iClicker Question and Answers
imagine you have a pop of 100 dogs and you are trying to determine what the inbreeding co-efficient is. You know that there are 51 individuals that are AA and 30 that are aa. What is F, if you know that H=2pq(1-F)
0.78
The Shepherd's purse plant can produce two different shaped seed capsules. When a plant (AABB) with heart-shaped seed capsules is crossed with a plant (aabb) with narrow seed capsules, it produces a plant (AaBb) with only heart-shaped capsules. If plants in that F1 generation are then self-crossed, what will the PHENOTYPE ratio be if a dominant allele at EITHER of the loci produces plants with heart-shaped alleles?
15:1
Tay Sachs is an autosomal recessive genetic disease (q^2) in humans with a frequency of about 2 x 10 ^-6, assuming random mating. people with Tay Sachs disease die before 2 years (S=1). if the disease is at mutation selection balance, what can we estimate the mutation rate will be?
2 x 10 ^-6
Recall the difference between absolute and relative fitness. If an organism in a population had 3 offspring, and if the fittest individual in the population had 5 offspring, the relative fitness of this organisms would be:
3/5 = 0.6
you want to increase the number of flowers produced by roses in your green house. Heritability for flower number is 0.5 and the plants have an average of 6.5 flowers each. You only allow plants with lots of flowers to reproduce (mean = 9.5). What do you expect to be the mean number of flowers produced by their offspring (the next generation)?
8.0
these two graphs generated by Rosemary and Peter Grant of Darwin/s finches on the Galapagos Islands demonstrate that:
Evolution is observable because the mean beak size changed in a subsequent generation after a drought
one postulate of natural selection is that parents pass to their offspring changes in a trait that are acquired during their lifetime
False
which of the following is a correct statement regarding the effect of selection on allele frequencies?
Heterozygote superiority maintains allelic diversity
how does inbreeding depression occur?
Inbreeding increases homozygosity and exposes deleterious recessive phenotypes to selection at a higher rate than random mating
Who is originally responsible for the ideas that lineages change through time?
Lamarck
in a population where f(AA) = 0.49, can you determine if the population is in H-W equilibrium?
No, not enough information. you cannot calculate the allele frequencies (p or q) without heterozygote frequencies.
f(AA) = 0.15, f(Aa) = 0.26, f(aa) = 0.59 Is the pop. in Hardy-Weinburg equilibrium?
No, there is an excess of homozygotes pred- 0.08, 0.40, 0.52 obse- 0.15, 0.26, 0.59
Which of the following selection regimes would result in the most rapid fixation of a rare allele, e (and loss of allele E)?
Relative fitness values: EE = 0.6, Ee = 0.8, ee = 1
Which of the following is a contribution of Linnaeus to evolutionary thinking?
Species can be grouped by similarity and organized in a hierarchical way
A buck rabbit has the genotype AaBb> why will none of its gametes (sperm cells) contain the genotype Aa?
The Law of Segregation states that allele pairs separate during gamete formation
Initially, there is a high frequency of an allele for high venom production (H) in the western part of the range of the prairie rattle snake and a low frequency of the allele (H) in the eastern part of the range. the rate of migration is the same in both directions. How will the frequency of the H allele change in the eastern pop. and in the western pop. if migration is the only evolutionary process that is acting?
The allele frequency will eventually be the same in both the eastern and western pop.
A new rare allele "A" occurs in a population where the common allele is "a." these are the relative fitness values of the three genotypes in the population. AA = 1, Aa = 1, aa = 0.6 What do you predict will happen to the frequency of the "A" allele across generations?
The frequency of "A" will increase rapidly at first but will slow down as "A" becomes more common.
Which of the following best describes the geologic process known as uniformitarianism?
The gradual erosion of mountains by water
Thomas Malthus was known for arguing that...
The rate of population growth exceeds the rates of increases in food, as he described in the Principal of Population
which of the following statements is true?
a mutation-selection balance maintain allelic diversity and low levels of deleterious alleles
In the early 1900s, biometricians argues that
all of these answers are incorrect: - only discrete variation evolves - continuous variation is not inherited - mutation created new species suddenly
there are several reasons to think that asexual parthenogenesis should be more common than it is. Which of the following is a benefit of reproducing asexually?
asexual lineages have a "two-fold" advantage with respect to the number of descendants produced
Which of the following is most likely to result in speciation events?
chromosome polyploidy
The purpose of the Freeman et al (2020) study was to
compare nest predation of birds in both tropical and temperate regions
in a human population, children of cousins have a relative fitness of 0.85 while of non-relatives have a relative fitness of 1. What is the coefficient of inbreeding depression for the offspring of cousins in this population?
delta = 1 - (wi/wo) delta = 1 - (0.85/1) delta = 1 - 0.85 = 0.15 answer = 0.15
which of the following is a correct statement about chromosomal mutations?
duplication events are a potential source of new genes
male peacocks have large, showy tail feathers which females find attractive. To escape predatory cats (like leopards) peacocks and peahens roost in trees. However, birds with very long tails are too heavy to fly into trees. What is this an example of?
evolutionary trade-off
in a pop. that you know is in H-W equilibrium, if f(AA) = 0.49, what are the allele frequencies?
f(AA) = 0.49 --> p^2 = 0.49 --> f(A) = p = 0.7 f(a) = 1 - p = 1 - 0.7 = 0.3 p = 0.7, q = 0.3
The pangenesis theory of inheritance states that
gametes contain hereditary material contributed from all parts of the body
inbreeding increases the frequency of deleterious recessive alleles in a pop. This is demonstrated by
high F coefficient
Bt bacteria produce a natural pesticide. widespread use of Bt has led to Bt resistant among insects. What is the best answer to explain why this is occurring
individual insects that have mutations providing resistance to Bt can survive in the presence of Bt. The survivors pass this Bt resistance on to their offspring
In Drosophila melanogaster, there is a mutation that increases sensitivity to CO2. the rate of this mutation is low, and the mutation is slightly deleterious in effect. approximately, what do you expect the frequency of mutation to be in drosophila melanogster?
intermediate frequency
genetic drift is a process that
involved random changes in allele frequencies
in both the prairie chicken and Florida panther examples, introductions seemed to be beneficial. What was one possible risk of introducing new individuals to these populations?
it could have swamped local adaptations
When Freeman et al (2020) found latitudinal differences did not explain rates in different nest predation, they tested an alternative hypothesis that
longer nesting period is associated with decreased rate of nest predation
evolutionary theory predicts that traits closely associated with fitness should generally have
lower levels of heritability than traits that are less important for fitness
conservation managers often try to purchase corridors of undeveloped habitat so that larger preserves are linked into networks. What genetic goals does this aim to accomplish?
maintain gene flow between the populations and prevent loss of variation
which of the following statements is false?
migration-selection balance decreases allelic diversity
does evolution occur as a result of non-random mating?
no, because allele frequencies do not change under non-random mating
Which of the following statements is correct?
non-random mating (acting alone in a pop) causes genotype frequencies to change without changing allele frequencies
On his travels on the HMS Beagle, Darwin observed that
organisms in one part of the world has similar counterparts in other parts some organisms are endemic to certain locations, like islands organisms on the Galapagos Islands were similar to those on the mainland of South America
male and female eastern bluebirds are sexually dimorphic (have different coloration) and are monogamous. however, birds of equal levels of relative brightness, as well as those that demonstrate similar levels of territorial aggression, pair up. This is an example of
phenotypic assortative mating
consider two pop. of elk: one in Rocky Mountain national park and one in Yellowstone national park. In both pop. individuals who breed are 10 pounds heavier than the mean of the population as a whole. The heritability for weight is twice as great in the Rocky Mountain pop when compared to the Yellowstone pop. The response to selection will be:
positive in both populations, but larger in Rocky Mountain population than in the Yellowstone population
which of the following is an accurate statement about natural selection
selection acts on phenotypes but can change allele frequencies
which of the following is a correct statement regarding selection?
selection acts on phenotypes but changes allele frequencies (for heritable traits)
how does sexual reproduction "break" Muller's ratchet
sex can rid a lineage of genetic load (of deleterious alleles)
a volcano erupted on an island. the ash released from the volcano changed the acidity (pH) of the soil from the level it had been for hundreds of years. The significant changes resulted in new environmental pressures on species in the soil. Which of the following is a likely outcome of these pressures?
some species will disappear from the soil because they do not have individuals with traits that allow them to survive in more acidic soil
a population of tree-dwelling rodents lives on a single tree species that is characterized by feeble, widely-spread branches. Smaller individuals with shorter limbs are unable to move easily throughout the tree to collect food whereas overweight individuals break the branches and fall out of the tree. What type of selection pattern would you expect to see overtime?
stabilizing selection
independent assortment refers to which of the following observations?
the alleles of two different unlinked genes are inherited randomly in all possible combinations
which of the following is not a cost of sex
the cost of producing offspring
a long-term effect of genetic drift is
the fixation of alleles
A frog with genotype GG is green, Gg is yellow, and gg is yellow. Which of the following is true?
the g allele is dominant because the heterozygote has the same phenotype as the gg homozygote
a genetic analysis of a single locus with the two alleles (A and a) in a pop. of thrips reveals that 2 out of 200 individuals are heterozygous at this locus, and the frequency of the A allele is 0.5. Which of the following is a reasonable conclusion from this study? H=2pq(1-F)
the high value of F suggests that this population has experienced a lot of inbreeding
Purging can occur over multiple generations of inbreeding. the term purging is best described as
the removal of deleterious alleles by selection
genetic drift is a strong evolutionary force in small populations because
the time to fixation of an allele due to drift is shorter in small populations, so selection does not have much time to act
Freeman et al (2020) were motivated to study bird nest predation because other evolutionary biologists had hypothesized that
there are more ecological interactions in tropical regions, and this may lead to faster rates of adaption
Across 25 villages in eastern Europe, the blood pressure of 2760 individuals was recorded. High blood pressure is associated with decreased longevity. The scientists found that when F=0, the prevalence of high blood pressure was 18% when F=0, the prevalence of high blood pressure was 55% when F = 0.5. This study provided evidence that
there is a positive relationship between increased inbreeding and decreased fitness.
Suppose that cod that are slow to mature are more likely to be harvested before they reproduce. We would expect to see a response (change in the age-at-maturity) to this selection pressure only if:
there is heritable variation for this trait
Freeman et al (2020) used the strong inference approach because
they tested multiple alternative hypotheses
according to the "tangled bank" hypothesis, sexually produced offspring should be more variable than asexually-produced offspring, which could provide a survival benefit in a variable or changing physical environment
true
you hypothesize that a long proboscis in sphinx moths represents an adaptation for reaching nectar in long tubular flowers. you test this hypothesis by studying proboscis length in sphinx moths and flower length in the plants they visit. you decide to use "independent contrast" in your analysis. to fo this you would:
use an evolutionary phylogenic tree to determine differences in the proboscis length and flower length between sister species of sphinx moths
