Question 1

Which of the following is not a prezygotic isolating mechanism for two species found in the same geographical location?
A) The two species occupy different habitats.
B) The two species are active during different parts of the day.
C) The two species mate during different times of the year.
D) The two species have incompatible genitalia.
E) The two species can mate, but the offspring are sterile.

Accepted Answer

The instance where the two species are capable of mating, but produce sterile offspring, is an example of a postzygotic isolating mechanism, since the event that prevents the two species from interbreeding occurs when the offspring are unable to reproduce.

Question 2

Which of the following correctly reflects the division of the history of life on Earth, from most inclusive to least inclusive?
A) Era - Period - Epoch
B) Epoch - Period - Era
C) Era - Epoch - Period
D) Epoch - Era - Period
E) Period - Epoch - Era

Accepted Answer

An era is composed of two or more periods, and a period is composed of two or more epochs.

Question 3

Which of the following is an example of sympatric speciation?
A) two populations of salamanders that live on isolated islands and eventually become separate species, unable to interbreed
B) different breeds of dog, which live in different areas of the world, but are able to produce fertile offspring
C) a horse and a donkey, which may interbreed to produce a mule, which is sterile and unable to reproduce
D) two related plant species living in the same area that hybridize, then undergo chromosome doubling, which results in the creation of a third species of plant that is unable to reproduce with either of the two original species
E) three species that evolve from a common ancestral species due to reproductive isolation, and adaptation to different habitats

Accepted Answer

Sympatric speciation refers to populations that develop into two or more new species without prior geographic isolation. Hybridization followed by polyploidy in plants is an excellent example of this type of speciation mechanism.

Question 4

The pollen from a red maple is unable to fertilize the eggs from a sugar maple. This is an example of what type of isolating mechanism?
A) mechanical isolation
B) habitat isolation
C) temporal isolation
D) hybrid sterility
E) gamete isolation

Accepted Answer

This is an example of gamete isolation, because the gametes from the two species are unable to fuse.

Question 5

All of the following are criteria by which a species may be defined except
A) the ability to reproduce.
B) possession of a shared gene pool.
C) ability to hybridize through interbreeding.
D) reproductive isolation.
E) the ability to produce fertile offspring.

Accepted Answer

Reproductive isolation does not necessarily mean that two populations are separate species. For example, two isolated populations of the same species can still reproduce and produce fertile offspring if members of the population are brought together.

Question 6

Which of the following is not part of the punctuated equilibrium model?
A) There is a period of no change interrupted by speciation.
B) Transitional fossils are less likely to be found.
C) It is difficult to determine when speciation occurred.
D) It often involves an isolated subpopulation.
E) Speciation often occurs rapidly.

Accepted Answer

In the punctuated equilibrium model, speciation occurs rapidly after long periods of little to no change, making transitional fossils rare. Rapid speciation events can occur from isolated populations, but once fossils of the new species are discovered, it is relatively straightforward to determine the point in time at which the speciation event occurred.

Question 7

Which of the following is not thought to have contributed to the many mass extinction events that have occurred through Earth's history?
A) plate tectonics
B) habitat loss
C) meteorite impacts
D) continental drift
E) punctuated equilibrium

Accepted Answer

The movement of continents (continental drift) as a result of plate tectonic activity is thought to have greatly reduced some types of habitat and contributed towards mass extinctions at various times. Likewise, cataclysmic events such as a meteorite impact may have caused the mass extinction of the dinosaurs. Only the punctuated equilibrium model, which merely suggests that species tend to remain mostly the same for long periods of time before rapidly evolving, is not a cause of mass extinctions.

Question 8

A major difference between allopatric and sympatric speciation is whether
A) resulting species are reproductively isolated or not.
B) gene flow continues to occur or not.
C) two or three species result.
D) geographic isolation is required or not.
E) the new species are separated by a prezygotic or postzygotic isolating mechanism.

Accepted Answer

The prefix allo- means "different," whereas the prefix sym- means "same." The root word of both terms, patria, loosely means "homeland." Thus, the two types of speciation are differentiated by whether or not geographical isolation is required-allopatric meaning "different homeland," and sympatric meaning "same homeland."

Question 9

Sympatric speciation occurs more commonly in which types of organisms?
A) plants
B) humans
C) birds
D) fish
E) insects

Accepted Answer

Plants are more prone to sympatric speciation because hybrid sterility is not as much of a problem. Since plants are tolerant of polyploidy, the doubling of chromosomes within a hybrid may allow it to undergo meiosis successfully and reproduce, producing a new species.

Question 10

Two species are said to be closely related if they
A) possess a common ancestor.
B) can interbreed, but not produce fertile offspring.
C) are reproductively isolated from each other.
D) have a shared gene pool.
E) can interbreed and produce fertile offspring.

Accepted Answer

Two species are related if they possess a common ancestor. The ability to interbreed, whether or not fertile offspring are obtained, does not necessarily indicate that the two species are closely related.

Question 11

Significant mass extinctions occurred during which of the following epochs?
A) Pleistocene, Ordovician, and Triassic
B) Ordovician, Triassic, and Jurassic
C) Triassic, Permian, and Cretaceous
D) Triassic, Permian, Cretaceous, Pleistocene, Ordovician, and Devonian
E) Ordovician, Triassic, Jurassic, Silurian, Eocene, and Oligocene

Accepted Answer

The Triassic, Permian, Cretaceous, Pleistocene, Ordovician, and Devonian periods all ended with mass extinction events. However, most scientists also agree that mass extinctions continue throughout the modern Holocene epoch due to the activities of human civilization.

Question 12

Which of the following correctly shows a possible order of events resulting in allopatric speciation?
A) postzygotic reproductive isolation - geographic isolation - natural selection
B) geographic isolation - prezygotic reproductive isolation - genetic drift
C) geographic isolation - natural selection - prezygotic reproductive isolation
D) natural selection - postzygotic reproductive isolation - geographic isolation
E) natural selection - prezygotic reproductive isolation - postzygotic reproductive isolation

Accepted Answer

In allopatric speciation, two populations of the same species are separated geographically, preventing them from interbreeding with each other. Over time, the species gradually change, and prezygotic and postzygotic isolating mechanisms develop, preventing the two populations from reproducing if the populations ever come into contact again.

Question 13

Most dinosaurs became extinct at the end of which of the following periods of the Mesozoic?
A) Jurassic
B) Cretaceous
C) Devonian
D) Triassic
E) Permian

Accepted Answer

Dinosaurs first appeared during the Triassic period, flourished during the Jurassic period, and then most became extinct at the end of the Cretaceous period, marking the end of the Mesozoic era.

Question 14

The finches of the Galápagos islands evolved as a result of what type(s) of speciation?
A) allopatric speciation
B) adaptive radiation
C) sympatric speciation
D) both allopatric speciation and adaptive radiation
E) both sympatric speciation and adaptive radiation

Accepted Answer

The Galápagos finches are usually presented as an example of adaptive radiation, a mechanism by which multiple species arise from a common ancestor. However, the speciation of the finches also involves allopatric speciation, in which the reproductive isolation of populations of finches resulted in their speciation. Thus, the speciation of finches in the Galápagos reflects both adaptive radiation and allopatric speciation.

Question 15

The fossils of a new species of reptile are found in deposits dating to the Permian period. Later, scientists discover that fossils of the species changed somewhat over time, and can be found in deposits dating from the Permian period all the way up to the Cretaceous period. The fossils vary from one continent to another, but many seemingly intermediate forms are found, and the fossils are spread over most continents. The scientists' observations most strongly support which evolutionary models?
A) allopatric speciation
B) punctuated evolution
C) adaptive radiation
D) both allopatric speciation and adaptive radiation
E) gradualistic evolution

Accepted Answer

The observations that the fossils are found on most continents and that they have changed over long periods of time suggest the gradualistic model of evolution. The spread of the fossils over multiple continents also suggests that after speciation occurred in the Permian period, when the continents were joined together, and that a slow, gradual evolution occurred while the continents separated, throughout the Paleozoic and Mesozoic eras. The observation that many intermediate forms are found suggests that all of the fossils belong to the same species, since significant amounts of interbreeding between populations probably occurred.

Question 16

A reproductive barrier that prevents interbreeding because the two species mate during different times of the year is called a A) hybrid sterility isolation. B) postzygotic isolating mechanism. C) F₂ fitness isolation. D) temporal isolation. E) behavioral isolation.

Accepted Answer

Temporal isolation refers to a type of prezygotic isolating mechanism that prevents interbreeding when two species reproduce at different times of the year, or during different times of day.

Question 17

The punctuated equilibrium model of evolution suggests that new species appear
A) gradually; as groups become isolated, they slowly evolve through their own individual pathway.
B) only after older species disappear from the fossil record.
C) suddenly after long periods of time with little to no change.
D) gradually after long periods of time with little to no change; as groups become isolated, they slowly evolve through their own individual pathway.
E) gradually, but over very short periods of time, so that intermediate species are often observed in the fossil record.

Accepted Answer

In the punctuated model of evolution, a species remains fairly stable for long periods of time, which are suddenly punctuated by rapid spurts of evolution where new species appear. This suggests that intermediate, or transitional, species are rare, and are thus seldom found in the fossil record.

Question 18

A zygote fails to undergo mitosis because of a mismatched numbers of chromosomes. This is an example of
A) hybrid sterility.
B) zygote mortality.
C) prezygotic isolation.
D) temporal isolation.
E) allopatric speciation.

Accepted Answer

In this case, mating occurs, but fails after the zygote dies due to the inability to complete mitosis. Thus, this is an example of zygote mortality.

Question 19

Which of the following would be considered a separate species as defined by the biological species concept?
A) the red maple and the sugar maple, which are found throughout large parts of North America, but rarely hybridize
B) two populations of fox squirrels, one that lives on a hillside, and one that lives in the river valley
C) two populations of North American orioles, one that lives on the east coast, and one that lives on the west coast
D) separate populations of bobcats, one that lives on a rocky slope, and one that lives in an upland forest several miles distant
E) the Chihuahua and the Siberian husky, two different breeds of dog

Accepted Answer

The red maple and sugar maple are unable to reproduce and form fertile offspring, even though they may often be found in the same area. However, different dog breeds, such as the Chihuahua and the Siberian husky, are able to interbreed and can produce fertile offspring, and are considered part of the same species.

Question 20

Elaborate courtship behaviors in animals, such as the blue-footed booby of the Galápagos islands, is an example of which of the following reproductive barriers?
A) behavioral isolation
B) mechanical isolation
C) temporal isolation
D) postzygotic isolation
E) hybrid sterility

Accepted Answer

Since female blue-footed boobies reject a mate that does not perform the correct courtship behavior, this is an example of a behavioral isolation mechanism.

Quiz 16: Evolution on a Large Scale

Which of the following is not a prezygotic isolating mechanism for two species found in the same geographical location?

Which of the following correctly reflects the division of the history of life on Earth, from most inclusive to least inclusive?

Which of the following is an example of sympatric speciation?

The pollen from a red maple is unable to fertilize the eggs from a sugar maple. This is an example of what type of isolating mechanism?

All of the following are criteria by which a species may be defined except

Which of the following is not part of the punctuated equilibrium model?

Which of the following is not thought to have contributed to the many mass extinction events that have occurred through Earth's history?

A major difference between allopatric and sympatric speciation is whether

Sympatric speciation occurs more commonly in which types of organisms?

Two species are said to be closely related if they

Significant mass extinctions occurred during which of the following epochs?

Which of the following correctly shows a possible order of events resulting in allopatric speciation?

Most dinosaurs became extinct at the end of which of the following periods of the Mesozoic?

The finches of the Galápagos islands evolved as a result of what type(s) of speciation?

A reproductive barrier that prevents interbreeding because the two species mate during different times of the year is called a

The punctuated equilibrium model of evolution suggests that new species appear

A zygote fails to undergo mitosis because of a mismatched numbers of chromosomes. This is an example of

Which of the following would be considered a separate species as defined by the biological species concept?

Elaborate courtship behaviors in animals, such as the blue-footed booby of the Galápagos islands, is an example of which of the following reproductive barriers?