Evolution ❮ 149Why is it important that there was no oxygen to start? Alexander Oparin and J. B. S.
Haldane hypothesized that oxygen would have prevented the formation of simple mole-
cules because it is too reactive, and would have taken the place of any other element in
chemical reactions. Stanley Miller and Harold Urey tested this hypothesis by simulating a
primordial environment, and found that in the absence of oxygen, they were able to form
organic molecules (including amino acids).Review Questions
- Which of the following is an evolutionary process
notbased on random factors?
A. Genetic drift
B. Natural selection
C. Mutation
D. Gene flow
E. Bottlenecks - Which of the following is not a sexually selected
trait?
A. Fruit fly wings
B. A male baboon’s canine teeth
C. Peacock tail feathers
D. Male/female dimorphism in body size in many
species
E. A frog’s throat sac - An adaptation
A. can be shaped by genetic drift.
B. cannot be altered.
C. evolves because it specifically improves an
individual’s mating success.
D. affects the fitness of an organism if it is
altered.
E. can be deleterious to an organism. - Which of the following is nota requirement for
natural selection to occur?
A. Variation between individuals
B. Heritability of the trait being selected
C. Sexual reproduction
D. Differences in reproductive success among
individuals
E. Survival of the fittest
5. Why can Hardy-Weinberg equilibrium occur
only in large populations?
A. Large populations are likely to have more
variable environments.
B. More individuals means less chance for nat-
ural selection to occur.
C. Genetic drift is a much stronger force in
small versus large populations.
D. Large populations make random mating
virtually impossible.
E. Large populations tend to last longer than
small ones.
6. A population of frogs consists of 9 percent with
speckles (the recessive condition) and 91 percent
without speckles. What are the frequencies of the
pandq alleles if this population is in Hardy-
Weinberg equilibrium?
A. p=0.49,q=0.51
B. p=0.60,q=0.40
C. p=0.70,q=0.30
D. p=0.49,q=0.30
E. p=0.49,q=0.09
7. Frequency-dependent selection is
A. particularly important during speciation.
B. one way in which multiple alleles are
preserved in a population.
C. possible only when there are two alleles.
D. most common in bacteria.
E. the same as heterozygote advantage.
8. All of the following provide evidence for evolution
except
A. vestigial characters.
B. Darwin’s finches.
C. homologous characters.
D. embryology.
E. mutations.
BIG IDEA 1.D.1
There are several
hypotheses about
the origin of life,
each with evidence
to support it.
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