Unit 1 Test

Which of the following statements might best explain the increase in average beak size in the finch population during the drought?

Finches with bigger beaks are better able to crack thick-walled seeds and produce more surviving offspring.

Cows, which eat grass that is rich in cellulose, contain a special species of bacteria in their digestive tract that helps the cow digest the cellulose. As a result of cellulose digestion, what molecule then becomes available to both the cow and the bacteria?

Glucose

Fitness is a term often used by biologists to explain the evolutionary success of certain organisms. Which feature would a biologist consider to be most important in determining which guppies are "most fit?"

High number of offspring that survive to reproductive age

The process shown above is called:

Hydrolysis

The pesticide DDT was widely used in the 1940s as a method of insect control. In the late 1950s the first DDT-resistant mosquitoes were discovered, and eventually DDT-resistant mosquitoes were found globally. When DDT is used now, the development of DDT resistance in mosquito populations occurs in months rather than years.

Natural selection favors DDT-resistant mosquitoes that are already present in a population when DDT exposure occurs.

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?

The beak size in a large number of finches was measured every year from 1981 to 1987

he bond between the oxygen and a hydrogen within one water molecule is called a polar covalent bond. This means that

The oxygen and hydrogen share electrons unequally, so that the oxygen has a slightly more negative charge than the hydrogen

Water molecules move from the roots of a plant to its leaves via the plant's stem. What property allows it to move up the plant in this way?

Water molecules form hydrogen bonds between them

Which of the following best describes the mechanism behind the change in beak size in the finch population?

A change in gene frequencies in the finch population due to selective pressure from the environmental change

The products of the process shown above:

Provide energy to cells

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

Which of the following correctly illustrates a dipeptide and an amino acid in the optimal position to form a tripeptide?

A.

The introduction of antibiotics such as penicillin many years ago was immediately effective in combating infections caused by the bacteria Staphylococcus. In 1958, however, there were several outbreaks of staphylococcal infections. People with the infections did not respond to treatment with any of the antibiotics, and there was a large number of deaths. The best explanation for this situation is that

Antibiotic-resistant bacteria survived and multiplied, and these were the forms causing the infections

Carbohydrates, phospholipids, and proteins are similar in that they

Are broken down into monomers by the process of hydrolysis

A culture of Spirogyra (an autotrophic alga) is maintained in a water solution containing dissolved carbon dioxide and a source of phosphates but lacking nitrogen compounds. A researcher determines the rates of synthesis of several organic compounds found in the Spirogyra before and after several weeks in the water solution. Which of the following graphs best illustrates a likely result of the experiment?

Carbohydrates, lipids, and nucleic acids all increased, but proteins remained the same.

A researcher is investigating the relationship between the existing species diversity in a community and the ability of an introduced nonnative species to destabilize the community. Which of the following graphs is most consistent with the claim that communities with high diversity are more resistant to change than are communities with low diversity?

D) Y-axis: Survival of invaders X-axis: Species diversity Line: Linear line, Negative slope

Which of the following pictures and description shows the formation of polymers?

Figure 1, which shows dehydration synthesis

The mustard plant Arabidopsis thaliana has several varieties that flower in response to different duration of cold temperatures. One gene, called FLC, controls when the plant produces a flower. Variety 1, found in the Arctic circle, requires at least nine weeks of cold weather to produce a flower, while the more common variety 2 requires on four weeks. Which of the following best explains the variation in flowering response found in Arabidopsis plants?

Random mutations in the FLC gene sequence led to a permanent change in the DNA between the two varieties.

An example of a hydrogen bond is the bond between

The H of one water molecule and the O of another water molecule

Researchers conducted a controlled experiment to investigate the effect of diet on the health of beef cattle. The initial hypothesis was that an abrupt change in diet will benefit beef cattle by reducing the sizes of bacterial populations living in the digestive systems of the cattle. In the experiment, the researchers determined the relative abundance of two bacterial species found in the rumen of cattle. The rumen is a part of the stomach that acts as a fermentation chamber in cattle and other ruminants. Shown in the table are the results from before and after an abrupt change in the cattle's diet. Based on the results, which of the following best explains why the initial hypothesis should be revised?

The abundance of one of the bacterial species increased in response to the change in diet.

In a hypothetical population of beetles, there is a wide variety of color, matching the range of coloration of tree trunks on which the beetles hide from predators. The graphs illustrate four possible changes to the beetle population as a result of a change in the environment due to pollution that darkened the tree trunks. Which of the following includes the most likely change in the coloration of the beetle population after pollution and a correct rationale for change?

The coloration in the population shifted toward more darker-colored beetles, as in diagram IV. The lighter-colored beetles were found more easily by the predators than were the darker-colored beetles.

A group of mice was released into a large field to which no other mice had access. Immediately after the release, a representative sample of the mice was captured, and the fur color of each individual in the sample was observed and recorded. The mice were then returned to the field. After 20 years, another representative sample of the mice was captured, and fur color of each individual in the sample was again recorded. Which of the following best explains the change in the frequency distribution of fur color phenotypes in the mouse population, as shown in the figures above?

The field was composed primarily of light-colored soil and little vegetation, affording gray mice protection from predators

Guppies are small fish found in streams in Venezuela. Male guppies are brightly colored, with black, red, blue and iridescent spots. Males cannot be too brightly colored or they will be seen and consumed by predators, but if they are too plain, females will choose other males. Natural selection and sexual selection both influence the guppy population. When a guppy population lives in a stream without predators, the number of mles that are bright and flashy increases in the population. If a few aggressive predators are added to the same stream, the number of brightly-colored males decreases with about 5 months (3-4 generations). 14. A typical natural population of guppies consists of hundreds of guppies. Which statement best describes the guppies of a single species in an isolated population?

The guppies share many essential characteristics, but also vary in many features.

In a guppy population, what changes would occur gradually over time?

The proportions of guppies having different traits with a population changes.

MRSA is the acronym for methicillin-resistant Staphylococcus aureus. Many of the strains of the common bacterium are also resistant to other antibiotics in use today. The resistance of linked to a collection of genes carried on plasmids that are passed from one bacterium to another by conjugation. Suppose a newly discovered, chemically different antibiotic is used in place of methicillin. Which of the following would be the most likely effect on Staphylococcus aureus antibiotic resistance?

Transmission of the methicillin-resistance plasmid by conjugation would increase among the Staphylococcus aureus population due to destruction of bacteria without the plasmid through the use of the new antibiotic.