Deck 23: Broad Patterns of Evolution

Question 1

The following questions refer to the description and Figure 23.1.
Figure 23.1 represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 23.1
Assuming that the rate of sea-floor spreading was constant during the 1-million-year period depicted in Figure 23.1, on average Earth's magnetic field has undergone reversal once every

A) 10,000 years.
B) 25,000 years.
C) 100,000 years.
D) 250,000 years.
E) 1,000,000 years.

Answer 1

D

Question 2

If the half-life of carbon-14 is about 5,730 years, then a fossil that has one-sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old?

A) 1,400
B) 2,800
C) 11,200
D) 16,800
E) 22,900

Answer 2

E

Question 3

If a fossil is encased in a stratum of sedimentary rock without any strata of igneous rock (for example, lava, volcanic ash) nearby, then it should be

A) easy to determine the absolute age of the fossil, because the radioisotopes in the sediments will not have been "reset" by the heat of the igneous rocks.
B) easy to determine the absolute age of the fossil, because the igneous rocks will not have physically obstructed the deposition of sediment of a single age next to the fossil.
C) easy to determine, as long as there is enough metamorphic rock nearby.
D) difficult to determine the absolute age of the fossil, because the "marker fossils" common to igneous rock will be absent.
E) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock.

Answer 3

E

Question 4

Which measurement(s) would help determine absolute dates by radiometric means?

A) the accumulation of the daughter isotope
B) the loss of parent isotopes
C) the loss of daughter isotopes
D) Three of the responses above are correct.
E) Two of the responses above are correct.

Question 5

The major evolutionary episode corresponding most closely in time with the formation of Pangaea was the

A) Cambrian explosion.
B) Permian extinctions.
C) Pleistocene ice ages.
D) Cretaceous extinctions.

Question 6

The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene

A) duplication (gain in number).
B) elimination (loss).
C) mutation (change).
D) silencing (loss of expression).

Question 7

The evolution of mammals from early tetrapods

A) is well documented by a series of transitional fossils.
B) involves specialization in teeth.
C) involves changes in the temporal fenestra of the skull.
D) is an example of macroevolution.
E) All of the above statements are true.

Question 8

Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in which they eventually pupate. Adult female bagworm moths are larval in appearance; they lack the wings and other structures of the adult male and instead retain the appearance of a caterpillar even though they are sexually mature and can lay eggs within the bag. This is a good example of

A) allometric growth.
B) paedomorphosis.
C) sympatric speciation.
D) adaptive radiation.
E) changes in homeotic genes.

Question 9

Larval flies (maggots) express the Ubx gene in all of their segments, and thereby lack appendages. If this same gene continued to be expressed throughout subsequent developmental stages, except in the head region, and if the result was a fit, sexually mature organism that still strongly resembled a maggot, this would be an example of

A) exaptation.
B) homochrony.
C) paedomorphosis.
D) adaptive radiation.

Question 10

Many species of snakes lay eggs. However, in the forests of northern Minnesota where growing seasons are short, only live-bearing snake species are present. This trend toward species that perform live birth in a particular environment is an example of

A) natural selection.
B) sexual selection.
C) species selection.
D) goal direction in evolution.
E) directed selection.

Question 11

Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that

A) dinosaurs were as fully endothermal (warm-blooded) as modern birds and mammals.
B) their feathers originally served as insulation, and only later became flight surfaces.
C) the earliest reptiles could fly, and the feathers of flightless dinosaurs were vestigial flight surfaces.
D) the feathers were plucked from the bodies of other adults to provide nest-building materials.
E) all fossils with feathers are actually some kind of bird.

Question 12

One explanation for the evolution of insect wings suggests that wings began as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air, and selection later refined them as flight-producing wings. If this hypothesis is correct, modern insect wings could best be described as

A) adaptations.
B) mutations.
C) exaptations.
D) isolating mechanisms.
E) examples of natural selection's predictive ability.

Question 13

In the 5 to 7 million years that the hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, often with several species coexisting in time and space. As recently as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the following?

A) species selection
B) uniformitarianism
C) sexual selection
D) convergent evolution

Question 14

The following questions refer to the description and Figure 23.1.
Figure 23.1 represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 23.1
Which section of sea-floor crust should have the thickest layer of overlying sediment, assuming a continuous rate of sediment deposition?

A) A
B) B
C) C
D) D
E) E

Question 15

The first terrestrial organisms probably were considered which of the following? 1. burrowers
2) photosynthetic
3) multicellular
4) prokaryotes
5) eukaryotes
6) plants and their associated fungi

A) 2 and 4
B) 3 and 5
C) 1, 3, and 5
D) 2, 3, and 6
E) 2, 3, 5, and 6

Question 16

What is true of the fossil record of mammalian origins?

A) It is a good example of punctuated equilibrium.
B) It shows that mammals and birds evolved from the same kind of dinosaur.
C) It includes transitional forms with progressively specialized teeth.
D) It indicates that mammals and dinosaurs did not overlap in geologic time.
E) It includes a series that shows the gradual change of scales into fur.

Question 17

The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that

A) a larger volume-to-surface area ratio is beneficial to all mammals.
B) an unseen guiding force is at work.
C) evolution always tends toward increased complexity or increased size.
D) in particular environments, similar adaptations can be beneficial in more than one species.
E) evolution generally progresses toward some predetermined goal.

Question 18

If two continents converge and are united, then the collision should cause

A) a net loss of intertidal zone and coastal habitat.
B) the extinction of any species adapted to intertidal and coastal habitats.
C) an overall decrease in the surface area located in the continental interior.
D) a decrease in climatic extremes in the interior of the new supercontinent.
E) the maintenance of the previously existing ocean currents and wind patterns.

Question 19

An organism has a relatively large number of Hox genes in its genome. Which of the following is true of this organism?

A) These genes are fundamental, and are expressed in all cells of the organism.
B) The organism must have multiple paired appendages along the length of its body.
C) The organism has the genetic potential to have a relatively complex anatomy.
D) Most of its Hox genes owe their existence to gene fusion events.
E) Its Hox genes cooperate to bring about sexual maturity at the proper stage of development.

Question 20

The existence of the phenomenon of exaptation is most closely associated with which of the following observations that natural selection cannot fashion perfect organisms?

A) Natural selection and sexual selection can work at cross-purposes to each other.
B) Evolution is limited by historical constraints.
C) Adaptations are often compromises.
D) Chance events affect the evolutionary history of populations in environments that can change unpredictably.

Question 21

The following questions refer to the description below.
All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.
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.

Question 22

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

Question 23

Figure 23.3
Hawaii is the most southeastern of the seven islands and is also closest to the sea-floor spreading center from which the Pacific plate originates, which lies about 5,600 km further to the southeast. Assuming equal sedimentation rates, what should be the location of the thickest sediment layer and, thus, the area with the greatest diversity of fossils above the oceanic crust?

A) between the island of Hawaii and the sea-floor spreading center
B) around the base of the island of Hawaii
C) around the base of Kauai, the oldest of the Hawaiian islands
D) where the islands are most concentrated (highest number of islands per unit surface area)

Question 24

The following questions refer to the description below.
All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.
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.

Question 25

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.

Question 26

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.

Question 27

The following questions refer to the description below.
All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.
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.

Question 28

The following questions refer to the description and Figure 23.1.
Figure 23.1 represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 23.1
How many other bands of sea-floor crust in Figure 23.1 have the same magnetic polarity as the crust that directly straddles the rift valley?

A) 2 bands
B) 4 bands
C) 6 bands
D) 8 bands
E) 10 bands

Question 29

The following questions refer to the description and Figure 23.1.
Figure 23.1 represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 23.1
If a particular marine organism is fossilized in the sediments immediately overlying the igneous rock at the arrow labeled "II," at which other location(s), labeled A-E, would a search be most likely to find more fossils of this organism?

A) B only
B) C only
C) D only
D) B and C
E) C and D

Question 30

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

Question 31

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.

Question 32

The following questions refer to this hypothetical situation.
A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island, and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly, for their flight wings are absent, and their balancing organs (in other words, halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap.
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.

Question 33

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.

Question 34

Figure 23.2
The following questions refer to the paragraph below.
A sediment core is removed from the floor of an inland sea. The sea has been in existence, off and on, throughout the entire time that terrestrial life has existed. Researchers wish to locate and study the terrestrial organisms fossilized in this core. The core is illustrated as a vertical column, with the top of the column representing the most recent strata and the bottom representing the time when land was first colonized by life.
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

Question 35

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

Question 36

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.

Question 37

The following questions refer to the description and Figure 23.1.
Figure 23.1 represents a cross section of the sea floor through a mid-ocean rift valley, with alternating patches of black and white indicating sea floor with reversed magnetic polarities. At the arrow labeled "I" (the rift valley), the igneous rock of the sea floor is so young that it can be accurately dated using carbon-14 dating. At the arrow labeled "III," however, the igneous rock is about 1 million years old, and potassium-40 dating is typically used to date such rocks. Note: The horizontal arrows indicate the direction of sea-floor spreading, away from the rift valley.
Figure 23.1
Assuming that the rate of sea-floor spreading was constant during the 1-million-year period depicted in Figure 23.1, what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labeled "II"?

A) 10,000 years
B) 250,000 years
C) 500,000 years
D) 1,000,000 years

Question 38

Figure 23.3
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