10.3 speciation #2

A certain species of land snail exists as either a cream color or a solid brown color. Intermediate individuals are relatively rare. Which of the following terms best describes this? a. disruptive selection b. artificial selection c. stabilizing selection d. sexual selection e. directional selection

A

In a very large population, a quantitative trait has the following distribution pattern: nar001-1.jpg Figure 23.1 If the curve shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations, then which of these is (are) probably occurring? 1. immigration or emigration 2. directional selection 3. adaptation 4. genetic drift 5. disruptive selection a. 2 and 3 b. 1, 2, and 3 c. 4 and 5 d. 4 only e. 1 only

A

In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population? a. directional selection b. No selection would operate because the population is in Hardy-Weinberg equilibrium. c. stabilizing selection d. sexual selection e. disruptive selection

A

Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this? a. stabilizing selection b. directional selection c. disruptive selection d. artificial selection e. sexual selection

B

Heterozygote advantage should be most closely linked to which of the following? a. random selection b. stabilizing selection c. sexual selection d. disruptive selection e. directional selection

B

The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant's diet lacks the amino acid, phenylalanine. What maintains the presence of this harmful allele in a population's gene pool? a. heterozygote advantage b. diploidy c. stabilizing selection d. balancing selection

B

Which describes an African butterfly species that exists in two strikingly different color patterns? a. sexual selection b. disruptive selection c. artificial selection d. directional selection e. stabilizing selection

B

Which describes brightly colored peacocks mating more frequently than drab peacocks? a. stabilizing selection b. disruptive selection c. sexual selection d. directional selection e. artificial selection

C

Cattle breeders have improved the quality of meat over the years by which process? a. artificial selection b. directional selection c. stabilizing selection d. A and B e. A and C

D

In a very large population, a quantitative trait has the following distribution pattern: nar001-1.jpg Figure 23.1 What is true of the trait whose frequency distribution in a large population appears above? It has probably undergone a. random selection. b. directional selection. c. sexual selection. d. stabilizing selection. e. disruptive selection.

D

Most Swiss starlings produce four to five eggs in each clutch. Those producing fewer or more than this have reduced fitness. Which of the following terms best describes this? a. artificial selection b. directional selection c. sexual selection d. stabilizing selection e. disruptive selection

D

The average birth weight for human babies is about 3 kg. Which of the following terms best describes this? a. artificial selection b. disruptive selection c. sexual selection d. stabilizing selection e. directional selection

D

When imbalances occur in the sex ratio of sexual species that have two sexes (i.e., other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of a. balancing selection. b. sexual selection. c. stabilizing selection. d. frequency-dependent selection. e. disruptive selection.

D

Male satin bowerbirds adorn structures that they build, called "bowers," with parrot feathers, flowers, and other bizarre ornaments in order to attract females. Females inspect the bowers and, if suitably impressed, allow males to mate with them. The evolution of this male behavior is due to a. natural selection. b. frequency-dependent selection. c. disruptive selection. d. artificial selection. e. sexual selection

E

Mules are relatively long-lived and hardy organisms that cannot, generally speaking, perform successful meiosis. Consequently, which statement about mules is true? a. Mutations cannot occur in their genomes. b. Their offspring have less genetic variation than the parents. c. When two mules interbreed, genetic recombination cannot occur by meiotic crossing over, but only by the act of fertilization. d. If crossing-over happens in mules, then it must be limited to prophase of mitosis. e. They have a relative evolutionary fitness of zero.

E