Deck 14: The Origin of Species

Question 1

Two species that occasionally mate and produce zygotes, but that have incompatible genes that prevent the resulting embryo from developing, are affected by

A) gametic isolation.
B) reduced hybrid fertility.
C) reduced hybrid viability.
D) behavioral isolation.

Answer 1

C

Question 2

Two populations of organisms belong to the same biological species when they

A) cannot mate with each other because mating occurs at different times.
B) use different types of behaviors or physical features to attract mates.
C) have anatomical features that make it difficult for organisms from the two populations to mate with one another.
D) encounter each other, mate, and produce viable, fertile offspring under natural conditions.

Answer 2

D

Question 3

The Monterey pine and the Bishop's pine inhabit some of the same areas of central California. The Monterey pine releases pollen in February, while the Bishop's pine does so in April. This is an example of ________ isolation.

A) postzygotic
B) temporal
C) habitat
D) mechanical

Answer 3

B

Question 4

Which of the following types of reproductive barriers separates two species of sea cucumbers whose sperm and eggs often bump into each other but do not cross-fertilize because of incompatible proteins on their surfaces?

A) temporal isolation
B) habitat isolation
C) mechanical isolation
D) gametic isolation

Question 5

The biological species concept is

A) applicable to all forms of life, past and present.
B) applicable to all present life-forms but not to fossil organisms whose reproductive behavior cannot be observed.
C) easy to apply to all present sexually reproducing organisms but harder to apply to asexual organisms and fossils.
D) sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils.

Question 6

Which of the following would a biologist describe as microevolution?

A) the formation of new species
B) the extinction of species
C) dramatic biological changes, such as the origin of flight, within a taxon
D) a change in the gene pool of a population from one generation to the next

Question 7

In which of the following situations would speciation be most likely to occur?

A) A population of juniper shrubs is split in two by a canyon. Every year, strong winds carry a small amount of the shrubs' pollen across the canyon.
B) A Japanese mollusk species whose larvae are often carried from port to port in ship bilge (waste) water now flourishes in San Francisco Bay, a busy commercial port.
C) Bighorn sheep occupy mountains from Canada to Death Valley in Southern California, interbreeding all the way. The populations at the two ends of the range live in very different environments.
D) Seven monkeys escape from an enclosure. To everyone's surprise, they establish a small but viable population, coexisting successfully with humans in a partly suburban environment very different from their native African habitat.

Question 8

Which of the following types of reproductive barriers separates a pair of species that could interbreed but for the fact that one mates at dusk and the other at dawn?

A) temporal isolation
B) habitat isolation
C) behavioral isolation
D) mechanical isolation

Question 9

Which of the following types of reproductive barriers separates a pair of moth species that could interbreed but for the fact that the females' mating pheromones are not attractive to the males of the other species?

A) temporal isolation
B) behavioral isolation
C) mechanical isolation
D) gametic isolation

Question 10

Which of the following statements regarding the definition of species is false?

A) The ecological species concept identifies species in terms of their ecological niches.
B) The phylogenetic species concept defines a species as a set of organisms that shares a common ancestor and forms one branch on the tree of life.
C) The morphological species concept relies upon comparing the DNA sequences of organisms.
D) Under the biological species concept, the gap between species is maintained by reproductive isolation.

Question 11

Uplift and formation of a mountain range divide a freshwater snail species into two isolated populations. Erosion eventually lowers the mountain range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of

A) sympatric speciation.
B) allopatric speciation.
C) incomplete speciation.
D) diversifying speciation.

Question 12

Under the biological species concept, a species is a group of organisms that

A) are physically similar.
B) share a recent common ancestor.
C) live together in a location and carry out identical ecological roles.
D) have the potential to interbreed in nature and produce fertile offspring.

Question 13

Frequently, a group of related species will each have a unique courtship ritual that must be performed correctly for both partners to be willing to mate. Such a ritual constitutes a ________ and ________ reproductive barrier.

A) mechanical; postzygotic
B) behavioral; prezygotic
C) temporal; prezygotic
D) gametic; postzygotic

Question 14

Diane Dodd raised different fruit fly populations on different food sources. She found that after about 40 generations the evolution of reproductive isolation was under way. The mechanism of evolution responsible for this was

A) natural selection.
B) genetic drift.
C) gene flow.
D) hybridization.

Question 15

Which of the following types of reproductive barriers separates two flowering plant species that could interbreed but for the fact that one has a deep flower tube and is pollinated by bumblebees whereas the other has a short, narrow flower tube and is pollinated by honeybees?

A) habitat isolation
B) behavioral isolation
C) mechanical isolation
D) gametic isolation

Question 16

Speciation, or the formation of new species, is

A) a form of microevolution.
B) responsible for the diversity of life.
C) necessary for natural selection and adaptation.
D) an event that has occurred only a few times in the history of the planet.

Question 17

Two species interbreed occasionally and produce vigorous, fertile hybrids. When the hybrids breed with each other or with either parent species, however, the offspring are feeble or sterile. These species are affected by

A) gametic isolation.
B) reduced hybrid fertility.
C) reduced hybrid viability.
D) hybrid breakdown.

Question 18

Two species that sometimes mate and produce vigorous but sterile offspring are affected by

A) gametic isolation.
B) reduced hybrid fertility.
C) reduced hybrid viability.
D) hybrid breakdown.

Question 19

The geographic isolation of a population from other members of the species and the subsequent evolution of reproductive barriers between it and the parent species describes ________ speciation.

A) punctuated
B) sympatric
C) allopatric
D) biogeographic

Question 20

Which of the following types of reproductive barriers separates a pair of insect species that could interbreed but for the fact that one lives on goldenrod plants and the other on autumn daisies in the same general area?

A) temporal isolation
B) habitat isolation
C) behavioral isolation
D) gametic isolation

Question 21

The emergence of a new plant species over a brief period of time followed by a long period of little change is consistent with which of the following theories?

A) the gradual model of speciation
B) allopatric speciation
C) punctuated equilibrium
D) adaptive radiation

Question 22

The emergence of many diverse species from a common ancestor is called

A) adaptive radiation.
B) gradualism.
C) allopatric speciation.
D) hybridization.

Question 23

When plants undergo allopatric speciation, an initial reproductive barrier is often

A) polyploidy.
B) gametic isolation.
C) temporal isolation.
D) pollinator choice.

Question 24

The fossil record shows that for many plant and animal groups, the time between speciation events

A) is usually about 50,000 years.
B) varies greatly, but averages 6.5 million years.
C) is usually greater than 40 million years.
D) is equivalent to the length of 100 generations of a species.

Question 25

Which of the following descriptions best represents the gradual model of speciation?

A) Speciation occurs regularly as a result of the accumulation of many small changes.
B) An isolated population differentiates quickly from its parent stock as it adapts to its local environment.
C) Speciation occurs under unusual circumstances and therefore transitional fossils are hard to find.
D) Species undergo little change over long periods interrupted only by short periods of rapid change.

Question 26

Most polyploid species arise from

A) a single diploid parent plant.
B) a single triploid parent plant.
C) a single tetraploid parent plant.
D) the hybridization of two parent species.

Question 27

In a hybrid zone, ________ can occur if the reproductive barrier between two species is weak, as seen among cichlids in the murky waters of modern Lake Victoria.

A) reinforcement
B) fusion
C) allopatric speciation
D) reproductive isolation

Question 28

A group of ants escaped from a picnic basket carried to the top of a mountain and thrived in this area where there were no other ants. Many years later descendants of these ants crawled into a picnic basket on the mountain and traveled back to the valley from which their ancestors had come. Which of these observations would cause you to conclude that the ants on top of the mountain had become a different species from those in the valley?

A) The mountain ants and valley ants were different colors.
B) The mountain ants and valley ants were different sizes.
C) The mountain ants ate different food than the valley ants.
D) The mountain ants could not mate with the valley ants.

Question 29

One of the key contributions of the punctuated equilibrium model is that it helps explain

A) why transitional fossils are more common than Darwin would have predicted.
B) why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans.
C) how new species arise from hybridization events.
D) why large, widespread populations tend to be the ones that evolve most rapidly and unpredictably.

Question 30

Organisms that possess more than two complete sets of chromosomes are said to be

A) haploid.
B) polyploid.
C) diploid.
D) hybrids.

Question 31

Speciation has become complete when

A) two populations of organisms have been separated for a very long time.
B) a change in allele frequency has occurred.
C) organisms of one population do not recognize the mating call of another population and so mating does not occur.
D) offspring of mating from members of two different populations are able to mate with members of either population.

Question 32

The ________ suggests that speciation occurs in brief spurts.

A) adaptive model of the origin of species
B) allopatric speciation model
C) gradual model of the origin of species
D) punctuated equilibrium model

Question 33

One of the finest available sequences of fossils shows how horses have changed slowly and by subtle steps from small, shrub-browsing ancestors to the large, grass-grazing modern horse. A large number of fossil species have been named, and it is often difficult to decide on the identity of a fossil horse because transitional forms are common. This record of evolution best fits the idea of

A) the gradual model of speciation.
B) punctuated equilibrium.
C) adaptive radiation.
D) hybrid breakdown.

Question 34

Which of the following statements about the Galápagos finches is false?

A) The Galápagos finch species differ in their feeding habitats.
B) Each island in the Galápagos chain has one and only one isolated, unique species of Darwin's finch.
C) Most speciation events of the Galápagos finches occurred when some finches made it to another island, evolved in isolation, and accumulated enough changes to become a new species.
D) The evolution of the Galápagos finches is an excellent example of adaptive radiation.

Question 35

Diane Dodd's experiments using fruit flies demonstrated that

A) the evolution of reproductive barriers occurs much too slowly to produce measurable effects in the laboratory.
B) new species can form in a single generation by the production of new reproductive structures.
C) formation of a reproductive barrier between two populations is more likely if they experience and adapt to different environmental conditions.
D) reproductive barriers usually are absolute: Either two populations are fully willing and able to interbreed, or they are strictly separated by a fully effective reproductive barrier.

Question 36

Speciation without geographic isolation is called ________ speciation.

A) sympatric
B) allopatric
C) incomplete
D) diversifying

Question 37

When a tetraploid flower pollinates a diploid flower of the parental species, the resulting offspring will be

A) pentaploid and sterile.
B) diploid and fertile.
C) triploid and fertile.
D) triploid and sterile.

Question 38

Sympatric speciation commonly occurs through ________ in plants but is more likely to occur through ________ in animals.

A) polyploidy; habitat differentiation and sexual selection
B) habitat differentiation and sexual selection; polyploidy
C) asexual reproduction; chromosome duplications
D) self-pollination; polyploidy and other genetic mechanisms

Question 39

Two bird species overlap in a hybrid zone. They are isolated by a slight difference in the male songs and by the females' tendency to select males with the "correct" song. Hybrid offspring tend to have reduced fertility compared to either of the parent species. What effect might natural selection have in this situation?

A) Natural selection might favor males with less distinctive calls and/or females that are less "choosy."
B) Natural selection might favor males with more distinctive calls and/or females that are more "choosy." As a result, the reproductive barrier between the two species could be reinforced.
C) Natural selection could lead to the hybrid species taking over and eliminating the weaker parent species.
D) Natural selection could lead to the stronger of the two species taking over and eliminating the other species.

Question 40

Which of the following would tend to promote adaptive radiation?

A) An organism has a very stable set of features and capabilities over long spans of evolutionary time.
B) An organism colonizes an isolated area that is habitable but relatively devoid of life.
C) An organism colonizes an area that already has a high level of existing species diversity.
D) A single species goes extinct, but it has several competitors that quickly expand to assume its ecological roles.

Question 41

After reading the paragraph below, answer the questions that follow.
In the North Pacific Ocean, two groups of the same species of killer whales (Orcinus orca) appear to be forming two different species based on what they eat. One group eats fish and the other eats mammals such as seals. Scientists can tell what they eat based on their teeth, because whales that feed on fish have significantly different wear patterns.
Which of the following describes the type of speciation event that is occurring in these whales?

A) sympatric speciation
B) allopatric speciation
C) geographic speciation
D) punctuated speciation

Question 42

After reading the paragraph below, answer the questions that follow.
In the North Pacific Ocean, two groups of the same species of killer whales (Orcinus orca) appear to be forming two different species based on what they eat. One group eats fish and the other eats mammals such as seals. Scientists can tell what they eat based on their teeth, because whales that feed on fish have significantly different wear patterns.
Another difference between the two groups is in how they hunt. Whales that hunt fish tend to travel in large pods (groups of whales) and vocalize often. Whales that hunt seals, however, tend to travel in very small groups and vocalize very little, likely because of the excellent hearing ability of seals. If these differences brought about speciation, the separation would be considered

A) habitat isolation.
B) temporal isolation.
C) behavioral isolation.
D) mechanical isolation.

Question 43

If the divergence illustrated here is based on some female insects preferring large males and others preferring small males, then this would be an example of

A) temporal isolation.
B) hybrid inviability.
C) sexual selection.
D) allopatric speciation.

Question 44

The data in this graph indicate

A) there were fewer total tough seeds in 1976 than in 1977.
B) plants that produced soft seeds in 1976 produced tougher seeds in 1977.
C) available seeds were generally tougher in 1977 than in 1976.
D) seed abundance in 1977 was severely reduced by finch feeding.

Question 45

Which of these is the best hypothesis about what led to the change seen in the data?

A) Birds with deeper beaks were more likely to survive the drought.
B) Birds with deeper beaks were better able to defend their territories and therefore had more food sources than those with shallower beaks.
C) In conflicts over individual seeds, birds with deeper beaks were better competitors.
D) During the reproductive season, each bird with a deep beak laid more eggs than each bird with a shallower beak.

Question 46

The Grants' work on natural selection would have been impossible to complete if the traits they examined were

A) modified by the environment during the bird's lifetime.
B) adapted to particular environmental conditions.
C) completely heritable.
D) present to some degree in all finches.

Question 47

For speciation to occur there must be

A) sexual reproduction.
B) genetic variation.
C) isolation.
D) natural selection.

Question 48

The Grants' finch research included morphological, geographic, genetic, and ecological data. Which of these could not be directly determined by examining the birds as they tagged them?

A) Morphological measurements could be directly made of bird size and weight in addition to measurements on beak depth.
B) Geographic data could be directly recorded according to where on the island the bird was found.
C) Complete genetic makeup could be directly determined though analysis of phenotypes.
D) Ecological data could be gathered by direct observation of food preference.

Question 49

Which butterfly has changed gradually but significantly from its ancestor through microevolutionary events that were not part of a speciation event?

A) butterfly A
B) butterfly B
C) butterfly C
D) butterfly D

Question 50

A new plant species may arise in a single generation by

A) errors in meiosis leading to polyploidy.
B) a sudden geological disruption causing separation of two populations.
C) mutations in genes for flower color.
D) changes in the pollinator species.

Question 51

If H. floresiensis were reunited with H. erectus at a much later date but the two populations could no longer interbreed, it would be correct to conclude that

A) H. floresiensis is no longer fertile as a species.
B) the two groups had been isolated for more than 50,000 years.
C) H. floresiensis has become less fit than H. erectus.
D) a reproductive barrier had evolved.

Question 52

Allopatric speciation is not likely to occur when

A) there is no disruption in gene flow between two populations.
B) a geographic barrier forms between two populations.
C) several populations become isolated from one another as drying conditions cause a large body of water to become separate, smaller bodies of water.
D) separated populations adapt to different environmental conditions.

Question 53

In the chiclid populations in Lake Victoria, what trait in females acted as a selection factor on which males they mated with?

A) color vision
B) body color
C) preferred water depth
D) ability to hear sounds made by the male

Question 54

These data collected by the Grants show that

A) all birds surviving after the drought had deeper beaks than those existing before the drought.
B) most birds died as a result of the drought.
C) before the drought all birds had beaks between 9 and 9.5 mm deep and after the drought all birds had beaks between 9.5 and 10 mm deep.
D) after the drought the average bird had a deeper beak.

Question 55

Speciation often occurs when a habitat becomes more heterogeneous. In Lake Victoria different species of cichlids are found in different areas of the lake. The best explanation for this speciation is that

A) natural selection favored different heritable variations in different parts of the lake.
B) male cichlids that lived in deep water needed to be seen by females, so they became colorful.
C) food was scarce in the lake, so some fish had to learn how to scrape algae, some had to learn to eat insects, and some had to learn to bite leaves.
D) humans selected for many different traits in cichlids in order to market them to the aquarium trade.

Question 56

Two populations that have been separated by a river are most likely to become separate species if

A) fur color is different in the two populations.
B) genes controlling ear development become different so that members of one population have much longer ears than the other.
C) genes controlling molecules on the surface of the sperm that bind with egg receptors are different in the two populations.
D) feeding habits are different in the two populations.

Question 57

After reading the paragraphs below, answer the questions that follow.
In 2004, scientists announced the discovery of the fossil remains of some extremely short early humans on the Indonesian island of Flores. The new species has been named Homo floresiensis. One hypothesis is that H. floresiensis evolved from Homo erectus, another early human species. How did a population of H. erectus become isolated on this remote island? Early humans constructed boats and rafts, so perhaps they were blown far off course by strong winds during a storm. H. erectus averaged almost 6 feet in height, but the remains show that adults of H. floresiensis were only about 3 feet tall. It is hypothesized that limited resources on this hot and humid island (only 31 square miles) exerted selection pressure, and succeeding generations began to shrink in size. Small bodies require less food, use less energy, and are easier to cool than larger bodies. Evolution of small size in similar circumstances has been observed in many other species but never before in humans. This find demonstrates that evolutionary forces operate on humans in the same way as on all other organisms.
The evolution of H. floresiensis is an example of

A) sympatric speciation.
B) allopatric speciation.
C) adaptive radiation.
D) hybridization.

Question 58

After reading the paragraph below, answer the questions that follow.
In the North Pacific Ocean, two groups of the same species of killer whales (Orcinus orca) appear to be forming two different species based on what they eat. One group eats fish and the other eats mammals such as seals. Scientists can tell what they eat based on their teeth, because whales that feed on fish have significantly different wear patterns.
Which of the following would be the least useful procedure to perform in determining whether or not this speciation has occurred?

A) Compare teeth of whales alive today to teeth of whales in ancient samples.
B) Compare DNA samples from fish eaters and mammal eaters.
C) Compare stomach contents of whales from each of the two populations.
D) Compare body shape of whales from each population.

Question 59

In a population of plants with a diploid number of 12, a new individual appeared with a chromosome number of 24. If this organism could self-fertilize, forming offspring with the same number of chromosomes (24), scientists would consider this an example of

A) sympatric speciation.
B) behavioral isolation.
C) formation of a hybrid zone.
D) reduced hybrid fertility.