Bio Ch. 13

The core theme of biology, which explains both the unity and diversity of life, is A. metabolism. B. genetics. C. evolution. D. ecology.

Aristotle believed that A. an individual's use of a body part causes it to further evolve. B. the best evidence for change within species is seen in fossils. C. species evolve through natural selection and other mechanisms. D. species are fixed (permanent) and perfect.

Darwin found that many of the species on the Galápagos islands A. resembled species on the nearest mainland. B. resembled species in Europe. C. resembled species from Australia. D. were identical to South American species.

Lyell's book Principles of Geology, which Darwin read on board the H.M.S. Beagle, argued in favor of which of the following concepts? A. Earth's surface is shaped mainly by occasional catastrophic events. B. Earth's surface is shaped by natural forces that act gradually and are still acting. C. Meteorite impacts may have been a major cause of periodic mass extinctions. D. The processes that shape Earth today are very different from those that were at work in the past.

Who developed a theory of evolution almost identical to Darwin's? A. Lyell B. Aristotle C. Lamarck D. Wallace

Which of the following would prevent an organism from becoming part of the fossil record when it dies? A. It is fully decomposed by bacteria and fungi. B. It is buried in fine sediments at the bottom of a lake. C. It gets trapped in sap. D. It is frozen in ice.

Which of the following statements regarding natural selection is false? A. Natural selection starts with the creation of new alleles that are directed toward improving an organism's fitness. B. Natural selection depends on the local environment at the current time. C. Natural selection can be observed working in organisms alive today. D. Natural selection and evolutionary change can occur in a short period of time (a few generations).

Which of the following statements regarding the currently available fossil record is false? A. The currently available fossil record documents gradual evolutionary changes that link one group of organisms to another. B. The currently available fossil record shows that the first life-forms were eukaryotes. C. The currently available fossil record shows that younger strata were laid down on top of older strata. D. The currently available fossil record shows that the earliest fossils of life are about 3.5 billion years old.

Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species' early embryos are very similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of A. adaptation by natural selection. B. homology. C. geographic similarity. D. coincidental similarity.

Which of the following disciplines has found evidence for evolution based on the native distributions (locations) of living species? A. molecular biology B. geographic distribution C. comparative anatomy D. paleontology

Which of the following represents a pair of homologous structures? A. the wing of a bat and the flipper of a whale B. the antennae of an insect and the eyes of a bird C. the wing of a bat and the scales of a fish D. the wing of a bat and the wing of a butterfly

What evidence is used to determine the branching sequence of an evolutionary tree? A. an overall assessment of general similarities between organisms B. anatomical or molecular homologous structures C. experiments in artificial selection D. the genetic code

Darwin was the first person to draw an evolutionary tree, a diagram that represents A. records of breeding in domesticated animals. B. groupings of organisms based on overall similarity. C. records of lineages in humans (also known as a family tree). D. evidence-based hypotheses regarding our understanding of patterns of evolutionary descent.

According to this figure, which pair of organisms shares the most recent common ancestor? A. lungfishes and amphibians B. amphibians and lizards C. lizards and ostriches D. mammals and crocodiles

Which of the following statements would Darwin have disagreed with? A. Descent with modification occurs through inheritance of acquired characteristics. B. Descent with modification occurs by natural selection. C. Living species have arisen from earlier life-forms. D. Species change over time.

During the 1950s, a scientist named Lysenko tried to solve the food shortages in the Soviet Union by breeding wheat that could grow in Siberia. He theorized that if individual wheat plants were exposed to cold, they would develop additional cold tolerance and pass it to their offspring. Based on the ideas of artificial and natural selection, do you think this project worked as planned? A. Yes, because this is generally the method used by plant breeders to develop new crops. B. Yes; the wheat probably evolved better cold tolerance over time through inheritance of acquired characteristics. C. No, because Lysenko took his wheat seeds straight to Siberia instead of exposing them incrementally to cold. D. No, because there was no process of selection based on inherited traits. Lysenko assumed that exposure could induce a plant to develop additional cold tolerance and that this tolerance would be passed to the plant's offspring.

Broccoli, cabbages, and Brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by A. artificial selection. B. genetic drift. C. inheritance of acquired characteristics. D. natural selection.

Which of the following best expresses the concept of natural selection? A. inheritance of acquired characteristics B. a process of constant improvement, leading eventually to perfection C. change in response to need D. differential reproductive success based on inherited characteristics

Which of the following assumptions or observations is not part of Darwin's idea of natural selection? A. Heritable traits that promote successful reproduction should gradually become more common in a population. B. Whether an organism survives and reproduces is almost entirely a matter of random chance. C. Organisms compete for limited resources. D. Populations produce more offspring than their environment can support.

Which of the following thinkers argued that much of human suffering was the result of human populations increasing faster than food supply, an argument that later influenced Charles Darwin's ideas of natural selection? A. Jean-Baptiste Lamarck B. Charles Lyell C. Gregor Mendel D. Thomas Malthus

A dog breeder wishes to develop a breed that does not bark. She starts with a diverse mixture of dogs. Generation after generation, she allows only the quietest dogs to breed. After 30 years of work she has a new breed of dog with interesting traits, but on average, the dogs still bark at about the same rate as other dog breeds. Which of the following would be a logical explanation for her failure? A. There was no selection (differential reproductive success) related to barking behavior. B. The selection was artificial, not natural, so it did not produce evolutionary change. C. The tendency to bark is not a heritable trait. D. There is no variation for the trait (barking).

Which of the following statements about adaptation is true? A. An individual that has learned how to survive cold winters has become adapted to the cold. B. Adaptation is possible when all the alleles in a gene pool are the same. C. A population that has an increase in frequency of alleles for thicker fur has become adapted to the cold. D. Adaptation results when cold temperatures cause mutations for longer fur.

The ultimate source of all new alleles is A. genetic drift. B. chromosomal duplication. C. natural selection. D. mutation.

A population of butterflies has an allele B for big spots on the wings and b for small spots on the wings. The table below provides data about this population. Regarding these data about the butterfly population, which of the following statements is correct? A. The population is in Hardy-Weinberg equilibrium because the number of B alleles is equal to the number of b alleles. B. The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium. C. The population is not in Hardy-Weinberg equilibrium because p 2 and 2pq are different. D. The population is in Hardy-Weinberg equilibrium because half of the heterozygotes are B and half are b.

A population is A. a group of individuals of different species living in the same place at the same time. B. a group of individuals of a species plus all of the other species with which they interact. C. a group of individuals of the same species that live in the same area and interbreed. D. all individuals of a species, regardless of location or time period in which they live.

Microevolution, or evolution at its smallest scale, occurs when A. an individual's traits change in response to environmental factors. B. a population's allele frequencies change over a span of generations. C. a new species arises from an existing species. D. a community of organisms changes due to the extinction of several dominant species.

The frequency of homozygous dominant individuals in a population that is in Hardy-Weinberg equilibrium is equal to A. p2. B. 2p. C. q or p. D. 2pq.

Which of the following terms represents the frequency of heterozygotes in a population that is in Hardy-Weinberg equilibrium? A. p B. q C. q2 D. 2pq

Which of the following conditions would tend to make the Hardy-Weinberg equation more accurate for predicting the genotype frequencies of future generations in a population of a sexually reproducing species? A. a small population size B. a tendency on the part of females to mate with the healthiest males C. mutations that alter the gene pool D. little gene flow with surrounding populations

Imagine that you are studying a very large population of moths that is isolated from gene flow. A single gene controls wing color. Half of the moths have white-spotted wings (genotype WW or Ww) and half of the moths have plain brown wings (ww). There are no new mutations, individuals mate randomly, and there is no natural selection on wing color. How will p, the frequency of the dominant allele, change over time? A. p will decrease because of genetic drift. B. p will fluctuate rapidly and randomly because of genetic drift. C. p will increase; the dominant allele will eventually take over and become most common in the population. D. p will neither increase nor decrease; it will remain more or less constant under the conditions described.

The recessive allele of a gene causes cystic fibrosis. For this gene among Caucasians, p = 0.98. If a Caucasian population is in Hardy-Weinberg equilibrium with respect to this gene, what proportion of babies is born homozygous recessive and therefore suffers cystic fibrosis? A. 2(0.02 × 0.98) = 0.0392 B. (0.02)2 = 0.0004 C. (0.98)2 = 0.9604 D. 0.02

Brown-eye genes are dominant over blue-eye genes. What is the best explanation for the fact that all the blue-eye alleles have not disappeared in the human population? A. People with brown eyes tend to choose mates with brown eyes, and blue-eyed people tend to choose mates with blue eyes. B. The population is likely in Hardy-Weinberg equilibrium for that locus. C. Some blue alleles are always hidden in heterozygotes. D. Brown-eyed people sometimes have a blue-eyed parent.

Genetic drift resulting from a disaster that drastically reduces population size is called A. natural selection. B. the bottleneck effect. C. gene flow. D. the founder effect.

In populations of the greater prairie chicken in Illinois, genetic diversity was A. lost through mutation and restored by natural selection. B. lost through gene flow and restored by mutation. C. lost through genetic drift and restored by gene flow. D. lost through genetic drift and restored by natural selection.

A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a characteristic determined by a recessive allele. The others are green, a characteristic determined by a dominant allele. A hurricane on the island kills most of the birds from this population. Only 10 remain, and those birds all have yellow feathers. Which of the following statements is true? A. The hurricane has caused a population bottleneck and a loss of genetic diversity. B. This situation illustrates the effect of a mutation event. C. Assuming that no new birds come to the island and no mutations occur, future generations of this population will contain both green and yellow birds. D. The 10 remaining birds will mate only with each other, and this will contribute to gene flow in the population.

Thirty people are selected for a long-term mission to colonize a planet many light-years away from Earth. The mission is successful, and the population rapidly grows to several hundred individuals. However, certain genetic diseases are unusually common in this group, and the group's gene pool is quite different from that of the Earth population they have left behind. Which of the following phenomena has left its mark on this population? A. bottleneck effect B. founder effect C. high rates of mutation D. natural selection

Genetic differences between populations tend to be reduced by A. natural selection. B. gene flow. C. the founder effect. D. mutation.

Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population, through evolution, has become very different from populations of pupfish in other springs. Which of the following statements represents a probable explanation for differences among pupfish populations? A. Each new species contains all the original genotypes of the larger populations. B. The isolated populations had restricted gene pools. C. New genes entered the population through migration. D. The frequency of genotypes reached equilibrium.

Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population, through evolution, has become very different from populations of pupfish in other springs. The variation in gene pools among the 30 pupfish populations occurred through an evolutionary mechanism called A. the bottleneck effect. B. random mating. C. directional selection. D. Hardy-Weinberg equilibrium.

Which of the following statements best describes the true nature of natural selection? A. The strong eliminate the weak in the race for survival. B. Organisms change by random chance. C. Heritable traits that promote reproduction become more frequent in a population from one generation to the next. D. Only the strongest survive.

Which of the following will tend to produce adaptive changes in populations? A. gene flow B. genetic drift C. the founder effect D. natural selection

Some butterflies can ingest toxic chemicals from the milkweed plants they feed on and then can store those chemicals in their body. Because toxins stored in the butterflies are toxic to birds, the birds avoid eating the butterflies. Which of the following is the best explanation for this situation? A. Butterflies developed a mutation that led them to be able to store the chemical because they needed to avoid being eaten. B. Butterflies that stored the chemicals were never eaten by predators, so those butterflies survived. C. Any butterfly allele that allowed milkweed toxin storage would be likely to persist because butterflies that had it were more likely to survive. D. Milkweed plants wanted the butterflies to ingest the chemical so they would no longer feed on the plant, but the butterflies fooled the milkweed by storing the toxic chemicals.

Which of the following statements regarding fins on fishes is true? A. Fins came about because animals couldn't live in water without them. B. Fins resulted from a mutation caused by a movement from land to water. C. Fins evolved so that fish could swim better. D. Fins are an adaptation that aid in swimming.

A news article discussing the evolution of domestic dogs from wolves included this statement: "On its way from pack-hunting carnivore to fireside companion, dogs learned to love-or at least live on-wheat, rice, barley, corn, and potatoes." What is a more scientifically accurate way to state what happened with dogs? A. Dogs were created at the same time as wolves. B. Dogs mutated to be able to eat wheat, rice, barley, corn, and potatoes. C. Some wolves may have had variants in their digestion that allowed them to eat wheat, rice, barley, corn, and potatoes and so were able to survive with humans. D. Being around humans represented an advantage, so wolves were able to take advantage of that by changing their digestion to be able to eat wheat, rice, barley, corn, and potatoes.

An elk herd is observed over many generations. Most of the full-grown bull elk have antlers of nearly the same size, although a few have antlers that are significantly larger or smaller than this average size. The average antler size remains constant over the generations. Which of the following effects probably accounts for this situation? A. directional selection B. a bottleneck effect that resulted in low genetic diversity C. stabilizing selection D. a high rate of gene flow

After a copper smelter begins operation, local downwind populations of plants begin to adapt to the resulting air pollution. Scientists document, for example, that the acid tolerance of several plant species has increased significantly in the polluted area. This is an example of A. directional selection. B. genetic drift. C. disruptive selection. D. stabilizing selection.

A rabbit population consists of animals that are either very dark on top or very light on top. The color pattern is not related to sex. No rabbit shows intermediate coloration (medium darkness). This pattern might result from A. directional selection. B. sexual selection. C. stabilizing selection. D. disruptive selection.

In a large population of plants, notches in the leaves are caused by a dominant allele N and lack of notches by a recessive allele n. Over many generations the proportion of plants in the population with notched leaves increases. What is the most likely cause? A. Dominant alleles generally increase in frequency over time. B. Genetic drift caused a steady movement toward a greater proportion of plants with notched leaves. C. The recessive alleles were all masked by the dominant alleles. D. Directional selection favored plants with notched leaves.

Which statement best describes the mode of selection depicted in the figure? A. stabilizing selection, changing the average color of the population over time B. directional selection, changing the average color of the population over time C. directional selection, favoring the average individual D. disruptive selection, favoring the average individual

The change in curves in the graph represents A. a decrease in genetic variation in a population of mice. B. a shift in the range of genetic variation in a population of mice. C. a lack of genetic variation for light fur color in the original population of mice. D. the appearance of a new allele for darker color in a population of mice.

Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population, through evolution, has become very different from populations of pupfish in other springs. If, in one population of pupfish all of the individuals have a blood pigment that is extraordinarily effective at carrying oxygen, but this trait is not seen in any of the other populations, what likely happened? A. The ancestral population probably had this type of blood pigment, but it was lost through genetic drift in the other 29 populations. B. The other populations did not need this pigment, so they did not evolve it. C. Because oxygen was low where these pupfish lived, a new allele for an effective blood pigment arose. D. This population was lucky to have an individual with a random mutation for an effective blood pigment, and the frequency of this allele was increased in subsequent generations through natural selection.

Large antlers in male elk, which are used for battles between males, are a good example of a trait favored by A. disruptive selection. B. intrasexual selection. C. intersexual selection. D. stabilizing selection.

Mate-attracting features such as the bright plumage of a male peacock result from A. disruptive selection. B. stabilizing selection. C. intrasexual selection. D. intersexual selection.

A woman struggling with a bacterial illness is prescribed a month's supply of a potent antibiotic. She takes the antibiotic for about two weeks and feels much better. Should she save the remaining two-week supply, or should she continue taking the drug? A. She should save the drug for later, because if she keeps taking it the bacteria will evolve resistance. B. She should save the drug because antibiotics are in short supply and she may need it to defend herself against a bioterrorism incident. C. She should save the drug for use the next time the illness strikes. D. She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise, some bacteria may remain in her system, and they will probably be resistant.

If you were just diagnosed with a serious bacterial disease, which of these would predict the most positive outcome for treatment? The disease was acquired A. in a hospital, where most of the bacteria are probably already weakened by antibiotics in the environment. B. in a remote, sparsely populated area where the bacteria have not been exposed to antibiotic drugs. C. in a big city where antibiotics are routinely prescribed by doctors. D. in a livestock barn where the animals have been treated with antibiotics.

Which of the following would most quickly be eliminated by natural selection? A. a harmful recessive allele in a sexual, diploid population B. any harmful allele, regardless of the system of inheritance in a population C. a harmful allele in an asexual, haploid population D. a harmful recessive allele in a sexual, polyploid population

The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations? A. Natural selection occurs very slowly, but elimination of the sickle-cell allele is expected to occur soon. B. In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele. C. Natural selection is a positive force, so it does not eliminate alleles. D. Mutations keep bringing the allele back into circulation.

Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to A. eliminate rare alleles and favor whichever allele is initially most frequent. B. maintain two phenotypes in a dynamic equilibrium in a population. C. produce random changes in allele frequencies. D. stimulate new mutations.

Tay-Sachs is inherited as an autosomal recessive allele. Homozygous individuals die within the first few years of life. However, there is some evidence that heterozygous individuals are more resistant to tuberculosis. Which of the following statements about Tay-Sachs is true? A. This situation is an example of heterozygote advantage if tuberculosis is present in a population. B. This situation is an example of disruptive selection. C. The allele for Tay-Sachs is selected against. D. Heterozygotes will be more fit than either homozygote regardless of environmental conditions.

Some of your DNA may not code for any protein and has no known function in gene regulation; it is sometimes referred to as "junk" DNA. How do nucleotide sequences of "junk DNA" evolve? A. They evolve through genetic drift and other chance processes. B. They evolve through natural selection. C. They evolve by gradually being eliminated from the gene pool. D. They evolve to be more useful by taking on new functions.

A farmer decides to go into the business of raising trout for tourists who enjoy fishing. She builds six trout ponds and stocks each of them with trout from genetically identical stock. Her friends tell her that because she started each pond with just a few trout, she has created a bottleneck effect and her trout populations are likely to become genetically different rapidly. Which of the following statements about her trout is likely true? A. Because the ponds are different and the populations are likely to experience different mutations, the populations will likely diverge evolutionarily, but only over many generations. B. Because they are all genetically alike, they will all remain alike even though the ponds are different. C. The increase in genetic diversity caused by sexual reproduction will promote evolutionary divergence over time. D. Because each population started off with just a few individuals, every mutation that occurs will have a huge impact on the population, so they are likely to evolve in different directions quickly.

Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as A. the outcome of a trade-off: Webbed feet perform poorly on land, but are very helpful in diving for food. B. an example of a trait that is poorly adapted. C. an example of a trait that has not evolved. D. a curiosity that has little to teach us regarding evolution.

Mothers and teachers often say they need another pair of eyes on the backs of their heads. And another pair of hands would come in handy in many situations. You can imagine that these traits would have been advantageous to our early hunter-gatherer ancestors as well. According to sound evolutionary reasoning, what is the most likely explanation for why humans do not have these traits? A. Because every time they have arisen before, the individual mutants bearing these traits have been killed by chance events. Chance and natural selection interact. B. Because they actually would not be beneficial to the fitness of individuals who possessed them. Natural selection always produces the most beneficial traits for a particular organism in a particular environment. C. Because these variations have probably never appeared in a healthy human. As tetrapods, we are pretty much stuck with a four-limbed, two-eyed body plan; natural selection can only edit existing variations. D. Because humans are a relatively young species. If we stick around and adapt for long enough, it is inevitable that the required adaptations will arise.

A group of dog breeders is trying to design and develop an ideal dog. They want a dog with a gentle disposition, black fur, long ears, short legs, and a strong sense of smell. Which of the following comments from fellow dog breeders represents the biggest challenge they are likely to face? A. Artificial selection is artificial and cannot change the genetics of a breed like natural selection. B. There does not seem to be any genetic variation in sense of smell. C. There are breeds with long ears and breeds with short leg, but no breeds with both. D. Most dogs with black fur have long legs.

How are adaptations beneficial to organisms? A. Adaptations help organisms survive and reproduce in any environment, such that organisms can easily move into different environments. B. Adaptations are developed by individual organisms through the use of certain body parts to accomplish particular tasks. C. Adaptations help organisms survive and reproduce in a particular environment. D. Adaptations allow organisms to tolerate dramatic changes in their environment (such as when a lake dries up).

Why was Darwin's acceptance of an ancient, continuously changing Earth so important in his development of his ideas about evolution? A. Darwin hypothesized that as Earth changed due to volcanic eruptions, new species would appear from deep within the Earth. B. He had to accept that Earth could change in order to also accept that organisms can change. C. Darwin hypothesized that species changed gradually, over long spans of time, in response to diverse and changing habitats. D. Darwin hypothesized that as Earth changed, a divine force replaced the existing species with new species that were perfectly suited to the new environment.

Which of the following is a true statement about Charles Darwin? A. He based his theory on the inheritance of acquired characteristics. B. He proposed natural selection as the mechanism of evolution. C. He worked out the principles of population genetics. D. He was the first to discover that living things can change, or evolve.

In Europe at the time Darwin voyaged on HMS Beagle, the popularly accepted explanation of the origin of Earth's plants and animals held that the various species __________. A. had been created rapidly by a divine creator a few thousand years before B. had evolved from now-extinct organisms C. arose continually from nonliving materials by spontaneous generation D. were all related to one another

What was significant to Darwin about the fauna and flora of the Galápagos Islands? A. The organisms there were the same as those seen on similar island environments around the world B. The species were similar to South American species, indicating common descent, but they had been extensively modified and were well-adapted to island life. C. The organisms there were similar to fossils found elsewhere, indicating that the Galápagos chain held many ancient species. D. The species on the Galápagos Islands were not similar to those anywhere else, indicating that they had been created specifically to inhabit this environment.

Which best describes the fossil record? A. The fossil record is a sequence of fossils arranged from oldest (top layers of rock) to youngest (bottom layers of rock). B. The fossil record is a database in which fossil names and dates are collected. C. The fossil record is the highly ordered sequence in which fossils are found in layers of sedimentary rock. D. The fossil record is the sequence in which fossils are found in layers of sedimentary rock. It is chaotic (jumbled), making it difficult to find any consistent patterns in life's evolution.

Which best summarizes the order of appearance of major life-forms (from earliest to most recent) and the time at which life first appeared as documented by the fossil record? A. prokaryotes, unicellular eukaryotes, multicellular eukaryotes, with the oldest life-forms appearing about 4 million years ago B. prokaryotes, unicellular eukaryotes, multicellular eukaryotes, with the oldest life-forms appearing about 3.5 billion years ago C. multicellular eukaryotes, prokaryotes, unicellular eukaryotes, with the oldest life-forms about 3.5 billion years old D. unicellular eukaryotes, prokaryotes, multicellular eukaryotes, with the oldest life-forms about 3.5 billion years old

Which statement reflects a possible weakness of the fossil record? A. The fossil record cannot answer any questions about behavior. B. The fossil record does not indicate chronology (the sequence of events). C. Many species probably did not die in the right place at the right time to be captured in fossils, and many fossils will never by found by paleontologists. D. Only large animals can be fossilized.

The first tetrapods (four-legged animals) were amphibians, which evolved from a specialized group of lobed-fin fish. An unusual fossilized animal (named Tiktaalik) was recently found; this animal possessed a mixture of fish and amphibian characteristics. What is the term used to describe such an intermediate organism? A. vestigial B. mutant C. transitional form D. homologous

Whereas some modern whales possess a small and useless __________ pelvis, __________ linking modern whales to their four-legged evolutionary ancestors possess a larger and even functional pelvis. A. mutant; heterozygotes B. intrasexual; sexual dimorphisms C. dimorphic; bony fish D. vestigial; transitional forms

If whales evolved from land-dwelling mammals, one would expect the fossil record to include intermediate forms, creatures more whale-like than land-dwelling mammals yet still possessing hind limbs and a pelvis lacking in modern whales. Such intermediates are termed __________. A. homologous structures B. vestigial features C. hybrids D. transitional forms

The forelimbs of humans, cats, and bats have a number of detailed similarities in their construction. What best explains these similarities? A. The forelimbs are similar because all of these organisms inherited the basic forelimb design from a common ancestor. B. The forelimbs are similar because of adaptation through the process of natural selection. C. The forelimbs are similar because there is only one workable way to construct a useful arm, leg, or wing. D. The similarities are coincidental.

All known organisms use genetic information to produce protein molecules via the same genetic code. This finding strongly supports the hypothesis that __________. A. the genetic code readily evolves by natural selection B. the earliest macromolecules probably arose when lightning struck an oxygen-free atmosphere C. all organisms are descended from one or a few common ancestors D. there's only one possible way to encode information in a macromolecule

An important challenge to traditional (pre-1860) ideas about species was the observation that seemingly dissimilar organisms, such as hummingbirds, humans, and whales, have similar skeletal structures. This most directly suggested to biologists that __________. A. only the best-adapted organisms can survive B. advantageous changes can be passed along to offspring C. most evolution occurs rapidly following a mass extinction D. these seemingly dissimilar organisms might have evolved from a distant, common ancestor

Which of the following is true of homologous structures? A. They are structures that are ideal for the function they serve in the organism. B. They are used for the same function in different species. C. They are structurally similar due to inheritance from a common ancestor. D. They no longer have a function in the modern organism that possesses them.

Organisms that possess homologous structures probably __________. A. share a common ancestor that also had this structure B. by chance had similar mutations in the past C. live in a similar environment D. have a common ancestor

Which option best describes the concept of an evolutionary tree diagram? A. It is a diagram that organizes species into groups based on their overall similarities and joins them into a tree of life. B. Evolutionary trees relate species to each other by adaptation. Species that are adapted to similar environments share branches on the tree of life. At the root is a common ancestor that could live in most environments known to occur on Earth. C. Evolutionary trees relate species to each other by ancestry. An ancestor common to all of the species is placed at the root of the tree. Branch points are defined by homologous features that are shared by the descendant species along a particular branch. D. It is a diagram that shows how individuals are related to one another within a species. For humans, an example would be a family tree.

Which of the following list of assumptions was part of Charles Darwin's theory of natural selection? A. 1. Organisms vary in heritable ways. 2. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 3. Some traits improve the survival and reproduction of individuals who possess them. 4. Mutations directly cause the changes in species. B. 1. Organisms vary in heritable ways. 2. Some traits improve the survival and reproduction of individuals who possess them. 3. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 4. Earth and its life are very old. C. 1. Earth and its life are very old. 2. Populations produce more offspring than their environment can support. 3. Organisms vary in heritable ways. 4. Mutation rates were higher in the past than they are now. D. 1. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 2. Some traits improve the survival and reproduction of individuals who possess them. 3. There is little genetic variability. 4. Organisms vary in heritable ways.

German shorthaired pointers, Scottish terriers, and Beagles are capable of interbreeding and producing viable, fertile offspring. The diversity seen in these breeds of dogs is the result of __________. A. sexual recombination during meiosis B. natural selection C. artificial selection D. chance

If members of a population have traits that are both heritable and variable among individuals, then _____. A. advantageous traits will probably become more widespread in subsequent generations B. only neutral evolutionary change can occur over time C. the environment will have no influence on phenotypes D. no evolutionary change is likely to occur over time

In natural selection, _____ determine which phenotypes are successful. A. future (anticipated) environmental conditions B. chance events C. catastrophes that reduce the population to a very small number of survivors D. current conditions in the local environment

In artificial selection, humans provide the selective pressure for species to change and shape the evolution of various breeds. What provides the selective pressure in natural selection? A. scientifically trained humans B. the environment C. disease D. the degree of natural genetic variation in a population

A population of small fish lives in a lake with a sandy bottom. The major predator of these fish is a wading bird that hunts by sight. Most of the fish are light sandy brown, but about 10% are mottled. The color pattern is heritable. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction? A. According to the Hardy-Weinberg equilibrium, the ratios will not change. B. There is no way to guess the result, because evolution occurs at random. C. As the sand-colored fish are eaten, more will be produced to keep their frequency at 90%. D. The proportion of mottled fish will increase over time.

When they were first sold, certain insecticides were highly effective in killing mosquitoes. Today, dozens of mosquito generations later, a much smaller proportion of these insects die when sprayed with the same chemicals. Fewer insects are killed today because _____. A. many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics B. mosquitoes that survive spraying develop an immunity to the insecticide C. the original spraying has caused a permanent mutation, giving the insects genetic resistance to the spray D. mosquitoes are deliberately adapting themselves to this man-made change in the environment

Experiments and observations indicate that natural selection acts _____. A. quickly and decisively, permanently optimizing the organism's traits to the local environment B. fairly quickly in some circumstances (within a few generations), and often temporarily in response to changes in the immediate environment C. slowly to create new species when the environment changes D. extremely slowly, requiring thousands of years to have an appreciable effect on an organism's phenotype

Sometimes critics charge that evolution is based on mere speculation because it cannot be directly observed or experimentally induced. Is this true of evolution by natural selection? A. Yes. Natural selection makes sense, but it works too slowly to produce observable changes in organisms. B. The statement is partly true when applied to natural selection. Natural selection can be observed in bacteria and insects, but not in other organisms. C. No. Natural selection changes the traits of some organisms quite quickly, in ways that are clearly adaptive. Scientists have documented such changes in thousands of studies. D. Yes, it is technically true. However, the effects of natural selection are very obvious and it is hard to come up with a better explanation for adaptations.

Mutation plays a large role in the microevolution of bacterial populations. Why? A. Bacteria multiply very rapidly, and they are haploid so that a mutant allele will immediately have a full effect on the phenotype. B. A bacterium is much more likely to produce a mutant offspring than a larger organism. C. Bacteria are usually diploid, so mutations have double the effect on their phenotypes. D. Bacteria are so small and simple that a mutation has a big effect on them.

Sexual recombination occurs when chromosomes are shuffled in _____ and fertilization. A. genetic drift B. meiosis C. mitosis D. natural selection

The original source of all genetic variation is _____. A. recombination B. mutation C. natural selection D. meiosis

Genetic variation in a population of animals or plants depends mainly on which of the following? A. migration of genes among the chromosomes B. sexual recombination C. mutation D. the organism being haploid

Of the choices listed below, which contributes the most to genetic variation among individuals in most prokaryote species? A. crossing over B. genetic drift C. mutation D. independent assortment of homologous chromosomes

Members of the same population _____. A. cannot interbreed under natural conditions B. share a common gene pool C. have the same phenotype D. share the same genotype

The smallest unit that can evolve is a _____. A. gene B. species C. genotype D. population

What is the term for a change in the relative frequencies of alleles in a population over several generations? A. microevolution B. independent assortment C. gene pool D. macroevolution

Of the scenarios below, which represents the occurrence of evolution at its smallest scale? A. An adult human moves from near sea level to a city high in the Andes Mountains. Her physiology changes to improve her performance in the thin atmosphere. B. A pesticide spray is heavily used on a particular farm. Initially it kills 98% of the grasshoppers on contact. Over several generations, the local grasshopper population becomes resistant to the pesticide through inheritance of resistance alleles. Other nearby grasshopper populations do not change in any noticeable way. C. Over many thousands of years, the beak shape of a bird species changes to exploit a new food source. D. An individual organism begins as a single cell and develops into an adult, changing dramatically through a series of life stages.

Consider a hypothetical insect population of 100 individuals. Two equally represented alleles (A and a) exist for a particular gene. Which scenario is an example of microevolution in this population? A. The population is reduced in size due to loss of their food source. Fifty insects remain, and the two alleles are still present in their original proportions. B. Several insects migrate to a new location. The population is left with 80 insects, but the two alleles are still equally represented. C. The population doubles in size, and the two alleles are maintained at their original proportions. D. The population is exposed to a toxin that kills individuals with the A allele. After exposure to the toxin the population has 25 surviving individuals, and 95% of them have the aa genotype.

If a population is in Hardy-Weinberg equilibrium and remains in equilibrium, which of the following will be true? A. Individuals survive and reproduce equally well regardless of their genotype. B. The relative frequencies of three genotypes (AA, Aa, aa) will gradually become stabilized at 1:1:1. C. The population organisms will evolve. D. The dominant allele will take over.

Suppose that, with regard to a particular gene with two alleles, A and a, we know that 60% of the alleles in the gene pool of a particular large population are A. We observe this population for five generations, during which we know that no mutation, selection, or migration has occurred. After this period, the frequency of the a allele is expected to be _____. A. 0.25 B. 0.4 C. 0.16 D. 0.6

In a large population of randomly breeding individuals, the frequency of a recessive allele is initially 0.3. There is no migration and no selection. Humans enter this ecosystem and selectively hunt individuals showing the dominant trait. When the gene frequency is reexamined at the end of the year, __________. A. the frequency of the homozygous dominants will go up, the frequency of the heterozygous genotype will go down, and the frequency of the homozygous recessives will go up B. the frequency of the individuals who express the dominant phenotype will go down, and the frequency of homozygous recessive individuals will go up C. the frequency of the homozygous dominants will go down, the frequency of the heterozygous genotype will go up, and the frequency of the homozygous recessives will remain the same D. the frequency of the homozygous dominants will go down, the frequency of the heterozygous genotype will remain the same, and the frequency of the homozygous recessives will go up

Which condition would disturb the Hardy-Weinberg equilibrium and cause the gene pool to change? A. No mutations occur. B. Several homozygous recessive individuals leave the population. C. All genotypes on average produce an equal number of fertile adult offspring. D. Mating occurs at random.

In a certain group of African people, 4% are born with sickle-cell disease (homozygous recessive). In this case, only homozygous recessive individuals have sickle-cell disease. Heterozygous individuals not only don't have sickle-cell disease, they are resistant to malaria. If this group is in Hardy-Weinberg equilibrium, what percentage of the population is heterozygous and resistant to malaria? A. 4% B. 32% C. 80% D. 16%

Approximately one out of every 2,500 Caucasians in the United States is born with the recessive genetic disorder cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately how many people are carriers? A. 1 in 10 B. 1 in 50 C. 1 in 25 D. 96 in 100

The frequency of a particular lethal recessive allele in a population is 0.02. Given this information, calculate the percentage of individuals who are carriers of the lethal recessive allele. A. approximately 0.04% B. 10% C. approximately 2% D. approximately 4%

Which of the following scenarios would most likely result in the microevolution of a population of humans? A. A colony of twelve humans is established on the moon and remains isolated from Earth. B. A plane crashes, killing 212 random individuals out of a total U.S. population exceeding 275 million. C. Only random mating takes place in all the people that reproduce in North America. D. Excess ultraviolet radiation causes a major increase in mutation rates within the skin cells of adults.

Which of the following is the best example of gene flow? A. A polyploid plant develops. B. An earthquake kills most individuals in a tree population, leaving just a few survivors. C. Genes are shuffled by the crossing over of chromosomes during meiosis. D. Wind blows pollen from one population of plants to another, and cross-fertilization occurs.

Each of us is part of the ongoing evolution of the human species. Which of the following forms of microevolution is currently most important in human populations worldwide? A. Global travel and migration are promoting gene flow on an unprecedented scale. B. Genetic drift is causing numerous random changes in the human gene pool. C. New mutations are occurring faster than ever. D. Natural selection is occurring for traits such as strength and disease resistance.

Genetic drift is _____. A. the mechanism by which new alleles originate B. more likely to have an impact on small populations C. adaptive D. an important microevolutionary mechanism in large populations

The Illinois populations of the Greater Prairie Chicken benefited when managers brought in prairie chickens from other populations. This restored genetic variation to the Illinois populations through the process of __________. A. a founder effect B. mutation C. gene flow D. a bottleneck effect

Natural selection and evolution are two terms that are sometimes confused, even by freshman biology students. What is the relation between natural selection and evolution? A. Natural selection is one of several mechanisms of evolution. B. When natural selection is occurring, evolution is not, and vice versa. C. Any phenomenon that causes evolution is natural selection. D. Natural selection happens over long periods of time; evolution is a short-term process.

Which of the following most accurately and directly measures an organism's Darwinian fitness compared to other individuals in the same population? A. its mutation rate B. how many fertile offspring it produces C. how successful it is when pitted against others in contests of strength or endurance D. its ability to withstand environmental extremes

Which of the following changes in the gene pool results in an adaptation to the environment? A. genetic drift B. gene flow C. natural selection D. sexual selection

Which person has the highest evolutionary fitness? A. a woman who lives for 105 years and has no children B. a man who lives to be 68 and has 7 children and 15 grandchildren C. a woman who lives to be 78, has 10 children, but no grandchildren D. a man who can run a marathon in less than 3 hours

Blue poppies native to China are grown at a plant-breeding center in California, where those with the thickest leaves survive and reproduce best in the drier climate. This evolutionary adaptation of the poppies to their new environment is due to _____. A. genetic drift B. disruptive selection C. stabilizing selection D. directional selection

A geneticist studied a large grass population growing in an area of erratic rainfall and found that plants with alleles for curled leaves reproduced better in dry years, and plants with alleles for flat leaves reproduced better in wet years. This situation would __________. A. preserve the variability in the grass population B. lead to uniformity in the grass population C. lead to directional selection in the grass population D. cause genetic drift in the grass population

A large population of mice is isolated on an island. There are two varieties of the mice, brown and gray. Their fur colors closely match the gray rock outcrops and brown soils of the island. Hawks are their main predators. This situation most likely reflects the outcome of __________. A. disruptive natural selection B. stabilizing natural selection C. directional natural selection D. genetic drift

This figure is an example of _____ because it shows _____. A. stabilizing selection; a population in which individuals at both extremes of a phenotypic range have been selected for B. directional selection; a shift in the overall makeup of a population toward one phenotypic extreme C. stabilizing selection; a favoring of an intermediate variant D. disruptive selection; a shift in the overall makeup of a population toward one phenotypic extreme

Selection that acts, over evolutionary time, to enhance traits that increase an individual's ability to mate frequently or with quality partners is known as __________. A. sexual selection B. directional selection C. disruptive selection D. stabilizing selection

Which would be a good example of intrasexual selection? A. Female birds discriminate among potential mates and choose their partners based on the quality of the song. B. Bright-colored male bluebirds are more attractive to mates than dull-colored individuals. C. Male elk suffer heavy wolf predation because of their large antlers, producing selection against increased antler size in the population. D. Male elephant seals use their huge bodies to batter each other in battles for access to mates.

What usually occurs during intersexual selection? A. Neither males nor females participate in sexual selection rituals because they are costly to overall survival. B. A member of one sex usually chooses their mate based on queues that exhibit good genes. C. Males always choose females with whom to mate. D. Males fight with other males for access to females.

Certain bacterial strains have traits that allow them to resist the effects of antibiotic drugs. How do the resistance traits arise in a bacterial population, and under what circumstances will the resistance traits be most common? A. The resistance traits arise as the immune systems of the bacteria detect and respond to the drugs. Therefore, individual bacteria become more and more resistant if they are exposed to antibiotic drugs. B. The resistance traits are developed by bacteria when they detect the drugs in their environment, through mutations that counteract the drugs' effects. Thus, they are most common wherever the drugs are present. C. The resistance traits are produced by chance mutations and are present to varying degrees in most bacterial populations. Resistance traits will be most prevalent, however, in bacteria that are chronically exposed to antibiotic drugs. D. Resistance traits are produced because antibiotic drugs cause mutations in bacterial cells. The resistance traits only occur in the presence of antibiotics.

Scientists have warned doctors of the danger of their increasing use of antibiotics for treating minor illnesses. They are concerned because __________. A. the drugs will be metabolized more quickly by our bodies, decreasing their effectiveness B. these drugs should be used to treat viral diseases, but not bacterial illnesses, against which they have no effect C. humans will become tolerant to the effects of the drugs D. strains of bacteria that are resistant to these drugs will become more widespread

By what means has the overuse of antibiotics in medicine and agriculture lead to the current global problem of antibiotic resistance? A. Indiscriminant use of antibiotics selects for resistant bacteria and increases their numbers. B. Humans develop an immunity to antibiotics, rendering them ineffective. C. Antibiotic resistance is a fabricated problem used to sell newer and more expensive antibiotics. D. The overuse of antibiotics significantly increases the bacterial mutation rate, causing more antibiotic-resistance mutations to occur.

Which example below presents a misconception about how antibiotic resistance develops? A. Antibiotics are often added to livestock feed. This selects for antibiotic resistance in bacteria found in and around livestock facilities. Thus, many meat products sold in supermarkets contain antibiotic-resistant bacteria. B. Individual bacteria and viruses become immune to antibiotics after they are exposed to them. Eventually the antibiotics are useless. C. If people do not take the full antibiotic treatment as prescribed, some microbes carrying the potential for resistance may be more likely to survive and prosper. D. Heavy use of antibiotics in hospitals produces selection pressure for antibiotic resistance in resident bacterial populations.

Under some conditions, heterozygotes have greater reproductive success than homozygotes. What is this called? A. frequency-dependent selection B. heterozygote advantage C. polymorphism D. incomplete dominance

Sickle-cell disease is a debilitating disease that results from being homozygous recessive for the "sickle-cell allele" of a hemoglobin gene. Why is the allele present and even common in many human populations? A. Only homozygous dominant individuals will be able to survive and reproduce. B. The sickle-cell allele confers malaria resistance to heterozygotes. In some regions where malaria is common, heterozygotes have an advantage over both homozygotes, and their reproductive success maintains the recessive allele at a high frequency in the population. C. Because homozygous recessive individuals die, the recessive allele will eventually be lost from the population. D. In the heterozygous condition, the dominant allele will overcome the recessive allele and only the dominant allele will be passed on to offspring.

Which genotype relative to the sickle-cell allele has the greatest reproductive success in regions where malaria is a common disease? A. the heterozygous genotype B. All genotypes have equal reproductive success. C. the homozygous dominant genotype D. the homozygous recessive genotype

Which of the following statements best describes how the process of natural selection works? A. Natural selection will lead to increasing population size over time. B. Better-adapted individuals will leave behind more offspring to carry on their genes, producing a dynamic "fit" between a population and its changing environment. C. Beneficial mutations will arise in response to a new environment. D. Only the strongest survive.

Which of the following is a misconception regarding natural selection? A. Individuals do not evolve; populations do. B. There is a struggle for existence among individuals because organisms tend to produce far more offspring than the environment can support. C. Natural selection progressively refines organisms' adaptations, eventually leading to perfection. D. Natural selection can only act to diminish or amplify heritable traits.

In the normal course of evolution and adaptation, what is the most likely way for wings to develop in a tetrapod (four-limbed organism)? A. A new, third pair of limbs will form. Unlike the other four limbs, these wings will have a lightweight skeletal structure that is designed "from scratch" and is perfectly suited for supporting flight. B. The forelimbs (or possibly hind limbs) will be used for the new purpose of flight. This new function will arise through many gradual steps, and there will be aspects of the wing that reflect its history and are not perfectly suited for flight. C. A major mutation will produce new limbs, called wings, with a skeletal structure suited to flight. If this does not happen, flight cannot be achieved. D. The forelimbs (or hind limbs) will be used for the new purpose of flight. Natural selection will totally rearrange the elements of the skeleton to perfect the limb for its new function as a wing.