Based on the differences between male and female gametes, which of the following hypotheses is most likely to be true? a) Males will have more offspring, on average, than females have, because males make many more sperm than females make eggs. b) Females will usually be choosier than males about whom to mate with, because each female has few eggs compared to each male's sperm count. c) Females will usually compete more intensely than males do for mates, because females must struggle to make sure all their eggs are fertilized.
B Because she as so few eggs and has invested so much in producing them, a female should be choosy, selecting for partners that offer good genes, abundant resources, or dedicated parental care. Male gametes are numerous and cheap to make, so males can afford to be less choosy.
Which hypothesis is supported by Andersson's results? a) H1 is supported: Females prefer extravagantly ornamented males. b) H2 is supported: Females prefer males with better territories. c) Neither hypothesis is supported.
A Although females do not show a strong preference for males with normal tails over males with short tails, they distinctly prefer males with long tails, even though such males are not seen in the wild.
Which of the following hypotheses does NOT offer a plausible explanation for this observation? a) Longer tails come with increased costs. The optimal tail length balances those survival costs with the reproductive benefits of attracting females. b) Half of a male's genetic makeup comes from his mother, who has a short tail. Genes from females set an upper limit on tail length. c) Widowbirds lack the genetic variability required for continued selection to occur.
B Just because a female has a short tail doesn't mean her son can't have a long one. Male and female traits can be controlled from different genes are are therefore different from each other.
Which results lend support to the hypothesis that peahens rely on a male's tail to indicate the quality of his genes (the Good Genes hypothesis)? a) Correlation between eyespot number and strength of male's immune system. b) Correlation between mean size of male's eyespots and survival of his offspring. c) Correlational and experimental evidence that females prefer males with more elaborate traits. d) All of the above.
D All three findings lend support to the Good Genes hypothesis.
All three statements below, if true, would support the idea that the peacock's elaborate tail is a result of sexy sons and runaway selection (the Sexy Sons hypothesis). There is strong support for TWO of the statements. Which is NOT supported by the data above? a) Females prefer males with more elaborate tails. b) Some aspects of train morphology are heritable. c) Female preference for elaborate traits is heritable.
C The Sexy Sons hypothesis assumes that female preference is heritable, but there is no evidence supporting this statement for peafowl.
Which of the following statements is best supported by the evidence? a) The hypothesis that peacocks' ornamented tails are used to signal good genes can be rejected. b) The hypothesis that peacocks' ornamented tails are a product of sexy sons and runaway selection can be rejected. c) Both hypothesis (Good Genes and Sexy Sons) are likely to have contributed to the evolution of peacocks' ornamented tails.
C Currently available evidence suggests that both mechanisms are likely to have contributed to peacock tail evolution. However, the relative importance of each mechanism remains to be determined.
Both strategies come with costs and benefits. What are the costs and benefits associated with a precocious parr that remains small and reaches sexual maturity early? a) Parr are more likely to survive to reproduce, but will have limited sperm production. b) Parr are more likely to survive to reproduce, and will maximize their sperm production. c) Parr are less likely to survive to reproduce, and will have limited sperm production. d) Parr are less likely to survive to reproduce, but will maximize their sperm production.
A Precocious parr are more likely to survive to reproduce age because they avoid the risks associated with migration and living at sea. However, because parr remain small, they produce relatively small numbers of sperm and can fertilize only a small potion of a female's eggs.
If the ESS for male Atlantic salmon includes a mix of large migratory males and small sneaky males, which of the following statements must be true? Check all that apply: a) Large migratory males do best when comparatively rare. b) Small sneaky males do best when comparatively rare.
A & B When the ESS is mixed, both phenotypes (strategies) will be present at equilibrium (with equal average fitness). Each phenotype does better when rare. Thus, small sneaky males do best when large migratory males are plentiful, and vice versa.
Does this experiment support the hypothesis that males adjust parental care in response to their confidence that they are the father? a) Yes, because the parental males who saw a sneaker male nearby while fertilizing eggs provided less care to those eggs. b) No, because parental males continued to provide care for young fish at the same level as before. c) No, because the parental males were actually the parent of all the eggs. None of them were fertilized by another male.
A
Which of the following scenarios would you expect for favor monogamy most strongly? a) The adult sex ratio is skewed such that females are much more abundant than males. b) Fertilization is external, with large numbers of individuals spawning together in swarms. c) Resources are scarce, and offspring are far more likely to survive if both parents provide care.
C Monogamy is likely when both parents can increase their fitness more by providing care than by seeking additional mating opportunities.
Which of the following statements about sexual selection is correct? a) Female choice is expected to produce males with extreme ornaments like birds with gaudy tail feathers. b) Female choice is expected to produce males with enhanced weaponry like antlers and horns. c) Male-male competition is expected to produce females with extreme ornaments like birds with gaudy tail feathers. d) Male-male competition is expected to produce females with enhanced weaponry like antlers and horns.
A
Which of the following species is most likely to exhibit paternal care? a) The polygynous topi antelope, one of nine species of lekking mammals. b) Atlantic cod, a broadcast spawner for which fertilization by satellite males in common. c) The monogamous great spotted woodpecker, a bird species, whose males have high paternity certainty. d) Bonobos, a polygynandrous primate with internal fertilization and very low paternity certainty.
C
When would a male be expected to improve his fitness by attempting to mate at sea rather than establishing a harem? a) A large, competitively dominant male will do better mating at sea when small males are relatively abundant. b) A large, competitively dominant male will do better mating at sea when suitable beaches are more common than are large, dominant males. c) A small male will do better mating at sea when suitable beaches are rare and successfully defended by large males. d) A small male will do better mating at sea when suitable beaches are more common than are large, dominant males.
C
Under what conditions would a female be expected to improve her fitness by mating with a small male at sea rather than with a large male defending a harem on shore? She would do better mating with a small male at sea: a) If a male seal's size and dominance is an honest signal of the expected survival of his offspring. b) If her offspring's survival is improved more by her continuing to feed at sea than by the superior genes of the beachmaster. c) If large, dominant males improve her survival by offering protection from the harassment of rival males. d) If the larger size of the dominant males is due to sexual selection.
B
Imagine that a group of individuals are playing the Iterated Vampire Bat's Dilemma. Each round, players pair off randomly to play. Can you predict which set of conditions would be most likely to lead to the evolution of cooperation? a) Cooperation is more likely to evolve in large groups with lots of pairs playing simultaneously and shuffling partners often. b) Cooperation is more likely to evolve when individuals frequently migrate in and out of the population. c) Cooperation is more likely to evolve when individuals repeatedly play the same partner and remember that partner's former behavior.
C If individuals play the game with each partner only once, there is no basis for cooperation, and defection is the best strategy. If players can't recognize each other and remember former behaviors, they don't have a way to punish defectors, or to forgive them. For cooperation to evolve, individuals must interact repeatedly and remember some aspects of prior interactions.
Prediction 1 relates to whether of not calling benefits the caller. For terrestrial predators, is it true that Calling decreases predation risk for caller? a) True b) False
B In this case, calling actually increases risk for the caller.
Prediction 2 relates to which sex is more likely to call. Which of the following is true for terrestrial predators? a) Males and females are equally likely to call. b) Females are more likely to call than males.
B
Prediction 3 relates to whether callers discriminate. Which of the following is true for terrestrial predators? a) Callers do not discriminate against non-callers. b) Callers know each other and discriminate against non-callers.
A
Evaluate Prediction 1: For aerial predators, is it true that Calling decreases predation risk for caller? a) True b) False
A
Evaluate Prediction 2: Which of the following is true for aerial predators? a) Males and females are equally likely to call. b) Females are more likely to call than males.
A
Evaluate Prediction 3: Which of the following is true for aerial predators? a) Callers do not discriminate against non-callers. b) Callers know each other and discriminate against non-callers.
A
A man shares more genes via inheritance with his cousin than he does with his uncle. a) True b) False
B On average, a man will share 1/4 (0.25) of his genome with his uncle, but only 1/8 (0.125) of his genome with his cousin.
A woman shares more genes via inheritance with her daughter than she does with her brother (a full sibling). a) True b) False
B On average, a woman with share 1/2 (0.5) of her genome with both her daughter and her full brother.
What does r = 0.42 suggest? a) Coalition partners are essentially unrelated. b) Coalition partners are about as related as full siblings are. c) Coalition partners are more closely related than mothers and sons.
B If all coalition partners were full siblings, r would average 0.5. The observed value is just slightly lower, suggesting that coalitions probably contain not only full siblings but also half siblings, cousins, etc.
Subordinate male turkeys can increase their inclusive fitness more by helping dominant males procure mates than they can be seeking mates on their own. a) True b) False
A The fact that rB - C > 0 indicates that subordinate males gain more inclusive fitness by helping dominant males than they do by attempting to mate on their own.
All else being equal, a female bee is most likely to improve her inclusive fitness by helping which of her relatives? a) Her daughter b) Her brother c) Her sister d) Her father
C The coefficient of relatedness between two haplodiploid sisters r = 0.75, which means they share more alleles with one another than with either parent or with brothers. This is perhaps why eusociality is so common among haplodiploid species.
The following statements are all true. Which of them DOES NOT lend support for the hypothesis that kin selection is a selective force for eusociality in haplodiploid species? a) Many haplodiploid species live in very large groups. b) Female worker insects in some haplodiploid species invest approximately three times as much in rearing a sister as a brother. c) Haplodiploid females are more closely related to their sisters than to their daughters.
A While many haplodiploid species do live in large colonies, haplodiploid individuals do not need to be part of a large colony in order to gain an advantage from helping their kin.
Reciprocity is MOST likely to occur in a species if which of the following is true? a) Individuals rarely interact with one another. b) The cost of helping is low but the recipient's benefit is great. c) Individuals have no means to recognize one another. d) The population is large and individuals move around a lot.
B
Imagine two wolves, a sister and a brother, are working together to raise the sister's litter of 10 pups, which were fathered by an unrelated male. The brother could strike out on his own, in which case he can expect to father 7 pups. However, if he leaves, only 5 of his sister's brood will survive. Given this information and Hamilton's rule, what should the brother do to maximize his fitness? a) Leave to seek a mate and father his own litter. b) Stay if his help ensures that 7 of his sister's pups survive. c) Stay if his help ensures all 10 of his sister's pups survive. d) Stay to help his sister regardless of how many of her pups will survive.
A
What is the most likely explanation for why an unrelated male will join a coalition of other unrelated males? a) Doing so will increase its direct fitness, especially if it is one of the two most dominant males. b) Doing so will increase its indirect fitness, especially if it is one of the two most dominant males. c) Doing so will have no effect on its fitness but will allow it to assist more dominant males in the group. d) Doing so will ensure the survival of the species.
A
Unrelated males are most likely to be found in what sort of coalition? a) In large coalitions of 4 or more males. b) In small coalitions of 2 males. c) In coalitions with males that are confused about relatedness. d) In coalitions where subordinate males never mate.
B
One hypothesis for why pikas give alarm calls is that callers gain a direct benefit from warning neighbors. Which of the following observations would provide the best support for this hypothesis? a) Callers are more likely to be targeted and killed by predators. b) Callers remain quiet if their neighbors never reciprocate by calling. c) Callers are more closely related to their neighbors than non-callers are. d) Callers are more likely to avoid predation.
D
Another hypothesis is that kin selection has favored alarm calls in pikas. Which of the following observations would provide the best support for this hypothesis? a) Callers are more likely to be targeted and killed by predators. b) Callers remain quiet if their neighbors never reciprocate by calling. c) Callers are more closely related to their neighbors than non-callers are. d) Callers are more likely to avoid predation.
C
When would you expect to have found giant sharks swimming around Kansas and other areas in the middle of North America? a) 20,000 years ago b) 40 million years ago c) 2 million years ago d) 90 million years ago
D Cretoxyrhina mantelli lived about 82-100 million years ago.
Which of the following statements is true for speciation that happens as a result of a vicariance event? a) Speciation occurs at the same time as the geologic event and in the same location as the ancestor population. b) Speciation occurs at a time independent of when the geologic event occurs and in the same location as the ancestor population. c) Speciation occurs at the same time as the geologic event and in a location not occupied by the ancestor population. d) Speciation occurs at a time independent of when the geologic event occurs and in a location not occupied by the ancestor population.
A Vicariance events split a widely distributed population into two or more distinct populations. Because this event initiates the speciation process, the timing of the two events is synchronous.
Which of the following predication about fruit flies follow from the gradient in island age in the Hawaiian archipelago? a) Closely related fly species will most frequently be found on adjacent islands. b) Closely related fly species will always be found on adjacent islands. c) Fly speciation events will be quite random relative to when each island was formed. d) At least some fly speciation events will coincide with when the islands were formed.
A & D Founder populations are more likely to colonize nearby unoccupied habitats than distinct ones, so flies from adjacent islands should be more closely related. When flies are moving east, from older islands to younger ones, this will produce a pattern where the more recently-derived species are found on the youngest islands. However, flies may sometimes move west, so the pattern will not be absolute.
Which of the following statements about an evolutionary tree will hold true when speciation results from dispersal? a) Speciation occurs at the same time as a geologic event. b) Speciation and geologic events occur independently. c) Younger species are found in the same locations as their ancestors. d) Younger species are found in different locations from their ancestors.
B & D Dispersal is not caused by geologic events, so the timing of speciation resulting from dispersal is independent of the times of any geologic events. By definition, the population is leaving the area in which the species originated and the new species will have a distribution that is distinct from its ancestors.
If the separation of Australia from Antarctica, a vicariance event, started the radiation of Australian marsupials, which of the following should be true? a) The only marsupials common to Australia and South America will be those that existed before Australia separated from Antarctica. b) The fossil record will show that Australian marsupials began diverging from Antarctic marsupials about the same time as the two continents separated. c) Fossils will show that other Australian taxa began diverging from their Antarctic and South American cousins at about the same time as marsupials. d) All of the above statements will be true.
D All of these predications stem from the hypothesis that the separation of Australia from the other continents was the vicariance event that allowed Australian marsupials to diverge from other marsupials.
If marsupials dispersed from North America into South America, across Antarctica, and into Australia, which of the following should be true, as evidence by the fossil record? a) Australian marsupials would be more closely related to marsupials in Antarctica than South America. b) Australian marsupials would be more closely related to marsupials in North America than in South America. c) Australian marsupials must have colonized Australia before it separated from Antarctica. d) All of the above statements will be true.
A The geographic arrangement of continents suggests the order in which they were colonized. If populations began to diverge at colonization, we expect neighboring populations to be more closely related than distant ones.
Observations can rule out vicariance as the initiator of a speciation, but no observation can rule out dispersal as the initiator of speciation. a) True b) False
A This is one of the big challenges facing biogeographers. You cannot prove that dispersal did not happen. Conversely, because the timing of a vicariance event and the speciation it initiated should coincide, an observation that they occurred at widely different times would strongly suggest that vicariance was not responsible.
If three species richness increases significantly with both AET and temperature, which hypotheses are supported? a) Net Primary Productivity b) Regional Energy Availability and Water Availability c) Regional Energy Availability and Net Primary Productivity d) Water Availability and Habitat Diversity
C The relationship with temperature supports the Regional Energy Availability hypothesis while the relationship with AET supports the Net Primary Productivity hypothesis.
Suppose you discover mammalian species richness is linearly related to both water availability and tree species richness, but the relationship is stronger with tree species richness. What would you conclude? a) The Habitat Diversity hypothesis is more likely true than the Water Availability hypothesis. b) The Habitat Diversity and the Water Availability hypotheses together must be the causes of the mammalian latitudinal gradient. c) Habitat Diversity is the most likely of the four hypotheses to be true.
A Although this is not absolute proof, the hypothesis whose predictions are supported by the strongest regression is more likely to be true.
Is mammal species richness significantly related to temperature? a) Yes b) No
A
Which hypotheses do NOT explain the latitudinal gradient in mammal species richness? a) Regional Energy Availability b) Water Availability c) Net Primary Productivity d) Habitat Diversity
B & C
Which of the four hypotheses BEST explains mammal species richness? a) Regional Energy Availability b) Water Availability c) Net Primary Productivity d) Habitat Diversity e) There is not enough information to answer this question.
A Because both temperature and PET are significantly related to mammal species richness, the Regional Energy Availability hypothesis is best supported. There is some support for the Habitat Diversity hypothesis, but the relationship between mammal and tree species richness is clearly not linear and requires more sophisticated techniques to fully evaluate.
Which of the hypotheses provides the BEST explanation for tree species richness? a) Regional Energy Availability b) Water Availability c) Net Primary Productivity d) Habitat Diversity
C Although tree species richness varies significantly with temperature, precipitation, potential evapotranspiration, and actual evapotranspiration, it is actual evapotranspiration that provides the best explanation of tree species richness.
According to your regression analysis, mammal diversity is best predicted by which of the following? a) Precipitation b) Potential evapotranspiration (PET) c) Actual evapotranspiration (AET) d) Tree species richness
B
According to your regression analysis, tree diversity is best predicted by which of the following? a) Temperature b) Precipitation c) Potential evapotranspiration (PET) d) Actual evapotranspiration (AET)
D
The theory of plate tectonics explains how Earth's continents move. According to this theory, which of the following statements is FALSE? a) Earth's crust is composed of relatively thin, light plates that float atop the dense, viscous upper layer of the mantle. b) Ocean basins grow as one wedge-shaped oceanic plate plows through another, causing the ocean floor to split and spread apart. c) Continental plates have relatively stable shapes because they are lighter than oceanic plates and tend to slide up on top of oceanic plates where the two collide. d) Many of Earth's mountains resulted from the collision of two continental plates along a convergent boundary.
B
Although primates are widely distributed, biogeographers have debated the origin of South American monkeys. Some argue that monkeys originated in Africa and dispersed to South America. Others argue that the separation of South America from Africa is responsible for different species on the two continents (vicariance). Which of the following, if true, would allow you to reject one of the two hypotheses? a) If fossil evidence places New World monkeys in South America well before South America separated from Africa, you must reject the dispersal hypothesis. b) If South America separated from Africa about the same time that South American monkeys diverged from African monkeys, you must reject the dispersal hypothesis. c) If the separation of the two continents occurred well before the arrival of the common ancestor of African and South American monkeys, you must reject the vicariance hypothesis.
C
A species for which you are developing a conservation plan has a three-stage life cycle: juveniles (not reproductive), young adults, and older adults. Fecundity is the same for young adults and adults. If the species displays Type I survivorship and you only have resources to improve survivorship of one life stage, which stage would you focus on protecting and why? a) Juveniles, because they have low survivorship. b) Young adults, because they have the greatest potential for future reproduction. c) Older adults, because they have the same fecundity as young adults but low survivorship.
C If the species has a Type 1 survivorship curve then older adults have higher mortality compared to younger adults. In this example, older adults reproduce as well as young adults. Increasing survivorship in the older adult group would be the best strategy for conservation.
A survivorship curve plots: a) Number of individuals in a cohort that survive to age X. b) Number of individuals who survive from age X-1 to age X. c) The number of individuals that don't survive to age X.
A
The survivorship data for the Northern Spotted Owl can be used to calculate the age-specific probability of death. If an owl survives its first year, its probability of dying in any subsequent year decreases to 0.13 and remains nearly constant for the rest of its life. Given this, which type of survivorship curve best describes the Northern Spotted Owl? a) Type I b) Type II c) Type III
B
Roughly, how do any differences in growth rate between the two species compare to the large differences in birth and death rates? a) Growth rate is higher for barnacles because its birth rate is higher. b) Growth rate is lower for barnacles because its death rate is higher. c) Growth rates are about the same for the two species because the relative values of birth and death rates are similar.
C Growth rate depends on the relative values of birth and death rates. These two populations grow at about the same rate, even though the absolute values for birth and death rates are higher for the barnacle population.
The barnacle population's age structure is shifted toward younger age classes, compared with dolphins. What about the differences in birth and/or death rates explains this pattern? a) Fecundity rates for barnacles are higher than for dolphins, so more young barnacles are produced. Mortality rates do not affect age structure. b) Both fecundity and mortality are higher for barnacles than for dolphins. Barnacles, therefore, have more young but they don't live as long. c) Because the two populations have about the same growth rate, the difference in age structure must be due to immigration/emigration and not due to fecundity/mortality. d) Barnacles have lower mortality than dolphins, which results in a higher number of juveniles.
B Higher fecundity and mortality rates for barnacles cause the barnacle population's age structure to be shifted toward younger age classes, compared with dolphins, who have fewer young that live longer.
A successful life history strategy would have populations that: a) Decrease in size over time b) Increase in size over time c) Do not change in size at all over time d) Either increase or do not change in size over time
D
If a population has an r value of 0.15, which statement is most likely to be true? a) Its size will increase in the short term. b) Its birth rate is less than its death rate. c) Its mortality rate is decreasing.
A
A population's fecundity rate is: a) The average total number of offspring per reproductive female over her lifetime. b) The average number of offspring per reproductive female per year (or other specified time). c) Equal to the number of births per year per 1000 individuals in the population.
B
When was the soybean aphid population growing fastest? a) When the population size was small. b) When the population size was medium-sized. c) When the population size was large.
C
If a water hyacinth population has an r value of 0, how will the population size change through time? a) The population size would increase. b) The population size would not change. c) The population size would decrease.
B
Species rarely grow exponentially, but do occasionally. Under which of the following conditions is this likely to happen? a) An abundance of available resources b) A lack of other species competing for resources c) A lack of natural predators d) All of the above
D
When the population size (N) equals the carrying capacity (K), dN/dt will be: a) Zero b) A positive value c) A negative value
A dN/dt = 0 means that the population size is not changing.
When was the instantaneous population growth rate, dN/dt, the highest? a) At the smallest population sizes. b) At medium population sizes. c) At the largest population sizes. d) The instantaneous population growth rate did not change with population size.
B A logistically growing population grows fastest at a medium size, because there are enough individuals for reproduction (as a whole) to be high, but not so many individuals that competition for resources limits population growth.
When was the per capita growth rate (dN/dtN) the highest? a) At the smallest population sizes. b) At medium population sizes. c) At the largest population sizes. d) The per capita growth rate did not change with population sizes.
A Although the population is small, the number of new individuals added per unit time, per existing individual, is at its highest.
Compare the impact of fungal disease and thunderstorms, both when population size was low (500) and also when population size was high (1600). How did the two disturbance types affect the population, proportionally, at each size? a) The proportional impact of both disease and thunderstorms did not depend on population size. b) The proportional impact of disease decreased at lower population density. The proportional impact of thunderstorms did not depend on population size. c) The proportional impact of thunderstorms decreased at lower population density. The proportional impact of disease did not depend on population size. d) The proportional impact of both disease and thunderstorms decreased at lower population density.
B The impact of disease was proportionally greater when there were more aphids, but thunderstorms had the same proportional impact no matter how many aphids there were. That is why we say that the disease is density-dependent but the thunderstorm is density-independent.
Is food limitation an example of a density-dependent factor or a density-independent factor? a) Density-dependent b) Density-independent
A The higher the population of aphids, the harder it is for any given aphid to find enough food.
When a population is growing logistically, at what stage is the change in population size over the change in time, i.e. dN/dt, the greatest? a) When N is very small b) When N is just a little smaller than K c) When N is half the size of K
C
Which of the following is true regarding density-dependent and density-independent factors affecting population growth? a) The effect of most density-dependent factors on population growth is greater with a larger population size. b) The effect of most density-dependent factors on population growth is greater with a smaller population size. c) The effect of most density-independent factors on population growth is greater with a larger population size.
A
With a low immigration rate, does the population ever go extinct? a) Yes, it still goes extinct and stays extinct. b) Yes, it still goes extinct but does not stay extinct. c) No, it never goes extinct.
B Sometimes a new immigrant recolonizes the patch.
With a high immigration rate, what would an ecologist doing a short survey likely say about this patch? a) There appears to be no salamanders here. b) There appears to be a small but healthy salamander population here. c) There appears to be a large and healthy salamander population here.
B With a high immigration rate the population rarely goes extinct. We say that the immigrants rescue the population.
How does the extinction rate change when the patches are closer to each other? a) Several patches go extinct every few weeks but all of those are recolonized within a few weeks. b) Several patches go extinct every few weeks and those take 20 - 50 weeks on average to be recolonized. c) One or two patches go extinct occasionally and those are recolonized within a few weeks. d) Patches never go extinct.
C When the patches are very close together, there is enough dispersal between patches that it is almost like a single larger population. Patches rarely go extinct, and when they do, they are quickly recolonized.
What is the qualitative difference between the lower and higher patch extinction rates? a) At the lower patch extinction rate, there are always some occupied patches. At the hgher rate, the whole metapopuilation will go extinct.
A At a lower extinction rate, there are fewer extinctions than colonizations