantity and quality
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Selection on parental fitness often favors ofspring smaller than the size favored by selection of offspring fitness, resulting in a ___ __ ____ between the parents and offspring.
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conflict of interest
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the lizards were tested for two assumptions, trade-off between size and number of eggs, and fate of individual hatchings. What did the study reveal about these assumptions?
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1. That there was a trade-off between size and number of eggs
2. in 1989 selection favored larger offspring; in 1990, selection favored medium-sized offspring. |
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What happened to the Snowy Campion from Europe when it was introduced into the U.S.?
Why? |
It became an invasive weed in the U.S. because it had no predators.
When compared to a European Snowy Campion, both resulted in significant differences,e.g. the American Snowy Camion grew faster, made more flowers, and had a higher survival rate. This was due to a life history trade-off, in which the energy that was used for defense, can now be used to increase fitness of the plant. |
