1. Which statement best describes the relationship between the speed of ecological processes versus evolutionary processes?
a. Evolutionary processes are much slower than ecological processes.
b. Ecological processes are much slower than evolutionary processes
c. Biologists used to think that evolutionary processes are much slower than ecological processes, but they now recognize that evolution can happen so fast that ecologists need to understand and be aware of it.
d. Biologists used to think that ecological processes are much slower than evolutionary processes, but they now recognize that ecological processes can happen so fast that evolutionary biologists need to understand and be aware of them.
2. When heavily armored marine sticklebacks have invaded freshwater lakes where there are no predatory fish, their populations have evolved lighter body armor. Why does this happen?
a. Because young sticklebacks only grow heavy armor when they see predatory fish in their environment.
b.Because when individual sticklebacks don't use their armor, it shrinks. They then pass lighter armor to their offspring.
c. Because chemicals in polluted water disrupt the growth of armor.
d.Because heavily armored fish grow more slowly, remain vulnerable to predatory insect larvae for a longer time, experience higher winter mortality, and breed later.
3. Evolution is
a. a change in the composition of a population from one generation to the next.
b. a phenomenon that must be inferred from evidence, because it cannot be observed directly.
c. the transformation of an individual to better fit its environment.
d. driven by the use or disuse of a body part, as when a finch uses its beak to crack open seeds.
4. In a famous test of the notion that evolution happens by the inheritance of acquired characteristics, August Weismann maintained a population of mice in his lab for 22 generations. Each generation he measured tail length, randomly chose individuals to be breeders, snipped off the breeders' tails, and then let breeders mate to produce the next generation. Average tail length did not change from the 1st generation to the 22nd. That is, the population failed to evolve. What's the most likely reason the population did not evolve?
a. Because after Weismann cut off their tails, the breeder mice showed no variation in tail length.
b. Because even if Weismann hadn't cut off their tails, offspring tail length would not at all resemble parental tail length.
c. Because tail length (that is, the length of tails mice were born with) had negligible influence on which individuals surivived to reproduce.
d. Because laboratory mice don't need long tails.
5. Orchids are a type of flowering plant. How would biologists explain how a living orchid species lacking leaves evolved from an ancestral orchid species that had leaves?
6. A dominant allele will always increase in frequency over time.
a. Yes
b. No
7. When a gene has two alleles, the allele frequencies in a population automatically move toward an equilibrium of 50:50, then stay there.
a. Yes
b. No
8. All else being equal, alleles associated with higher reproductive success increase in frequency more so than other alleles.
a. Yes
b. No
9. Flower color in Linanthus parryae is controlled largely by a single gene with two alleles. Individuals with genotype BB or Bb are blue; individuals with genotype bb are white. Linanthus parryae grows in patches in the desert. Some patches have only blue individuals, some have only white, and some are mixed. Based only on this information, which explanation is possible? Check all that apply.
a. The difference among patches is due to natural selection. Blue individuals have higher reproductive success in some patches, white plants have higher success in some patches, and the two colors do equally well in some patches.
b.The difference among patches is due to the founder effect. Some patches were founded by homozygous blue individuals, some patches by white individuals, and some patches by individuals carrying both alleles.
c. The difference among patches is due to genetic drift. Particularly if population size in a patch is small, one color or the other might be lost simply as a result of chance events, such as drought or herbivory.
10. Bollworms experience a trade-off between development time on normal cotton and survival on Bollgard cotton. Why is this trade-off important to the management of Bt-resistance?
a. Because this trade-off is the reason that Bt-resistance is heritible.
b. Because without this trade-off, pink bollworms would have no need to become resistant to Bt-toxin.
c. Because longer overall development time on Bollgard cotton means that individual pink bollworms develop resistance to Bt-toxin more slowly.
d. Because if Bt-resistant bollworms did just as well as susceptible bollworms on normal cotton, resistance would tend to evolve in any field containing even a small portion of Bollgard.
11. Farmers growing Bollgard cotton should reserve some space in their fields for normal cotton because:
Normal cotton has higher yield.
a. A refuge allows Bt-susceptible bollworms to survive, thereby reducing the fitness advantage of being resistant.
b.Planting normal cotton is the only way to find out whether a field is susceptible to infestation by pink bollworms.
c. Normal cotton is less expensive.
12. The boll weevil, an insect native to Mexico and Central America, is another pest of commercial cotton. When chemical insecticides were first discovered, they proved highly effective in controlling boll weevil outbreaks. Within a few decades, however, many boll weevil populations were resistant. Using what you've learned in this chapter, explain how the boll weevil populations changed.
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