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Which agent of evolution increases genetic variation in a population?
mutation natural selection genetic drift migration All of these
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natural selection artificial selection genetic drift mutation All of the above
Which agent of evolution increases genetic variation in a population?
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stabilizing selection. disruptive selection. directional selection. artificial selection.
All of the following are types of natural selection EXCEPT:
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biogeography. phylogeny. ecology. geobiography. molecular biology.
The study of the distribution patterns of living organisms around the world is called:
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are identical--otherwise the hemoglobin cannot function properly. differ depending on how long it has been since the species last shared a common ancestor. reflect differences in how the hemoglobin functions in the species. can only be compared among mammalian species since non-mammalians do not possess hemoglobin. differ depending on whether the species are marine or terrestrial.
The amino acid chains making up hemoglobin in different species:
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Evolution occurs:
only through natural selection. only when the environment is changing. only via natural selection, genetic drift, migration, or mutation. almost entirely because of directional selection. by altering physical traits but not behavioral traits
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the bottleneck effect. the founder effect. the Hardy-Weinberg effect. the mutation effect. the genetic load.
When a sudden change in the environment, such as a flood or fire, reduces the size of a population, the survivors’ collective gene pool will be only a limited representation of what was present before the disaster. This phenomenon is called:
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Directional Stabilizing Disruptive Intermittent Intense
_____________ selection favors organisms with phenotypes that are at one extreme relative to the average phenotype.
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Organisms that are not directly related develop similar traits. Closely related organisms develop similar traits. Closely related organisms adapt to a wide range of different traits. Similar traits evolve at the same time in different organisms. Different organisms merge to become one species.
Which of the following is a statement that describes the concept of convergent evolution?
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occurs too slowly to be observed in nature. can occur in the wild but not in a laboratory. is responsible for the increased occurrence of antibiotic-resistant bacteria. does not occur in human-occupied habitats. * None of these statements is correct.
Evolution:
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A gene pool consists of:
alleles for a gene that all confer the same fitness. the total of all alleles present in a population. the entire genome of an individual of reproductive age. all of the gametes in a population. All of the above are correct.
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small. large. characterized by extensive gene flow. in Hardy-Weinberg equilibrium. undergoing natural selection.
Genetic drift has the strongest effects in populations that are:
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Disruptive Stabilizing Directional Intense Intermittent
______________ selection favors organisms that have character values at both extremes of the phenotypic distribution.
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Extremely different species are fundamentally unrelated in any way. Only DNA sequences can be used to compare relatedness between species. Birds are more closely related to humans than dogs are. Genetic similarities demonstrate species relatedness. The longer two species have been evolving on their own, the fewer the genetic differences between them.
What can be concluded about comparing differences in molecular biology between different species?
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the greater the genetic differences there are likely to be between them. the more different they will look. the more likely their hemoglobin will be composed of the same sequence of amino acids. the more likely they will be to share a common embryology.
The longer two species have been evolving on their own:
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The origin of all genetic variation is:
mutation. glycolosis. mitosis. digestion. respiration
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the gene cannot undergo mutation. one allele exhibits complete dominance over the other alle for that gene. only one allele appears for that gene in that population. the gene causes the organism to be infertile. The gene is located near the centromere on the chromosome, reducing its ability to recombine.
If a gene is fixed in a population:
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the mean value (i.e., average value) and variation of the trait can change. the mean increases and variation increases. the mean changes and the variation decreases. the mean stays approximately the same and the variation decreases. the mean stays approximately the same and the variation increases.
In general, in a population in which a trait is exposed to stabilizing selection over time:
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genetic differences homologous structures convergences DNA bases genetic similarities
The longer two species have been evolving on their own, the greater the number of _____________________ that accumulate between them.
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members of a small population have reduced rates of mating. gene flow increases in the colonizing population. mutations are more common in novel environments. new environments tend to be inhospitable, reducing survival there. small founding populations are rarely genetically representative of the initial population.
When a group of individuals colonizes a new habitat, the event is likely to be an evolutionary event because:
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Most mutations:
are random, meaning they are unrelated to how useful or harmful they might be to the organism in which they occur. are beneficial to the organism in which they occur. are in response to natural selection. are random, meaning that they only occur in small populations. migrate from one population to another.
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evolutionary change due to natural selection. evolutionary change due to random events. changes in the proportion of homozygous recessive individuals due to non-random mating. changes in the proportion of homozygous recessive individuals due to random mating. a random change in allele frequencies that benefits the population.
Genetic drift is best described as:
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one extreme phenotype. two extreme phenotypes. one narrow intermediate phenotype. two otherwise maladapted phenotypes. one broad intermediate phenotype.
Directional selection favors:
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live in the same geographic area. are separated by a barrier such as a new river. evolve under similar selective forces. have a recent common ancestor. are both inedible to predators.
Convergent evolution can occur only when two species:
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Natural selection involves changes in allele frequencies in a population, while genetic drift does not. Natural selection relies on underlying genetic variation as its source, while genetic drift does not. Natural selection involves differential reproductive success in the struggle for existence in an environment, while genetic drift does not. Natural selection is random, while genetic drift is not.
Which of the following is an IMPORTANT difference between natural selection and genetic drift?
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