CHAPTER 23 MCQS Flashcards

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

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.

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.

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.

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

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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

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.

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.

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.

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

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

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

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

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

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)

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

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