Mastering Biology Chapter 13 – Flashcards

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).

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.

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.

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

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

The evolution of populations due to chance is A). genetic variation. B). natural selection. C). has more effect in large populations than in small populations. D). genetic drift. E). gene flow.

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles, A). this causes the population to evolve due to gene flow. B). the frequency of the brown allele will increase. C). the frequency of the green allele will increase. D). the frequencies of the brown and green alleles will not change. E). this causes the population to evolve due to genetic drift.

In a population with brown and green alleles for color, genetic drift A). has more effect on the evolution of a small population. B). has more effect on the evolution of a large population. C). always increases the frequency of brown alleles in the population. D). causes populations to become better adapted to their environments. E). occurs when individuals move into or out of a population, changing the allele frequencies in the population.

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct? A). Natural selection causes the frequency of the brown allele to increase. B). Natural selection causes the frequency of the green allele to increase. C). Gene flow causes the frequency of the brown allele to increase. D). Gene flow causes the frequency of the green allele to increase. E). This is an example of genetic drift.

Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection? A). Green beetles migrate out of the population. B). Green beetles leave more offspring than brown beetles because they are better at finding food. C). A storm kills more green beetles than brown beetles by chance. D). Green beetles migrate out of the population, and brown beetles migrate into the population. E). Green beetles and brown beetles always leave the same number of offspring.

A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are individuals with other characteristics is called _____. A). evolution B). natural selection C). descent with modification D). evolutionary adaptation E). homology

Evidence from molecular biology supports the theory of evolution by showing that __________. A). closely related organisms have more similar DNA and proteins B). homologous proteins have arisen separately in many different animal groups C). closely related animal species have similar geographic distributions D). closely related organisms have similar physical characters E). closely related organisms have similar stages of development

Which of the following is the study of the geographic distribution of species on Earth? A). comparative anatomy B). microevolution C). comparative embryology D). biogeography E). paleontology

"Differential success in reproduction" is just another way of saying _____. A). variation B). genetic drift C). recombination D). natural selection E). mutation

Which one of the following statements most closely agrees with the theory of evolution by means of natural selection, as put forth by Darwin? A). Organisms better adapted to their immediate environment are most likely to survive and reproduce. B). Organisms deliberately evolve the structures they need to survive. C). Only the best-adapted organisms will survive. D). Humans arose from chimpanzees. E). Organisms mutate under unfavorable conditions to become better adapted.

Which of the following is a requirement for natural selection? A). nonheritable traits B). variation in individuals C). low numbers of individuals D). a long period of time E). greater numbers of offspring from those that do not survive

When they were first sold, aerosol insecticides were highly effective in killing flies and mosquitoes. Today, some 30 years later, a much smaller proportion of these insects die when sprayed. The reason fewer insects are being killed is that __________. A). mosquitoes are deliberately adapting themselves to this man-made change in the environment B). the original spraying has caused a permanent mutation, giving the insects genetic resistance to the spray C). mosquitoes that survive spraying develop an immunity to the insecticide D). many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics E). over time, evolution produces stronger insects

Scientists have warned doctors of the danger of their increasing use of antibiotics (for instance, penicillin) for treating minor illnesses. They are concerned because _____. A). the drugs are not meant to treat minor illnesses and have numerous side effects B). humans will become tolerant to the effects of drugs C). strains of microorganisms that are resistant to these drugs will increase D). the drugs will be metabolized more quickly by our bodies, decreasing their effectiveness E). excessive use of these drugs leads to a diminished sensitivity to them

Which one of the following was an assumption of Charles Darwin's theory of natural selection? A). Organisms are similar in many ways. B). Traits are inherited as discrete particles. C). Earth is very young. D). Organisms cooperate for limited resources. E). Populations produce more offspring than their environment can support.

A population is __________. A). the number of humans per unit area B). the number of organisms in a particular habitat C). all living organisms on Earth D). a group of individuals of the same species occupying a given area E). organisms of different species that live together

The smallest unit that can evolve is a _____. A). genotype B). species C). gene D). population E). morph

In a population of bears, which is most likely to be considered to have the greatest Darwinian fitness? A). the bear having the largest number of mutations B). the bear that leaves the most descendants C). the bear that blends in with its environment the best D). the biggest bear E). the strongest, fiercest bear

The population of American bison used to number in the millions of animals. Hunting and other problems greatly decreased the number of bison to about 1,000 animals. But today, the numbers are recovering to estimates of more than 200,000 animals. This crash in the population of bison and recent recovery is a good example of _____. A). genetic drift B). the founder effect C). the bottleneck effect D). gene flow E). stabilizing selection

Imagine that a new population of humans is established on a new planet from ten randomly selected people in your biology class. Over thousands of years, the descendants of those ten people reproduce and prosper, but do not reflect well the diversity of humans on Earth. This change in the diversity of people on the new planet is an example of _____. A). genetic drift B). the founder effect C). gene flow D). the bottleneck effect E). stabilizing selection