How Animal are Evolved Answer Key

Practice Test This activity contains 30 questions. Darwin originally defined evolution as __________. ( Overview) the passing of acquired characteristics to offspring an individual's ability to adapt to its environment descent with modification a way to classify organisms based on morphological similarities None of the listed responses is correct. Which of the following is a key observation that must be explained in a unifying theory about life? ( Overview) All living things require oxygen to survive. Many basic characteristics are shared by all living things. Evolution is based on descent with modification. Earth is very old. Organisms are rarely well-suited to their environments. The scala naturae, or scale of nature, is based on the ideas of __________. ( Concept 22.1) Darwin Lamarck Aristotle Linnaeus Lyell At the time Darwin voyaged on HMS Beagle, the popularly accepted theory in Western culture that explained the origin of Earth's plants and animals held that the various species __________. ( Concept 22.1) arose continually from nonliving materials by spontaneous generation had been created by divine intervention a few thousand years before had evolved from now-extinct organisms arose from a single species that had survived the biblical flood are all related to one another Carolus Linnaeus is considered to be the founder of __________, and he __________. ( Concept 22.1) paleontology ... believed in catastrophism uniformitarianism ... believed the same geologic forces are operating today that occurred in the past genetics ... described the mechanism for descent with modification evolution ... first proposed that acquired characteristics are inherited the binomial classification system ... thought that resemblances among different species reflected the pattern of their creation The modern idea of extinction as a common occurrence in Earth's history was first proposed in the early 19th century writings of __________. ( Cuvier Lamarck Aristotle Wallace Lyell Concept 22.1) Lyell's principle of uniformitarianism __________. ( Concept 22.1) was rejected by Darwin in favor of catastrophism was compatible with the idea of Earth being only a few thousand years old was similar to Lamarck's theory of inheritance of acquired characteristics states that current geologic processes are very different from those that operated in the past strongly influenced Darwin's view of how living organisms could change over time Which of the following is a true statement about Charles Darwin? ( Concept 22.2) He was the first to discover that living things can change, or evolve. He based his theory on the inheritance of acquired characteristics. He worked out the principles of population genetics. He proposed natural selection as the mechanism of evolution. He was the first to conclude that Earth is billions of years old. At the time Charles Darwin sailed on HMS Beagle, __________. ( Concept 22.1) the idea that animals and plants might change over time was absent from Western science several biologists had proposed that species might change over time, but none had suggested a convincing mechanism that might cause the change the idea of evolution was widely accepted because it could fit into the biblical story of creation the idea of evolution was widely accepted by scientists, but Darwin's great impact was to popularize it for the layperson None of the listed responses is correct. Because he was well aware of the effect his theory of evolution would have on the public and on the Church of England, Darwin delayed publishing his work for several decades while he gathered additional evidence. After invoking selective breeding of domesticated species as evidence that groups of organisms are capable of change, he then proposed that natural populations can change as well. On which two lines of evidence did he base this proposal? ( Concept 22.2) Individuals within a population vary, yet island species around the world all appear to be related to each other. Organisms produce more offspring than can be supported by their environment, and adaptations to specific environments increase an organism's ability to survive and reproduce. Organisms within a population vary, and all populations produce more offspring than can be supported by the environment, resulting in competition for survival within the population. During his voyage around the world, Darwin was inspired to think about evolution by __________. ( Concept 22.2) the works of others such as Lamarck fossils he collected studying adaptations of organisms to their environments the unique organisms he saw in the Galápagos Islands All of the listed responses are correct. In Darwin's view of descent with modification __________. ( Concept 22.2) an organism's traits only affect its own survival natural selection can improve the match between an organism and its environment individuals can evolve environmental changes have no effect on the organisms living in that environment natural selection only operates when an organism needs to evolve What insight did Darwin gain from reading Thomas Malthus's essay on human suffering? ( 22.2) Concept Organisms have the capacity to produce more offspring than the environment can support. Natural selection should be capable of considerable modifications over hundreds of thousands of generations. Population size usually remains relatively stable. Favorable characteristics of a population accumulate over time. All of the listed responses are correct. The breeding of plants and animals for particular traits by humans is called __________. ( 22.2) Concept natural selection sexual recombination paleontology artificial selection homology During periods of rapid environmental change, what may happen to a species that was well-suited to the former environment? ( Concept 22.2) The species may go extinct. Individuals with particular traits that provide an advantage in the new environment will have higher reproductive success. The population may change so much in adapting to the new environment that it is considered a new species. Traits that were favorable in the original environment may be detrimental in the new environment. All of the listed responses are correct. The smallest unit that can evolve is a(n) __________. ( Concept 22.2) species genotype individual population morph Which of the following is an example of the process of evolution? ( Overview and Concept 22.3) the existence of homologous traits such as the forelimbs of mammals the large number and diversity of species of marsupials in Australia the changes in organisms over time observed in the fossil record herbivory the observed match between organisms and their environments According to the theory of evolution, anatomical and molecular homologies should __________. ( Concept 22.3) be completely independent of each other produce similar patterns of evolutionary relatedness yield very different hierarchical patterns link all of the species currently present on Earth be understood to have come about by chance alone When they were first sold, aerosol insecticides were highly effective in killing flies and mosquitoes. Now, several decades later, a much smaller proportion of these insects die when sprayed. The reason fewer insects die when they are sprayed is that __________. ( Concept 22.3) mosquitoes that survive spraying develop an immunity to the insecticide many mosquitoes today are descendants of mosquitoes with insecticide-resistant characteristics mosquitoes are deliberately adapting themselves to this man-made change in the environment the original spraying has caused a permanent mutation, giving the insects genetic resistance to the spray None of the listed responses is correct. A population of zooplankton is exposed to a small number of predatory fish that feed on the largersized (adult) zooplankton. Which of the following predictions would most likely occur based on the principles of natural selection? ( Concept 22.3) The predatory fish will evolve smaller mouths so that they do not drive their prey to extinction. The zooplankton will become sexually mature at larger sizes. The predatory fish will evolve poor eyesight so as to preserve their food supply. The population will come to contain adult zooplankton that reach sexual maturity when they are still relatively small. The first and the third listed responses are both good predictions. How did some strains of Staphylococcus aureus become resistant to antibiotic drugs? ( 22.3) The drug did not work in the way that the developers intended. Concept The population will come to contain adult zooplankton that reach sexual maturity when they are still relatively small. The first and the third listed responses are both good predictions. How did some strains of Staphylococcus aureus become resistant to antibiotic drugs? ( 22.3) Concept The drug did not work in the way that the developers intended. Patients did not take the drug as it was prescribed. The bacterium mutated in response to the drug. Some members of the bacteria population must have had a genetic variation that made them resistant to antibiotics, and these bacteria had greater reproductive success than sensitive individuals. None of the listed responses is correct. Seemingly dissimilar organisms such as hummingbirds, humans, and whales have similar skeletal structures. This most directly suggested to biologists that __________. ( Concept 22.3) only the best-adapted organisms can survive advantageous changes can be passed along to offspring most evolution occurs rapidly following a mass extinction dissimilar organisms might have evolved from a distant, common ancestor All of the listed responses are correct. Animals that possess homologous structures probably __________. ( Concept 22.3) are headed for extinction evolved from the same ancestor have increased genetic diversity by chance had similar mutations independently in the past are not related On an evolutionary tree __________. ( Concept 22.3) organisms that are positioned close to each other are closely related homologous characteristics form a nested pattern scientists are sure of the correct placement and relationships of all organisms the concept of descent with modification is not well-represented None of the listed responses is correct. Which of the following is an example of convergent evolution? ( Concept 22.3) Human embryos and fish embryos both have pharyngeal pouches. Dolphins and sharks have a similar streamlined body shape. Cats and bats have similar skeletal configurations in their forelimbs. Both gymnosperms (cone-bearing plants) and angiosperms (flowering plants) produce seeds. Blind cave fish possess remnants of eye structures under their scales. Vestigial organs are __________. ( Concept 22.3) evidence for Lamarck's theory of use and disuse remnants of structures that were useful to an organism's ancestors, but which are now non-functional or show reduced function one piece of evidence that does not support the theory of evolution examples of anatomical imperfections such as the human knee homologies that can only be observed in embryos All known organisms translate genetic information to produce protein molecules via the same genetic code. This finding strongly supports the hypothesis that __________. ( Concept 22.3) there's only one possible way to encode information in a macromolecule the earliest macromolecules probably arose when lightning struck an oxygen-free atmosphere all organisms are descended from a single common ancestor the genetic code will never be broken None of the listed responses is correct. Evidence from molecular biology supports the theory of evolution by demonstrating that __________. ( Concept 22.3) homologous proteins have arisen independently in many different animal groups closely related animal species have similar geographic distributions closely related organisms have more similar DNA and proteins than more distantly related organisms closely related organisms have similar stages of development None of the listed responses is correct. What did Darwin observe about species on islands? ( Concept 22.3) They are rarely endemic. They are often closely related to species from similar ecological niches all over the world. They are often closely related to species from the nearest mainland or neighboring islands. Darwin only studied the Galápagos and, therefore, could not develop many insights about species on islands. None of the above is correct. To describe evolution as a "scientific theory" means that __________. ( Concept 22.3) it is an untested idea it is not factual it is a matter of opinion it is a broad model that is supported by many observations and much experimental evidence it can be considered dogma In the context of populations, how do we define evolution? ( Overview) Evolution is the tendency for some individuals in a population to leave more offspring than others. Evolution is a change in a population's allele frequencies over generations. Evolution is the explanation for how organic molecules formed from inorganic molecules. Evolution is the way in which sexual reproduction can rapidly spread advantageous traits throughout a population. Evolution is always caused by natural selection. Allele frequencies can be altered by __________. ( Overview) natural selection genetic drift gene flow All of the listed responses are correct. None of the listed responses is correct. Which example below correctly describes average heterozygosity? ( Concept 23.1) Average heterozygosity refers to the average percentage of loci that are heterozygous in a population. Average heterozygosity is measured by looking at changes in karyotypes. Average heterozygosity refers to the number of individuals in a population that are heterozygous for a certain gene. Average heterozygosity is measured by comparing the nucleotide sequences of DNA samples, and then averaging the data from the comparison. Average heterozygosity is usually less than the average difference between nucleotide sequences. The human genome consists of approximately 3 billion base pairs. If humans typically differ from one another by about 3 million base pairs, what is the nucleotide variability of Homo sapiens? ( 23.1) Concept 1% 10% 0.1% 50% 3% Which of the following mechanisms can form entirely new alleles? ( Concept 23.1) the environment genetic drift mutation natural selection sexual recombination Sexual recombination includes the shuffling of chromosomes in __________ and fertilization. ( Concept 23.1) mutation meiosis natural selection mitosis genetic drift Which type of mutation plays the most important role in increasing the number of genes in the gene pool? ( Concept 23.1) point mutation changes in nucleotide sequence duplication rearrangement of gene loci Mutations are so rare that there are no mutations that can have such an important effect. Which of the following would seem to be an example of neutral variation? ( Concept 23.1) moth coloration human fingerprints polymorphism of the Galápagos finches homozygosity in some prairie chicken populations founder effect What is the importance of neutral variation in evolution? ( Concept 23.1) Relative frequencies of neutral variations are controlled by natural selection. Neutral variation is usually removed from the population by natural selection because it does not confer an advantage in the current environment. DNA forensics relies on neutral variation among humans. Neutral variation increases genetic variation, allowing a population to carry more alleles that may help it respond to environmental change. Many mutations are silent and do not affect the amino acid that is coded for. Consider a gene that exists in two allelic forms in a simple Mendelian dominant/recessive pair. In a large population of randomly breeding organisms, 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, __________. ( Concept 23.2) 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 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 down In the Hardy-Weinberg equation, p2 represents __________. ( Concept 23.2) the frequency of homozygous recessive individuals in the population the frequency of heterozygous individuals in the population the frequency of dominant alleles in the population the total alleles in the gene pool the expected frequency of homozygous dominant individuals in the population In a large population of bonobos, the frequency of the recessive allele is initially 0.1. There is no migration and no selection. What is the frequency of the dominant allele? Assume that there are two alleles of this gene. ( Concept 23.2) 0.1 0.2 0.5 0.9 0.99 In a population in Hardy-Weinberg equilibrium, 1% of the individuals in a population show the recessive trait of a certain characteristic. In this situation, what is the value of p? ( Concept 23.2) 0.81 0.99 0.9 0.18 The answer cannot be determined from the information given. In the equation for Hardy-Weinberg equilibrium, 1 represents __________. ( Concept 23.2) the sum of the frequencies of the genotypes for a particular gene locus all the possible phenotypes in the population the frequency of heterozygous individuals in the populations the frequency of homozygous dominant individuals in the population the frequency of homozygous recessive individuals in the population Approximately 1 out of every 2,500 Caucasians in the United States is born with the recessive disease cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately what percentage of people are carriers? ( Concept 23.2) about 10% about .08% about 96% about 4% about 2% In a certain group of African people, 4% are born with sickle-cell disease (homozygous recessive). If this group is in Hardy-Weinberg equilibrium, what percentage of the group has the selective advantage of being more resistant to malaria (heterozygous) than those individuals who are homozygous for normal hemoglobin or for sickle-cell disease? ( Concept 23.2) 20% 80% 16% 32% 4% Assume a population in Hardy-Weinberg equilibrium with these genotypic frequencies: AA = 0.25, Aa = 0.50, and aa = 0.25. If you remove all the homozygous dominants and allow the remaining population to reproduce (again under Hardy-Weinberg conditions), what will be the frequency of homozygous dominants in the next generation? ( Concept 23.2) 0 0.11 0.22 0.44 0.50 Which of the following sets of conditions is required for Hardy-Weinberg equilibrium? ( 23.2) Concept no mutations, no natural selection, with sexual selection random mating, a small population, and no mutations random mating, no natural selection, and a large population a large population, no mutations, with natural selection a large population, random mutations, and no migration of alleles in or out of the population __________ and __________ generate variation, whereas __________ results in an adaptation to the environment. ( Concept 23.2) Overproduction of offspring ... mutation ... sexual recombination Sexual recombination ... natural selection ... overproduction Natural selection ... mutation ... sexual recombination Mutation ... sexual recombination ... natural selection Genetic drift ... natural selection ... mutation A population of 15 birds inhabits a fairly new island. Ten of the birds are dark brown and five of them are light brown. By chance, two of the dark brown birds and three of the light brown birds die before producing any offspring. All of the birds in the next generation are dark brown. This change in phenotypic frequency can be attributed to __________. ( Concept 23.3) gene flow natural selection mutation genetic drift sexual selection An earthquake hits a small island. All but a small group of closely related lizards are eliminated, and the survivors spread out over the island. This is an instance of __________. ( Concept 23.3) mutation genetic drift sexual selection An earthquake hits a small island. All but a small group of closely related lizards are eliminated, and the survivors spread out over the island. This is an instance of __________. ( Concept 23.3) mutation natural selection bottleneck effect gene flow founder effect Which of the following scenarios would most likely result in the microevolution of a population of humans? ( Concept 23.3) A colony of humans on the moon is isolated from Earth. Only random mating takes place among all the people that reproduce in North America. The incidence of skin cancer in adults over age 40 rises significantly. Hundreds of thousands of people are killed in a natural disaster. All of the listed responses are correct. Which of the following is the best example of gene flow? ( Concept 23.3) A small population of humans colonizes a newly formed island. A fire drastically reduces the size of a white-tailed deer population. The remaining individuals spread out throughout the remaining forest. Genes are shuffled by the crossing over of chromosomes during meiosis. An earthquake results in the formation of a canyon, splitting a population of toads apart. Wind blows pollen from one population of plants to another and cross-fertilization occurs. Which of the following most accurately measures an organism's fitness? ( Concept 23.4) its ability to withstand environmental extremes how much food it is able to make or obtain how many fertile offspring it produces its mutation rate how strong the organism is when pitted against others of its species Antibiotic resistance in bacteria is an example of which of the following? ( Concept 23.4) stabilizing selection disruptive selection directional selection macroevolution Hardy-Weinberg equilibrium For several years, scientists have warned doctors of the danger of overprescribing antibiotics such as penicillin. Scientists are concerned because __________. ( Concept 23.4) strains of microorganisms that are resistant to these drugs will be selected for the organisms that produce many of the antibiotics are overexploited and could become extinct the drugs will be metabolized more quickly by our bodies, decreasing their effectiveness humans will become tolerant to the effects of drugs None of the listed responses is correct. A population of squirrels is preyed on by small hawks. The smaller squirrels can escape into burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very small or very large. What process is responsible for this outcome? ( Concept 23.4) balancing selection Hardy-Weinberg equilibrium stabilizing selection directional selection disruptive selection Stabilizing selection __________. ( Concept 23.4) favors intermediate variants in a population occurs only in plants usually results in two distinct phenotypes prevents mutations from occurring occurs when some individuals migrate to an area with different environmental conditions Birds with average-size wings survived a severe storm more successfully than other birds in the same population with longer or shorter wings. If severe storms occur regularly, then over time, one should expect these storms to bring about __________. ( Concept 23.4) stabilizing selection the bottleneck effect disruptive selection gene flow directional selection The lethal genetic disorder Tay-Sachs disease occurs in individuals with two copies of a recessive allele of the responsible gene. Which of the following statements is true? ( Concept 23.4) Homozygous dominant individuals will be more likely to reproduce than heterozygous individuals. Only homozygous dominant individuals will be able to survive and reproduce. Because homozygous recessive individuals die, the recessive allele will eventually be lost from the population. In the heterozygous condition, the dominant allele will overcome the recessive allele and only the dominant allele will be passed on to offspring. Heterozygous individuals will survive and may pass the recessive allele on to their offspring. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very small or very large. What process is responsible for this outcome? ( Concept 23.4) balancing selection Hardy-Weinberg equilibrium stabilizing selection directional selection disruptive selection Stabilizing selection __________. ( Concept 23.4) favors intermediate variants in a population occurs only in plants usually results in two distinct phenotypes prevents mutations from occurring occurs when some individuals migrate to an area with different environmental conditions Birds with average-size wings survived a severe storm more successfully than other birds in the same population with longer or shorter wings. If severe storms occur regularly, then over time, one should expect these storms to bring about __________. ( Concept 23.4) stabilizing selection the bottleneck effect disruptive selection gene flow directional selection The lethal genetic disorder Tay-Sachs disease occurs in individuals with two copies of a recessive allele of the responsible gene. Which of the following statements is true? ( Concept 23.4) Homozygous dominant individuals will be more likely to reproduce than heterozygous individuals. Only homozygous dominant individuals will be able to survive and reproduce. Because homozygous recessive individuals die, the recessive allele will eventually be lost from the population. In the heterozygous condition, the dominant allele will overcome the recessive allele and only the dominant allele will be passed on to offspring. Heterozygous individuals will survive and may pass the recessive allele on to their offspring. Which type of selection maintains stable frequencies of two or more phenotypic forms in a population? ( Concept 23.4) balancing selection stabilizing selection neutral variation directional selection heterozygote advantage Selection that acts over evolutionary time to preserve traits that increase an individual's ability to mate is known as __________. ( Concept 23.4) directional selection disruptive selection balancing selection stabilizing selection sexual selection Which statement below is true about sexual selection? ( Concept 23.4) Showy secondary sexual characteristics cannot be explained because they break all of the rules of natural selection. In most vertebrates, females court the males. Intrasexual selection leads to the death of most unfit males in combat. Sexual selection can result in sexual dimorphism—marked differences between the sexes in secondary sexual characteristics that are not associated directly with reproduction. There is no evidence that intrasexual selection takes place between females. How does natural selection fashion organisms? ( Concept 23.4) Brand new body plans arise often, giving natural selection many new possibilities to work with. Chance and the environment interact with natural selection, so that the best available traits are selected for. Neutral traits are often selected for because they will eventually produce alleles that confer an advantage. The best traits for the current environment arise in the population and are selected for. Sexual selection acts to make organisms better adapted to their environments. A number of mosquito populations today are resistant to insecticides that were once quite effective. Biologists think that insecticide resistance evolved in mosquitoes because __________. ( Concept 23.4) a few mosquitoes were probably resistant to the insecticide before it was ever used, and these individuals were more likely to survive and reproduce in the presence of insecticide mosquitoes attempted to adapt to their environment individual mosquitoes built up an immunity to an insecticide after being exposed to it mosquitoes needed to develop insecticide resistance to survive after the insecticide was used a new allele developed in response to the insecticide that provided future generations the benefit of resistance