Deck 19: The Origin of Species

Question 1

Reproductive isolation is ______ by natural selection to lead to speciation.

Answer 1

reinforced

Question 2

Scientists found that different beak shapes lead to different mating songs in Darwin's finches. This result best supports which hypothesis?

A) Darwin's finches are not different species according to the Biological Species Concept.
B) Adaptation to different food sources indirectly led to behavioral isolation in Darwin's finches.
C) Behavioral isolation in Darwin's finches is unrelated to beak shape.
D) Adaptation to different food sources likely occurred after reproductive isolation in Darwin's finches.

Answer 2

Adaptation to different food sources indirectly led to behavioral isolation in Darwin's finches.

Question 3

Scientists studying a group of related bird species on an island archipelago discover that these species are always more closely related to each other within an island than they are between any two islands. The most likely explanation for this result is that

A) each bird species evolved different adaptations in allopatry and then colonized the other islands.
B) one bird species colonized each island and then evolved into distinct species on that island through character displacement.
C) each bird species colonized one island and then no further speciation occurred.
D) many ancestral bird species colonized each island.

Answer 3

one bird species colonized each island and then evolved into distinct species on that island through character displacement.

Question 4

Studies of snapping shrimp on either side of the Isthmus of Panama have shown that each Caribbean shrimp species is more closely related to a Pacific shrimp species than it is to any other Caribbean shrimp species. The most likely explanation for this result is

A) snapping shrimp in the Caribbean and the Pacific were never part of the same population.
B) snapping shrimp species were completely diverged prior to the formation of the Isthmus of Panama.
C) the formation of the Isthmus of Panama had no effect on speciation in snapping shrimp.
D) snapping shrimp species diverged after the formation of the Isthmus of Panama.

Question 5

Two hundred years ago, the fly species Rhagoletis pomonella only laid its eggs on fruit of the hawthorn tree. Today, different "host races" of R. pomonella lay their eggs on hawthorns OR apples. Apples occur within the range of hawthorns, so divergence between apple flies and hawthorn flies could be the first step in sympatric speciation. Choose the evidence that supports that R. pomonella is undergoing sympatric speciation. Check all that apply.

A) Apple flies typically mate with apple flies, and hawthorn flies typically mate with hawthorn flies.
B) Apple flies and hawthorn flies emerge from their hosts at different times of the year.
C) Apple flies and hawthorn flies are able to form fertile hybrids.
D) Apple flies and hawthorn flies are physically indistinguishable from each other.

Question 6

A virgin pine forest covers a valley, and one of the inhabitants is a red squirrel species. A large volcanic eruption occurs and separates the valley with a huge lava flow that the squirrels cannot cross, thus producing two isolated populations of squirrels. What change needs to occur for the two populations of squirrels to become separate species?

A) The two squirrel populations must eat distinct species of plants.
B) The area that the squirrel populations occupy changes so that the squirrel populations exist in distinct habitats.
C) The fur color of the two squirrel populations must become distinct.
D) The two squirrel populations select mates using the same sexual behavior.
E) The two squirrel populations become reproductively isolated.

Question 7

Adaptive radiation is best described as the

A) existence of groups of closely related species recently evolved from a common ancestor.
B) existence of groups of distantly related species recently evolved from a common ancestor.
C) existence of groups of closely related species recently evolved from different ancestors through hybridization.
D) existence of individuals of closely related species that originated in different areas within diverse habitats, but that have rejoined as a single species.

Question 8

Lake Victoria is famous for its variety of cichlid fishes. In fact, they offer the most diverse assembly of vertebrates presently known to science. One trait that scientists have focused on as one possible reason for their adaptability is

A) a second set of scales that lie beneath the top outermost scales.
B) a second set of jaws in their throats.
C) gill arches that are not covered by an operculum, which prevents hiding places for gill parasites.
D) digestive tracts that are able to process most substrates, which has eliminated the need for feeding specialization.
E) ability to change color in relationship to their environment.

Question 9

Indicate which examples would be considered different species under the Biological Species Concept. Check all that apply.

A) Two bear species that are able to breed in zoos but have separate ranges in nature.
B) Two skunk species that look morphologically similar but are unable to interbreed.
C) Two snake species that look morphologically different but regularly form fertile hybrids.
D) Two plant species with no gene flow between them.

Question 10

Several new tetraploid species of plant known as the salsifies have arisen in western North America. These new species arose from diploid species that went through the process of allopolyploidy. This mode of speciation is known as ________ and it occurs _______.

A) allopatric speciation; almost instantaneously
B) allopatric speciation; very slowly
C) sympatric speciation; almost instantaneously
D) sympatric speciation; very slowly
E) adaptive radiation; very slowly

Question 11

Which statements about the Lake Victoria cichlid fishes are true? Check all that apply.

A) The adaptive radiation of the estimated 300 species of cichlid fish was very rapid and took place during the last 200,000 years.
B) The adaptive radiation of the Lake Victoria cichlids may have resulted from a key evolutionary innovation.
C) Speciation of the Lake Victoria cichlids was mainly sympatric.
D) The diversity of the Lake Victoria cichlids continues today because the lake is devoid of predators.
E) Many of the Lake Victoria cichlids have very specialized adaptations that allow them to occupy diverse habitats within the lake.

Question 12

Which statements about the adaptive radiation of New Zealand alpine buttercups are true? Check all that apply.

A) Allopatric speciation occurred mainly during periods of glacial recession.
B) Divergence occurred mainly during periods of glacial advance.
C) The availability of a variety of habitats favored diversification.
D) Reproductive isolation was reinforced mainly during periods of glacial recession.

Question 13

Which statements about gradualism and punctuated equilibrium are true? Check all that apply.

A) Darwin's publication On the Origin of Species changed the view of evolution from gradualism to that of punctuated equilibrium.
B) According to the theory of punctuated equilibrium, evolutionary change occurs only during brief periods of speciation.
C) Stasis is likely caused by periods of disruptive and directional selection.
D) Gradualism suggests that evolutionary change is not linked to speciation.

Question 14

Two species regularly come into contact and form hybrids that have higher fitness than either of the parental species. What are the possible consequences of regular hybridization between these species? Check all that apply.

A) evolution of a third species
B) reinforcement of prezygotic isolating mechanisms
C) extinction of the parental species
D) increased gene flow between the parental species

Question 15

NASA Scientists send a small population of dogs to a new planet in order to test if it will be hospitable for human colonization. Through a random lottery, only Great Dane and St. Bernard dog breeds are sent, and the resulting population consists of tall, longhaired dogs. After 100 years these dogs return to earth and are no longer able to mate with earth dogs. This scenario is an example of

A) allopatric speciation through genetic drift.
B) allopatric speciation through natural selection.
C) sympatric speciation through genetic drift.
D) sympatric speciation through natural selection.

Question 16

Scientists investigating speciation in fruit flies divided a single population of flies into separate populations that each lived in their own cage on one of two food sources: maltose-based food or starch-based food. After several generations, the flies' mate preference was tested, and it was found that flies strongly preferred to mate with other flies that were raised on the same food source. This results suggests that

A) selection on food source indirectly led to the evolution of reproductive isolating mechanisms.
B) selection on reproductive isolating mechanisms indirectly led to the evolution of different food preferences.
C) reproductive isolating mechanisms evolved primarily through genetic drift.
D) different food preferences evolved primarily through genetic drift.

Question 17

The most famous and well-studied mass extinction occurred at the end of the Cretaceous period (65 million years ago), at which time the dinosaurs and a variety of other terrestrial and aquatic organisms went extinct. Recent findings have supported the hypothesis that this extinction event was triggered when a large asteroid slammed into Earth. Which of the following could cause a global mass extinction following an asteroid strike? (Check all that apply)

A) The impact triggered global forest fires that obscured the sun.
B) The asteroid killed animals it hit upon impact.
C) The asteroid was very hot when it entered the atmosphere and heated up the planet.
D) The asteroid created a massive dust cloud that obscured the sun.

Question 18

Scientists estimate that as much as one-fourth of all species will become extinct in the near future, a rate of extinction not seen on Earth since the Cretaceous mass extinction. How are humans contributing to this mass extinction? (Check all that apply)

A) Contributing to climate change.
B) Intentionally killing all members of a species.
C) Destroying habitat.
D) Blocking evolution.