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Which of the following statements does not describe natural selection:
If a group of organisms relocates to a new environment, or if its current environment changes, the organisms that have a higher fitness in the new environment will leave more offspring and may, over time, give rise to a new species.
Humans have modified many species by selectively breeding individual species to develop new species with specific, desired characteristics
Individual organisms with certain characteristics are more fit for their environment than organisms without certain characteristics. The organisms with the best suited characteristics for their environment will live to reproduce, and pass those characteristic on to their offspring
Natural selection can increase the proportion of favorable traits in a population
Question 1 Explanation:
The correct answer is (B). Choice (B) explains artificial selection, the selective breeding of domesticated organisms to increase the expression of desired traits.
Evidence from which of the following does not support evolution:
Direct observation of natural selection
Question 2 Explanation:
The correct answer is (D). Analogous structures are similarities that are not attributable to common ancestry.
Although the leaves of a pitcher plant, a Venus flytrap, and a cactus do not appear to be very similar, they are derived from a structure present in a common ancestor. This is an example of:
Question 3 Explanation:
The correct answer is (A). Homologous structures have a common ancestry.
Male peacocks are famous for their colorful, showy tails, whereas female peahens are brown with no fancy tails. This is an example of sexual dimorphism, found in organisms with two different looks within the species. What mode of selection produces species exhibiting sexual dimorphism?
Question 4 Explanation:
The correct answer is (C). Sexual selection can lead to the evolution of characteristics, both phenotypic and behavioral, that have an adverse impact on survival but promote fitness.
This type of evolutionary fitness is referred to as:
Frequency dependent selection
Question 5 Explanation:
The correct answer is (B). Heterozygote advantage is exhibited in individuals who are heterozygous for a particular trait, and gives the carrier of the trait greater fitness.
Northern elephant seals were hunted by humans in the 1890s, reducing their population size to 20 individuals. Even though their population is now over 30,000, the seals still have reduced genetic variation. What’s the best explanation of this phenomenon?
Question 6 Explanation:
The correct answer is (A). A severe drop in population size can cause a bottleneck effect. In this case, certain alleles were overrepresented in the population of survivors, and other alleles were underrepresented.
Certain cavefish and salamanders have non-functional eyes, which are remnants of the functional eyes of their ancestors. Such examples of “leftover” structures are referred to as:
Question 7 Explanation:
The correct answer is (C). Vestigial structures are of little, if any, importance to the fitness of the organism. They are historical remnants of structures that promoted fitness in their ancestors.
Which of the following statements best indentifies the type of selection resulting in the typical reddish brown to grayish brown coat of white-tailed deer?
Question 8 Explanation:
The correct answer is (C). Stabilizing selection removes extreme variants (white coat) from the population and preserves the intermediate phenotypes (reddish brown to grayish brown).
The Mexican population had significantly lower gene diversity, few alleles at each locus, and the gene frequencies were significantly different from populations at other locations. The Mexican population was sampled from a breeding nursery used to screen for resistance to this pathogen. The nursery is located far away from the wheat population area and has a limited potential for influx of natural inoculation, and was inoculated with a limited number of strains of the pathogen. This is an excellent example of:
Question 9 Explanation:
The correct answer is (A). Founder effect occurs when a few individuals have been isolated from a larger population, and thus a smaller group of individuals establishes a new population whose gene pool differs from the source population. In this case, the Mexican population of the speckled leaf spot was isolated from the general population. This presents a clear example of genetic drift due to a small founding population.
In Australia, only a relatively small number of individuals arrived on this continent with the introduction of modern agriculture, and therefore
It is likely that a sudden change in the environment caused a bottleneck effect
Mutations resulting from natural selection have created new pathogens in the original strain
The low gene diversity is consistent with the founder effect
The transfer of alleles into a new population
Question 10 Explanation:
The correct answer is (C). With the introduction of modern agriculture to Australia, a few individuals of the speckled leaf spot were isolated from the larger population, and thus less genetic diversity was present.
The geographic area with the highest level of gene diversity speckled leaf spot is likely to be the center of origin. Based on this data, that area would be
Question 11 Explanation:
The correct answer is (C). Israel has the highest average gene diversity, and is likely to be the center of origin.
This movement of polar bear populations provides a prime example of
Question 12 Explanation:
The correct answer is (A). Gene flow is the movement of allele frequencies into or out of a population due to the movement of fertile individuals and their gametes.
We can use these data to calculate the allelic frequencies for a given locus, such as the ME locus in the California population. How many S alleles are there in the population?
Question 13 Explanation:
The correct answer is (A). Each individual with the genotype SS has two copies of the S allele; therefore the 16 individual with this genotype have a count of 32 S alleles. The heterozygote individuals (SF) have one of each allele, so there are 11 S alleles and 11 F alleles among them, bringing the total of S alleles to 43 (16 + 16 + 11).
The number of S alleles in the California population at the EST locus is 94, and the number of F alleles is 34. If this population is in Hardy-Weinberg equilibrium, what would be the expected genotype frequencies for SF for the EST locus in the California population?
Question 14 Explanation:
The correct answer is (B). First, it is necessary to calculate the allelic frequencies by dividing the number of S or F alleles by the total number of alleles: 94/128 = 0.734 = p = frequency of the S allele, and 34/128 = 0.266 = q = frequency of the F allele. If the population is in Hardy-Weinburg equilibrium, we would expect the genotype frequency for SF = 2pq = 2(0.734)(0.266) = 0.390.
Which of the following is not a correct condition for Hardy-Weinburg equilibrium to be met:
No gene flow
No natural selection
Question 15 Explanation:
The correct answer is (D). If individuals mate preferentially within a population, random mixing of gametes will not occur and the genotype frequencies change.
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