Mastering Biology - Ch 22

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? A B C D

C

Identify the four postulates of natural selection. Select all that apply: Survival and reproductive success are variable among individuals in a population. Individuals in a population all possess the same traits. Individuals with certain traits are more likely to survive and reproduce. All individuals in a population have equal reproductive success. Some trait differences are heritable. Individuals in a population vary in the traits they possess.

Darwin's four postulates can be summarized as follows: Individuals in a population vary in the traits they possess. Some trait differences are heritable. Survival and reproductive success are variable among individuals in a population. Individuals with certain traits are more likely to survive and reproduce.

True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics.

True In an environment without antibiotics, individual cells probably would not differ in their reproductive rates or their survival. Without the application of the drug (antibiotic), it would be very difficult to analyze any differences—one wouldn't even be able to sort the cells!

A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year's crop: Individual A—Yield: 179 bushels/acre; drought resistance: high Individual B—Yield: 220 bushels/acre; drought resistance: low Individual C—Yield: 185 bushels/acre; drought resistance: medium Individual D—Yield: 140 bushels/acre; drought resistance: high Individual E—Yield: 200 bushels/acre; drought resistance: medium Which of the following crosses would produce the highest corn yield with the highest resistance to drought? a. A and E b. C and E c. A and B d. B and B

a. A and E This cross would result in an average corn yield of 189.5 bushels/acre and have a medium-high drought resistance, which is the best you can get for both traits.

Which of the following organisms could be produced by artificial selection? a. A cow that produces a large quantity of milk. b. A chimpanzee that communicates through sign language. c. A dog that serves as the "eyes" for a blind individual. d. A rabbit that is housebroken.

a. A cow that produces a large quantity of milk. A cow's ability to produce milk is a heritable trait that can be manipulated by artificial selection.

For which one of the following observations were both Lamarck's hypothesis and Darwin's hypothesis in complete agreement? a. Gradual evolutionary change explains why organisms are well-suited to their environments. b. Acquired characteristics are inherited. c. More complex species are descended from less complex species. d. Use and disuse of organs determines their size in progeny.

a. Gradual evolutionary change explains why organisms are well-suited to their environments.

The island fox, Urocyon littoralis, is endemic to the Channel Islands, which are located off the coast of southern California. Six of the eight Channel Islands support fox populations, and each of these islands is home to a distinct subspecies, as shown in the table below. Northern Channel Islands: Island - Santa Cruz, Subspecies - U. l. santacruzae; Island - Santa Rosa, Subspecies - U. l. santarosae; Island - San Miguel, Subspecies - U. l. littoralis Southern Channel Islands: San Nicolas, Subspecies - U. l. dickeyi; Island - San Clemente, Subspecies - U. l. clementae; Island - Santa Catalina, Subspecies - U. l. catalinae The island fox shares a common ancestor with the gray fox, Urocyon cinereoargenteus, which is found on the mainland. Both species have similar coloration and a diploid chromosome number of 66. One structural difference between the two species is the reduced size of the island fox, a feature known as dwarfism. The various island subspecies also differ from each other in size, number of tail vertebrae, and other characteristics. The phylogenetic tree below shows the evolutionary relationships between the island fox subspecies and the gray fox. Drag the labels to their appropriate locations on the tree.

a. Group 1 - ancestor of gray foxes and island foxes b. Group 1 - ancestor of Santa Rosa and San Miguel foxes c. Group 2 - dwarfism d. Group 1 - ancestor of northern Channel Island foxes e. Group 3 - most closely related f. Group 1 - ancestor of southern Channel Island foxes g. Group 1 - ancestor of island foxes h. Group 1 - ancestor of Santa Catalina and San Clemente foxes

Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype? a. No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host. b. Yes, drug-susceptible cells can infect a new host more easily than drug-resistant cells. c. Yes, drug-resistant cells can infect a new host more easily than drug-susceptible cells.

a. No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host. A cell's drug susceptibility or resistance does not affect its ability to infect another host, although a cell's drug resistance would increase that cell's chances to spread in an environment containing antibiotics due to increased survival.

Which term describes a trait that increases an individual's ability to survive in a particular environment? a. Fitness b. Adaptation c. Heritability d. Evolution

b. Adaptation An adaptation is a trait that increases an individual's ability to survive in a particular environment.

Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection? a. Heritable variation does not exist among individuals in a population. b. Heritable variation exists for traits among individuals in a population. c. Drug resistance exists among all individuals in a population. d. Environmental variation exists for traits among individuals in a population.

b. Heritable variation exists for traits among individuals in a population.

Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection? a. Individuals experience no success in their ability to survive or reproduce. b. Individuals experience differential success in their ability to survive or reproduce due to differences in certain traits. c. Individuals experience uniform success in their ability to survive or reproduce. d. Individuals experience unlimited success in their ability to survive or reproduce.

b. Individuals experience differential success in their ability to survive or reproduce due to differences in certain traits. Variation in fitness is required for selection to change the characteristics of a population over time. Remember that selection also requires that the variation in fitness be related to a heritable trait.

Which pair of chickens should a farmer breed to produce larger chickens? a. Small hen, small rooster b. Large hen, large rooster c. Large hen, small rooster d. Small hen, large rooster

b. Large hen, large rooster Large parents should be bred to produce larger offspring.

Which of the following statements about natural selection is true? a. Natural selection is a process whereby genes are selected randomly for preservation in the next generation. b. Natural selection favors individuals that reproduce more than others. c. Natural selection occurs in opposition to evolution. d. Natural selection can be used by farmers to generate organisms with desirable traits.

b. Natural selection favors individuals that reproduce more than others. Individuals who are better able to survive and reproduce are more likely to be selected for than individuals who don't survive or cannot reproduce.

Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment? a. The drug-susceptibility trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. b. The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. c. The drug-susceptibility trait is an adaptation to the environment of antibacterial soaps. d. The drug-resistance trait is an adaptation to the environment in which human hosts travel worldwide and are exposed to new strains of bacteria.

b. The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. Bacterial cells have higher fitness when they are drug resistant in the new environment in which people have been medicated with antibiotics.

What are adaptations? a. geologic changes over time b. inherited characteristics of organisms that enhance their survival c. rocks containing fossils d. descent with modification from a common ancestor

b. inherited characteristics of organisms that enhance their survival

Which term describes the ability of a trait to be passed on to offspring? a. Fitness b. Adaptation c. Heritability d. Evolution

c. Heritability Heritability is the ability of a trait to be passed on to offspring.

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? a. The corn borer must lack variation in resistance to the toxic protein. b. The corn borers must experience no success in their ability to survive or reproduce. c. 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. d. The corn borers must experience unlimited success in their ability to survive or reproduce.

c. 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. If all these conditions are true, then the corn borer might evolve resistance to the toxic protein.

Of the following anatomical structures, which is homologous to the bones in the wing of a bird? a. chitinous struts in the wing of a butterfly b. bones in the hind limb of a kangaroo c. bones in the flipper of a whale d. bony rays in the tail fin of a flying fish

c. bones in the flipper of a whale

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. In Darwin's tree of life, each fork in the tree represents ________. a. groups of living organisms b. morphologic gaps in the fossil record c. the most recent common ancestor of the subsequent branches d. groups of extinct organisms

c. the most recent common ancestor of the subsequent branches

Some monkey flowers (Mimulus guttatus) living near the sites of copper mines can grow in soil containing high concentrations of copper, which is toxic to most plants. Copper tolerance is a heritable trait. The map below shows the area near an old copper mine, which contaminated the nearby soil with copper. A stream flows past the mine toward the lake at the bottom right of the map. Select the three statements that are true: a. Natural selection favors copper tolerance in all soils near the old mine, not only in the contaminated soils. b. Copper contamination in the soil created copper-tolerant plants. c. Copper-tolerant plants are found only in contaminated soils. d. If you were to test monkey flowers growing on the shore of the lake, you would expect nearly 100% of them to be copper tolerant. e. The population that existed before mining must have included both copper-tolerant and copper-intolerant plants. f. Nearly 100% of monkey flowers growing in copper-contaminated soil are copper tolerant.

d. If you were to test monkey flowers growing on the shore of the lake, you would expect nearly 100% of them to be copper tolerant. e. The population that existed before mining must have included both copper-tolerant and copper-intolerant plants. f. Nearly 100% of monkey flowers growing in copper-contaminated soil are copper tolerant.

Scientific evidence documents the pattern of evolution. The evidence exists in a variety of categories, including direct observation of evolutionary change, the fossil record, homology, and biogeography. Sort the following examples into the correct categories. Drag each phrase to the appropriate bin.

direct observation of evolutionary change: development of drug resistance in bacteria; fossil record: discovery of shells of extinct species, discovery of transitional forms of horses; homology: vestigial pelvis in right whales, similarities in mammalian forelimbs, same genetic code in fireflies and tobacco plants; biogeography: similarity of endemic island species to nearby mainland species, the high concentration of marsupial species in Australia Scientists have directly observed evolution occurring in many instances, including the development of drug resistance in bacteria and other pathogens. The fossil record has provided evidence for extinct species and for transitional forms of organisms, such as the ancestors of present-day horses. Homologies include similarities in structure, development, and DNA sequences in different organisms. Vestigial structures are homologous structures that have a reduced function or no function at all. Examples include the pelvic bones of whales. The geographic distribution of species, such as the high concentration of marsupial mammals in Australia, can provide evidence about common ancestors. In addition, the endemic species found on many island chains yield information about evolution on those islands.