Bio 322 - Evolutionary Biology » Spring 2022 » Quiz 5 Genetic Drift

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Question #1
What is the difference between natural selection and genetic drift?
A.   Genetic drift describes survival of the fittest, while selection decribes artificial breeding methods.
B.   Genetic drift describes random changes in allele frequences, while selection is influenced by the fitness of the alleles.
C.   Genetic drift involves non-synonimous (neurtal) mutations, and selection involves synonymous mutations.
Question #2
How does genetic drift affect populations of small effective size?
A.   Small populations do not experience genetic drift.
B.   Small populations are subject to stronger effects of genetic drift.
C.   Small populations are subject to lesser effects of genetic drift.
Question #3
What is a population bottleneck, and what risk does it pose?
A.   This describes a very large population that drifts towards its environmental capacity until it cannot expand more (bottleneck). For example, the Tyranosarus rex could not increase further in population due to insufficient mammuts present as prey.
B.   This describes a population that transitions through a small effective population size. It will either collapse or recover. Maintaining sufficient genetic diversity (standing variation) is a concern during this transition.
C.   Bottleneck describes a deleterious mutation of the 9th cervical vertebra of tetrapods due to inbreeding. This neck was charactersitic of the Habsburg Royal family in northern Rheinland (France). It is believed the Notredamme story is based on the Habsburg neck.
Question #4
What is a selective sweep?
A.   When a beneficial mutation is lost due to genetic drift.
B.   When a deleterious mutation transitions through an adaptive valley.
C.   When a beneficial mutation is so strongly selected for, that it replaces (deletes) the other allele and becomes fixed in the population.
Question #5
What is inbreeding in genetic terms?
A.   Loss of beneficial alelles and fixation of deleterious alleles by genetic drift in populations of small effective size.
B.   When artificial breeding is used for a genetic sweep.
C.   When beneficial alleles become fixed in a population through a peak shift.
Question #6
What are ways in which populations achieve gene flow and increase genetic diversity?
A.   Migration and dispersal.
B.   Through converging evolution.
C.   Through adaptation.
Question #7
How can you measure gene flow between populations at different locations?
A.   By comparing the frequency of an allele between populations (e.g. via the F-ST statistic).
B.   By comparing the population size (using the molecular clock).
C.   By looking at the relative fixation probability.
Question #8
If an mouse population migrates into a new, darker environment where an allele affecting its phenotype (e.g. dark fur) is under strong postitive selection, what do you expect to happen?
A.   The allele will slowly decrease in frequency.
B.   The allele will keep the frequency from the original population’s location.
C.   The allele will increase in frequency.
Question #9
What factors are at work to achieve a peak shift from an adaptive valley to an adaptive peak?
A.   Both genetic drift and natural selection.
B.   Only natural selection.
C.   Only genetic drift.
Question #10
In a changing climate, some species can migrate to keep in their preferred climate zone (if they can’t adapt physiologically). What factors are important to consider though?
A.   A dispersal barrier in form of a mountain, or ocean can limit migration possibilites.
B.   This does not makes sense, because global warming is global, so migrations to a different climate do not happen.
C.   If the climate change occours slowly, the species does not notice it. Only quick changes trigger succesful migration (frog in the boiling water syndrome).

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