unit 3

Select all true statements. A) Allele frequencies in a very large population of snakes changing by chance from one year to the next is due to genetic drift. B) Chance is involved in the production of variation in genetic drift but not in natural selection or sexual selection. C) If a fungal disease quickly spreads through a population of oak trees and a small number of individuals survive but the presence of a specific allele strongly predicts individual survival, this is an example of genetic drift. D) Random allele frequency changes are expected to be larger in small populations than in large populations. E) The direction of an allele frequency change (up or down) that occurs when a population is suddenly reduced to a very small size is not predictable.

A) Allele frequencies in a very large population of snakes changing by chance from one year to the next is due to genetic drift. D) Random allele frequency changes are expected to be larger in small populations than in large populations. E) The direction of an allele frequency change (up or down) that occurs when a population is suddenly reduced to a very small size is not predictable.

Select all true statements A) In a high sun environment, individuals (humans) with light pigmentation are expected to have lower fitness than individuals with dark pigmentation due to folate breakdown. B) In a low sun environment, individuals (humans) with light pigmentation are not expected to differ in fitness from individuals with dark pigmentation. C) In humans, when all food types are abundant, including milk products, the frequency of high lactase activity alleles is expected to increase due to natural selection. D) When milk products are the only food available, the frequency of high lactase activity alleles is expected to increase due to natural selection. E) When milk products are the only food available, the frequency of low lactase activity alleles is expected to increase due to genetic drift.

A) In a high sun environment, individuals (humans) with light pigmentation are expected to have lower fitness than individuals with dark pigmentation due to folate breakdown. D) When milk products are the only food available, the frequency of high lactase activity alleles is expected to increase due to natural selection.

Which of the following statements is TRUE about biological evolution? A) Populations evolve and adapt, but individuals don't. B) Populations evolve and adapt, and individuals can too. C) Individuals evolve and adapt, but populations cannot.

A) Populations evolve and adapt, but individuals don't.

Select all correct statements. A) Scientists have not directly observed the vast majority of variation that exists in living organisms. B) When solving biological problems, it is best to consider rare genetic variants as exceptions or outliers and not useful for helping to answer these problems. C) Genetic variants that are now common first originated as common variants in a large number of individuals. D) There is selective pressure for organisms to have few or no new mutations in their genomes. E) Mutations in any specific gene are rare but in a very large population there is likely to be multiple mutations in every gene.

A) Scientists have not directly observed the vast majority of variation that exists in living organisms. E) Mutations in any specific gene are rare but in a very large population there is likely to be multiple mutations in every gene.

Select all true statements. A) Sexual selection affects standing genetic variation non-randomly. B) Sexual selection is expected to result in phenotypic differences between males and females. C) If a population of animals has a large difference in body size between males and females, then body size has been affected by both sexual selection and natural selection, but not genetic drift. D) If males and females in a population are similar in their body form, size, and color, then this is evidence that sexual selection is not occurring in this population. E) If resources like food and water are concentrated in a few spots within the habitat of an animal population, male phenotypes that attract females will likely be more important for fitness than male weapon phenotypes.

A) Sexual selection affects standing genetic variation non-randomly. B) Sexual selection is expected to result in phenotypic differences between males and females.

In an evolutionary context, fitness refers to: A. The reproductive output of an individual B. The ability of an organism to survive C. The strength, size, speed, and other physical attributes of an organism D. The health of an organism

A. The reproductive output of an individual

A population of oak trees produces acorns with many different sizes. What kind of selection is occurring if the smallest acorns have the highest probability of survival? A. directional selection B. stabilizing selection C. disruptive selection D. no selection is likely occurring

A. directional selection

Which of the following is most likely to increase the strength of genetic drift in a population of mice? A) Decreasing the amount of food available B) Decreasing the population size C) Increasing the population size D) Decreasing the strength of natural selection

B) Decreasing the population size

Which of the following is NOT necessary for natural selection to occur? A. Genetic variation B. Environmental change C. Differences among individuals in survival or reproduction D. Transmission of alleles from parents to offspring

B. Environmental change

How can offspring inherit alleles that are not present in the body cells of their parents? A. Mutations during DNA replication in cell division in the bodies of the offspring B. Mutations during DNA replication when gametes were made in their parents C. Both A and B are true D. Neither A nor B is true

B. Mutations during DNA replication when gametes were made in their parents

Each of the following could cause the dewlaps of Anolis lizards to differ in different places EXCEPT A. The production of different dewlaps by mutation and recombination. B. The lizard's desire to have an attractive dewlap. C. The interest of females in different dewlap colors. D. The visibility of the dewlap color in the environment. E. The visibility of the dewlap to mates.

B. The lizard's desire to have an attractive dewlap.

Evolution is: A) Dependent upon the increased fitness of individuals to proceed B) The process by which natural selection fixes beneficial alleles in a population C) A change in allele frequency over time D) Survival of the fittest

C) A change in allele frequency over time

Select all true statements. A) Fitness refers to health, vigor, and the number of sexual partners. B) Individuals within a species can evolve. C) Only heritable traits can evolve. D) Traits that are not used by an organism are less likely to be inherited. E) Natural selection is the only cause of evolutionary change.

C) Only heritable traits can evolve.

Which of the following statements are TRUE? SELECT ALL. A. Natural selection is considered a theory because it describes patterns of biological change. B. Natural selection is the only cause of evolutionary change. C. Natural selection is one of several causes of evolutionary change. D. Natural selection is the same as evolution.

C. Natural selection is one of several causes of evolutionary change.

A species of butterfly is poisonous to bird predators. Birds learn to avoid this species because when they attack and eat butterflies, the birds get sick. The butterfly species colonizes an island with no predators and over the next one million years gradually loses its toxicity. Which of the following is the most likely explanation for this? A. The butterflies became non-poisonous because they no longer needed protection from birds. B. The butterflies stopped producing toxins because there were no birds attacking them. C. On the island, butterflies without toxins had higher fitness than butterflies with toxins. D. Birds on the island no longer attack the butterflies because they expect them to be poisonous. E. Butterflies on the island no longer produce the toxin because it is too costly to produce.

C. On the island, butterflies without toxins had higher fitness than butterflies with toxins.

Select all true statements. A) The accumulation of genetic differences between isolated populations over time requires sexual selection. B) The accumulation of genetic differences between isolated populations over time requires natural selection. C) New mutations will always happen but two populations that are completely isolated from each other for long periods of time (millions of years) will not always accumulate genetic differences. D) The production of genetic variation, transmission of genetic variation, and sorting of genetic variation are required for speciation to occur. E) The accumulation of genetic differences between isolated populations over time requires competition.

D) The production of genetic variation, transmission of genetic variation, and sorting of genetic variation are required for speciation to occur.

Which of the following is pre-zygotic reproductive isolating mechanism? A) low fertility of hybrid offspring B) low survivorship of young hybrids before reproductive age C) death of hybrid offspring during development D) inability of sperm from one population to fertilize eggs from the other population

D) inability of sperm from one population to fertilize eggs from the other population

The arctic fox has a thick layer of fat under its skin that helps keep it warm in its cold climate. They do not hibernate (sleep through winter) and actively look for food all winter. At the beginning of winter they typically have about 30 days of energy stored in fat. Available evidence shows that this species of fox evolved from ancestors that lived in warmer areas and did not have a thick fat layer. What was most likely true regarding genetic mutations that occurred during the time the fox species was evolving the thick fat layer? A. Most of the mutations helped the foxes survive in their new environment. B. The number of mutations occurring in the fox population increased when the foxes moved into the cold climates and then decreased when the foxes finished adapting to their environment. C. The mutations occurred because foxes had to adapt in order to survive and reproduce in the cold climates. D. The mutations were not affected by temperature or the needs of the foxes.

D. The mutations were not affected by temperature or the needs of the foxes.

Select all true statements. A) Natural selection is best defined by three ideas or concepts: heritable variation, environmental change, and differential survival/reproduction. B) Natural selection is best defined by three ideas or concepts: mutation, competition for resources, and differential survival/reproduction. C) Natural selection is best defined by three ideas or concepts: mutation, environmental change and survival of the fittest. D) Natural selection is best defined by three ideas or concepts: recombination, heritable variation and survival of the fittest. E) Natural selection is best defined by three ideas or concepts: variation, heritability of variants and differential survival/reproduction.

E) Natural selection is best defined by three ideas or concepts: variation, heritability of variants and differential survival/reproduction.

Which of the following processes caused lactase mutations to originate in human populations that used dairy products? A)Environmental pressures B)Evolutionary pressures C)Selective pressures D)All of the above E) None of the above statements are true

E) None of the above statements are true

Which of the following statements is CORRECT? A. Species are reproductively isolated. B. Reproductive isolation can contribute to the formation of new species. C. Geographic isolation or separation can contribute to speciation. D. Species are groups of actually or potentially reproducing natural populations. E. ALL of the above are correct.

E. ALL of the above are correct.