BIO 263 Study Guide
(Quiz #2) Which of the following organisms would be most likely to fossilize? -A common worm -A rare worm -A common squirrel -A rare squirrel
A common squirrel
(Quiz #1) Cotton-topped tamarins are small primates with tufts of long white hair on their heads. While studying these creatures, you notice that males with longer hair get more opportunities to mate and father more offspring. To test the hypothesis that having longer hair is an adaptation in males, you should first ________. -test whether males with shaved heads are still able to mate -test whether other traits in these males are also adaptive -look for evidence of hair in ancestors of tamarins -determine if hair length is heritable
determine if hair length is heritable
(Quiz #1) Similar gill pouches in embryos of a chick, human, and cat are an example of ________. -structural homology -developmental homology -the inheritance of acquired characters -genetic homology
developmental homology
(Quiz #3) Imagine there is a single locus that codes for red stripes in a snake species. The gene has two alleles (r1 and r2) and is under Hardy-Weinberg equilibrium. What is the frequency of the heterozygotes if the frequency of the r2 allele is 0.3?
1-0.3=0.7 r1 allele is 0.7 r1r1 r1r2 r1r2 r2r2 0.7x0.7=0.49 0.7x0.3=0.21 0.7x0.3=0.21 0.3x0.3=0.09 0.21+0.21=0.42 (r1r2)
(Quiz #1) Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection?1. Well-adapted individuals leave more offspring than do poorly-adapted individuals.2. A change occurs in the environment.3. Genetic frequencies within the population change.4. Poorly-adapted individuals have decreased survivorship.
2 → 4 → 1 → 3
(Quiz #5) 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 ________. -56 -28 -14 -12 -16
28
(Quiz #4) Genetic drift occurs in a population. Which of the following statements might be TRUE? Genetic drift decreased the population's fitness. Genetic drift increased the population's fitness. The population was relatively small. The population experiences a decrease in genetic variation.
Any of these statements can be true.
(Quiz #2) Which of the following is an example of homoplasy? -Fur in bears and seals -Scales in snakes and lizards -Chlorophyll in flowering plants and algae -Bipedalism (locomoting primarily on rear limbs) in kangaroos and humans.
Bipedalism (locomoting primarily on rear limbs) in kangaroos and humans.
(Quiz #1) This question refers to the accompanying figure, which shows an outcrop of sedimentary rock whose strata are labeled A-D. If x indicates the location of fossils of two closely related species, then fossils of their most recent common ancestor are most likely to occur in which stratum?
C
(Quiz #4) Which of the following is the most predictable outcome of increased gene flow between two populations? -Lower average fitness in both populations -Increased genetic drift -Decreased genetic difference between the two populations -Higher average fitness in both populations -Increased genetic difference between the two populations
Decreased genetic difference between the two populations
(Quiz #1) European whitefish (Coregonus lavaretus) show heritable variation in gill raker length related to differences in their diets. Longer gill rakers appear to function better for capturing open-water (pelagic) prey, while shorter gill rakers function better for capturing shallow-water (benthic) prey. Which of the following types of selection is most likely to be found in a large lake (open water in the middle and shallow water around the sides) with a high density of these fish? -Directional selection -Stabilizing selection -Sexual selection -Disruptive selection
Disruptive selection
(Quiz #5) A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild solanaceous plants such as Datura. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preference in these moths. Based on the above information, what might be occurring in this moth species? -Postzygotic isolation -Divergence due to habitat fragmentation -Polyploidization -Divergence in sympatry
Divergence in sympatry
(Quiz #5) Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related tree frogs in South America. If reinforcement is occurring, what would you expect if you compare the calls of the two species in zones of sympatry versus zones of allopatry? -Calls would be more different in areas of sympatry. -Calls would be equally similar in both areas. -Calls would be more similar in areas of sympatry. -None of the above outcomes would be expected.
Calls would be more different in areas of sympatry.
(Quiz #2) Answer "True" or "False" for the following statement. Ants are more closely related to beetles than to flies because there are only two nodes between ants and beetles but three nodes between ants and flies.
False
(Quiz #2) Answer "True" or "False" for the following statement. If butterflies were added to the tree as a sister group to moths, beetles would become more distantly related to flies.
False
(Quiz #2) Identify whether each statement about this phylogenetic tree is true or false.
False
(Quiz #2) Identify whether each statement about this phylogenetic tree is true or false: Dragonflies are more closely related to crickets than to cockroaches.
False
(Quiz #2) If cockroaches were removed from the tree, crickets would become more closely related to ants.
False
(Quiz #2) Interpret the statement: "This tree shows that red algae evolved into green algae, which evolved into mosses, which evolved into ferns, and so on."
False
(Quiz #3) The frequencies of the three genotypes add up to 1 only if the gene is in Hardy-Weinberg equilibrium.
False
(Quiz #3) p + q = 1 only if the gene is in Hardy-Weinberg equilibrium.
False
(Quiz #4) Which of the following terms refers to the hypothetical grouping of all of the alleles from all the gametes produced in each generation by a group of organisms? -Gene pool -Hardy—Weinberg equilibrium -Punnett square -Gamete pool
Gene pool
(Quiz #4) Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence? -Genetic drift -Natural selection -Gene flow -Nonrandom mating -Mutation
Genetic drift
(Quiz #5) The Isthmus of Panama (a narrow strip of land connecting North and South America) started rising about 10 million years ago. The Pacific and Caribbean oceans were completely separated by the isthmus about 3 million years ago.Researchers have examined species of snapping shrimp on both sides of the isthmus. Based on the morphological species concept, there appear 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 seldom courted each other, and those that did mate seldom 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.)There are currently two large, permanent bridges that span the Panama Canal. The bridges are about eight miles apart. If snapping shrimp avoid swimming at night and avoid swimming under shadows, then what do these bridges represent for the snapping shrimp? -Sources of a hybrid zone between the two bridges -Geographic barriers -Sources of refuge -Sources for increased gene flow
Geographic barriers
(Quiz #4) Which of the graphs shown best represents the relationship between the intensity of directional selection and the genetic variation present within a population?
Graph A
(Quiz #5) The Earth's organisms are now experiencing the sixth mass extinction, with extinction rates higher than those experienced during the end-Cretaceous extinction 66 million years ago. Which of the following is thought to be responsible for this sixth mass extinction? -An asteroid impact in the Yucatan region of Mexico -Human impacts including habitat loss, pollution, overexploitation, invasive species, and climate change -A series of volcanoes in India -There is no evidence of a sixth mass extinction.
Human impacts including habitat loss, pollution, overexploitation, invasive species, and climate change
(Quiz #2) With which of the following statements would a biologist be most inclined to agree? -Humans represent the pinnacle of evolution and have escaped from being affected by natural selection. -Humans evolved from chimpanzees. -Humans and other apes are the result of disruptive selection in a species of chimpanzee. -Humans evolved from Old World monkeys. -Humans and other apes represent divergent lines of evolution from a common ancestor.
Humans and other apes represent divergent lines of evolution from a common ancestor.
(Quiz #5) Male frogs give calls that attract female frogs to approach and mate. Researchers examined mating calls of closely related but separate species of tree frogs in South America. What outcomes could possibly occur where the ranges of two species overlap? I.The species will interbreed, eventually fusing over time. II.A stable hybrid zone will form if hybrids are better adapted to the area of overlap than either parent species is. III.Species will continue to diverge and be isolated by behavioral or genetic mechanisms.
I, II, and III
(Quiz #5) A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly and their balancing organs (halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap.Fly species W, found in a certain part of the island, produces fertile offspring with species Y. Species W does not produce fertile offspring with species X or Z. If no other species can hybridize, then which of the following statements about species W and Y is/are TRUE? I.Species W and Y have genomes that are still similar enough for successful meiosis to occur in hybrid flies. II.Species W and Y have more genetic similarity with each other than either did with the other two species. III.Species W and Y may fuse into a single species if their hybrids remain fertile over the course of many generations.
I, II, and III are correct.
(Quiz #4) Swine are vulnerable to infection by bird flu virus and human flu virus, which can both be present in an individual pig at the same time. When this occurs, it is possible for genes from bird flu virus and human flu virus to be combined. If the human flu virus contributes a gene for Tamiflu resistance (Tamiflu is an antiviral drug) to the new virus, and if the new virus is introduced to an environment lacking Tamiflu, then what is most likely to occur?
If the Tamiflu-resistance gene involves a cost, it will experience directional selection leading to reduction in its frequency.
(Quiz #4) Why doesn't inbreeding depression, by itself, cause evolution? -It decreases the population's average fitness. -It violates the Hardy-Weinberg assumptions. -It limits gene flow. -It does not change the population's allele frequencies. -It increases homozygosity (the percentage of homozygotes in a population).
It does not change the population's allele frequencies.
(Quiz #2) We know the streamlined bodies shown in the accompanying figure are examples of homoplasy. If the following groups also had streamlined bodies, which of the groupings would give the most support to this body type being homologous?
Lizards, pterosaurs, dinosaurs, birds, synapsids, monotremes, marsupials, rodents, and primates
(Quiz #1) Darwin integrated work that he read into his own ideas. Given that, a) what did Malthus say that is relevant to evolution? b) how was this important for Darwin's ideas about evolution by natural selection?
Malthus specifically said that not all the individuals of a population will survive due to competition for resources, allowing Darwin to state that those with more favorable traits will the the ones who survive
(Quiz #5) How do mass extinctions differ from background extinctions? -Mass extinctions cause a larger proportion of organisms to go extinct than background extinctions. -Mass extinctions typically result from Hox gene mutations, and background extinctions typically result from changes in weather patterns. -Mass extinctions, but not background extinctions, are generally caused by competition. -Mass extinctions occur over a longer period of time than background extinctions.
Mass extinctions cause a larger proportion of organisms to go extinct than background extinctions.
(Quiz #4) In a small population of alpine foxes, you observe increased ear length over a 10-year period. Can you conclude that increase in ear length is advantageous in this population?
No
(Quiz #5) 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. The dark- and light-colored forms readily interbreed with each other. By about 1900, approximately 90 percent 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? -Yes, because natural selection has affected the frequency of the two different forms. -Yes, because they have completely different coloration and natural selection has affected the frequency of the two different forms. -Yes, because they are reproductively isolated based on habitat. -Yes, because they have completely different coloration. -No
No
(Quiz #4) For a biologist studying a small fish population in the lab, which Hardy—Weinberg condition is easiest to meet? -No genetic drift -No gene flow -Random mating -No mutation -No selection
No gene flow
(Quiz #3) Use the accompanying information to answer the question: Researchers studying a small milkweed population note that some plants produce a toxin and other plants do not. They identify the gene responsible for toxin production. The dominant allele (T) codes for an enzyme that makes the toxin, and the recessive allele (t) codes for a nonfunctional enzyme that cannot produce the toxin. Heterozygotes produce an intermediate amount of toxin. The genotypes of all individuals in the population are determined (see chart) and used to determine the actual allele frequencies in the population. Refer to the accompanying figure. Is this population in Hardy—Weinberg equilibrium? -No; there are more homozygotes observed in the population than expected. -No; there are more heterozygotes observed in the population than expected. -Yes -It is impossible to tell.
No; there are more homozygotes observed in the population than expected.
(Quiz #1) DDT (a pesticide) 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? -The frequency of DDT application should have been higher. -Larger doses of DDT should have been applied from the air, into water, and within the soil. -All habitats should have received applications of DDT at about the same time. -DDT application should have been continual. -None of the insect pests had had genetic variations that resulted in DDT resistance.
None of the insect pests had had genetic variations that resulted in DDT resistance.
(Quiz #1) Martin Wikelski and L. Michael Romero (Body size, performance, and fitness in Galápagos marine iguanas, Integrative and Comparative Biology 43 [2003]: 376-86) measured the snout-to-vent length of Galápagos marine iguanas and observed the percent survival of different sized animals, all of the same age. The graph shows the log snout—vent length (SVL, a measure of overall body size) plotted against the percent survival of these different-sized classes for males and females. Examine the accompanying figure. What type of selection for body size appears to be occurring in these marine iguanas? -Directional selection -Disruptive selection -Stabilizing selection -You cannot determine the type of selection from the above information.
Stabilizing selection
(Quiz #5) Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers but also mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it? -Sympatric speciation; allopolyploidy -Sympatric speciation; microhabitat preferences -Sympatric speciation; sexual selection -Allopatric speciation; behavioral isolation -Allopatric speciation; temporal isolation
Sympatric speciation; microhabitat preferences
(Quiz #1) Biological fitness is best defined as ________. -competition among individuals for resources that allow them to have more offspring -similar reproductive success among individuals in a population -variability in the population for a trait that increases survival -a heritable trait that increases the match of an individual to its environment -the ability of an individual to produce offspring that survive and reproduce, relative to other individuals in the population
The ability of an individual to produce offspring that survive and reproduce, relative to other individuals in the population.
(Quiz #4) Some of the steelhead trout (Oncorhynchus mykiss) in the Hood River of Oregon were raised in hatcheries and released to supplement dwindling wild populations. In one study, researchers captured and determined the parents of a group of trout and found some were offspring of wild x wild, others had one wild parent and one hatchery-raised parent, and a third group were offspring of captive x captive parents. The data in the accompanying figure show the relative fitness of these offspring. What statement best summarizes the results? -The gene flow between hatchery-reared and wild populations is neither helping nor hindering the fitness of the wild population. -The gene flow between hatchery-reared and wild populations is increasing the fitness of the wild populations. -These data do not help us understand effects of gene flow on fitness. -The gene flow between hatchery-reared and wild populations is leading to a decline in fitness of wild populations.
The gene flow between hatchery-reared and wild populations is leading to a decline in fitness of wild populations.
(Quiz #5) Which of the following could be a vicariance event? -The level of water in a lake recedes, creating two lakes where there used to be one. -Some insects get blown in a storm to a new mountain range, where they lay eggs. -Global warming allows populations of mosquitoes to survive at higher elevations. -Radiation near Chernobyl increases mutation rates, causing an increase in autopolyploidy.
The level of water in a lake recedes, creating two lakes where there used to be one.
(Quiz #5) 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.). The sister populations on opposite sides of the isthmus are true species under which species concept? (Select the best answer). -The phylogenetic species concept -The biological species concept -The morphological species concept -Both the morphological species and phylogenetic species concepts -The morphological species, biological species, and phylogenetic species concepts
The morphological species, biological species, and phylogenetic species concepts
(Quiz #5) Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if TRUE, would be cause for this reclassification? -The two forms are very similar in coloration. -The two forms interbreed often in nature, and their offspring have good survival and reproduction. -The two forms have similar food requirements. -The two forms have many genes in common. -The two forms live in similar habitats.
The two forms interbreed often in nature, and their offspring have good survival and reproduction.
(Quiz #2) Members of two different species possess a similar-looking structure that they use in a similar way to perform about the same function. Which of the following would suggest that the similarities more likely represent homology instead of homoplasy? -The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical. -The two species live at great distance from each other. -Both species are well adapted to their particular environments. -The structures in adult members of both species are similar in size. -All of the above.
The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.
(Quiz #2) How do the branch lengths in these two trees differ? -The branch lengths in both trees represent the same distance between taxa. -Tree I branch lengths represent genetic distance between taxa, whereas tree II branch lengths represent time since divergence between the taxa. -Tree I branch lengths are arbitrary, whereas the branch lengths in tree II represent time since divergence. -Tree I branch lengths represent genetic distance between taxa, whereas tree I branch lengths are arbitrary.
Tree I branch lengths represent genetic distance between taxa, whereas tree II branch lengths represent time since divergence between the taxa.
(Quiz #2) A student has drawn a phylogenetic tree of several plants. Evaluate this statement: "Cones are a homologous trait in pines and cedars."
True
(Quiz #2) A student has drawn a phylogenetic tree of several plants. Evaluate this statement: "Flowers are a homologous trait in magnolias and cacao."
True
(Quiz #2) Interpret the statement: "The most recent common ancestor of apples and roses is more recent than the most recent common ancestor of roses and red algae."
True
(Quiz #3) The frequencies of the three genotypes add up to 1 even if the gene is not in Hardy-Weinberg equilibrium.
True
(Quiz #3) p + q = 1 even if the gene is not in Hardy-Weinberg equilibrium.
True
(Quiz #4) Interpret the model of two moss populations that occur only at certain altitudes in the mountains. Is the following statement True or False? "This model shows that evolution is occurring."
True
(Quiz #4) Interpret the model of two moss populations that occur only at certain altitudes in the mountains. Is the following statement True or False? "This model shows the origin of a new allele via mutation."
True
(Quiz #1) This question refers to the accompanying figure, which shows an outcrop of sedimentary rock whose strata are labeled A-D. If x indicates the fossils of two closely related species, neither of which is extinct, then their remains may be found in how many of these strata?
Two strata
(Quiz #1) The Greek philosopher Plato claimed that every organism was an example of a perfect essence created by god, and that they were unchanging. What type of thinking is Plato's description of species? -Evolutionary -Typological -Organismal -Scientifically supported
Typological
(Quiz #1) There is a population of beetles that typically have black wings. A scientist studying these beetles knows that their eggs hatch in early spring, the young insects grow through the late spring and summer, they lay eggs in the early fall, and they die in the early winter. There is no parental care. Recently some beetles have been born with white wings. Early in life, the black- and white-winged beetles seem to be very similar in number of mating events, eggs laid, and survival rates, but shortly after laying their eggs, the white beetles die, and there are only black-winged beetles during the late fall. Which of the following is a TRUE statement about the beetles? -The number of baby white-winged beetles will decrease in frequency over time. -White- and black-winged beetles have equal fitness. -Black-winged beetles have a higher fitness than white-winged beetles. -White wings are an adaptation.
White- and black-winged beetles have equal fitness.
(Quiz #3) You suspect that you've found the first population of humans whose MN blood group gene is evolving. You take blood tests and find the following. Are you correct, and why or why not? MM = 0.9 MN = 0.091 NN = 0.009
[INCOMPLETE]
(Quiz #4) In 1983, a population of dark-eyed junco birds became established on the campus of the University of California, San Diego (UCSD), which is located many miles from the junco's normal habitat in the mixed-coniferous temperate forests in the mountains. Juncos have white outer tail feathers that the males display during aggressive interactions and during courtship displays. Males with more white in their tail are more likely to win aggressive interactions, and females prefer to mate with males with more white in their tails. Females have less white in their tails than do males and display it less often. (Pamela J. Yeh. 2004. Rapid evolution of a sexually selected trait following population establishment in a novel habitat. Evolution 58[1]:166-74.)The UCSD campus male junco population tails were, on average, 36 percent white, whereas the tails of males from nearby mountain populations averaged 40-45 percent white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to ________. -gene flow between populations -a genetic bottleneck -mutations in the UCSD population -a founder effect -sexual selection
a founder effect
(Quiz #1) In those parts of equatorial Africa where the malaria parasite is most common, the sickle-cell allele constitutes 20 percent of the β hemoglobin alleles in the human gene pool. The sickle-cell allele is pleiotropic (i.e., it affects more than one phenotypic trait). Specifically, this allele affects oxygen delivery to tissues and affects one's susceptibility to malaria. Heterozygous individuals who have one normal and one sickle-cell allele have a phenotype that has both costs and benefits. The cost: Under conditions of low atmospheric oxygen availability, individuals heterozygous for this allele can experience life-threatening sickle-cell "crises." The benefit: Such individuals are less susceptible to malaria. Thus, pleiotropic genes/alleles reveal that ________. -chance events can affect the evolutionary history of populations -new advantageous alleles do not arise on demand -evolution is limited by historical constraints -adaptations are often compromises
adaptations are often compromises
(Quiz #5) 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 ________. -autopolyploidy -prezygotic isolation -sympatric speciation -allopatric speciation -reinforcement
allopatric speciation
(Quiz #4) Natural selection ________. completely eliminates harmful mutations creates beneficial mutations is a random process can favor beneficial mutations
can favor beneficial mutations
(Quiz #5) Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm nuclei) from one species are unable to germinate and make pollen tubes to bring the sperm nuclei to the female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by ________. (Choose the one best answer) -habitat isolation -gametic isolation -temporal isolation -morphological isolation -behavioral isolation
gametic isolation
(Quiz #2) If, someday, an Archaean cell is discovered with a ribosomal RNA sequence that is more similar to that of humans than the sequence of mouse ribosomal RNA is to that of humans, the best explanation for this apparent discrepancy would be ________. coevolution of humans and the Archaean cell -homology -homoplasy -common ancestry -retro-evolution by humans
homoplasy
(Quiz #5) Reinforcement is most likely to occur when ________. -the environment is changing -prezygotic isolating mechanisms are in place -gene flow is low -hybrids have lower fitness than either parent population
hybrids have lower fitness than either parent population
(Quiz #4) Mutation is the only evolutionary mechanism that ________. -does little to change allele frequencies -has no effect on genetic variation -decreases fitness -is more important in eukaryotes than in prokaryotes -is the ultimate source of variation in natural populations
is the ultimate source of variation in natural populations
(Quiz #1) Fossils of Thrinaxodon, a species that lived during the Triassic period, have been found in both South Africa and Antarctica. Thrinaxodon had a reptile-like skeleton and laid eggs, but small depressions on the front of its skull suggest it had whiskers and, therefore, fur. Thrinaxodon may have been endothermic (metabolically generated heat to maintain body temperature). The fossils of Thrinaxodon are consistent with the hypothesis that ________. -mammals evolved from a reptilian ancestor -fossils found in a given area look like the modern species in that same area -the environment where it lived was very warm -Antarctica and South Africa separated after Thrinaxodon went extinct
mammals evolved from a reptilian ancestor
(Quiz #4) Genetic variation ________. -must be present in a population before natural selection can act upon the population -arises in response to changes in the environment -is created by the direct action of natural selection -tends to be reduced by when diploid organisms produce gametes
must be present in a population before natural selection can act upon the population
(Quiz #2) Phylogenetic trees constructed from molecular sequence data are based on similarities in ________. -morphology -biochemical pathways -the pattern of embryological development -mutations to homologous genes -habitat and lifestyle choices
mutations to homologous genes
(Quiz #3) Does p + q ever not equal 1? If so why? If not, why not?
p + q will always be equal to 1 since 1 represents 100% of alleles for a trait in a population.
(Quiz #3) People with cystic fibrosis (CF) are homozygous recessive for mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. These mutations cause the CFTR protein to become dysfunctional, and it is unable to move chloride to the cell surface. Ultimately mucus can build up in organs, and in the lungs, the mucus clogs the airways and traps bacteria, leading to infections, inflammation, and respiratory failure. In a human population, if 9 in 10,000 newborn babies are born with CF, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy-Weinberg model in that population?
p = 0.9700, q = 0.0300
(Quiz #3) There is a species of geese with two morphs: white and blue. The difference results from a single gene, with the blue allele (b) recessive and the white allele (B) dominant. If 36% of a goose population is blue, then what is the frequency of the white allele? Assume the population is in Hardy Weinberg equilibrium.
q^2 = 0.36, so q = 0.6 Thus, p = 1-0.6 = 0.4 40% frequency for the white allele
(Quiz #5) On the volcanic, equatorial West African island of São Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands, and is also found on the African mainland, located about 200 miles away. At higher elevations, and only on São 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, but 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). São Tomé rose from the Atlantic Ocean about 14 million years ago.If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, these conditions will most likely lead to ________. -stability -fusion -further speciation events -reinforcement
reinforcement
(Quiz #4) When nonrandom mating occurs in a population so that individuals prefer to mate with similar individuals, allele frequencies should -remain the same, but heterozygotes will be overrepresented in the population. -change and heterozygotes will be overrepresented in the population. -remain the same, at Hardy-Weinberg equilibrium. -change and homozygotes will be overrepresented in the population. -remain the same, but homozygotes will be overrepresented in the population.
remain the same, but homozygotes will be overrepresented in the population.
(Quiz #5) 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 ________. -allopatric speciation and habitat isolation -sympatric speciation -allopatric speciation and gametic isolation
sympatric speciation
(Quiz #5) The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division, is an example of ________. -allopatric speciation and autopolyploidy -sympatric speciation and autopolyploidy -allopatric speciation and allopolyploidy -sympatric speciation and allopolyploidy
sympatric speciation and allopolyploidy
(Quiz #5) A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island as selection favors those birds with larger beaks. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________. -tend to promote adaptation to the new food plants -represent a colonizing event -tend to slow adaptation to the new food plants -speed up the process of speciation
tend to slow adaptation to the new food plants
(Quiz #1) Researchers discovered that a new strain of bacteria that causes tuberculosis (M. tuberculosis) has a point mutation in the rpoB gene that codes for part of the RNA polymerase enzyme. This mutant form of RNA polymerase does not function as well as the more common form of RNA polymerase. A commonly used antibiotic called rifampin does not affect the mutant rpoB bacteria.A researcher mixes M. tuberculosis with and without the rpoB mutation and adds the bacteria to cell cultures. Half the cell cultures contain only standard nutrients, while the other half of the cell cultures contain rifampin and the standard nutrients. After many cell generations, the researcher finds that ________.
very few M. tuberculosis in the standard nutrient cell cultures carry the rpoB gene mutation, but almost all of the M. tuberculosis in the cell cultures with rifampin carry the rpoB mutation
(Quiz #4) The cause of genetic drift is sampling error, which occurs ________.
when allele frequencies of a chosen subset of a population are different from those in the total population, by chance