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Test 3 (11962) You scored 85 out of 95
Question 1 Your answer is CORRECT.
The figure below shows size of asexual plants at maturity. Each line connects clones of a single
genotype grown in two environments. Based on this figure, which of the following is true? a) There is adaptive phenotypic plasticity for size of flowering. b) There is phenotypic plasticity for size at flowering. c) There is a genotype by environment interaction (GxE) for size at flowering. d) Size at maturity experiences net stabilizing selection. e) The population could quickly evolve a smaller size at flowering in the cold environment (the red
circled "X" in the figure).
f) There is a tradeoff between age and size at flowering mediated by temperature. g) all of the above. h) B and C. i) B, C, and E. j) A and C. k) A, C and E. Question 2 Your answer is CORRECT.
The figure below shows three things: Panel A illustrates the current size distribution for age at first
reproduction in a lightning bug population on the mainland, Panel B shows the pattern of selection
currently experienced by the lighting bugs in this population, and Panel C shows the pattern of selection
experienced by a group of lighting bugs transplanted from the mainland by wind to an island during a
hurricane; this warmer environment favors a different size at maturity than the mainland. Heritability for
size at maturity was estimated on the mainland as being very high, nearly 0.8. Using this as a guide, a
researcher predicts that within a few generations, the island population will evolve to the new optimum
body size. Is this prediction likely to be correct? a) Yes, the island population will evolve a larger size at maturity. b) Yes, the island population will evolve a smaller size at maturity. c) One cannot say because the new optimum falls outside the range of the mainland phenotype
d) One cannot say because the heritability estimated on the mainland may not be accurate in novel
e) One cannot say because there may be new genotype by environment (GxE) interactions on the
f) C, D and E. g) C and E. h) C and D. i) D and E. Question 3 Your answer is CORRECT. Eurasian magnetic pinching beetles are able to produce and detect subtle variations in local magnetic
fields. Male magnetic pinching beetles provide extensive parental care; they stick eggs to their backs
using biomagnetic fields and once the space on their back is occupied, they cannot accept more eggs.
Once the eggs hatch, males locate and process ferrous-rich food for the young. Female magnetic
pinching beetles, on the other hand, simply leave their tiny eggs with each male with which she mates
before moving on in search of additional mating opportunities. Females attract males by producing a
long-range magnetic pulse, which also serves as an index of female genetic quality and health because it
is difficult to sustain and impossible to fake. They broadcast this mating call from large metal objects
because these amplify the signal. Males select female mates based on several factors, including the
sheen of her metallic shell and the iron content of a small pebble she provides when laying eggs on the
male's back. Given this description and what you know about mating system evolution, which of the
following are NOT reasonable, fitness-enhancing strategies?
a) Instead of spending time finding her own iron-rich pebble, females might enhance their fitness by
stealing one pebbles from other females.
b) Low-quality females could enhance their fitness by sitting within the long-range magnetic signal
of a high quality female and intercept males as they come in to mate.
c) When a female finds a male, she could enhance her fitness by depolarizing him, causing him to
shed the eggs other females have attached to his back and thereby making space for her own.
d) Females could defend prime-broadcasting locations from other females, giving her exclusive
access to the males attracted to her high-quality spot.
e) Females could stick themselves to a male, thereby preventing him from mating with other females. f) Females could reverse the polarity of the magnetic sensing organ in a male after mating with him,
thereby making him unable to find other females.
g) Females could be choosey and evaluate males based on their parenting skills. h) All of the above are sound fitness-enhancing strategies. i) None of the above are sound fitness-enhancing strategies. Question 4 Your answer is CORRECT.
Several factors affect the likelihood that a polyphenism will evolve and be maintained by selection.
Among these are which of the following?
a) The relative frequency of the different selective environments. b) The relative fitness of each morph in each environment. c) The relative fitness of a genetically determined morph versus a plastic morph. d) The timing and reliability of the environmental morph-inducing cue. e) Genetic variation for the evolution of the response. f) All of the above. g) None of the above. Question 5 Your answer is CORRECT.
In many bird species, 'helpers' are sexually mature individuals that skip reproduction in their first year
and invest instead in aiding their parents efforts to rear more chicks. This increases the number of chicks
produced by a nest in a given year beyond that which either the parents helpers could produce alone.
This is an example of:
a) Optimization of reproductive effort by the parents. b) Reproductive exploitation of helpers by parents. c) Inclusive benefits for the helpers via 'good genes'. d) Decrement in total fitness of the helpers because of the missed critical first year of breeding. e) Parent-offspring conflict. f) Eusocial breeding. g) Indirect fitness gains for the parents. h) Inclusive fitness gains for the helpers. i) all of the above. j) B, G, and H. k) A, G, and H. l) D, E, and G. Question 6 Your answer is CORRECT.
The figure below shows the relationship between offspring size and offspring number for a species of
mosquito. In most populations, there are no predators and larval survival is high whereas in other
populations a new predator greatly reduces juvenile survival. Assuming there are no constraints on the
response to selection, which of the following is true according to the figure? a) Increases in offspring size have a large effect on the probability of survival in environments with
b) Increases in offspring size have a large effect on the probability of survival in predator-free b) Increases in offspring size have a large effect on the probability of survival in predator-free
c) Increases in offspring size above ~5g reduces parental fitness in predator-free environments. d) Increases in offspring size above ~5g do not affect parental fitness in predator-free environments. e) Offspring size will increase in populations subject to juvenile predation. f) Offspring size will decrease in populations subject to juvenile predation. g) A, C, and E. h) B, D, and F. i) None of the above. Question 7 Your answer is CORRECT.
As a result of founder effects and drift, an island population of snakes has diverged from the mainland
population in color, behavior, and many life history traits. Construction of a bridge connecting the island
to the mainland has brought the differentiated island population back into contact with the mainland
population. When snakes from the island and mainland populations meet, they mate and produce viable,
fit hybrid offspring. What is the likely fate of these populations?
a) Reinforcement will favor the rapid evolution of prezygotic isolating mechanisms. b) Reinforcement will favor assortative mating. c) The populations will fuse to become a single evolutionary unit. d) Hybrid vigor will favor disassortative mating. e) A and B. f) None of the above. Question 8 Your answer is CORRECT.
In a unique halpo-diplo species of fish, heritability for the size of a stripe on the tailfin is estimated from
a field selection experiment over several generations as h2 = 0.5. A change in the environment favors a
shift to a smaller stripe, from the current average of 250mm to a new mean of 100mm. Using the
breeder's equation R = h2 S (where R is the response to selection and S is the selection differential), how
many generations will the population take to get to the new optimum with a selection differential of
100mm? Note that you have a calculator on the computer you are using.
a) based on the information given, you cannot calculate the answer. b) 1.5 generations. c) 3 generations. d) 4.5 generations. e) 5 generations. f) 6 generations. g) 7.5 generations. h) 9 generations. i) 10 generations. j) 10.5 generations. k) 12 generations. l) 15 generations. m) C for males, E for females. n) C for females, E for males. o) none of the above. Question 9 Your answer is CORRECT.
Parasitoid wasps lay their eggs in or on specific kinds of insect hosts. When the eggs hatch, the larvae
consume the host, sometimes from the inside out, eventually killing it. Successful parasitism requires
escaping the external defenses of the host, such as spines or entangling hairs, as well as evading the
host's internal chemical defenses and immune system. Consequently, many parasitoids become
specialists on a narrow range of host species. However, ecological factors may limit the range of
appropriate hosts as well. One way to determine if a particular insect could serve as a host is to bring
parasitoid and host together and see what happens. Which of these are NOT correct interpretations of
possible outcomes of this approach?
a) When presented with the novel host, the parasitoid does not oviposit. This indicates that the host
cannot be used by the parasitoid.
b) Parasitoid larvae placed experimentally into the novel host are able to grow. This indicates that if
given the ecological opportunity, the parasitoid could exploit the novel host type.
c) Parasitoid larvae placed experimentally into the novel host grow poorly and die before emergence.
This indicates that if given the ecological opportunity, the host probably would not be used by the
d) The parasitoid oviposits in the novel host and the larvae do well. This indicates that the host could
be used by the parasitoid in nature if given the opportunity.
e) B and D are incorrect. f) A and D are incorrect. g) B and C are incorrect. h) They are all correct interpretations of experimental outcomes. Question 10 Your answer is CORRECT.
The presence of alleles that cause increases in reproductive investment early in life at the expense of
lifespan is one evolutionary explanation for ageing. Which of these concepts relates most directly to this
a) linkage disequilibrium b) mutational pleitoropy c) disruptive pleiotropy d) antagonistic pleiotropy e) disruptive selection f) mutation accumulation g) muller's ratchet h) costs of reproduction i) diminishing returns epistasis (negative epistasis) j) none of the above Question 11 Your answer is CORRECT.
Given the relationship illustrated in the figure below for a haplodiploid insect system, what is the
theoretical relatedness between two female workers, and what could cause this estimate to be incorrect? a) 1/4 b) 1/2 c) 3/4 d) Reproductive females can mate with multiple males. e) Workers distort sex ratio of young. f) Colonies may be founded by multiple queens in some species. g) A, D, E, and F. h) B, D, E, and F. i) C, D, E, and F. j) A, D, and F. k) B, D, and F. l) C, D, and F. Question 12 Your answer is CORRECT.
Sexual selection has produced a diversity of elaborate traits that enhance mating success of the
individuals possessing them. Which of the following are the likely products of intersexual selection? a) combat for territories b) altruism c) sperm plugs d) mate guarding e) infanticide f) honest signals of health g) all of the above Question 13 Your answer is CORRECT.
When a small subpopulation colonizes a new area and becomes a new species, this is most precisely
a) Parapatric b) Vicariance c) Symptric d) Paropatric e) Cryptic f) Peropatric g) Prezygotic h) Epistatic i) Reiforcement j) Allopatric k) Peripatric l) None of the above Question 14 Your answer is CORRECT.
Antigenic shift in viruses can be particularly dangerous because it:
a) brings together genomic elements of disparate viruses. b) results in a virus with novel H and N element combinations. c) has the potential to produce pandemics not only in humans but other hosts as well. d) can produce a new viral strain for which no previous immunity exists. e) can be contagious, moving new diseases into the population that spread rapidly. f) all of the above. g) none of the above. h) all but C. Question 15 Your answer is INCORRECT.
Killing of a host would seem to be counterproductive for a pathogen because it destroys the very entity
that the virus needs for replication. Consequently, historically it was thought that viruses and parasites
would evolve towards a benign existence with their hosts. However, this is not the case. Which of the
following does not address this point?
a) Selection may favor killing the host if doing so facilitates transmission to other hosts. In this case,
virulence is favored.
b) Killing the host is irrelevant if transmission is frequent as the virus has moved on to another host
before the current host dies. Hence, there is no selective force opposing the evolution of virulence.
c) Selection operating at the level of the virus favors rapid, aggressive replication, resulting in shortterm local fitness gains at the expense of longer-term transmission.
e) A, B, and C. d) None of the above; over time, maintaining the host is always favored evolutionarily. Question 16 Your answer is CORRECT.
Using an environmental genomics approach, scientists have determined which genes are present in many
different environments. Which of the following statements is true of what these scientists have found?
a) None of the same genes are found in soil and a whale carcass. b) There is an unexpected disagreement between gene content and mode of living. c) There are many genes found by this approach whose function is unknown. d) Proteorhodopsins are only found in the Sargasso Sea. e) New species are no longer identified because we have already sampled most environments so
Question 17 Your answer is CORRECT.
All eukaryotes have either fully functioning mitochondria or vestigial mitochondria. This suggests that:
a) The eukaryotes that do not have mitochondria are unrelated to those that do have mitochondria. b) Endosymbiosis that resulted in the origin of mitochondria occurred early in the evolutionary
history of eukaryotes.
c) Organisms cannot survive without mitochondria. d) Stabilizing selection eliminated all of the variants that did not have mitochondria. e) Endosymbiosis occurs very rarely in eukaryotes. f) None of the above. Question 18 Your answer is CORRECT.
The figure below shows the nucleotide GC content of a region of a genome. The arrows represent genes
along the genome and the graph below is the %GC content at that region of the genome. (The blue line
is 50% GC.) Which of the following processes most likely resulted the differing GC content of the
genes shown in red? a) Trade-offs b) Lateral gene transfer c) Speciation d) Host shift e) Phenotypic plasticity f) None of the above Question 19 NOT GRADED YET.
In the context of sexual selection, what does it mean when a trait acts as an 'honest signal'? When is it
important that a trait subject to sexual selection be an 'honest signal'? When does it not matter? Give an
example of a sexually selected trait that is an honest signal and one that is not. Be careful, this question
is not necessarily as easy as it might seem.
In intersexual selection, the sex that invests the most in the development of offspring optimizes its reproductive fitness by being "choosey" when selecting a mate. Choice
of mate can be made based on the resources the potential mate provides to the choosing sex, or based on some quality that the potential mate possesses. In the later
case, the choosey sex may select a mate because it is healthy, or has "good genes", or is attractive. Each of these three qualities provides the choosey sex with either direct
(e.g. lack of infection by mate) or indirect (e.g. healthy or sexy offspring) fitness gains. If a particular trait (signal) evolves that is closely correlated with some other high
fitness trait (selected-upon), then the signal can be used to select a mate with the selected-upon trait. For example, if building elaborate structures in bowerbirds
correlates with birds that are able to defend a large territory and thus control more food to provide to potential offspring, then the chooser that selects a mate with an
elaborate structure will also get more food for its young. Thus, preference for elaborate structures may persist in a population because the selected-upon trait increases
the fitness of the chooser.
A signal is honest when only the highest quality males are able to maintain the signal. Signal honesty is important when the signal is not directly related to the trait being
selected for. For example, the growth of long horns allows some ungulates to effectively compete against other males for access to females. Horns are a sexually selected
trait and may signal health and vigor. In this case, however, males can not "cheat" and grow horns to attract females without being able to effectively compete in
competitions with other males. The trait that is being selected upon in and of itself is the trait that confers higher fitness. In the case of a signal trait that stands for some
other trait being selected upon, however, a male may be able to display the signal trait without possessing the selected upon trait. Returning to the bowerbird, if females
want a mate which can provide food, but any male can build an elaborate structure, then the structure is not an honest signal of food-providing ability. In this case, the
signal must be honest, in order for it to mean anything, otherwise even low quality males could give the "I've-got-food" signal without actually having a good territory.
Addtitionally, for the honest signal to be efficient, the signal trait must not only correlate with the selected-upon trait, but there must be a steep rise in fitness
accompanying an increase in the signal trait. ...
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