Chapter 22 & 23 Quiz MDC Bio 2
Which statement about variation is true?
All new alleles are the result of nucleotide variability.
You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?
Allele frequency cannot be determined from this information. Submit
Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?
Simple morphologies convey some advantage in most parasites.
Pseudogenes are _____.
nonfunctional vestigial genes
When Cuvier considered the fossils found in the vicinity of Paris, he concluded that the extinction of species _____.
occurs, but that there is no evolution
Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?
Populations tend to increase at a faster rate than their food supply normally allows
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the frequency of individuals that are homozygous for this allele?
0.09
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals that are heterozygous for this allele?
0.32
The following question refer to the evolutionary tree in the figure below.The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V-Z) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.How many distinct species, both living and extinct, are depicted in this tree?
11
Suppose 64% of a remote mountain village can taste phenylthiocarbamide (PTC) and must, therefore, have at least one copy of the dominant PTC taster allele. If this population conforms to Hardy-Weinberg expectations for this gene, what percentage of the population must be heterozygous for this trait?
48%
If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be _____.
54%
The following question refer to the figure below, which shows an outcrop of sedimentary rock whose strata are labeled A-D.If x indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?
C
During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?
Characteristics acquired during an organism's life are generally not passed on through genes.
Which of these conditions are always true of populations evolving due to natural selection?Condition 1: The population must vary in traits that are heritable.Condition 2: Some heritable traits must increase reproductive success.Condition 3: Individuals pass on most traits that they acquire during their lifetime
Conditions 1 and 2
What must be true of any organ described as vestigial?
It must be homologous to some feature in an ancestor.
Use the following information to answer the question(s) below.Researchers studying a small milkweed population note that some plants produce a toxin and other plants do not. They identify the gene responsible for toxin production. The dominant allele (T) codes for an enzyme that makes the toxin, and the recessive allele (t) codes for a nonfunctional enzyme that cannot produce the toxin. Heterozygotes produce an intermediate amount of toxin. The genotypes of all individuals in the population are determined (see chart) and used to determine the actual allele frequencies in the population.Refer to the figure above. Is this population in Hardy-Weinberg equilibrium?
No; there are more homozygotes than expected.
DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Instead, DDT is largely useless against many insects. Which of these would have prevented this evolution of DDT resistance in insect pests?
None of the insect pests would have genetic variations that resulted in DDT resistance.
Currently, two extant elephant species (X and Y) are classified in the genus Loxodonta, and a third species (Z) is placed in the genus Elephas. Thus, which statement should be true?
Species X and Y share a greater number of homologies with each other than either does with species Z.
A biologist studied a population of squirrels for fifteen years. During that time, the population was never fewer than thirty squirrels and never more than forty-five. Her data showed that over half of the squirrels born did not survive to reproduce, because of both competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to eighty. Which inference(s) about this most recent surge in the population size might be true?
The amount of available food may have increased and/or the predators that prey upon squirrels may have decreased.
The following question is based on information from Frank M. Frey, "Opposing Natural Selection from Herbivores and Pathogens May Maintain Floral-Color Variation in Claytonia virginica (Portulacaceae)," Evolution 58(11), 2004: 2426-37.Claytonia virginica is a woodland spring herb with flowers that vary from white to pale pink to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time?
The percentage of pink flowers should increase over time.
If the bacterium Staphylococcus aureus experiences a cost for maintaining one or more antibiotic-resistance genes, what would happen in environments that lack antibiotics?
These bacteria would be outcompeted and replaced by bacteria that have lost these genes
A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened?
Triazine-resistant weeds were more likely to survive and reproduce.
The questions below refer to the following evolutionary tree, in which the horizontal axis represents time (present time is on the far right) and the vertical axis represents morphological change.Which species is most closely related to species W?
V is most closely related to species W.
Which of the following scientists argued that variation among individuals allows evolution to occur?
Wallace
Currently, two of the living elephant species (X and Y) are placed in the genus Loxodonta and a third surviving species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate phylogenetic tree?
Z has less ties than Y and X
Prior to the work of Lyell and Darwin, the prevailing belief was that Earth is _____.
a few thousand years old, and populations are unchanging
Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of _____.
a vestigial trait
A population of organisms will not evolve if _____.
all individual variation is due only to environmental factors
Of the following anatomical structures, which is homologous to the bones in the wing of a bird?
bones in the flipper of a whale
The role that humans play in artificial selection is to _____.
choose which organisms reproduce
Which of the following is the most predictable outcome of increased gene flow between two populations?
decreased genetic difference between the two populations
Which of the following is the best modern definition of evolution?
descent with modification
Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____.
dismissed the idea that species are constant and emphasized the importance of variation and change in populations
Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, which develop from similar embryonic tissues. These structural similarities are an example of _____.
homology
Mutation is the only evolutionary mechanism that _____.
does little to change allele frequencies
Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing _____.
gene flow
Which of the following must exist in a population before natural selection can act upon that population?
genetic variation among individuals
In the formula for determining a population's genotype frequencies, the "2" in the term 2pq is necessary because _____.
heterozygotes can come about in two ways
In the formula for determining a populations genotype frequencies, the "pq" in the term 2pq is necessary because _____.
heterozygotes have two alleles
Genetic variation _____.
must be present in a population before natural selection can act upon the population
Catastrophism was Cuvier's attempt to explain the existence of _____.
the fossil record
The following question refer to the figure below, which shows an outcrop of sedimentary rock whose strata are labeled A-D.If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?
two strata
With what other idea of his time was Cuvier's theory of catastrophism most in conflict?
uniformitarianism