Mastering Bio Ch 7

Horses and donkeys can reproduce to produce mules. Thus, horses and donkeys are considered to be a single species. A. True B. False

B. False Mules are sterile. Thus, even though horses and donkeys can reproduce, they are still considered to be separate species. This type of reproductive barrier is called hybrid weakness.

Where are the Galapagos Islands located? A. northeast of Australia along the Great Barrier Reef B. in the Mediterranean Sea, as part of the Greek Islands C. near the tip of South Africa D. 600 miles west of Ecuador, near the equator

D. 600 miles west of Ecuador, near the equator

As proposed by Darwin, what sorts of traits are favored by natural selection? A. Any traits that are produced by mutation and can be inherited. B. Traits that reduce the number of offspring an individual produces, thus helping to reduce the struggle for existence in the next generation. C. Traits that reduce the mutation rate and cut down on unnecessary variation within populations. D. Heritable traits that help individuals survive and reproduce more successfully than others in the same population.

D. Heritable traits that help individuals survive and reproduce more successfully than others in the same population.

Which species is threatening the natural wildlife on the Galapagos Islands? A. mountain lions B. Asian carp C. humans D. zebra mussels

C. humans

Which of the following sets of animals are likely to be found on the Galapagos Islands? A. frogs, lungfish, mountain goats B. beaver, snakes, armadillos C. tortoises, finches, blue-footed boobies D. ostriches, cougars, porcupines

C. tortoises, finches, blue-footed boobies

Imagine that four people are infected with HIV from a common source (an infected blood sample). Initially, the patients' HIV populations are genetically identical. By the time they develop full-blown AIDS, how would the viral populations of the four patients compare? A. Each patient's viral population would be unique, specifically adapted to deal with—and overcome—his or her unique immune system responses. B. The viral populations would still be genetically identical to each other and would be unchanged from the time of infection. C. The viral populations would have evolved to a new and more dangerous strain, but that strain would be identical across all four patients. This is the strain of virus found in every person suffering full-blown AIDS.

A. Each patient's viral population would be unique, specifically adapted to deal with—and overcome—his or her unique immune system responses.

Darwinian fitness is measured only in terms of the number of healthy offspring produced. A. True B. False

A. True By definition, Darwinian fitness is the contribution that an individual makes to the gene pool of the next generation in comparison to the contributions from other individuals.

Tourism on the Galapagos Islands is being restricted by requiring tourists to _____. A. be escorted by trained guides at all times B. visit each island in groups of only ten individuals at a time C. stay at least 100 feet away from all animals on the islands D. view the islands only from the water

A. be escorted by trained guides at all times

Speciation is always a slow, gradual process. A. True B. False

B. False The fossil record has many examples of species that appear suddenly, persist with little change, and then suddenly disappear. The term "punctuated equilibrium" describes this type of species change through time.

Imagine that you start with a population of red, white, and blue flowers, a trait controlled by genetics. If you always cut blue flowers before they have a chance to reproduce, the number of blue flowers will change from generation to generation; however, the gene pool will still remain constant. A. True B. False

B. False The gene pool represents all the forms of all of the genes at any one time. It will change as a result of the enhanced reproductive success of the red and white flowers compared to that of the blue flowers.

The human immune system cannot effectively suppress the HIV virus on its own. What key feature of HIV makes it so hard to beat? A. The HIV virus can survive harsh conditions for years as a dormant particle. B. The HIV virus has an extremely high rate of mutation. C. The HIV virus has a special protein coat that protects it from attack by all known human immune defenses. D. The HIV virus replicates its genome with a great deal of precision (i.e., has a low mutation rate).

B. The HIV virus has an extremely high rate of mutation.

Natural selection is best described as _____. A. a creative force that efficiently develops the best and simplest solutions for all problems in nature B. a forward-looking process that anticipates future problems and designs the necessary tools to solve them through mutation C. a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations D. a completely random and unpredictable process of change, or evolution

C. a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations

The Galapagos Islands were the first place on Earth to _____. A. suffer the complete extinction of all native species B. be invaded by human-introduced species C. be declared a world heritage site D. be declared off-limits to all humans

C. be declared a world heritage site

Which of the following are testable hypotheses that could explain the researchers' data? Select all that apply. A. The population size of cliff swallows living near roads has decreased over time. B. The number of cars driving on these roads has increased over time. C. Scavenger population sizes have increased, and more road-killed swallows get eaten before they can be found. D. Traits that help individuals avoid being hit by cars have evolved through natural selection in the cliff swallow population. E. An unknown element has been protecting the swallows.

A. The population size of cliff swallows living near roads has decreased over time. C. Scavenger population sizes have increased, and more road-killed swallows get eaten before they can be found. D. Traits that help individuals avoid being hit by cars have evolved through natural selection in the cliff swallow population.

HIV has become an important source of mortality for humans. If AIDS persists as a major factor for humans for many generations in the future, natural selection theory predicts that _____. A. any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time B. AIDS should gradually become less variable with a lower mutation rate C. humans will develop weaker immune systems as an evolutionary response to natural selection D. individual humans will evolve to become immune to AIDS as long as they are exposed to it as young children

A. any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time