AP Bio Unit 6 Part 2
A swim bladder is a gas-filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of _____. A) exaptation B) paedomorphosis C) adaptive radiation D) changes in Hox gene expression
A
About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. (N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629-32.) Refer to the paragraph about the formation of the Isthmus of Panama. If the isthmus formed gradually rather than suddenly, what pattern of genetic divergence would you expect to find in these species pairs? Use the following information to answer the question(s) below. About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. Refer to the paragraph about the formation of the Isthmus of Panama. If the isthmus formed gradually rather than suddenly, what pattern of genetic divergence would you expect to find in these species pairs? A) greater percentage of difference in DNA sequence between species that inhabit deep water than between species that inhabit shallow water B) similar percentages of difference in DNA sequence between all pairs of sister species C) greater percentage of difference in DNA sequence between species that inhabit shallow water than between species that inhabit deep water
A
Among known plant species, which of these have been the two most commonly occurring phenomena that have led to the origin of new species? A) sympatric speciation and polyploidy B) allopatric speciation and polyploidy C) sympatric speciation and sexual selection D) allopatric speciation and sexual selection
A
Dogs (Canis lupus familiaris) and gray wolves (Canis lupus) can interbreed to produce viable, fertile offspring. These species shared a common ancestor recently (in geologic time) and have a high degree of genetic similarity, although their anatomies vary widely. Judging from this evidence, which two species concepts are most likely to place dogs and wolves together into a single species? A) biological and phylogenetic B) biological and morphological C) ecological and phylogenetic D) ecological and morphological
A
Neutral theory proposes that _____. A) a significant proportion of mutations are not acted upon by natural selection B) most mutations of highly conserved DNA sequences should have no functional effect C) DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R-groups) have a neutral pH D) molecular clocks are more reliable when the surrounding pH is close to 7.0
A
Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in _____. A) mutations to homologous genes B) the pattern of embryological development C) morphology D) biochemical pathways
A
The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that _____. A) in particular environments, similar adaptations can be beneficial to more than one species B) evolution generally progresses toward some goal C) evolution tends toward increased complexity or increased size D) a larger volume-to-surface area ratio is adaptive in many mammals
A
The following question refer to the description below. All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than five hundred million years ago. Fruit-fly eyes are of the compound type, which is structurally very different from the camera-type eyes of mammals. Even the camera-type eyes of molluscs, such as octopi, are structurally quite different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar versions of Pax-6. The fact that the same gene helps produce very different types of eyes is most likely due to _____. The following question refer to the description below. A) differences in the control of Pax-6 expression among these organisms B) variations in the number of Pax-6 genes among these organisms C) the few differences in nucleotide sequence among the Pax-6 genes of these organisms D) the independent evolution of this gene at many different times during animal evolution
A
The importance of computers and of computer software to modern cladistics is most closely linked to advances in _____. A) molecular genetics B) radiometric dating C) fossil discovery techniques D) light microscopy
A
The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma. These species have apparently undergone speciation from ancestral stock since the last glacial retreat about ten thousand years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species? A) mitochondrial DNA B) amino acids in proteins C) ribosomal RNA D) conserved regions of nuclear DNA
A
The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic effects of Pitx1 gene _____. A) silencing (loss of expression) B) duplication (gain in number) C) elimination (loss) D) mutation (change)
A
Why would gene duplication events, such as those seen in the Hox gene complex, set the stage for adaptive radiation? A) One copy of a gene can perform the original function, while other copies are available to take on new functions. B) There are more copies of genes, meaning speciation had occurred by polyploidy. C) Without duplicated genes, species would be vulnerable to extinction. D) The original gene copy is the outgroup, and the new gene copies are the adaptive radiation.
A
You want to study divergence of populations, and you need to maximize the rate of divergence to see results within the period of your grant funding. You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed. What combination of characteristics would maximize your chance of seeing divergence in this study? 1. Choose a random sample of individuals to form the new population. 2. Choose individuals from one extreme to form the new population. 3. Choose a species to study that produces many offspring. 4. Choose a species to study that produces a few, large offspring. 5. Place the new population in the same type of environment as the source population. 6. Place the new population in a novel environment compared to that of the source population. You want to study divergence of populations, and you need to maximize the rate of divergence to see results within the period of your grant funding. You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed. What combination of characteristics would maximize your chance of seeing divergence in this study? 1. Choose a random sample of individuals to form the new population. 2. Choose individuals from one extreme to form the new population. 3. Choose a species to study that produces many offspring. 4. Choose a species to study that produces a few, large offspring. 5. Place the new population in the same type of environment as the source population. 6. Place the new population in a novel environment compared to that of the source population. A) 2, 3, and 6 B) 1, 4, and 6 C) 1, 3, and 6 D) 2, 3, and 5
A
If one organ is an exaptation of another organ, then these two organs _____. A) are found in the same species B) are homologous C) are undergoing convergent evolution D) have the same function
B
On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about two hundred miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about fourteen million years ago. Using only the information provided in the paragraph, which of the following is the best initial hypothesis for how D. santomea descended from D. yakuba? Use the following description to answer the question(s) below. A) autopolyploidy B) habitat differentiation C) sexual selection D) allopolyploidy
B
The best classification system is that which most closely _____. A) reflects the basic separation of prokaryotes from eukaryotes B) reflects evolutionary history C) unites organisms that possess similar morphologies D) conforms to traditional, Linnaean taxonomic practices
B
The difference between geographic isolation and habitat differentiation (isolation) is the _____. A) amount of genetic variation that occurs among two gene pools as speciation occurs B) relative locations of two populations as speciation occurs C) identity of the phylogenetic kingdom or domain in which these phenomena occur D) speed (tempo) at which two populations undergo speciation
B
The most important feature that permits a gene to act as a molecular clock is _____. A) a recent origin by a gene-duplication event B) a reliable average rate of mutation C) a large number of base pairs D) being acted upon by natural selection
B
The original habitat of the North American maggot fly, Rhagoletis pomonella, was native hawthorn trees. About 200 years ago, some populations colonized newly introduced apple trees. The two populations are still classified as subspecies, but sympatric speciation is under way. What has contributed to incipient speciation in the maggot fly? A) Maggot flies that feed and lay eggs on apples have gradually become adapted to this fruit. B) Because apples mature more quickly than hawthorn fruit, the apple-feeding flies have been selected for more rapid development. C) Apple maggot flies try to avoid mating with hawthorn maggot flies.
B
What does the biological species concept use as the primary criterion for determining species boundaries? A) geographic isolation B) gene flow C) morphological similarity D) niche differences
B
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 A) 4, 1, 2, 3, 5 B) 4, 1, 3, 2, 5 C) 4, 3, 1, 5, 2 D) 4, 3, 2, 1, 5
B
A paleontologist finds a new tyrannosaur in a site she is excavating, and wishes to date the fossil. What is the most likely method she will use? A) She will determine the fossil's age by measuring the ratio of carbon-14 to carbon-12 in the fossil. B) She will measure the amount of the radioisotope uranium-238 in the stratum where she found the tyrannosaur. C) She will infer the age of the fossil by dating layers of volcanic rock above and below the stratum containing the fossil.
C
Eukaryotes that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their _____. A) homologous genes that are poorly conserved B) plasmids C) homologous genes that are highly conserved D) mitochondrial genomes
C
How were conditions on the early Earth of more than three billion years ago different from those on today's Earth? Unlike Earth today, early Earth _____. A) had an oxidizing atmosphere B) experienced little high energy radiation from the sun C) had an atmosphere rich in gases released from volcanic eruptions D) had an atmosphere with significant quantities of ozone
C
Select the correct statement about phylogenetic trees. A) All phylogenetic trees are similarly shaped. B) Phylogenetic trees always show increased branching, representing increased diversity over time. C) Phylogenetic trees may expand quickly to maximum width and then narrow over time.
C
The Permian period ended and then rapid speciation occurred as new animal and plant forms evolved. The most likely explanation for this is _____. I) adaptive radiation II) ecological opportunity III) lack of competition IV) morphological innovation A) just one of the above B) two of the above C) three of the above D) all of the above
C
The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as _____. A) structural homologies B) vestiges C) homoplasies D) the result of shared ancestry
C
The production of sterile mules by interbreeding between female horses (mares) and male donkeys (jacks) is an example of _____. A) mechanical isolation B) reduced hybrid viability C) reduced hybrid fertility D) hybrid breakdown
C
Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what characteristic, leading to which phenomenon? A) mass extinctions, leading to bottleneck effect B) adaptive radiation, leading to founder effect C) a variety of empty ecological niches, leading to adaptive radiation D) major evolutionary innovations, leading to rafting to nearby continents
C
Which of the following statements supports the hypothesis of "an RNA world" on early Earth? A) The oldest known fossils contain traces of RNA molecules. B) Single-stranded RNA molecules are linear and cannot form three-dimensional shapes. C) Some RNA molecules are important catalysts in modern cells.
C
Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily? A) to see if the lily and the orchids show all the same shared derived characters (synapomorphies) B) to demonstrate likely homoplasies C) to serve as an outgroup D) to see if the lily is a cryptic orchid species
C
A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of _____. A) the influence of environment on development B) paedomorphosis C) heterochrony D) a change in a developmental gene or its regulation that altered the spatial organization of body parts
D
About 3 million years ago, the Isthmus of Panama (a narrow strip of land connecting North and South America) formed, dividing marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. Refer to the paragraph about the formation of the Isthmus of Panama. The sister populations on opposite sides of the isthmus are true species under which species concept? A) the biological species concept B) the phylogenetic species concept C) the morphological species concept D) the morphological species, biological species, and phylogenetic species concepts
D
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. A) 1, 2, and 3 B) 1, 2, and 5 C) 1, 2, 3, and 4 D) 1, 2, 4, and 5
D
An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to _____. A) prevent the formation of an ozone layer B) change the atmosphere from oxidizing to reducing C) make it easier to maintain reduced molecules D) cause iron in ocean water and terrestrial rocks to rust (oxidize)
D
In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of _____. A) allopatric speciation and habitat isolation B) sympatric speciation and temporal isolation C) allopatric speciation and gametic isolation D) sympatric speciation and habitat isolation
D
Most causes of speciation are relatively slow, in that they may take many generations to see changes, with the exception of _____. A) reinforcement B) natural selection C) colonization D) polyploidy
D
Rank the following in order from most general to most specific: 1. gametic isolation 2. reproductive isolating mechanism 3. sperm-egg incompatibility in sea urchins 4. prezygotic isolating mechanism A) 4, 2, 1, 3 B) 2, 3, 1, 4 C) 4, 1, 2, 3 D) 2, 4, 1, 3
D
The following question are based on the observation that several dozen different proteins comprise the prokaryotic flagellum and its attachment to the prokaryotic cell, producing a highly complex structure. Certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This evidence supports the claim that _____. A) bacteria that possess flagella must have lost the ability to pump certain chemicals across their plasma membranes B) natural selection produces organs that will be needed in future environments C) the motors of bacterial flagella must have originated in other organisms D) natural selection can produce new structures by coupling together parts of other structures
D
There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared _____. A) derived character of mammals, even if cynodonts continue to be classified as reptiles B) derived character of the amniote clade and not of the mammal clade C) ancestral character of the amniote clade, but only if cynodonts are reclassified as mammals D) derived character of mammals, but only if cynodonts are reclassified as mammals
D
Which of the following describes the most likely order of events in allopatric speciation? A) genetic isolation, divergence, genetic drift B) genetic drift, genetic isolation, divergence C) divergence, genetic drift, genetic isolation D) genetic isolation, genetic drift, divergence
D
Which of the following is the correct sequence of events in the origin of life? I. formation of protobionts II. synthesis of organic monomers III. synthesis of organic polymers IV. formation of DNA-based genetic systems A) II, III, IV, I B) I, III, II, IV C) I, II, III, IV D) II, III, I, IV
D
Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees? A) Parsimony allows the researcher to "root" the tree. B) The outgroup roots the tree, allowing the principle of parsimony to be applied. C) The molecular clock validates the principle of parsimony. D) Similarity due to common ancestry should be more common than similarity due to convergent evolution.
D
Which of the following would be LEAST likely in the fossil record? A) burrowing species B) marsh-dwelling species C) marine-dwelling species D) desert-dwelling species
D
Which of the following would be useful in creating a phylogenetic tree of a taxon? I) morphological data from fossil species II) genetic sequences from living species III) behavioral data from living species A) I B) II C) III D) I, II, and III
D
Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves _____. A) have very similar morphologies B) are both members of the order Carnivora C) belong to the same order D) share a very recent common ancestor
D
