unit 7 test
Humans vary in their ability to taste the bitter chemical compound phenylthiocarbamide (PTC)
0.29
The biologist discovered that from 1988 to 1993, the average beak size declined to pre-1981 levels. The reversal in beak size from 1988 to 1993 was most likely related to which of the following events?
A loss of food supply for the finches
Transposable elements are significant features in the genomes of almost all eukaryotic organisms.....Which of the following best predicts how phylogenetic relationships might be revised if transposon 1 was not found in chimpanzees?
Chimpanzees would be more closely related to humans than to bonobos.
A scientist is attempting to provide support for the hypothesis that RNA was the first genetic material. Which of the following would be a workable alternate hypothesis?
RNA can be observed to self-replicate without the assistance of proteins, while DNA always requires protein-based enzymes to replicate.
A group of people whose ancestors immigrated to North America 200 years ago have certain allele frequencies that differ significantly from those in surrounding populations in the United States. Which of the following is the most likely explanation for the difference in allele frequencies
Reproductive isolation
Which of the following best explains the impact of these new selective pressures on the organisms involved?
The plant species will flower earlier in the spring in response to rising temperatures before the arrival of the pollinators, so seeds will not be produced.
Which of the following statements might best explain the increase in average beak size in the finch population during the drought?
A- Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.
Researchers observed selected internal structures of four different microscopic organisms as part of a larger study on the divergence between eukaryotes and prokaryotes. Their observations are recorded in Figure 1.Which organism would the researchers most likely predict to be the most distantly related to eukaryotes?
A- Organism I
Which of the following best describes the process responsible for the change in the percent of tuskless female elephants in the Gorongosa National Park population shown in Figure 1 ?
A-Human hunting of elephants with tusks between 1977 and 1992.
Some scientists claim that amphibians are currently experiencing a period of mass extinction.Which of the following should be included in an alternative hypothesis that would best support this claim?
A-The current extinction rate of amphibians compared with the background rate of extinction as determined by the fossil record
Interactions among populations determine how they access resources within a community. In Costa Rica, t
C- R. richardsoni is found significantly more frequently on Species 3 and Species 4 compared to Species 1 and Species 2.
In eastern gray squirrels, Sciurus carolinensis, the allele for black fur...
C- The frequency of the BB allele increased due to the selective pressures of the environment.
Which of the following questions about the origin of life on Earth is most scientifically testable?
Can simple organic molecules form spontaneously in an oxygen-free atmosphere?
A researcher hypothesizes that RNA molecules were present in the most recent common ancestor of all living organisms. Which of the following scientific questions would best test the hypothesis?
Do any known organisms function entirely without RNA?
Blackcap birds (Sylvia atricapilla) migrate out of Germany before wintertime. Prior to the 1960s, all members of a particular blackcap population flew to Spain, which had an abundant natural food source. Now, some members of the same blackcap population fly to the United Kingdom, where food placed in feeders by humans is abundant. The blackcaps return to the same forests in Germany to nest during the breeding season.Some blackcaps that migrate to the United Kingdom have become distinguishable by certain physical and behavioral traits from blackcaps that migrate to Spain. Which of the following best predicts the effect on the blackcap population if humans in the United Kingdom continue to place food in feeders during the winter?
The blackcaps that migrate to the United Kingdom will become reproductively isolated from the blackcaps that migrate to Spain, resulting in speciation in the blackcap population. The blackcaps will begin nesting at their wintering sites in Spain or the United Kingdom, resulting in a larger blackcap population migrating back to Germany after the breeding season has ended.
Which of the following pieces of evidence best supports the hypothesis that birds and crocodilians (crocodiles and alligators) are more closely related to each other than they are to other organisms?
The skulls of birds and crocodilians have an opening that is absent in the skulls of other reptiles.
In a long‑term study of a population of gray squirrels, researchers observed that most of the squirrels had gray fur. However, there were some individuals in the population with white fur (albino). Genetic analysis revealed that the albino condition is expressed by individuals who are homozygous recessive (gg). Over a ten-year period, the average frequency of albino squirrels in the population was 0.18. If the population is assumed to be in Hardy-Weinberg equilibrium, the average frequency of the dominant allele is closest to which of the following?
0.58
Gaucher disease type 1 (GD1) is a recessive genetic disease that affects 1 in 900 individuals in a particular population. GD1 is caused by a mutation in the enzyme glucocerebrosidase.Assuming the population is in Hardy-Weinberg equilibrium, calculate the frequency of the wild-type (nonmutant) allele for the enzyme glucocerebrosidase.
0.967
Which of the following best explains the relationship between coat color and predation rate in the rock pocket mouse population on the lava flow rocks with respect to the different coat color phenotypes?
A dark coat color provides camouflage to mice on the lava flow rocks; therefore, mice with dark coats have a lower predation rate in that habitat.
Which of the following statements best supports the claim that organisms share fundamental processes as a result of evolution?
All organisms share a genetic code organized into triplet codons, making it possible for one organism to express a gene from another organism.
Which of the following best describes the mechanism behind the change in beak size in the finch population?
B- A change in gene frequencies in the finch population due to selective pressure from the environmental change
A current challenge for doctors involves the bacterial strain Clostridioides difficile, which no longer responds to traditional antibiotic treatments.
B- The bacteria have high genetic variability and high reproductive rates.
Paleoclimatic analysis has generated a claim that there is a possible correlation between an extinction event around 29 million years ago that allowed grasslands to become abundant and the adaptive radiation of several groups of butterflies.Which of the following proposes the best alternative hypothesis for the claim?
B-Climate analysis conducted by sampling pollen preserved in amber shows an increase in grass pollen 29 million years ago, which indicates there was an increase in grasslands that correlates to an increase in butterfly speciation during the same time period.
The bird, Parus major, is commonly found in man-made habitats. During the summer these birds primarily feed on insects, and in the winter, when insects are scarce, they forage in gardens and bird feeders for seeds, nuts, and berries. Recently, climate change has led to a decrease in food available from gardens, and scientists have observed that the average beak length of the birds has increased.Which of the following best explains the directional shift in beak length in these birds?
C-Longer beaks allow the birds to better access seeds in bird feeders.
A biologist spent many years researching the rate of evolutionary change in the finch populations of a group of islands. It was determined that the average beak size (both length and mass) of finches in a certain population increased dramatically during an intense drought between 1981 and 1987. During the drought, there was a reduction in the number of plants producing thin-walled seeds.Which of the following procedures was most likely followed to determine the change in beak size?
C-The beak size in a large number of finches was measured every year from 1981 to 1987
Lobe-finned fishes were present in the oceans of the world approximately 400 million years ago. The first tetrapods (vertebrates that had limbs and could move on land) date to about 365 million years ago. One hypothesis states that early tetrapods evolved from lobe-finned fishes. Which of the following is the best plan for testing the hypothesis?
Comparing the arrangements of bones in the fins of lobe-finned fishes and limbs of the earliest tetrapods
A small number of lizards from a mainland population have been deposited on four isolated islands because of the effects of a rare strong storm.Which of the following best predicts the outcome of these lizards reproducing for many generations on the islands?
D-The isolation prevents gene flow; thus, the lizards on different islands experience prezygotic isolation.
Finch beak depth was measured before and after a severe drought in 1977. The averaged results are shown in Figure 1. After the drought, there were fewer seeds available for the finches to eat and the seeds that did remain were larger and harder to crack open. Researchers claim that when large, hard seeds are the predominate food source, the average beak depth of these finches tends to increase in subsequent generations.Using the evidence provided, which of the following best justifies the researchers' claim?
Finch beak depth increased as a consequence of selective pressure after the drought because the remaining seeds were larger and harder.
If geologic events lead to a series of new mountain ranges that divide the plateau into several discrete valleys, which of the following best describes how the L. clathratus population would be affected?
Geographic isolation will create separate gene pools, leading to speciation over time.
Rock pocket mice live in the deserts of the American southwest. Ancestral pocket mice all had light-colored coats that blended in with the region's rocks and sandy soil, keeping the mice hidden from predatory owls.
Light-colored mice are significantly more susceptible to predation by owls in habitats with lava rocks than in habitats with sandy soil.
Over several years, bacteria were isolated from members of a human population and tested for antibiotic resistance. The percent of bacterial isolates that were found to be antibiotic resistant is presented in the graph above for each year of the study. Which of the following conclusions is best supported by the information presented in the graph?
Natural selection over multiple generations is favoring antibiotic resistance in the population of bacteria.
Researchers examined the ability of cultures of the bacterium Pseudomonas aeruginosa to adapt to the antibiotics ceftazidime and avibactam when they are administered together. The researchers grew four replicate cultures in growth medium with no antibiotics added (control) and four additional replicate cultures in the same growth medium with added ceftazidime and avibactam. At the conclusion of the experiment, samples of the replicates exposed to the antibiotics were removed and their genomes were sequenced. All of the antibiotic-resistant mutants were missing three genes (hmgA, galU, mexXY). It is known that one of these three genes makes wild-type P. aeruginosa susceptible to the two antibiotics. However, the researchers do not know which gene it is.Which of the following experiments would specifically determine which gene is responsible for ceftazidime-avibactam sensitivity in P. aeruginosa ?
Perform gene knockout (targeted mutation) of either the hmgAhmgA, galUgalU, or mexXYmexXY gene on separate cultures of the wild-type P. aeruginosa. For each individual mutant, determine whether or not ceftazidime-avibactam resistance has occurred.
Which of the following best explains the phenotypic pattern in the moths over time?
The increased air pollution of the nineteenth century due to the use of coal led to a darkening of surfaces from soot. The darker backgrounds conferred a selective advantage to the black variety, as described by natural selection. A shift to less polluting fuel in the twentieth led to cleaner air and a lightening of the moth's normal habitat.
All of the following are examples of prezygotic genetic isolating mechanisms EXCEPT:
The progeny of a cross between two different lizard species fail to develop properly.
Scientists want to determine whether the rapid economic growth in China between 1950 and 2000 caused a mass extinction of animal species during that time period. A mass extinction event is considered to occur when the rate of species extinction far exceeds the background extinction rate. The scientists collected data on the number of extinctions of selected
There is no significant difference between the extinction rate of animals between 1950 and 2000 in China and the background extinction rate.
Which of the following statements best explains how a condition of Hardy-Weinberg equilibrium results in a population that exhibits stable allele frequencies
Without migration or mutation, new alleles cannot be introduced to the population.
The different species of finches on the Galapagos Islands are believed to have arisen as a result of natural selection acting on populations of finches that had experienced
geographic isolation
