Bio M01 Cheroske Spring 2014 Chapter 13

Blank blank favors phenotypes at both ends of a range over intermediate phenotypes. This type of selection may occur when the habitat is varied.

Disruptive selection

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

Populations produce more offspring than their environment can support.

Blank blank favors intermediate phenotypes, selecting against phenotypes at both ends of a range and reducing variation.

stabilizing selection

Which of the following is the study of the geographic distribution of species on Earth? paleontology microevolution comparative anatomy biogeography comparative embryology

biogeography

Genetic drift is the change in the gene pool of a population due to blank.

chance

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

closely related organisms have more similar DNA and proteins

The evolution of populations due to chance is genetic variation. natural selection. genetic drift. gene flow. has more effect in large populations than in small populations.

genetic drift.

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

has more effect on the evolution of a small population.

In a type of sexual selection often called blank blank, individuals of one sex (usually females) are choosy in selecting their mates. This choice is often based on the showy appearance or behavior of the male.

mate choice

"Differential success in reproduction" is just another way of saying _____. natural selection variation recombination genetic drift mutation

natural selection

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

natural selection

The smallest unit that can evolve is a _____. population species genotype morph gene

population

In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in blank blank, differences between the sexes in size, appearance, and behavior.

sexual dimorphism

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 _____. the bottleneck effect the founder effect stabilizing selection gene flow genetic drift

the bottleneck effect

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 _____. the founder effect the bottleneck effect genetic drift stabilizing selection gene flow

the founder effect

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

the frequency of the green allele will increase.

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

variation in individuals

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

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

Blank blank favors phenotypes at one end of a range and is common in periods of environmental change.

Directional selection

Blank blank is when a population may gain or lose alleles when fertile individuals move into or out of the population or when gametes are transferred between populations (pollen in the wind).

Gene flow

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? This is an example of genetic drift. Natural selection causes the frequency of the brown allele to increase. Gene flow causes the frequency of the brown allele to increase. Natural selection causes the frequency of the green allele to increase. Gene flow causes the frequency of the green allele to increase.

Gene flow causes the frequency of the brown allele to increase.

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

Green beetles leave more offspring than brown beetles because they are better at finding food.

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

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

Blank blank is a type of sexual selection in which individuals of one sex (usually males) compete directly for mates. This may involve ritualized displays or physical combat.

Intrasexual selection

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

Organisms better adapted to their immediate environment are most likely to survive and reproduce.

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

The HIV virus has an extremely high rate of mutation.

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

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

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

a group of individuals of the same species occupying a given area

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 _____. any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time AIDS should gradually become less variable with a lower mutation rate humans will develop weaker immune systems as an evolutionary response to natural selection individual humans will evolve to become immune to AIDS as long as they are exposed to it as young children

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