A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never larger than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80 squirrels. Which inference(s) about this population might be true?

In a hypothetical population’s gene pool, an autosomal gene, which had previously been fixed, undergoes a mutation that introduces a new allele, one inherited according to incomplete dominance. This means that a heterozygote will express a blending of the phenotypes of the homozygous dominant and recessive allele. Natural selection then causes stabilizing selection at this locus. Consequently, what should happen over the course of many generations?

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?

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?

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?

The most accurate conclusion to be drawn sole from the graph is that

A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do not seem to be optimally arranged because

Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution?

In the wild, male house finches (Carpodus mexicanus) vary considerably in the amount of red pigmentation in their head and throat feathers, with colors ranging from pale yellow to bright red. These colors come from carotenoid pigments that are found in the birds’ diets; no vertebrates are known to synthesize carotenoid pigments. Thus, the brighter red the male’s feathers are, the more successful he has been at acquiring the red carotenoid pigment by his food – gathering efforts (all other factors being equal).

During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following is true of this situation?

If a population is in Hardy-Weinberg equilibrium, then no evolution is occurring. Which of the following is NOT a condition for HW equilibrium?

The frequency of genotypes for a given trait are given in the data table and represented by the graph below. Which of the following processes may be occurring in this population, given the allele frequencies?

In modern terminology, diversity is understood to be a result of genetic variation. Which of the following is a recognized source of variation for evolution?

The theory of continental drift hypothesizes that Africa and South America slowly drifted apart after once being a single landmass. The monkeys on the two continents, although similar, show numerous genetic differences. Which factor is probably the most important in maintaining these differences?

The table below compares the % sequence homology of four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic species. Introns are sections of “junk” DNA that are spliced out during the production of proteins, whereas exons are the coding sequences used to build proteins. Each part is numbered to indicate its distance from the promoter, which refers to the area where transcription begins on the gene sequence (i.e. Intron I is that closest to the promoter). The data reported for Species A were obtained by comparing DNA from one member of species A to another member of Species A.

Based on the tabular data, and assuming that time advances vertically, which cladogram is the most likely depiction of the evolutionary relationships among these five species?

Which of the following statements is TRUE regarding cladograms?

Rocky Mountain juniper (Juniperus scopulorum) and one–seeded juniper (J. monosperma) have overlapping ranges. If pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species, then which of these terms are applicable?

1. sympatric species

2. prezygotic isolation

3. postzygotic isolation

4. allopatric species

5. habitat isolation

6. reduced hybrid fertility

The diagram here displays speciation occurring in only 2 generations which is very short on the evolutionary timescale. Which of the following is the correct mechanism displayed?

Rhagoletis pomonella is a parasitic fly native to North America that infests fruit trees. The female fly lays her eggs in the fruit. The larvae hatch and burrow through the developing fruit. The next year, the adult flies emerge.

Prior to the European colonization of North America, the major host of Rhagoletis was a native species of hawthorn, Crataegus marshallii. The domestic apple tree, Malus domestica, is not native to North America, but was imported by European settlers in the late 1700s and early 1800s.

When apple trees were first imported into North America, there was no evidence that Rhagoletis could use them as hosts. Apples set fruit earlier in the season and develop faster, where hawthorns set later and develop more slowly.

Recent analysis of Rhagoletis populations has shown that two distinct populations of flies have evolved from the original ancestral population of flies that were parasitic on hawthorns. One population infests only apple trees, and the other infests only hawthorns. The life cycles of both fly populations are coordinated with those of their host trees. The flies of each population apparently can distinguish and select mates with similar host preferences and reject mates from the population specific to the other host tree. There is very little hybridization (only about 5 percent) between the two groups.

Initially, which of the following isolating mechanisms is likely to have been the most important in preventing gene flow between the two populations of Rhagoletis?

Rhagoletis pomonella is a parasitic fly native to North America that infests fruit trees. The female fly lays her eggs in the fruit. The larvae hatch and burrow through the developing fruit. The next year, the adult flies emerge.

Prior to the European colonization of North America, the major host of Rhagoletis was a native species of hawthorn, Crataegus marshallii. The domestic apple tree, Malus domestica, is not native to North America, but was imported by European settlers in the late 1700s and early 1800s.

When apple trees were first imported into North America, there was no evidence that Rhagoletis could use them as hosts. Apples set fruit earlier in the season and develop faster, where hawthorns set later and develop more slowly.

Recent analysis of Rhagoletis populations has shown that two distinct populations of flies have evolved from the original ancestral population of flies that were parasitic on hawthorns. One population infests only apple trees, and the other infests only hawthorns. The life cycles of both fly populations are coordinated with those of their host trees. The flies of each population apparently can distinguish and select mates with similar host preferences and reject mates from the population specific to the other host tree. There is very little hybridization (only about 5 percent) between the two groups.

Mating between individuals from the two populations of Rhagoletis produce hybrid flies that appear to be healthy and have normal life spans. The eggs laid by these hybrid flies, however, hatch less often than those of flies from either of the two populations. What isolating mechanism seems to be important in this hybrid population?

1. If this evolutionary tree accurately depicts relatedness, then which of the following should be correct?

i. The entire tree is based on maximum parsimony.

ii. If all species depicted here make up a taxon, this taxon is monophyletic.

iii. The last common ancestor of species B and C occurred more recently than the last common ancestor of species D and E.

iv. Species A is the direct ancestor of both species B and species C.

v. The species present at position 3 is ancestral to C, D, and E.

Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?

On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and found only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n=4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago.

Which of these evolutionary trees represents the situation described in the paragraph above (NOTE: yakuba (I) represents the island population, and yakuba (M) represents the mainland population)?

A large assemblage of land snails is subdivided into two populations (A and B) by a river that effectively isolates the two populations for an indefinitely long period. From an evolutionary standpoint, which of the following is the LEAST likely to occur in the two populations?

The average human birth weight is 3.4Kg (7.5 lbs). Infants born too small or too large often have disadvantages and must rely on medical technology for survival. What type of selection is this an example of?

The table here shows selected characteristics used to determine relationships among four species of mammals.

Which of the following cladograms correctly represents the relationships among these species?

A researcher compared the nucleotide sequences of a homologous gene from five different species of mammals with the homologous human gene. The sequence of homology between each species’ version of the gene and the human gene is presented as a percentage of similarity:

What conclusion can be drawn validly from these data?

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference, instead, for cattle blood and mate only with fleas that, likewise, prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleas' habitat?

1. reproductive isolation

2. sympatric speciation

3. habitat isolation

4. prezygotic barriers

You are conducting an experiment to determine the effect of different wavelengths of light on the absorption of carbon dioxide as an indicator of the rate of photosynthesis in aquatic ecosystems. If the rate of photosynthesis increases, the amount of carbon dioxide in the environment will decrease and vice versa. You’ve added an indicator to each solution. When the carbon dioxide concentration decreases, the color of the indicator solution also changes.

Small aquatic plants are placed into three containers of water mixed with carbon dioxide and indicator solution. Container A is placed under normal light, B under green light, and C under red light. The containers are observed for a 24-hour period.

Based on your knowledge of the absorption spectrum graph for photosynthesis, the plant in the container placed under red light would probably...

You are conducting an experiment to determine the effect of different wavelengths of light on the absorption of carbon dioxide as an indicator of the rate of photosynthesis in aquatic ecosystems. If the rate of photosynthesis increases, the amount of carbon dioxide in the environment will decrease and vice versa. You’ve added an indicator to each solution. When the carbon dioxide concentration decreases, the color of the indicator solution also changes.

Small aquatic plants are placed into three containers of water mixed with carbon dioxide and indicator solution. Container A is placed under normal light, B under green light, and C under red light. The containers are observed for a 24-hour period.

Carbon dioxide absorption is an appropriate indicator of photosynthesis in this experiment because...

As a scientist employed by the FDA, you’ve been asked to sit on a panel to evaluate a pharmaceutical company’s application for approval of a new weight loss drug called Fat Away. The company has submitted a report summarizing the results of their animal and human testing. In the report, it was noted that Fat Away works by affecting the electron transport chain during cellular respiration. It decreases the synthesis of ATP by making the mitochondrial membrane permeable to H⁺, which allows H⁺ to leak from the intermembrane space to the mitochondrial matrix. This effect leads to weight loss, according to the report. If this report is accurate and the medicine works as described, then which of the following must be true?

Which of the following questions is most relevant to understanding the Calvin cycle?

A respirometer is a container used to measure the amount of oxygen consumed by an organism. A respirometer was used to determine how environmental temperature affects the uptake of oxygen in one 300-gram rat and one 50-gram mouse. The results of this experiment are shown in the graph here.

Which of the following statements best explains why oxygen is taken up more rapidly at 12^oC than at 20^oC?

A respirometer is a container used to measure the amount of oxygen consumed by an organism. A respirometer was used to determine how environmental temperature affects the uptake of oxygen in one 300-gram rat and one 50-gram mouse. The results of this experiment are shown in the graph here.

Which of the following hypothesis is best supported by the results of this experiment?

Which of the following represents the ΔG of the reaction?

Which of the following best describes the reaction?

In an experiment on the effects of deforestation of a portion of a northern temperate deciduous forest, all the trees were removed from a small mountainside watershed area and herbicides were applied for three years to prevent regrowth. Measurements of the concentration of calcium (an important nutrient) in runoff water were taken both before and after the deforestation. Monthly measurements also were made in a similar watershed in another part of the same forest that had been left undisturbed. The findings are displayed in the graph below.

To estimate the total amount of calcium lost annually by each of the two watersheds, it would be most useful to measure which of the following variables?

A student studied the effects of light intensity on oxygen production in green algae. The algae were suspended in water inside a sealed glass jar, and the jar was placed into a constant temperature, lightproof box containing a light source. A probe was inserted into the jar to record the concentration of oxygen. The probe was connected to a recording device. The setup is shown below. The student decreased the intensity of the light hourly and recorded the corresponding changes in oxygen concentration. The graph here shows the results obtained from the recording device.

An increase in the rate of oxygen production by algae would be accompanied by a comparable increase in the rate of production of which of the following substances?

A scientist studying the oxygen concentration in sealed chambers containing cultured plant cells finds that when the chambers are illuminated, the concentration of oxygen increases. However, when the chambers are kept in the dark, the concentration of oxygen decreases. Why does the oxygen concentration decrease when the chamber is kept in the dark?

The immediate energy source that drives ATP synthesis during oxidative phosphorylation is

Which metabolic pathway is common to both fermentation and cellular respiration?

The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is

Which of the following statements concerning the breakdown of glucose to CO₂ and water is (are) TRUE?

All of the following are functions of the Krebs cycle EXCEPT

Which metabolic process is MOST closely associated with intracellular membranes?

During aerobic respiration, electrons travel downhill in which sequence?

Which of the following is a true distinction between fermentation and cellular respiration?

Photosynthetic activity can be measured using chloroplasts suspended in a buffered solution containing DCPIP, a dye that can accept electrons from the electron transport chain of photosynthesis. Transfer of electrons to DCPIP decreases the relative absorbance of a specific wavelength of light (605 nm) by a solution that contains the dye.

A buffered solution containing chloroplasts and DCPIP was divided equally among six identical samples. The samples were placed at various distances from a lamp, and then all samples were exposed to white light from the lamp for 60 minutes at room temperature. Sample 3 was wrapped in foil to prevent any light from reaching the solution. At 20-minute intervals, the photosynthetic activity in each sample was determined by measuring the relative absorbance of 605 nm light. The results of the experiment are provided below.

If an additional sample containing the chloroplast/DCPIP solution was placed at a distance of 90 cm from the lamp, which of the following predictions would be most consistent with the experimental results?

Why is CO₂ necessary for the disks to float in light reaction based on our photosynthesis lab?

If you boiled the disks in photosynthesis lab, what will be the obvious result and why?