Biology: Chapter 19-21 Test

Disruptive selection

A biologist doing a long-term study on a wild spider population observes increased variation in silk thickness. Which of the following could the spider population be experiencing?

All organisms use essentially the same genetic code (DNA)

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

The appendix has a substantial amount of defensive lymphatic tissue

Which of the following statements most detracts from the claim that the human appendix is a completely vestigial organ?

Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency

Within six months of effectively using methicillin to treat S. aureus infections in a community, all new infections were caused by MRSA. How can this result best be explained?

A genetic bottleneck

An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?

Homologous; analogous

Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?

A mechanism for evolution that was supported by evidence

Charles Darwin was the first person to propose

Charles Lyell

Darwin's mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earth's ancient age?

Characteristics acquired during an organism's life are generally not passed on through genes. Changing organisms do not change to offsprings

During a study session about evolution, one of your fellow student's remarks, " The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result: Which is mostly likely to be helpful in correcting this student's misconception?

Stabilizing selection

Examine the figure above. What type of selection for body size appears to be occurring in these marine iguanas?

No gene flow

For a biologist studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet?

No mutation

For biologists studying a large flatworm population in the lab, which Hardy-Weinberg condition is most difficult to meet?

Must be present in a population before natural selection can act upon the population

Genetic variation

Their genomes should be more similar to each other than are the genomes of the five tree finch species.

If the six ground finch species have evolved most recently, then which of these is the most logical prediction?

More recently they shared a common ancestor

In Darwin's thinking, the more closely related two different organisms are, the

0.09

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?

The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.

In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer?

Lamarck

In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of

Directional selection; stabilizing selection

In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the β hemoglobin alleles in the human gene pool. In the United States, the parasite that causes malaria is not present, but African-Americans whose ancestors were from equatorial Africa are present. What should be happening to the sickle-cell allele in the United States, and what should be happening to it in equatorial Africa?

The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

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?

Stabilizing selection

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?

Bones in the flipper of a whale

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits, making them vestigial

Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

Founder effect

Refer to the paragraph on dark-eyed junco birds. The UCSD campus male junco population tails were, on average, 36% white, whereas the tails of males from nearby mountain populations averaged 40-45% white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to

Founder effect

Soon after the island of Hawaii rose above the sea surface (somewhat less than one million years ago), the evolution of life on this new island should have been most strongly influenced by

Two of the statements above are correct

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

Founder effect and genetic drift

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including those in their original homeland. Which of the following likely explains the genetic uniqueness of this population?

The population is small

The evolutionary effects of genetic drift are greatest when

C

The following question refers to the figure, 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?

Cuvier

The following question refers to the figure, which shows an outcrop of sedimentary rock whose strata are labeled A-D. Who would have proposed that the boundaries between each stratum mark the occurrence of different localized floods?

The limits of historical constraints

The inability of organisms to evolve anything that could be an advantage reflects

Humans synthesize methicillin and create environments in which bacteria frequently come into contact with methicillin.

The rise of methicillin-resistant Staphylococcus aureus (MRSA) can be considered to be an example of artificial selection because

Disruptive selection

Three-spined stickleback fish (Gasterosteus aculeatus) show substantial heritable variation in gill-raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water prey, while shorter gill rakers function better for capturing shallow-water prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish?

It must be homologous to some feature in an ancestor

What must be true of any organ that is described as vestigial?