Assuming the existence of fossilized markers for each of the following chemicals, what is the
sequence in which they should be found in this sediment core, working from ancient sediments
to recent sediments?
1. chitin coupled with protein
2. chlorophyll
3. bone
4. cellulose
A) 2, 4, 3, 1
B) 2, 4, 1, 3
C) 4, 2, 1, 3
D) 4, 2, 3, 1

2, 4, 1, 3

According to the theory of sea-floor spreading, oceanic islands, such as the Hawaiian Islands
depicted in Figure 23.3, form as oceanic crustal plates move over a stationary "hot spot" in the
mantle. Currently, the big island of Hawaii is thought to be over a hot spot, which is why it is the
only one of the seven islands that has active volcanoes. What should be true of the island of
Hawaii?
1. Scientists in search of ongoing speciation events are more likely to find them here than on the
other six islands.
2. Its species should be more closely related to those of nearer islands than to those of farther
islands.
3. It should have a rich fossil record of terrestrial organisms.
4. There is a good chance of finding endemic species on this island.
5. On average, it should have fewer species per unit surface area than the other six islands.
A) 1, 2, and 3
B) 1, 2, and 5
C) 1, 2, 3, and 4
D) 1, 2, 4, and 5
E) 2, 3, 4, and 5

1, 2, 4, and 5

Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what
characteristic, leading to which phenomenon?
A) mass extinctions, leading to bottleneck effect
B) major evolutionary innovations, leading to rafting to nearby continents
C) a variety of empty ecological niches, leading to adaptive radiation
D) adaptive radiation, leading to founder effect
E) overcrowding, leading to rafting to nearby lands

a variety of empty ecological niches, leading to adaptive radiation

In each fly species, the entire body segment that gave rise to the original flight wings is
missing. The mutation(s) that led to the flightless condition could have
A) duplicated all of the Hox genes in these flies' genomes.
B) altered the nucleotide sequence within a Hox gene.
C) altered the expression of a Hox gene.
D) all three of the responses are correct.
E) two of the responses are correct.

two of the responses are correct.

If these fly species lost the ability to fly independently of each other as a result of separate
mutation events in each lineage, then the flightless condition in these species could be an
example of
A) adaptive radiation.
B) species selection.
C) sexual selection.
D) allometric growth.
E) habitat differentiation.

species selection.

Which of these fly organs, as they exist in current fly populations, best fits the description of
an exaptation?
A) wings
B) balancing organs
C) mouthparts
D) thoraxes
E) walking appendages

balancing organs

Fruit fly eyes are of the compound type, which is structurally very different from the camera-
type eyes of mammals. Even the camera-type eyes of molluscs, such as octopi, are structurally
quite different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar
versions of Pax-6. The fact that the same gene helps produce very different types of eyes is most
likely due to
A) the few differences in nucleotide sequence among the Pax-6 genes of these organisms.
B) variations in the number of Pax-6 genes among these organisms.
C) the independent evolution of this gene at many different times during animal evolution.
D) differences in the control of Pax-6 expression among these organisms.

differences in the control of Pax-6 expression among these organisms.

Pax-6 usually causes the production of a type of light-receptor pigment. In vertebrate eyes,
though, a different gene (the rh gene family) is responsible for the light-receptor pigments of the
retina. The rh gene, like Pax-6, is ancient. In the marine ragworm, for example, the rh gene
causes production of c-opsin, which helps regulate the worm's biological clock. Which of these
most likely accounts for vertebrate vision?
A) The Pax-6 gene mutated to become the rh gene among early mammals.
B) During vertebrate evolution, the rh gene for biological clock opsin was co-opted as a gene for
visual receptor pigments.
C) In animals more ancient than ragworms, the rh gene(s) coded for visual receptor pigments; in
lineages more recent than ragworms, rh has flip-flopped several times between producing
biological clock opsins and visual receptor pigments.
D) Pax-6 was lost from the mammalian genome, and replaced by the rh gene much later.

During vertebrate evolution, the rh gene for biological clock opsin was co-opted as a gene for
visual receptor pigments.

The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on
the information, which explanation is most likely?
A) Pax-6 in all of these animals is not homologous; it arose independently in many different
animal phyla due to intense selective pressure favoring vision.
B) The Pax-6 gene is really not "one" gene. It is many different genes that, over evolutionary
time and due to convergence, have come to have a similar nucleotide sequence and function.
C) The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian period.
Animals with eyes or eyespots are descendants of this ancestor.
D) The perfectly designed Pax-6 gene appeared instantaneously in all animals created to have
eyes or eyespots.

The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian period.
Animals with eyes or eyespots are descendants of this ancestor.

Which factor most likely caused animals and plants in India to differ greatly from species in
nearby Southeast Asia?
A) The species became separated by convergent evolution.
B) The climates of the two regions are similar.
C) India is in the process of separating from the rest of Asia.
D) Life in India was wiped out by ancient volcanic eruptions.
E) India was a separate continent until 45 million years ago.

India was a separate continent until 45 million years ago.

Adaptive radiations can be a direct consequence of four of the following five factors. Select
the exception.
A) vacant ecological niches
B) genetic drift
C) colonization of an isolated region that contains suitable habitat and few competitor species
D) evolutionary innovation
E) an adaptive radiation in a group of organisms (such as plants) that another group uses as food

genetic drift

A researcher discovers a fossil of what appears to be one of the oldest-known multicellular
organisms. The researcher could estimate the age of this fossil based on
A) the amount of carbon-14 in the fossil.
B) the amount of uranium-238 in the fossil.
C) the amount of carbon-14 in the sedimentary rocks in which the fossil was found.
D) the amount of uranium-238 in volcanic layers surrounding the fossil.
E) the amount of uranium-238 in the sedimentary rocks in which the fossil was found.

the amount of uranium-238 in volcanic layers surrounding the fossil.

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate
limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This
type of change is illustrative of
A) the influence of environment on development.
B) paedomorphosis.
C) a change in a developmental gene or in its regulation that altered the spatial organization of
body parts.
D) heterochrony.
E) gene duplication.

a change in a developmental gene or in its regulation that altered the spatial organization of body parts.

A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the
swim bladder from the air-breathing organ (a simple lung) of an ancestral fish is an example of
A) an evolutionary trend.
B) exaptation.
C) changes in Hox gene expression.
D) paedomorphosis.
E) adaptive radiation.

exaptation.