Test 1 Questions/Answers
During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception? A. Characteristics acquired during an organism's life are generally not passed on through genes. B. Spontaneous mutations can result in the appearance of new traits. C. Only favorable adaptations have survival value. D. Disuse of an organ may lead to its eventual disappearance.
A. Characteristics acquired during an organism's life are generally not passed on through genes.
Claytonia virginica is a woodland spring herb with flowers that vary from white to pale pink to bright pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant also prefer pink to white flowers, so that Claytonia with pink flowers have greater relative fruit set than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. Given no other information, if the researcher removes all slugs from the study population, what do you expect to happen to the distribution of flower colors in the population over time? A. The percentage of pink flowers should increase over time. B. The percentage of white flowers should increase over time. C. The distribution of flower colors should not change. D. The distribution of flower colors should randomly fluctuate over time.
A. The percentage of pink flowers should increase over time.
A population of organisms will not evolve if _____. A. all individual variation is due only to environmental factors B. the environment is changing at a relatively slow rate C. the population size is large D. the population lives in a habitat without competing species present
A. all individual variation is due only to environmental factors
Which of the following is a defining characteristic that all protocells had in common? A. the ability to synthesize enzymes B. a surrounding membrane or membrane-like structure C. RNA genes D. the ability to replicate RNA
B. a surrounding membrane or membrane-like structure
You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen. A. Equal amounts of NaCl crystals will dissolve in both water and methanol. B. NaCl crystals will not dissolve in either water or methanol. C. NaCl crystals will dissolve readily in water but will not dissolve in methanol. D. NaCl crystals will dissolve readily in methanol but will not dissolve in water.
C. NaCl crystals will dissolve readily in water but will not dissolve in methanol.
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. None of the insect pests would have genetic variations that resulted in DDT resistance. D. DDT application should have been continual.
C. None of the insect pests would have genetic variations that resulted in DDT resistance.
In a hypothetical environment, fishes called pike-cichlids are visual predators of large, adult algae-eating fish (in other words, they locate their prey by sight). The population of algae-eaters experiences predatory pressure from pike-cichlids. Which of the following is least likely to result in the algae-eater population in future generations? A. selection for drab coloration of the algae-eaters B. selection for nocturnal algae-eaters (active only at night) C. selection for larger female algae-eaters, bearing broods composed of more, and larger, young D. selection for algae-eaters that become sexually mature at smaller overall body sizes
C. selection for larger female algae-eaters, bearing broods composed of more, and larger, young
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype? A. 0.20 B. 0.32 C. 0.42 D. 0.81
D. 0.81
Which of the following describes the most likely order of events in allopatric speciation? A. genetic drift, genetic isolation, divergence B. genetic isolation, divergence, genetic drift C. divergence, genetic drift, genetic isolation D. genetic isolation, genetic drift, divergence
D. genetic isolation, genetic drift, divergence
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. temporal reproductive isolation B. lack of hybrid viability C. behavioral reproductive isolation D. habitat isolation
D. habitat isolation
You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use? A. biological B. phylogenetic C. ecological D. morphological
D. morphological
Soon after the island of Hawaii rose above the sea surface (somewhat less than one million years ago), the evolution of life on this new island should have been most strongly influenced by _____. A. a genetic bottleneck B. sexual selection C. habitat differentiation D. the founder effect
D. the founder effect
Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)? A. Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. B. Ammonia has an overall positive charge. C. Ammonia has an overall negative charge. D. The nitrogen atom has a partial positive charge; each hydrogen atom has a partial negative charge.
A. Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
Starting from the wild mustard Brassica oleracea, breeders have created the strains known as Brussels sprouts, broccoli, kale, and cabbage. Therefore, which of the following statements is correct? A. In this wild mustard, there is enough heritable variation to permit these different varieties. B. Heritable variation is low in wild mustard—otherwise this wild strain would have different characteristics. C. Natural selection is rare in wild populations of wild mustard. D. In wild mustard, most of the variation is due to differences in soil or other aspects of the environment.
A. In this wild mustard, there is enough heritable variation to permit these different varieties.
What is true of the Cambrian explosion? A. There are fossils of animals in geological strata that are older than the Cambrian explosion. B. Only the fossils of monkeys are found in geological strata older than the Cambrian explosion. C. The Cambrian explosion is evidence for the instantaneous creation of life on Earth. D. The Cambrian explosion marks the disappearance of all fossil from the earth.
A. There are fossils of animals in geological strata that are older than the Cambrian explosion.
Which listing of geological periods is in the correct order, from oldest to most recent? A. Cambrian, Devonian, Permian, Cretaceous B. Devonian, Cambrian, Permian, Cretaceous C. Cambrian, Permian, Devonian, Cretaceous D. Permian, Cambrian, Cretaceous, Devonian
A. Cambrian, Devonian, Permian, Cretaceous
Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers from 92-100. Therefore, which of the following can be true? A. Molybdenum atoms can have between 50 and 58 neutrons. B. Molybdenum atoms can have between 50 and 58 protons. C. Molybdenum atoms can have between 50 and 58 electrons. D. Isotopes of molybdenum have different numbers of electrons.
A. Molybdenum atoms can have between 50 and 58 neutrons.
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. Postzygotic isolation exists between the two frog species. B. Prezygotic isolation exists between the two frog species. C. These two species are likely in the process of fusing back into one species. D. The hybrids form a separate species under the biological species concept.
A. Postzygotic isolation exists between the two frog species.
Which of the following was derived from an ancestral cyanobacterium? A. chloroplast B. mitochondrion C. flagella D. mitosome
A. chloroplast
You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to _____. A. cross your flies with flies from another lab B. reduce the number of flies that you transfer at each generation C. transfer only the largest flies D. change the temperature at which you rear the flies
A. cross your flies with flies from another lab
Which of the following is the best modern definition of evolution? A. descent with modification B. change in the number of genes in a population over time C. survival of the fittest D. inheritance of acquired characters
A. descent with modification
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. random fluctuations in beak size and shape D. no change in beak size and shape
A. evolution of yet larger, deeper beaks over time
It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that ____. A. island forms are descended from mainland forms B. common environments are inhabited by the same organisms C. island forms and mainland forms have identical gene pools D. the island forms and mainland forms are converging
A. island forms are descended from mainland forms
Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus, _____ A. the allele's frequency should not change from one generation to the next B. natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency C. two alleles are present in equal proportions D. individuals within the population are evolving
A. the allele's frequency should not change from one generation to the next
Why are hydrocarbons insoluble in water? A. The majority of their bonds are polar covalent carbon-to-hydrogen linkages. B. The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. C. They exhibit considerable molecular complexity and diversity. D. They are less dense than water.
B. The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
About thirteen different species of finches inhabit the Galápagos Islands today, all descendants of a common ancestor from the South American mainland that arrived a few million years ago. Genetically, there are four distinct lineages, but the thirteen species are currently classified among three genera. The first lineage to diverge from the ancestral lineage was the warbler finch (genus Certhidea). Next to diverge was the vegetarian finch (genus Camarhynchus), followed by five tree finch species (also in genus Camarhynchus) and six ground finch species (genus Geospiza). If the six ground finch species have evolved most recently, then which of these is the most logical prediction? A. They should be limited to the six islands that most recently emerged from the sea. B. Their genomes should be more similar to each other than are the genomes of the five tree finch species. C. They should share fewer anatomical homologies with each other than they share with the tree finches. D. The chances of hybridization between two ground finch species should be less than the chances of hybridization between two tree finch species.
B. Their genomes should be more similar to each other than are the genomes of the five tree finch species.
Differences among organisms are caused by differences in the _____. A. elemental composition from organism to organism B. types and relative amounts of organic molecules synthesized by each organism C. sizes of the organic molecules in each organism D. types of inorganic compounds present in each organism
B. types and relative amounts of organic molecules synthesized by each organism
In 1986, a nuclear power accident in Chernobyl, USSR (now Ukraine), led to high radiation levels for miles surrounding the plant. The high levels of radiation caused elevated mutation rates in the surviving organisms, and evolutionary biologists have been studying rodent populations in the Chernobyl area ever since. Based on your understanding of evolutionary mechanisms, which of the following most likely occurred in the rodent populations following the accident? A. Mutations caused major changes in rodent physiology over time. B. Mutation led to increased genetic variation. C. Mutation caused genetic drift and decreased fitness. D. Mutation caused the fixation of new alleles.
B. Mutation led to increased genetic variation.
Which of the following best describes the relationship between the atoms described below? (1,1H vs 3,1H) A. They are isomers. B. They are isotopes. C. They contain 1 and 3 protons, respectively. D. They each contain only 1 neutron.
B. They are isotopes.
Research indicates that ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that _____. A. have identical chemical formulas but differ in the branching of their carbon skeletons B. are mirror images of each other C. differ in the location of their double bonds D. differ in the arrangement of atoms around their double bonds
B. are mirror images of each other
Which two functional groups are always found in amino acids? A. carbonyl and amino groups B. carboxyl and amino groups C. amino and sulfhydryl groups D. hydroxyl and carboxyl groups
B. carboxyl and amino groups
In the formula for determining a population's genotype frequencies, the "2" in the term 2pq is necessary because _____. A. the population is diploid B. heterozygotes can come about in two ways C. the population is doubling in number D. two sounds so cool.
B. heterozygotes can come about in two ways
A compound contains hydroxyl groups as its predominant functional group. Therefore, this compound _____. A. lacks an asymmetric carbon and is probably a fat or lipid B. should dissolve in water C. should dissolve in a nonpolar solvent D. will not form hydrogen bonds with water
B. should dissolve in water
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. directional selection B. stabilizing selection C. disruptive selection D. sexual selection
B. stabilizing selection
The cow Bos primigenius (which is bred for meat and milk) has a smaller brain and larger eyes than closely related wild species of ungulates. These traits most likely arose by _____. A. natural selection, because these traits evolved in the population over time B. natural selection, because these traits were not consciously selected by humans C. artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content D. artificial selection, because these animals differ from their close relatives and common ancestor
C. artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content
Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____. A. was the first theory to refute the ideas of special creation B. proved that individuals acclimated to their environment over time C. dismissed the idea that species are constant and emphasized the importance of variation and change in populations D. was the first time a biologist had proposed that species changed through time
C. dismissed the idea that species are constant and emphasized the importance of variation and change in populations
Genetic variation _____. A. is created by the direct action of natural selection B. arises in response to changes in the environment C. must be present in a population before natural selection can act upon the population D. tends to be reduced by when diploid organisms produce gametes
C. must be present in a population before natural selection can act upon the population
Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be _____. A. 14 B. 16 C. 28 D. 56
C. 28
What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1. origin of mitochondria 2. origin of multicellular eukaryotes 3. origin of chloroplasts 4.origin of cyanobacteria 5. origin of fungal-plant symbioses
C. 4, 1, 3, 2, 5
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 temporal reproductive isolating mechanism B. a postzygotic isolating mechanism C. a behavioral reproductive isolating mechanism D. a gametic reproductive isolating mechanism
C. a behavioral reproductive isolating mechanism
House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of _____. A. prezygotic isolation B. reinforcement C. allopatric speciation D. sympatric speciation
C. allopatric speciation
In what way are elements in the same column of the periodic table the same? They have the same number of _____. A. protons B. electrons when neutral C. electrons in their valence shells when neutral D. electron shells when neutral
C. electrons in their valence shells when neutral
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. temporal isolation C. gametic isolation D. behavioral isolation
C. gametic isolation
Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms? A. temporal isolation B. behavioral isolation C. habitat isolation D. gametic isolation
C. habitat isolation
Which type of bond must be broken for water to vaporize? A. ionic bonds B. polar covalent bonds C. hydrogen bonds D. both polar covalent bonds and hydrogen bonds
C. hydrogen bonds
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 yet larger, deeper beaks over time, until all birds have relatively large, deep beaks B. evolution of smaller, pointier beaks over time, until all birds have relatively small, pointy beaks C. increased variation in beak size and shape over time D. no change in beak size and shape over time
C. increased variation in beak size and shape over time
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. If one builds a canal linking a predator-rich pond to a predator-poor pond, then what type(s) of selection should subsequently be most expected among the mosquitofish in the original predator-rich pond, and what type(s) should be most expected among the mosquitofish in the formerly predator-poor pond? A. stabilizing selection; directional selection B. stabilizing selection; stabilizing selection C. less-intense directional selection; more-intense directional selection D. less-intense disruptive selection; more-intense disruptive selection
C. less-intense directional selection; more-intense directional selection
For a biologist studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet? A. no selection B. no genetic drift C. no gene flow D. no mutation
C. no gene flow
The first genetic material on Earth was probably _____. A. DNA produced by reverse transcriptase from abiotically produced RNA B. DNA molecules whose information was transcribed to RNA and later translated in polypeptides C. self-replicating RNA molecules D. oligopeptides located within protobionts
C. self-replicating RNA molecules
Knowing the atomic mass of an element allows inferences about which of the following? A. the number of electrons in the element B. the number of protons in the element C. the number of protons plus neutrons in the element D. the number of protons plus electrons in the element
C. the number of protons plus neutrons in the element
Can the atomic mass of an element vary? A. No, it is fixed. If it changes at all then you have formed a different element. B. Yes. Adding or losing electrons will substantially change the atomic mass. C. Yes. Adding or losing protons will change the atomic mass without forming a different element. D. Yes. Adding or losing neutrons will change the atomic mass without forming a different element.
D. Yes. Adding or losing neutrons will change the atomic mass without forming a different element.
In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals that are heterozygous for this allele? A. 0.020 B. 0.04 C. 0.16 D. 0.32
D. 0.32
According to the theory of sea-floor spreading, oceanic islands, such as the Hawaiian Islands depicted in the figure above, form as oceanic crustal plates move over a stationary "hot spot" in the mantle. Currently, the big island of Hawaii is thought to be over a hot spot, which is why it is the only one of the seven large islands that has active volcanoes. What should be true of the island of Hawaii? 1. Scientists in search of ongoing speciation events are more likely to find them here than on the other six large islands. 2. Its species should be more closely related to those of nearer islands than to those of farther islands. 3. It should have a rich fossil record of terrestrial organisms. 4. It should have species that are not found anywhere else on Earth. 5. On average, it should have fewer species per unit surface area than the other six islands.
D. 1, 2, 4, and 5
A solution with a pH of 5 has how many more protons in it than a solution with a pH of 7? A. 2 times B. 20 times C. 10 times D. 100 times
D. 100 times
From its atomic number of 15, it is possible to predict that the phosphorus atom has _____. A. 5 neutrons, 5 protons, and 5 electrons B. 15 neutrons and 15 protons C. 8 electrons in its outermost electron shell D. 15 protons and 15 electrons
D. 15 protons and 15 electrons
You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population? A. 0.08 B. 0.09 C. 0.70 D. Allele frequency cannot be determined from this information.
D. Allele frequency cannot be determined from this information.
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 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. No.
D. No.
Which of the following is a fitness trade-off (compromise)? A. In some hornbill species, the male helps seal the female in a tree with her nest until the young are ready to fledge. B. Hummingbirds are the best pollinators of certain flowers, but bees are the best pollinators for orchids. C. The strong, thick beak of a woodpecker helps it find insects in trees. D. Turtle shells provide protection but are heavy and burdensome when moving.
D. Turtle shells provide protection but are heavy and burdensome when moving.
Which of the following organisms would be most likely to fossilize? A. a rare worm B. a common worm C. a rare squirrel D. a common squirrel
D. a common squirrel
An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake? A. directional selection B. disruptive selection C. a founder event D. a genetic bottleneck
D. a genetic bottleneck
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. convergent evolution B. a homologous structure C. natural selection D. a vestigial trait
D. a vestigial trait
Of the following anatomical structures, which is homologous to the bones in the wing of a bird? A. bones in the hind limb of a kangaroo B. wing of a butterfly C. bony rays in the tail fin of a flying fish D. bones in the flipper of a whale
D. bones in the flipper of a whale
How many electrons are involved in a double covalent bond? A. one B. two C. three D. four
D. four
