41) If after several generations most males have antlers with : 1380847.
41) If after several generations most males have antlers with 20 points, this development will have been the result of:
A) directional selection.
B) disruptive selection.
C) founder effect.
D) bottleneck effect.
42) If after several generations 30 percent of the males have antlers with 9 to 11 points, 40 percent have antlers with 15 to 17 points, and 20 percent have antlers with 12 to 14 points, this development will have been the result of:
A) directional selection.
B) disruptive selection.
C) founder effect.
D) stabilizing selection.
43) If after several generations all males have 12-point antlers, this development will have been due to:
A) directional selection.
B) disruptive selection.
C) founder effect.
D) stabilizing selection.
44) Phenotypes that show a wide range of almost continuous variation, such as height or skin color in humans, are probably:
A) due to several sets of alleles working together.
B) due to both alleles of one gene working together.
C) acquired characteristics.
D) dominant.
45) You are studying leaf size in a natural population of plants. The second season is particularly dry, and the following year the average leaf size in the population is smaller than the year before. But the amount of overall variation is the same, and the population size hasn’t changed. Also, you’ve done experiments that show that small leaves are better adapted to dry conditions than are large leaves. Which of the following has occurred?
A) stabilizing selection
B) directional selection
C) genetic drift
D) disruptive selection
46) The most important kind of selection acting on a well-adapted population in a relatively constant environment is:
A) disruptive.
B) stabilizing.
C) directional.
D) catastrophic.
47) Disruptive selection operates whenever:
A) a phenotype is more successful because it is rare.
B) natural selection is disrupted by genetic drift.
C) the extremes in a distribution of phenotypes are more fit than the average.
D) only the largest individuals survive.
48) How have Caesarean sections and intensive neonatal (near-birth) medical care likely affected the average birth weight of American babies?
A) Birth weight is now subject to disruptive selection instead of stabilizing selection.
B) Average birth weights have significantly decreased.
C) Gene flow will occur in the direction of larger and smaller infants.
D) Stabilizing selection for birth weight no longer has as much of an influence.
49) For a particular character, natural selection can favor an average phenotype or extreme phenotypes. In order to do this, a character must be:
A) under the control of many genes.
B) under the control of only two alleles for a gene.
C) not under the control of any genes.
D) controlled by a dominant allele for a gene.
50) African black-bellied seedcracker finches have beaks that are either large or small. Only large-beaked birds can crack open hard seeds, and small-beaked birds are more adept at handling small seeds. Both have an advantage over intermediate-sized beaks. This is an example of a response to:
A) directional selection.
B) stabilizing selection.
C) disruptive selection.
D) sexual selection.
51) Male guppies are known for their bright colors. Having bright colors attracts mates, but it also attracts predators. So in an environment with a lot of predators, male guppies have more dull colors. In an experiment, guppies were removed from an area with predators to an area without predators. Over a period of 12 months the population became much more colorful. This is an example of a response to:
A) directional selection.
B) stabilizing selection.
C) disruptive selection.
D) mutation.
41) If after several generations most males have antlers with : 1380847
