Bio Ch. 14
Organisms that possess more than two complete sets of chromosomes are said to be A. polyploid. B. hybrids. C. diploid. D. haploid.
A
Scientists estimate that _____% of plant species are polyploids, mostly generated through _____. A. over 75 ... hybridization between two species B. less than 10 ... hybridization between two species C. 25 ... hybridization between two species D. 50 ... tetraploids arising from a single diploid parent species
A
The fossil record shows that for many plant and animal groups, the time between speciation events A. varies greatly, but averages 6.5 million years. B. is usually about 50,000 years. C. is equivalent to the length of one hundred generations of a species. D. is usually greater than 40 million years.
A
The main focus of Charles Darwin's studies was on the gradual process of adaptation within populations. In other words, microevolution occurs by means of natural selection. Although critical to evolution this form of change, __________. A. cannot account by itself for the increase in species diversity over time B. is the main means by which new species arise C. explains all important forms of evolutionary change D. occurs mainly in small, isolated populations
A
Two animals are considered members of different biological species if they _____. A. are male and female, but cannot interbreed B. live in different habitats C. are geographically isolated D. look different
A
Which of the following is an example of a prezygotic barrier? A. Pollen is regularly exchanged between flowers of two groups of plants, but a mutual incompatibility exists so that sperm do not fertilize eggs from the "wrong" group. B. A hybrid fails to develop beyond the first few embryonic stages. C. A hybrid fails to reach sexual maturity. D. A hybrid fails to produce functional gametes.
A
According to a recent survey of many studies, an average plant or animal lineage might produce a new species approximately once every _____. A. 50 years B. 5 million years C. 500 years D. 5,000 years
B
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. adaptive radiation. B. the gradual model of speciation. C. hybrid breakdown. D. punctuated equilibrium.
B
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. male cichlids that lived in deep water needed to be seen by females, so they became colorful. B. natural selection favored different heritable variations in different parts of the lake. C. humans selected for many different traits in cichlids in order to market them to the aquarium trade. D. 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.
B
New branches form on the tree of life through the process of __________. A. microevolution B. genetic drift C. natural selection D. speciation
D
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
D
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. habitat isolation B. temporal isolation C. mechanical isolation D. gametic isolation
D
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. changes in the pollinator species. D. mutations in genes for flower color.
A
According to the _____ model, evolution occurs in spurts: Species evolve relatively rapidly and then remain unchanged for long periods. A. punctuated equilibrium B. adaptive radiation C. allopatric D. gradualist
A
Biologists have found more than 500 species of fruit flies on the various Hawaiian islands, all apparently descended from a single ancestor species. When this ancestor colonized the island chain, it found few competitors: Many insect and fly families present in other regions are absent from the isolated Hawaiian Islands. This example illustrates _____. A. adaptive radiation B. temporal isolation C. sympatric speciation D. allopatric speciation
A
Diane Dodd's experiments using fruit flies demonstrated that A. formation of a reproductive barrier between two populations is more likely if they experience and adapt to different environmental conditions. B. new species can form in a single generation by the production of new reproductive structures. C. 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. D. the evolution of reproductive barriers occurs much too slowly to produce measurable effects in the laboratory.
A
Each biological species is genetically isolated from other species. Why do the species evolve independently? A. The two species evolve independently because they do not exchange genes. Reproductive barriers keep them from successfully interbreeding. B. The species evolve separately because they look different and have different morphologies. C. The species evolve independently because they live in different geographic areas. D. The species evolve independently because they are free to interbreed and produce fertile hybrid offspring.
A
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 ________ ________ reproductive barrier. A. behavioral; prezygotic B. temporal; prezygotic C. gametic; postzygotic D. mechanical; postzygotic
A
Imagine that part of a population of flies is blown from the California coast to an offshore island. The island flies have no contact with the mainland flies for 10,000 years. Then an earthquake rearranges the landscape and the island is rejoined to the mainland. The former island flies can now mingle freely with the mainland flies. If attempts at mating between flies from the two groups are successful and the resulting offspring grow up strong and healthy and have offspring of their own, you could conclude that _____. A. over the past 10,000 years, no speciation occurred in these flies B. over the past 10,000 years, a single species had split into two species C. there is insufficient information available to determine how many species of flies are now present D. over the past 10,000 years, effective isolating mechanisms had evolved
A
In bowerbirds, the divergence illustrated in the figure is based on A. the females' preference for types of bower. B. the color of the plumage of the females. C. the color of bowers. D. how often females visit the bower built by males.
A
Microevolution is _____. A. changes in the gene pool of a population from one generation to the next B. speciation C. dramatic changes that take place over long periods of time D. evolution on a molecular level
A
Most polyploid species arise from A. the hybridization of two parent species. B. a single triploid parent plant. C. a single diploid parent plant. D. a single tetraploid parent plant.
A
One of the key contributions of the punctuated equilibrium model is that it helps explain A. why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans. B. why transitional fossils are more common than Darwin would have predicted. C. why large, widespread populations tend to be the ones that evolve most rapidly and unpredictably. D. how new species arise from hybridization events.
A
Scientists have found as many as 500 species of fish in the African Lake Victoria. What can account for this high level of diversity in a single habitat? A. Lake Victoria has a variety of environments such as rocky shores and muddy bottoms; this environment heterogeneity promotes speciation. B. Lake Victoria is located near the equator; therefore, it has great biodiversity, like the rainforests in South America. C. Lake Victoria is a very ancient lake; therefore, there has been more time for a variety of species to evolve. D. A typical value of diversity for a lake the size of Lake Victoria is 500 fish species.
A
Speciation is likely to occur between a parent population and a population that has become allopatric if _____. A. the allopatric population is small and is isolated from the parent population by a formidable barrier to dispersal B. it is in a similar environment to the "parent" population C. there is a lot of gene flow between the two populations D. both populations are large and exhibit a sufficient diversity of alleles
A
Sympatric speciation commonly occurs through ________ in plants but is more likely to occur through ________ in animals. A. polyploidy; habitat differentiation and sexual selection B. asexual reproduction; chromosome duplications C. habitat differentiation and sexual selection; polyploidy D. self-pollination; polyploidy and other genetic mechanisms
A
The ________ suggests that speciation occurs in brief spurts. A. punctuated equilibrium model B. allopatric speciation model C. adaptive model of the origin of species D. gradual model of the origin of species
A
The biological species concept is A. sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils. B. applicable to all forms of life, past and present. C. easy to apply to all present sexually reproducing organisms but harder to apply to asexual organisms and fossils. D. applicable to all present life-forms but not to fossil organisms whose reproductive behavior cannot be observed.
A
The following options are all reproductive barriers. Which one is an example of a prezygotic barrier in which the two different species do mate? A. Two dragonfly species regularly mate, but their gametes are incompatible. B. Hybrid mules produced by mating donkeys and horses are sterile. C. One bird species lives in wetlands, the other in dry forests; hence, they do not encounter each other. D. Two crayfish species cannot interbreed because their genitalia do not engage properly with each other.
A
Two populations of organisms belong to the same biological species when they A. encounter each other, mate, and produce viable, fertile offspring under natural conditions. B. have anatomical features that make it difficult for organisms from the two populations to mate with one another. C. cannot mate with each other because mating occurs at different times. D. use different types of behaviors or physical features to attract mates.
A
Under the biological species concept, a species is a group of organisms that A. have the potential to interbreed in nature and produce fertile offspring. B. live together in a location and carry out identical ecological roles. C. share a recent common ancestor. D. are physically similar.
A
Which is a postzygotic reproductive barrier? A. The hybrid offspring of two species of jimsonweeds always die before reproducing. B. One shrub lives on acid soil near bogs; another closely related species grows in basic soil on limestone cliffs. As a consequence, pollen is not carried between the two species. C. Two species of leopard frogs have different mating calls and do not mate with each other. D. Mallard and pintail ducks mate at different times of the year.
A
Which of the following is an example of a postzygotic reproductive barrier? A. Two fruit flies of different species produce viable but sterile offspring. B. One species of frog mates in April; another mates in May. C. The sperm of a marine worm penetrate eggs of the same species only. D. One species of flower grows in forested areas, another in meadows.
A
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. habitat isolation B. gametic isolation C. temporal isolation D. behavioral isolation
A
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. behavioral isolation B. mechanical isolation C. temporal isolation D. gametic isolation
A
Which statement is true of hybrid zones? A. Limited interbreeding occurs between two closely related species. Over time, evolution of a strong reproductive barrier may fully separate the species or the species may continue to hybridize, or the two species may fuse into a single species. B. Distantly related species come into contact and become similar due to extensive interbreeding. C. Limited interbreeding occurs between two closely related species. This always leads to fusion, because any level of gene flow will remove reproductive barriers between species. D. The absolute effectiveness of reproductive barriers between species is evident.
A
Which would be a typical scenario of sympatric speciation to produce a new plant species? A. Two diploid species hybridize, and for a period of time the hybrid reproduces asexually. Eventually, an error in cell division doubles the chromosome number and results in a fertile polyploid species. B. Differences in habitat are reinforced by sexual selection to produce a new species. C. A diploid (2n) species spontaneously mutates to produce a new triploid (3n) species. D. Two diploid species hybridize to form a new, fertile, reproductively isolated hybrid species.
A
A diploid cell in a plant undergoes chromosome duplication but fails to divide properly, initiating a tetraploid (4n) branch. This branch produces a 4n flower. What can happen next? A. The 4n flower produces 1n (haploid) gametes, which then cross-fertilize with gametes from the original diploid parent species to produce fertile offspring. B. The tetraploid (4n) flower produces 2n gametes and may then be able to self-pollinate to produce fertile 4n offspring. C. The 4n flower produces 4n (tetraploid) gametes, which then self-fertilize to produce fertile offspring. D. The 4n flower produces 2n gametes, which then cross-fertilize with gametes from the original diploid parent species to produce fertile offspring.
B
Allopatric speciation is not likely to occur when A. several populations become isolated from one another as drying conditions cause a large body of water to become separate smaller bodies of water. B. there is no disruption in gene flow between two populations. C. separated populations adapt to different environmental conditions. D. a geographic barrier forms between two populations.
B
For which of the following groups would the biological definition of species be useful? A. asexually reproducing plant and animal species that live in the present B. oaks and other sexually reproducing, extant (currently living) trees C. fossil bacteria, which are known to have reproduced asexually D. fossil dinosaurs, which are known to have reproduced sexually
B
How is modern bread wheat related to wheat found in mideastern farms 10,000 years ago? A. Modern bread wheat has the same number of chromosomes as wheat found in mideastern farming villages 10,000 years ago and researchers believe it is a direct descendant of that wheat. B. Modern bread wheat is the product of several instances of hybridization of wheat species including wheat found in mideastern farms 10,000 years ago. Development of modern wheat also involved errors in cell division and self fertilization. C. Modern bread wheat has larger seeds and more seed heads than ancient wheat, but it has fewer chromosomes than wheat from mideastern farming villages from 10,000 years ago. D. Modern bread wheat has only one of each of three ancestral sets of chromosomes.
B
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. hybridization. B. allopatric speciation. C. sympatric speciation. D. adaptive radiation.
B
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. reduced hybrid fertility. B. sympatric speciation. C. behavioral isolation. D. formation of a hybrid zone.
B
In the mountains of the southeastern United States, there are many similar but distinct salamander species that are restricted to particular mountaintops or ridge systems. They are found in patches of suitable high-elevation habitat, separated by unsuitable lowland areas. This distribution pattern indicates _____. A. a barrier based on temperature isolation B. numerous allopatric speciation events C. adaptive radiation D. numerous sympatric speciation events
B
In which of the following situations is adaptive radiation least likely to occur? A. A species has flexible morphological structures that lend themselves to specialization. B. A species with inflexible morphological traits finds itself in a species-rich, highly competitive environment. C. A new island chain forms far from shore and is reached by a few groups of long-distance colonists. D. The dominant organisms in an area become extinct.
B
Lake Victoria is home to a group of related fishes known as cichlids. Hundreds of forms are present, differing slightly in their color patterns, habitat use, and feeding behavior. What is the best method for scientists to determine conclusively whether the fish are members of a population that has a lot of variation or whether they are members of entirely different species? A. Keep them together in aquariums to see if they will interbreed and produce fertile offspring. B. Observe them together under natural conditions to see if they interbreed to produce fertile offspring. C. Scientists compare DNA sequences because the DNA of members of the same species should be identical. D. Conduct studies on comparative anatomy to find morphological differences between the species.
B
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.
B
Sympatric speciation typically occurs through _____ and _____. A. genetic drift in plants ... sexual selection in animals B. polyploidy in plants ... habitat differentiation in animals C. polyploidy in animals ... habitat differentiation in plants D. polyploidy in plants ... geographic barriers to dispersal in animals
B
The _____ species concept is practical for identification of unfamiliar species and has been used to describe most of the 1.8 million known species on Earth. A. phylogenetic B. morphological C. biological D. ecological
B
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 stronger of the two species taking over and eliminating the other species. D. Natural selection could lead to the hybrid species taking over and eliminating the weaker parent species.
B
Two rodent populations become separated when a large canyon develops in a previously unbroken forest. When is allopatric speciation between the two populations complete? A. When gene flow stops between the two populations (the species is incapable of crossing the canyon), allopatric speciation is complete and you have two separate species. B. When the two populations evolve to be different enough that they are incapable of interbreeding successfully when given the opportunity to do so under natural conditions, allopatric speciation is complete. C. When the two populations evolve to develop recognizably different physical traits, you would definitely have two separate biological species. D. As soon as gene flow is reduced between the two populations, they are properly considered separate species.
B
Two species of clams inhabit the same marine habitat along the Atlantic coast. One releases gametes into the water in early spring, and the second species releases gametes into the water in late summer. Which type of reproductive barrier is at work between these species? A. habitat isolation B. temporal isolation C. reduced hybrid viability D. gametic isolation
B
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.
B
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. diversifying speciation. B. allopatric speciation. C. incomplete speciation. D. sympatric speciation.
B
What is shown in the figure below? A. gradualism B. punctuated equilibrium C. directional selection D. stabilizing selection
B
What is the first step in allopatric speciation? A. polyploidy B. geographic isolation C. formation of a reproductive barrier D. genetic drift
B
What is the major evidence for the punctuated equilibrium model of evolution? A. Transitional fossils are increasingly common as paleontologists continue to unearth new fossils. B. Many fossil species appear suddenly in the fossil record, persist unchanged for long periods, and then disappear without transitional forms. C. Big changes could never occur by a steady accumulation of smaller ones. D. Populations do not adapt to the environment gradually.
B
When plants undergo allopatric speciation, an initial reproductive barrier is often A. temporal isolation. B. pollinator choice. C. gametic isolation. D. polyploidy.
B
When populations of closely related pied flycatchers and collared flycatchers live in different geographic areas, the males of both species look a lot alike. However, when populations of the two species share a common geographic area, there are significant differences in the appearance of the two species. What conclusions might you draw from this situation? A. This is a case of random variation within the population. B. This is a case where hybrid offspring of the two species are less fit than either of the parent species. In the geographic areas where the populations overlap, natural selection has reinforced color differences that serve as reproductive barriers between the two species. C. Hybrid offspring of the two species are more fit than either of the parent species. Eventually the two hybridizing species will fuse into one. D. Even though the colors of the males of the two species are very similar in the geographically isolated populations, you would expect that when researchers performed mate-choice experiments, females would never chose males from the wrong species.
B
Which of the following scenarios is most likely to lead to allopatric speciation? A. fleas in a doghouse and fleas in a veterinarian's office B. fish living in two different spring pools separated by a large expanse of desert C. whales of the same species on opposite sides of the Atlantic ocean D. mountain lions in the canyons of Colorado and in the canyons of neighboring parts of Utah
B
Which of these is an example of temporal isolation? A. The average weight of the individuals in one species is 100 pounds; in the other species the average is 640 pounds. B. One species is diurnal (day active) and mates at high noon; the other is nocturnal (night active) and mates at midnight. C. One species is found only in North America, the other only in Europe. D. One species can't dance; the other does not respond to species that can't dance.
B
Why is the morphological species concept still used to define and describe species? A. The morphological species concept defines a species in terms of its reproductive behavior, which is the most direct way to identify biological species. B. This is the most convenient way of identifying species, and it is one of the few ways to identify fossil or asexual species. C. Physical traits clearly define unique branches on the tree of life. D. If two organisms look alike, they must be the same biological species.
B
_____ generated many key crop plant species in the past, and continues to be an important method for plant geneticists today. A. Adaptive radiation B. Sympatric speciation by polyploidy C. Allopatric speciation D. Natural selection
B
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 ate different food than the valley ants. B. The mountain ants and valley ants were different sizes. C. The mountain ants could not mate with the valley ants. D. The mountain ants and valley ants were different colors.
C
Ancestral diploid wheat species had 2n = 14 chromosomes. What happened when two of these species hybridized? A. They produced a hybrid species with 28 chromosomes. B. They produced a viable, fertile hybrid species with 14 chromosomes. C. They produced a hybrid species with 14 chromosomes that was sterile because the chromosomes from the two different parent species did not pair up properly in meiosis. D. They produced a hybrid species that could not complete mitosis, so it did not develop properly.
C
For speciation to occur there must be A. natural selection. B. isolation. C. sexual reproduction. D. genetic variation.
C
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. mechanical isolation. B. habitat isolation. C. behavioral isolation. D. temporal isolation.
C
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. polyploid speciation B. allopatric speciation C. sympatric speciation D. geographic speciation
C
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 not be a useful procedure to perform in determining whether or not this speciation has occurred? A. Compare stomach contents of whales from each of the two populations. B. Compare DNA samples from fish-eaters and mammal-eaters. C. Compare body shape of whales from each population. D. Compare teeth of whales alive today to teeth of whales in ancient samples.
C
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. 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. C. 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. D. 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
Lake Victoria, in the African Rift Valley, is home to hundreds of species of cichlid fishes, each with slightly different diets and habits. All these fishes probably evolved from one or a few ancestors within the past 100,000 years, making them an example of _____. A. gradualism B. allopatric speciation C. adaptive radiation D. hybrid breakdown
C
Speciation has occurred when A. two populations of organisms have been separated for a very long time. B. offspring of mating from members of two different populations are able to mate with members of either population. C. organisms of one population do not recognize the mating call of another population and so mating does not occur. D. a change in allele frequency has occurred.
C
Speciation without geographic isolation is called ________ speciation. A. incomplete B. diversifying C. sympatric D. allopatric
C
Sympatric speciation is _____. A. initiated by the appearance of a geographic barrier B. the rapid emergence of many ecologically diverse species from a single ancestor C. the appearance of a new species in the same area as its parent species D. most common in animals
C
The _____ species concept is the most applicable to classifying species from the fossil record. A. ecological B. biological C. morphological D. phylogenetic
C
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. hybrid breakdown.
C
When a horse and a donkey mate, they produce infertile hybrids called mules. According to the _____ species concept, horses and donkeys are _____. A. biological ... the same species B. ecological ... different species C. biological ... different species D. ecological ... the same species
C
When a tetraploid flower pollinates a diploid flower of the parental species, the resulting offspring will be A. pentaploid and sterile. B. triploid and fertile. C. triploid and sterile. D. diploid and fertile.
C
Which of the following descriptions best represents the gradual model of speciation? A. Speciation occurs under unusual circumstances and therefore transitional fossils are hard to find. B. An isolated population differentiates quickly from its parent stock as it adapts to its local environment. C. Speciation occurs regularly as a result of the accumulation of many small changes. D. Species undergo little change over long periods interrupted only by short periods of rapid change.
C
Which of the following statements about plant speciation and hybridization is false? A. Plant biologists estimate that 80% of all living plant species are descended from ancestors that formed by polyploid speciation. B. Bread wheat grown widely today is the result of several hybridization events. C. Bread wheat is the ancestral diploid wheat plant. D. Modern plant geneticists use chemicals to induce meiotic and mitotic errors to try to create new hybrid plants with special qualities.
C
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. behavioral isolation B. habitat isolation C. temporal isolation D. mechanical isolation
C
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. behavioral isolation B. habitat isolation C. mechanical isolation D. gametic isolation
C
Which of the following would tend to promote adaptive radiation? A. A single species goes extinct, but it has several competitors that quickly expand to assume its ecological roles. B. An organism colonizes an area that already has a high level of existing species diversity. C. An organism colonizes an isolated area that is habitable but relatively devoid of life. D. An organism has a very stable set of features and capabilities over long spans of evolutionary time.
C
Which population would be most likely to undergo relatively rapid allopatric speciation? A. A population of flowering plants lives along the shore of a pond about one kilometer from the nearest neighboring population. Hummingbirds regularly fly back and forth across this distance and transport pollen between the two populations. B. A population of snakes becomes separated from other populations on a very large island that is formed by rising sea levels. Occasionally, a snake or two swims from the mainland to the island or from the island to the mainland. C. A group of wild horses is transported from Wyoming to a small desert island, previously without horses, off the coast of California. No additional horses reach the island thereafter. D. A group of birds develops a unique set of mating preferences so that they are unlikely to mate with other birds of the same species in the same geographic area.
C
Which provides the most general and correct description of the idea of a reproductive barrier? A. a geographic barrier that separates two species and prevents gene flow between them B. a difference in behavior that keeps two species from interbreeding C. a biological difference between two species that prevents them from successfully interbreeding D. any feature (of geography, behavior, or morphology) that keeps one species from mating with another
C
Which type of organism is most likely to undergo sympatric speciation by polyploidy? A. plant species that are incapable of asexual reproduction and do not self-pollinate B. animals, particularly those with highly selective females that select mates based on exaggerated traits C. plant species that are capable of self-pollination and some degree of asexual reproduction D. animal species with poor dispersal abilities whose populations exist in widely separated, small patches of habitat
C
A new species can arise in a single generation _____. A. through geographic isolation B. in rapidly evolving species such as insects C. if two forms of a species begin to use different habitats or food resources D. if a change in chromosome number creates a reproductive barrier
D
According to the biological species concept, a species is _____. A. a cluster of organisms that share a common ancestor B. a population whose members are physically able and willing to mate with each other C. a population with a distinct fossil record D. a group of populations whose members can interbreed in nature and produce fertile offspring
D
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. gene flow. B. genetic drift. C. mutation. D. natural selection.
D
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. 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. the two groups had been isolated for more than 50,000 years. B. H. floresiensis has become less fit than H. erectus. C. H. floresiensis is no longer fertile as a species. D. a reproductive barrier had evolved.
D
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. reproductive isolation B. reinforcement C. allopatric speciation D. fusion
D
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. 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. The species concept most applicable to these organisms would be A. the ecological species concept. B. the biological species concept. C. the phylogenetic species concept. D. the morphological species concept.
D
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. habitat C. mechanical D. temporal
D
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. allopatric speciation B. the gradual model of speciation C. adaptive radiation D. punctuated equilibrium
D
The emergence of many diverse species from a common ancestor is called A. hybridization. B. allopatric speciation. C. gradualism. D. adaptive radiation.
D
The evolution of numerous ecologically diverse species from a single ancestor in a relatively short time period, as seen in Darwin's finches, is called _____. A. sympatric speciation B. allopatric speciation C. polyploidy D. adaptive radiation
D
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. sympatric B. punctuated C. biogeographic D. allopatric
D
Three species of frogs—Rana pipiens, Rana clamitans, and Rana sylvatica—all mate in the same ponds, but they pair off correctly because they have different calls. This is a specific example of a _____ barrier, called _____. A. postzygotic ... behavioral isolation B. prezygotic ... temporal isolation C. postzygotic ... hybrid breakdown D. prezygotic ... behavioral isolation
D
Two populations that have been separated by a river are most likely to become separate species if A. feeding habits are different in the two populations. B. fur color is different in the two populations. C. genes controlling ear development become different so that members of one population have much longer ears than the other. D. genes controlling molecules on the surface of the sperm that bind with egg receptors are different in the two populations.
D
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.
D
Two species of water lilies in the same pond do not interbreed because one blooms at night and the other during the day. The reproductive barrier between them is an example of _____. A. hybrid breakdown B. habitat isolation C. mechanical isolation D. temporal isolation
D
What do Dodd's experiments with fruit flies indicate? A. Reproductive barriers will arise most quickly if the isolated populations are very small in number. B. Any division of a species into isolated populations will promote rapid formation of reproductive barriers between them. C. Reproductive barriers form so slowly that their formation cannot be observed even in rapidly evolving populations of fruit flies. D. Reproductive barriers will arise most quickly if isolated populations experience and become adapted to differing environments.
D
Which of the following is an example of mechanical isolation? A. A sponge excretes eggs and sperm into the water, but only gametes from the same species will fertilize each other. B. A female moth produces a pheromone to which male moths of another species are indifferent. C. A mule, the offspring of a horse and a donkey, is sterile. D. Many insects have intricate "lock and key" mechanisms that prevent the male genitalia of one species from engaging with the female genitalia of a different species.
D
Which of the following statements about reproductive barriers and speciation is true? A. Populations can split into separate species even in the absence of reproductive barriers. B. Reproductive barriers can arise only when populations are geographically separated. C. Reproductive barriers can arise in the absence of geographic isolation, but the process of speciation would be slow and take many generations. D. Speciation can occur with even a single gene mutation if that mutation involves reproductive barriers.
D
Which of the following statements about the Galápagos finches is false? A. The Galápagos finch species differ in their feeding habitats. B. The evolution of the Galápagos finches is an excellent example of adaptive radiation. 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. Each island in the Galápagos chain has one and only one isolated, unique species of Darwin's finch.
D
Which of the following statements regarding the definition of species is false? A. Under the biological species concept, the gap between species is maintained by reproductive isolation. 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 ecological species concept identifies species in terms of their ecological niches. D. The morphological species concept relies upon comparing the DNA sequences of organisms.
D
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
D
Which species of wheat shown is polyploid? A. T. monococcum B. the AB sterile hybrid C. T. tauschii D. T. turgidum
D