BIO 148 Exam 3

Small Aristelliger lizards have difficulty defending territories, but large lizards are more likely to be preyed upon by owls. Which kind of selection acts on the adult body size of these lizards? A. Stabilizing selection B. Directional selection C. Disruptive selection

A. Stabilizing selection

Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment? A. The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin. B. The drug-resistance trait is an adaptation to the environment in which human hosts travel worldwide and are exposed to new strains of bacteria. C. The drug-susceptiblity trait is an adaptation to the environment of antibacterial soaps. D. The drug-susceptiblity trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.

A. The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.

Which statement about vestigial traits is correct? A. Vestigial traits are similar to functional traits in closely related species. B. Vestigial traits improve the biological fitness of individuals. C. Vestigial traits cannot be explained by the theory of evolution by natural selection. D. Humans lack vestigial traits.

A. Vestigial traits are similar to functional traits in closely related species.

In biology, an adaptation is defined as _____. A. a heritable trait that increases the fitness of an individual in a particular environment B. a change in an individual's behavior in response to changes in environmental conditions C. a change in an individual's DNA sequence D. a change in an individual's body in response to changes in environmental conditions

A. a heritable trait that increases the fitness of an individual in a particular environment

The Irish "elk" described by Georges Cuvier suggests that _____. A. organisms could go extinct B. the Earth is old enough for evolution to have occurred C. organisms could not have originated by special creation D. the great flood or some other catastrophe caused the evolution of new species

A. organisms could go extinct

When using a cladistic approach to systematics, which of the following is considered most important for classification? A. shared derived characters B. overall phenotypic similarity C. the number of homoplasies D. shared primitive characters E. analogous primitive characters

A. shared derived characters

Which statement is correct? A. A monophyletic group may include an ancestral population and some, but not all, of its descendants. B. A monophyletic group consists of an ancestral population, all of its descendants, and only those descendants. C. A monophyletic group consists of all of the descendants of an ancestral population. D. A monophyletic group is a theoretical idea that does not exist in the real world.

B. A monophyletic group consists of an ancestral population, all of its descendants, and only those descendants.

If autopolyploidy is responsible for the formation of a tetraploid grape (with extra-large fruit) from a diploid population (with smaller fruit), which of the following events must have occurred? A. Mating of diploid individuals to individuals from a different species of grape B. Doubling of chromosome number in the diploid population C. Halving of chromosome number in the diploid population D. A point mutation that produces extra-large fruit

B. Doubling of chromosome number in the diploid population In autopolyploidy, reproductively isolated polyploid individuals are produced when chromosome number is doubled and all chromosomes come from the same species.

True or false? Heterozygote advantage refers to the tendency for heterozygous individuals to have better fitness than homozygous individuals. This higher fitness results in less genetic variation in the population. A. True B. False

B. False

Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection? A. Individuals experience no success in their ability to survive or reproduce. B. Individuals experience differential success in their ability to survive or reproduce. C. Individuals experience uniform success in their ability to survive or reproduce. D. Individuals experience unlimited success in their ability to survive or reproduce.

B. Individuals experience differential success in their ability to survive or reproduce.

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information? A. These two species are likely in the process of fusing back into one species. B. Postzygotic isolation exists between the two frog species. C. Prezygotic isolation exists between the two frog species. D. The hybrids form a separate species under the biological species concept.

B. Postzygotic isolation exists between the two frog species.

Women often have complications during labor while giving birth to very large babies, whereas very small babies tend to be underdeveloped. Which kind of selection is most likely at work regarding the birth weight of babies? A. Disruptive selection B. Stabilizing selection C. Directional selection

B. Stabilizing selection

Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following would suggest that the relationship more likely represents homology instead of convergent evolution? A. Both species are well adapted to their particular environments. B. The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical. C. The structures in adult members of both species are similar in size. D. The two species live at great distance from each other.

B. The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

Ichthyosaurs, now extinct, were aquatic reptiles with dorsal fins and tails, like fish. Their most recent ancestors were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are _____. A. examples of convergent evolution B. adaptations to a common environment and examples of convergent evolution C. homologous D. adaptations to a common environment and homologous E. adaptations to a common environment

B. adaptations to a common environment and examples of convergent evolution

Similar gill pouches in embryos of a chick, human, and cat are an example of _____. A. structural homology B. developmental homology C. genetic homology D. the inheritance of acquired characters

B. developmental homology

Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals? A. analogous; analogous B. homologous; analogous C. analogous; homologous D. homologous; homologous

B. homologous; analogous

Vestigial traits and neutral changes in DNA sequences are good examples of _____. A. developmental homology B. nonadaptive traits C. convergent traits D. adaptation E. acclimation

B. nonadaptive traits

The inability of organisms to evolve anything that could be an advantage reflects _____. A. the consequences of random mutations B. the limits of historical constraints C. the consequences of inbreeding D. the inability to compromise

B. the limits of historical constraints

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily? A. to see if the lily is a cryptic orchid species B. to serve as an outgroup C. to demonstrate likely homoplasies D. to see if the lily and the orchids show all the same shared derived characters (synapomorphies) E. to see if you were paying attention

B. to serve as an outgroup

On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. Which two of the following have operated to increase divergence between mosquitofish populations on Andros? 1. improved gene flow 2. bottleneck effect 3. sexual selection 4. founder effect 5. natural selection A. 3 and 4 B. 1 and 3 C. 3 and 5 D. 2 and 4 E. 2 and 3

C. 3 and 5

Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype? A. Yes, drug-susceptible cells can infect a new host more easily than drug-resistant cells. B. Yes, drug-resistant cells can infect a new host more easily than drug-susceptible cells. C. No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host.

C. No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host.

Do individuals change when natural selection occurs? Why or why not? A. Yes. Acquired characteristics produce adaptations. B. Yes. Individuals change because the population does. C. No. Individuals do not change, but the population does. D. No. Individuals do not change because the population does not.

C. No. Individuals do not change, but the population does.

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees? A. The molecular clock validates the principle of parsimony. B. Parsimony allows the researcher to "root" the tree. C. Similarity due to common ancestry should be more common than similarity due to convergent evolution. D. The outgroup roots the tree, allowing the principle of parsimony to be applied.

C. Similarity due to common ancestry should be more common than similarity due to convergent evolution.

Which is strong evidence that similar traits in different evolutionary lineages are the result of homology and not homoplasy? A. The traits are analogous. B. The traits are genetic, not morphological. C. The traits are also found in many intervening lineages on the tree of life. D. The traits are not also found in many intervening lineages on the tree of life.

C. The traits are also found in many intervening lineages on the tree of life.

How are two different species most likely to evolve from one ancestral species? A. sympatrically, by a point mutation affecting morphology or behavior B. sympatrically, due to extensive inbreeding C. allopatrically, after the ancestral species has split into two populations D. allopatrically, due to extensive inbreeding

C. allopatrically, after the ancestral species has split into two populations

Some beetles and flies have antler-like structures on their heads, much like male deer do. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of _____. A. a synapomorphy B. homology C. convergent evolution D. parsimony

C. convergent evolution

Which of the following is most likely to produce an African butterfly species in the wild whose populations show two strikingly different color patterns? A. stabilizing selection B. directional selection C. disruptive selection D. sexual selection E. artificial selection

C. disruptive selection

Which evolutionary mechanism always increases genetic variation in a population? A. founder effect B. genetic drift C. mutation D. genetic bottleneck

C. mutation

The approach to estimating phylogenetic trees is most like the approach of which species concept? A. biological species concept B. morphological species concept C. phylogenetic species concept

C. phylogenetic species concept

In biology, fitness is defined as _____. A. the ability of an individual to detect life-threatening situations B. the ability of an individual to successfully capture prey C. the ability of an individual to produce surviving offspring D. the ability of an individual to perform physical feats of strength

C. the ability of an individual to produce surviving offspring

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? A. lion B. leopard C. wolf D. tiger E. domestic cat

C. wolf

Which of the following would be useful in creating a phylogenetic tree of a taxon? I) morphological data from fossil species II) genetic sequences from living species III) behavioral data from living species A. I B. II C. III D. I, II, and III E. None. Not I, II, or III.

D. I, II, and III

Which statement is correct? A. A synapomorphy may arise due to convergent evolution. B. A synapomorphy is an ancestral trait. C. Synapomorphies are examples of homoplasy. D. Synapomorphies identify monophyletic groups.

D. Synapomorphies identify monophyletic groups.

Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of _____. A. natural selection B. a homologous structure C. convergent evolution D. a vestigial trait

D. a vestigial trait

Which of the following is an example of homoplasy? A. chlorophyll in flowering plants and algae B. scales in snakes and lizards C. fur in bears and seals D. cell walls in plants and fungi

D. cell walls in plants and fungi

Which of the following is the best modern definition of evolution? A. survival of the fittest B. inheritance of acquired characters C. change in the number of genes in a population over time D. descent with modification

D. descent with modification

What does the biological species concept use as the primary criterion for determining species boundaries? A. morphological similarity B. molecular (DNA, RNA, protein) similarity C. geographic isolation D. gene flow E. niche differences

D. gene flow

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves _____. A. are both members of the order Carnivora B. belong to the same order C. have very similar morphologies D. share a very recent common ancestor

D. share a very recent common ancestor

Genetic drift occurs in a population. Which of the following statements might be true? A. Genetic drift decreased the population's fitness. B. Genetic drift increased the population's fitness. C. The population experiences a decrease in genetic variation. D. The population was relatively small. E. Any of the statements can be true.

E. Any of the statements can be true.

To apply parsimony to constructing a phylogenetic tree, _____. A. choose the tree in which the branch points are based on as many shared derived characters as possible B. choose the tree with the fewest branch points C. choose the tree that assumes all evolutionary changes are equally probable D. base phylogenetic trees only on the fossil record, as this provides the simplest explanation for evolution E. choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology

E. choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology

Which of the following is the most predictable outcome of increased gene flow between two populations? A. lower average fitness in both populations B. increased genetic drift C. increased genetic difference between the two populations D. higher average fitness in both populations E. decreased genetic difference between the two populations

E. decreased genetic difference between the two populations

Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship. A. 2 → 4 → 1 → 3 B. 2 → 4 → 3 → 1 C. 4 → 2 → 3 → 1 D. 4 → 1 → 2 → 3 E. 4 → 2 → 1 → 3

A. 2 → 4 → 1 → 3

How might the timing of when fruit falls from a tree be important in sympatric speciation? A. Apple fruit drops earlier than hawthorn fruit to reduce the interaction of the fly species in time. B. Apple fruit falling earlier is a vicariant event. C. Fruit ripening is important for increased reproductive output. D. Apple fruits fall at the same time as hawthorn fruits, thereby being sympatric.

A. Apple fruit drops earlier than hawthorn fruit to reduce the interaction of the fly species in time. As sympatric speciation occurs in the same space, separation of species mating in time can be an important mechanism for evolution.

Why is the continual use of the antibacterial triclosan in soaps a potential health risk? A. Bacteria could evolve a resistance to commonly used antibiotics. B. Triclosan is lethal to mammals at low concentrations. C. Antibacterial soaps are often contaminated with viruses. D. The use of soap is ineffective at stopping the spread of disease.

A. Bacteria could evolve a resistance to commonly used antibiotics.

Which concept(s) for identifying species CANNOT be applied to asexual or fossil species? A.Biological species concept B. Phylogenetic species concept C. Morphospecies concept D. All of the above.

A. Biological species concept The criterion of reproductive isolation cannot be evaluated in fossil species or species that reproduce asexually.

Long necks make it easier for giraffes to reach leaves high on trees, while also making them better fighters in "neck wrestling" contests. In both cases, which kind of selection appears to have made giraffes the long-necked creatures they are today? A. Directional selection B. Stabilizing selection C. Disruptive selection

A. Directional selection

Which type of selection tends to increase genetic variation? A. Disruptive selection B. Stabilizing selection C. Directional selection

A. Disruptive selection

Which of the following statements best summarizes evolution by natural selection as it is viewed today? A. Evolution is the differential survival and reproduction of the most-fit phenotypes. B. Evolution is the production of adaptations that meet present and anticipated needs. C. Evolution is the descent of humans from the present-day great apes. D. Evolution represents the result of selection for acquired characteristics.

A. Evolution is the differential survival and reproduction of the most-fit phenotypes.

What is plausible evidence supporting the hypothesis that birds evolved from dinosaurs? A. Fossilized transitional forms are discovered that possess features of birds and dinosaurs yet are difficult to classify into either group. B. Bird fossils can be found alongside dinosaur fossils. C. Dinosaurs and birds are both predatory. D. The wing structure of a bird is similar to a dinosaur.

A. Fossilized transitional forms are discovered that possess features of birds and dinosaurs yet are difficult to classify into either group.

How might genotype frequencies change under directional selection? A. Genotypes that represent larger individuals become more prevalent. B. Genotypes that represent moderate-sized individuals become more prevalent. C. Genotypes that represent both smaller and larger individuals become more prevalent. D. Genotypes do not change under directional selection.

A. Genotypes that represent larger individuals become more prevalent.

How does the discovery of a past geological event that divided a once-continuous salt marsh in Florida support the tree depicted? A. It supports the concept of allopatric speciation via vicariance. B. It does not support the tree depicted because there are six groups, not two. C. It does not support the tree depicted because the DNA sequence difference between the species is only one percent. D. It supports the concept of allopatric speciation via dispersal.

A. It supports the concept of allopatric speciation via vicariance. A vicariant event likely split this ancestral population, causing the two groups to become isolated from one another.

Which statement is correct? A. Populations can evolve, but individuals cannot. B. Evolutionary change is not always due to genetic differences. C. Natural selection chooses between populations, not individuals. D. Natural selection can change an individual's allele frequencies.

A. Populations can evolve, but individuals cannot.

Biological fitness is best defined as A. Relative the ability of an individual to produce offspring that survive and reproduce. B. Variability in the population for a trait that increases survival. C. A heritable trait that increases the match of an individual to its environment. D. Similar reproductive success among individuals in a population. E. Competition among individuals for resources that allow them to have more offspring.

A. Relative the ability of an individual to produce offspring that survive and reproduce.

In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer? A. The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers. B. The corn borer must lack variation in resistance to the toxic protein. C. The corn borers must experience unlimited success in their ability to survive or reproduce. D. The corn borers must experience no success in their ability to survive or reproduce.

A. The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.

Which of the following could be a vicariance event for species in that habitat? A. The level of water in a lake recedes, creating two lakes where there used to be one. B. Some insects get blown in a storm to a new mountain range, where they lay eggs. C. Global warming allows populations of mosquitoes to survive at higher elevations. D. Radiation near Chernobyl increases mutation rates, causing an increase in autopolyploidy.

A. The level of water in a lake recedes, creating two lakes where there used to be one.

In a bell-shaped curve, the x-axis (horizontal direction) of the graph represents which of the following? A. The value of a particular characteristic; characteristics of an organism can include such traits as size and color. B. The number of individuals C. Time

A. The value of a particular characteristic; characteristics of an organism can include such traits as size and color.

There is an island in the middle of a large river that houses a large population of ants. Damming of the river causes the island to flood and only the highest points of the island are now above water. The ants cannot swim, so are now in multiple isolated populations. Which of the following best describes this event? A. This situation represents isolation by vicariance. B. This situation represents isolation by dispersal. C. Speciation will not occur in this case because of gene flow. D. This situation represents a form of sympatric speciation. E. Only a rare development of polyploidy could lead to speciation in this case.

A. This situation represents isolation by vicariance.

True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics. A. True B. False

A. True

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. The two populations are _____. A. different subspecies, under the morphological species concept B. different species, under the biological species concept C. different species, under the phylogenetic species concept

A. different subspecies, under the morphological species concept

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____. A. dismissed the idea that species are constant and emphasized the importance of variation and change in populations B. proved that individuals acclimated to their environment over time C. was the first theory to refute the ideas of special creation D. was the first time a biologist had proposed that species changed through time

A. dismissed the idea that species are constant and emphasized the importance of variation and change in populations

A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild solanaceous plants like Datura. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preference in these moths. Based on the above information, what might be occurring in this moth species? A. divergence in sympatry B. polyploidization C. postzygotic isolation D. divergence due to habitat fragmentation

A. divergence in sympatry

After the drought of 1977, researchers on the island of Daphne Major hypothesized that medium ground finches that had large, deep beaks, survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. If this hypothesis is correct, what would you expect to observe if a population of these medium ground finches colonizes a nearby island where Tribulus cistoides is the most abundant food for the next 1000 years? Assume that (1) even the survivors of the 1977 drought sometimes had difficulty cracking the tough T. cistoides fruits and would eat other seeds when offered a choice; and (2) food availability is the primary limit on finch fitness on this new island. A. evolution of yet larger, deeper beaks over time B. evolution of smaller, pointier beaks over time C. no change in beak size and shape D. random fluctuations in beak size and shape

A. evolution of yet larger, deeper beaks over time

A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do not seem to be optimally arranged because _____. A. natural selection is generally limited to modifying structures that were present in previous generations and in previous species B. though we may not consider the fit between the current skeletal arrangements and their functions excellent, we should not doubt that natural selection ultimately produces the best design C. in many cases, phenotype is determined by genotype and the environment D. natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time

A. natural selection is generally limited to modifying structures that were present in previous generations and in previous species

Imagine that you have data that shows that humans from a light-skinned population can exhibit greater similarity in DNA sequence with individuals from a dark-skinned population than with other individuals in the light-skinned population. Based on these hypothetical data, should these light- and dark-skinned human populations be considered separate species under the phylogenetic species concept? Why or why not? A. Yes. Regardless of the DNA sequence data, they have different skin colors. B. No. The DNA sequence data do not support the conclusion that they represent different clades. C. Yes. The DNA sequence data conclusively show that they represent different clades. D. Maybe. It depends on whether the two populations can interbreed and produce viable offspring

B. No. The DNA sequence data do not support the conclusion that they represent different clades. According to the DNA sequence data, they are too similar to form separate branches on the tree of life.

Why do related species share homologous traits? A. Related species have independently evolved similar traits. B. Related species inherited homologous traits from a common ancestor. C. Homologous traits are the products of divergent evolution. D. Related species have adapted to similar environments.

B. Related species inherited homologous traits from a common ancestor.

Which of the situations below describes vicariance? A. Six moose are transported from New Brunswick to Newfoundland, where they establish a large population. B. The Grand Canyon forms, separating two populations of squirrels on the North rim and the South rim. C. American bullfrogs expand their range into British Columbia. D. A small group of finches is blown from the mainland to a recently formed volcanic island.

B. The Grand Canyon forms, separating two populations of squirrels on the North rim and the South rim.

How do autopolyploidy and allopolyploidy differ? A. Only autopolyploidy involves an increase in chromosome sets. B. The chromosomes of an autopolyploid individual come from the same species, while an allopolyploid individual has sets of chromosomes from different species. C. Autopolyploidy is a mechanism of speciation in plants, while allopolyploidy is a mechanism of speciation in animals. D. Autopolyploidy is sympatric, while allopolyploidy is allopatric.

B. The chromosomes of an autopolyploid individual come from the same species, while an allopolyploid individual has sets of chromosomes from different species.

Which of Darwin's postulates about evolution by natural selection is most directly related to heritable variation? A. Individuals that survive are not a random sample of the population. B. The individual organisms that make up a population vary in the traits they possess. C. An individual's phenotype can change in response to a challenge from the environment. D. In each generation, many more offspring are produced than can possibly survive.

B. The individual organisms that make up a population vary in the traits they possess.

Why are human and chimpanzee DNA 96 percent similar? A. Humans and chimpanzees share several similar traits such as the use of tools. B. The two species descended from a recent common ancestor. C. Both groups show similarities in their fossil record. D. Natural selection has favored those particular genes in both humans and chimpanzees.

B. The two species descended from a recent common ancestor.

Which of the following is a fitness trade-off (compromise)? A. The strong, thick beak of a woodpecker helps it find insects in trees. B. Turtle shells provide protection but are heavy and burdensome when moving. C. Hummingbirds are the best pollinators of certain flowers, but bees are the best pollinators for orchids. D. In some hornbill species, the male helps seal the female in a tree with her nest until the young are ready to fledge.

B. Turtle shells provide protection but are heavy and burdensome when moving.

Over long periods of time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses? A. The ancestors of these organisms experienced harmful mutations that forced them to lose these structures. B. Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits. C. Natural selection cannot account for losses, but accounts only for new structures and functions. D. Natural selection accounts for these losses by the principle of use and disuse.

B. Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

There is a population of beetles that typically have black wings. A scientist studying these beetles knows that their eggs hatch in early spring, the young insects grow through the late spring and summer, they lay eggs in the early fall, and they die in the early winter. Recently some beetles have been born with white wings. Early in life, the black- and white-winged beetles seem to be very similar in number of mating events, eggs laid, and survival rates, but shortly after laying their eggs the white beetles die and there are only black-winged beetles during the late fall. Which of the following is a true statement about the beetles? A. Black-winged beetles have a higher fitness than white-winged beetles. B. White- and black-winged beetles have equal fitness. C. White wings are an adaptation. D. The number of baby white-winged beetles will decrease in frequency over time.

B. White- and black-winged beetles have equal fitness.

Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by _____. A. habitat isolation B. gametic isolation C. behavioral isolation D. isolation E. temporal isolation

B. gametic isolation

Which of the following describes the most likely order of events in allopatric speciation? A. genetic isolation, divergence, genetic drift B. genetic isolation, genetic drift, divergence C. divergence, genetic drift, genetic isolation D. divergence, genetic isolation, genetic drift E. genetic drift, genetic isolation, divergence

B. genetic isolation, genetic drift, divergence

Why is it that falcons cannot fly as fast as a fighter jet? A. Adaptive traits must conform to environmental conditions. B. Natural selection can produce deleterious alleles in individuals. C. Adaptive traits are constrained by historical and genetic factors. D. Not all adaptive traits are heritable.

C. Adaptive traits are constrained by historical and genetic factors.

Black-bellied seedcrackers have either small beaks (better for eating soft seeds) or large beaks (better for hard seeds). There are no seeds of intermediate hardness; therefore, which kind of selection acts on beak size in seedcrackers? A. Stabilizing selection B. Directional selection C. Disruptive selection

C. Disruptive selection

Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection? A. Environmental variation exists for traits among individuals in a population. B. Heritable variation does not exist among individuals in a population. C. Heritable variation exists for traits among individuals in a population. D. Drug resistance exists among all individuals in a population.

C. Heritable variation exists for traits among individuals in a population.

Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. All members of a species can potentially interbreed. A. I, II, and III B. II and III C. I and III D. I and II

C. I and III

Why are males usually the sex with exaggerated traits used in courtship? A. In most species, males protect their larger investment in offspring by being choosy about their mates. B. In most species, males compete for the opportunity to mate with females. C. In most species, females protect their larger investment in offspring by being choosy about their mates. D. In most species, females can afford to be choosy about their mates because of females' smaller investment in offspring.

C. In most species, females protect their larger investment in offspring by being choosy about their mates.

How could genetic drift explain differences in genotype frequencies among populations? A. Older lineages of human populations exhibit higher levels of genetic drift. B. Only island populations exhibit genetic drift. C. Isolation of certain populations results in an increased incidence of homozygosity. D. Isolation of certain populations results in an increased incidence of heterozygosity.

C. Isolation of certain populations results in an increased incidence of homozygosity.

How do stabilizing and disruptive selection differ? A. Stabilizing selection produces adaptation. Disruptive selection is nonadaptive. B. With stabilizing selection, the phenotype for a trait does not influence survival. With disruptive selection, the phenotype for a trait affects survival. C. Stabilizing selection reduces the amount of variation in a trait. Disruptive selection increases the amount of variation in a trait. D. With stabilizing selection, extreme individuals have high biological fitness. With disruptive selection, extreme individuals have low biological fitness.

C. Stabilizing selection reduces the amount of variation in a trait. Disruptive selection increases the amount of variation in a trait.

Which statement about adaptation is correct? A. Higher organisms are better adapted than lower organisms. B. Adaptations arise because they are needed in particular environments. C. The adaptive value of a trait varies as the environment changes. D. Better-adapted organisms are more complex than are poorly adapted organisms.

C. The adaptive value of a trait varies as the environment changes.

On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about two hundred miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about fourteen million years ago. The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea _____. A. arrived on the island before D. yakuba B. descended from a single colony of D. yakuba, which had been introduced from elsewhere, with no subsequent colonization events C. descended from an original colony of D. yakuba, of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere. D. descended from a now-extinct, non-African fruit fly

C. descended from an original colony of D. yakuba, of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere.

Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is adaptive in these males, you should _____. A. test whether males with shaved heads are still able to mate B. look for evidence of hair in ancestors of tamarins C. determine if hair length is heritable D. test whether other traits in these males are also adaptive

C. determine if hair length is heritable

Mutation is the only evolutionary mechanism that _____. A. happens in all populations B. is more important in eukaryotes than in prokaryotes C. does little to change allele frequencies D. decreases fitness E. has no effect on genetic variation

C. does little to change allele frequencies

Which mechanism causes postzygotic reproductive isolation? A. habitat isolation B. mechanical isolation C. hybrid sterility D. temporal isolation

C. hybrid sterility Sterile hybrids would isolate the two populations, but zygotes can still be formed.

Which of the species concepts are you using when you use a field guide to identify a bird? A. phylogenetic species concept B. biological species concept C. ecological species concept D. morphospecies concept

D. morphospecies You are identifying a species based on morphological characteristics.

If you found a well-preserved fossil specimen with many velociraptor-like characteristics (an extinct dinosaur of Jurassic Park fame), which species concept would you use to determine whether it is indeed a member of the velociraptor genus, a close relative, or a novel species? A. biological species B. phylogenetic species C. morphospecies

C. morphospecies Fossil evidence most directly informs morphospecies criteria including differences in size, shape, and structure.

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation? A. artificial selection B. sexual selection C. stabilizing selection D. directional selection E. disruptive selection

C. stabilizing selection

The morphospecies concept is broadly applicable but has disadvantages. Which of the following scenarios illustrates a disadvantage of using appearance to distinguish species? A. Two beetles are almost identical except that one has larger antennae. Scientists disagree whether this difference is sufficient to name the two beetles as different species. B. Dogs are highly variable yet can interbreed. C. Some butterflies in the Amazon are almost identical, yet biologists have determined from phylogenetic analysis that they have arisen from different groups within the butterflies. D. All of the listed responses are correct.

D. All of the listed responses are correct. The morphospecies concept is not useful for polymorphic species, cryptic species, or instances where the subjective opinion of a researcher is the only criterion used to determine species status.

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? A. Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation. B. Each bird evolved a deeper, stronger beak as the drought persisted. C. The frequency of the strong-beak alleles increased in each bird as the drought persisted. D. Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

D. Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

The fossil record resembles the living species in the same geographic area. How does this pattern support the theory of evolution by natural selection? A. It is evidence that Lamarck was right: Species become more complex over time. B. It is evidence of the law of succession. C. It is evidence of Aristotle's great chain of being. D. It is evidence that species can change over time.

D. It is evidence that species can change over time.

Which of the following is a weakness of the biological species concept? A. It relies on the subjective judgment of experts to decide whether populations are similar enough to be the same species. B. It requires phylogenetic trees, which haven't been estimated yet for many lineages. C. It is not applicable to sexually reproducing species because the offspring are genetically distinct from the parents. D. It isn't applicable to asexual, fossil, or geographically isolated species.

D. It isn't applicable to asexual, fossil, or geographically isolated species. Reproductive isolation cannot be evaluated in organisms that don't reproduce sexually or between populations that do not overlap in time and space.

What must be true of any organ described as vestigial? A. It need be neither homologous nor analogous to some feature in an ancestor. B. It must be both homologous and analogous to some feature in an ancestor. C. It must be analogous to some feature in an ancestor. D. It must be homologous to some feature in an ancestor.

D. It must be homologous to some feature in an ancestor.

How did the 1977 drought on Daphne Major cause evolutionary change in the medium ground finch population? A. There was not enough food to support the medium ground finch population. B. The drought was a particularly severe environmental perturbation. C. Ground finches learned to eat a different kind of seed. D. Medium ground finches with large and deep beaks had higher survival rates during the drought.

D. Medium ground finches with large and deep beaks had higher survival rates during the drought.

How does an apple fly's attraction to a particular type of fruit promote genetic divergence? A. On apple trees, they are much more likely to encounter hawthorn flies than other apple flies. B. The scent allows female flies to produce more offspring. C. It makes no difference in promoting genetic divergence. D. On apple trees, they are much more likely to encounter other apple flies than hawthorn flies.

D. On apple trees, they are much more likely to encounter other apple flies than hawthorn flies. Because of the fruit preferences of the two populations, little or no interbreeding occurs between apple flies and hawthorn flies, which reduces gene flow between them.

Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation? A. Parasites do not live long enough to inherit acquired characteristics. B. Parasites are lower organisms, and this is why they have simple morphologies. C. Parasites have not yet had time to progress, because they are young evolutionarily. D. Simple morphologies convey some advantage in most parasites.

D. Simple morphologies convey some advantage in most parasites.

Which is the first step in allopatric speciation? A. loss of genetic variation due to genetic drift B. differential natural selection in different environments C. genetic divergence due to mutation D. physical isolation of two populations

D. physical isolation of two populations

A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened? A. Triazine-resistant pigweed has less-efficient photosynthesis metabolism. B. The herbicide company lost its triazine formula and started selling poor-quality triazine. C. Natural selection caused the pigweed to mutate, creating a new triazine-resistant species. D. Triazine-resistant weeds were more likely to survive and reproduce.

D. Triazine-resistant weeds were more likely to survive and reproduce.

Which of these lists contains the four postulates of natural selection? A. Variation in population, heritable variation, selection, unlimited survival and reproduction B. Uniform population, heritable traits, selection, differential survival or reproduction C. Variation in population, environmental variation, selection, differential survival or reproduction D. Variation in population, heritable variation, selection, differential survival or reproduction

D. Variation in population, heritable variation, selection, differential survival or reproduction

Which is an example of a structural homology? A. The same group of embryonic cells forms the adult jaw of a perch and of a dog. B. All vertebrate embryos form a post-anal tail. C. All organisms share a common genetic code. D. Vertebrate forelimbs have the same number and arrangement of bones.

D. Vertebrate forelimbs have the same number and arrangement of bones.

Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact? A. a gametic reproductive isolating mechanism B. a temporal reproductive isolating mechanism C. a postzygotic isolating mechanism D. a behavioral reproductive isolating mechanism

D. a behavioral reproductive isolating mechanism

On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. Which type of reproductive isolation operates to keep the mosquitofish isolated, even when fish from different ponds are reunited in the same body of water? A. mechanical isolation B. gametic isolation C. temporal isolation D. behavioral isolation E. habitat isolation

D. behavioral isolation

Martin Wikelski and L. Michael Romero (Body size, performance and fitness in Galápagos marine iguanas, Integrative and Comparative Biology 43 [2003]:376-86) measured the snout-to-vent (anus) length of Galápagos marine iguanas and observed the percent survival of different-sized animals, all of the same age. The graph shows the log snout-vent length (SVL, a measure of overall body size) plotted against the percent survival of these different size classes for males and females. Currently the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferably catch and eat slower iguanas are introduced to the island, iguana body size is likely to _____ in the absence of other factors; the iguanas would then be under _____ selection. A. increase; disruptive B. decrease; disruptive C. stay the same; stabilizing D. decrease; directional E. increase; directional

D. decrease; directional

Which form of natural selection is most likely to play a role in speciation? A. stabilizing selection B. directional selection C. Natural selection does not lead to speciation. D. disruptive selection

D. disruptive selection

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate? A. lack of hybrid viability B. behavioral reproductive isolation C. temporal reproductive isolation D. habitat isolation

D. habitat isolation

After the drought of 1977, researchers hypothesized that on the Galápagos island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island? A. evolution of smaller, pointier beaks over time, until all birds have relatively small, pointy beaks B. evolution of yet larger, deeper beaks over time, until all birds have relatively large, deep beaks C. no change in beak size and shape over time D. increased variation in beak size and shape over time

D. increased variation in beak size and shape over time

Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been warm-blooded. The fossils of Thrinaxodon are consistent with the hypothesis that _____. A. the environment where it lived was very warm B. fossils found in a given area look like the modern species in that same area C. Antarctica and South Africa separated after Thrinaxodon went extinct D. mammals evolved from a reptilian ancestor

D. mammals evolved from a reptilian ancestor

Among known plant species, which of these have been the two most commonly occurring phenomena that have led to the origin of new species? A. allopatric speciation and sexual selection B. allopatric speciation and polyploidy C. sympatric speciation and sexual selection D. sympatric speciation and polyploidy

D. sympatric speciation and polyploidy

The peppered moth provides a well-known example of natural selection. The light-colored form of the moth was predominant in England before the Industrial Revolution. In the mid-nineteenth century, a dark-colored form appeared. The difference is produced by a dominant allele of one gene. By about 1900, approximately 90% of the moths around industrial areas were dark colored, whereas light-colored moths were still abundant elsewhere. Apparently, birds could readily find the light moths against the soot-darkened background in industrial areas and, therefore, were eating more light moths. Recently, use of cleaner fuels has greatly reduced soot in the landscape, and the dark-colored moths have been disappearing. Should the two forms of moths be considered separate species? A. Yes, because they have completely different coloration and natural selection has affected the frequency of the two different forms. B. Yes, because they have completely different coloration. C. Yes, because they are reproductively isolated based on habitat. D. Yes, because natural selection has affected the frequency of the two different forms. E. No.

E. No.

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Instead, DDT is largely useless against many insects. Which of these would have prevented this evolution of DDT resistance in insect pests? A. All habitats should have received applications of DDT at about the same time. B. The frequency of DDT application should have been higher. C. DDT application should have been continual. D. Larger doses of DDT should have been applied from the air, into water, and within the soil. E. None of the insect pests would have genetic variations that resulted in DDT resistance.

E. None of the insect pests would have genetic variations that resulted in DDT resistance.

The largest unit within which gene flow can readily occur is _____. A. the entire range of a phylum B. the entire range of a genus C.the hybrid zone D. a population E. a species

E. a species

Of the following anatomical structures, which is homologous to the bones in the wing of a bird? A. bony rays in the tail fin of a flying fish B. bones in the hind limb of a kangaroo C. cartilage in the dorsal fin of a shark D. chitinous struts in the wing of a butterfly E. bones in the flipper of a whale

E. bones in the flipper of a whale

Which of the following does not tend to promote speciation? A. natural selection B. polyploidy C. the founder effect D. disruptive selection E. gene flow

E. gene flow

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it? A. allopatric speciation; behavioral isolation B. sympatric speciation; sexual selection C. sympatric speciation; allopolyploidy D. allopatric speciation; ecological isolation E. sympatric speciation; habitat differentiation

E. sympatric speciation; habitat differentiation

About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. (N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629-32.) Refer to the paragraph about the formation of the Isthmus of Panama. The sister populations on opposite sides of the isthmus are true species under which species concept? A. the phylogenetic species concept B. both the morphological species and phylogenetic species concepts C. the morphological species concept D. the biological species concept E. the morpholoogical species, biological species, and phylogenetic species concepts

E. the morpholoogical species, biological species, and phylogenetic species concepts