BIOL 222 Final Exam Review Evolution
An endangered animal species has an effective population size of 50. What is the expected loss of heterozygosity in each generation?
1%
Consider a locus with two alleles in a population of 100 individuals, with the initial frequencies A1 = 0.7 and A2 = 0.3. If A1 and A2 are selectively neutral, what is the probability that the A2 allele will drift to fixation?
30%
An unrooted tree with three species (A, B, and C) is shown. If we added a new species, D, anywhere in the phylogeny, we could find ________ different unrooted species trees. Suppose that you find another species, E, that might belong to any branch of the four-species tree. By adding species E anywhere in the phylogeny, we could find ________ different unrooted species trees with the five species.
3; 15
Which of the following groups of taxa form a monophyletic group, according to the figure?
Artiodactyla, Canidae, Felidae
Which of the following is FALSE regarding phylogenetic inference methods?
Biologists cannot use statistical analysis in inferring phylogeny.
The antibiotic ciprofloxacin often is prescribed for serious cases of food poisoning caused by the bacterium Campylobacter jejuni, which is common in the intestines of farm animals and is not harmful to them, but may cause acute food poisoning in humans. Which of the following is correct given prolonged use of this antibiotic
Ciprofloxacin treatment kills or halts the growth of the sensitive strains, yet the resistant strains survive.
Which of the following is TRUE regarding the difference between a DNA molecule and an RNA molecule?
DNA is a double-stranded molecule, whereas RNA is a single-stranded molecule.
Which of the following is FALSE regarding the quantitative genetics study done by Steve Franks and his colleagues on a Brassica rapa population in the wilderness of southern California?
Franks and his colleagues were not able to determine heritability of flowering time in the population.
Anisogamy (different-size gametes) is a phenomenon found in many sexually reproducing species. Which of the following assumptions would NOT contribute to the notion that natural selection favors anisogamy?
Gamete size is not correlated with zygote survival or size.
Which of the following is NOT an assumption of the Hardy-Weinberg model?
Mating in the population is not random with respect to the locus in question.
Which of Gregor Mendel's laws contradicts the blending theory of inheritance?
Mendel's first law, the law of segregation
Consider two populations of fish that live in separate ponds, with no migration between them. How will mutation affect that degree of variation between these populations?
Mutation will increase the variation between populations.
Modern trait-group models specify the circumstances in which selection can favor group-beneficial traits even when such traits impose individual-level costs. Which of the following is TRUE for a trait-group selection model?
Natural selection operates at two levels—within the group and between groups.
Charles Darwin recognized that Thomas Malthus' argument applies to animal and plant populations as well as to human populations. Look at the figure and choose which observation Darwin made from this.
The difference between the growth of a population and its size allowed by the food supply shows the possibility of selection through the struggle for existence.
Manx cats are common on a remote island near Great Britain, though rare elsewhere. They have a reduced or absent tail and longer hind legs than forelegs. This phenotype is caused by a dominant allele, M, at an autosomal locus. Manx cats are always Mm heterozygotes because MM homozygotes are aborted prenatally. What is the best evolutionary explanation for the Manx cats' prevalence on this island?
The prevalence of the Manx phenotype on this island is a result of the founder effect and genetic drift.
In order to test the Red Queen hypothesis in snails, Curt Lively collected samples of 40-100 snails from different lakes and streams across New Zealand, assayed parasitic infections in these snails, and determined the frequency of males in each sample. Examine his results summarized in the following figure and choose the best explanation for these results.
The proportion of males correlates with the frequency of sexual individuals, and it is an indication that sexual reproduction prevails in highly infected populations.
What is the difference between the situations shown in the red and yellow lines?
The red line shows a dominant allele; the yellow line shows a recessive allele.
Which is TRUE of phylogenetic distance methods?
They measure either morphological or genetic distances between species.
What is the main difference between the three phylogenies in the figure?
They represent different evolutionary timescales.
What are homologous traits?
Traits that are found in two or more species because these species have inherited this trait from their common ancestor.
If a DNA sequence of the template strand (in the 3'-5' direction) reads ATG, what would be the corresponding mRNA codon (in the 5'-3' direction)?
UAC
Bats and hummingbirds both have wings and can fly. This is due to__________.
convergent evolution
Bluegill sunfish (Lepomis macrochirus) have three different morphs observed in their males, with each morph exhibiting different strategies for reproduction. This example describes _________.
intrasexual selection
A type of mutation in which a region of one chromosome is moved to a different chromosome is called __________.
translocation
A mouse population contains hybrids between New Zealand Black (NZB) and New Zealand White (NZW) mice. NZW homozygotes are healthy, but NZB homozygotes experience autoimmune disease. NZB/NZW heterozygotes experience even more severe autoimmune disease (so much so that they are used as a model for the human autoimmune disease lupus). This situation is an example of __________.
underdominance
All of the following are subversive strategies used by pathogens in manipulating the human immune system, except __________.
up-regulation of the expression of MHC molecules
Suppose you are studying a rare human genetic disease and find that the mutation rate for the disease causing allele is µ = 0.00012, and selection against the allele is s = 0.7. What would be the estimated equilibrium frequency for this recessive deleterious allele?
0.013 equilibrium frequency of a deleterious recessive allele (A2) = √µ/s = √0.00012/0.7 = 0.013.
Imagine that in a fishery laboratory experiment, you need to calculate h2 for the length of the caudal fin for a certain population of fish. If your average population measurement is 25 mm, the selected individuals have fins of 35 mm on average, and the offspring have fins of 30 mm on average, what is the narrow-sense heritability? Use the breeder's equation and the equations for R and S given in Figure 9.42 for your calculations.
0.5
Human populations are polymorphic for the gene coding for myoglobin, with two alleles, A1 and A2. Tomoya Takata and his colleagues (Takata et al. 2002) found that in a small Japanese population, the frequency of the A1 allele was 0.755. If the population is in Hardy-Weinberg equilibrium, what are the frequencies of the A1A1, A1A2, and A2A2 genotypes, respectively?
0.57, 0.37, 0.06
In a population of birds, wing feather pigmentation is determined by a single gene with two incompletely dominant alleles, A1 and A2. Suppose genotype A1A1 confers dark brown wings, genotype A1A2 is light brown, and genotype A2A2 is light beige. In a population of 1000 birds, 350 have dark brown wings, 500 have light brown wings, and 150 have light beige wings. What is the A1 allele frequency in this population?
0.60 Thus, to calculate the frequency of the A1 allele, add the number of A1A1 individuals (350) to one-half of the number of A1A2 individuals (250) and divide by the total population size (1000).(350 + 1/2(500))/1000 = 0.60
The figure describes the percent oil content in corn from different generations. In 1899, the mean oil content was 5.65% dry mass, the mean of the selected plants was 6.30% dry mass, and the mean of all plants in 1900 was 6.10% dry mass. What is the expected slope of a parent-offspring regression (narrow-sense heritability) for corn oil content?
0.69 h2 = R/S = 0.45/0.65 = 0.69.
Imagine that in a large coastal population of plants, the frequency of the A allele is 0.7 and the frequency of the a allele is 0.3 at a neutral locus. If a small group of individuals from this population (with the frequency of the A allele as 0.9) manages to reach a distant island in a one-time colonization event, what is the probability that A will become fixed on the island?
0.9
What was the approximate time when Homo sapiens began to use domestic crops and settle in one habitat?
10,000 years ago
If one human protein contains 400 amino acids, how many nucleotides need to be in the exons of the corresponding gene to properly code for it?
1200
In a population of about 50 walruses with 30 fertile females, only 4 males are mating, due to strong male-male competition. Suppose that you need to provide data for conservation efforts and are asked to calculate the effective population size (Ne). What would be your best estimate?
14 Ne = 4NmNf / Nm + Nf
The fruit fly (Drosophila melanogaster) has four pairs of chromosomes. How many chromosomes would you find in an unfertilized egg (female gamete or sex cell) of this species?
4
In a population of 200 diploid individuals, how long will it take on average for any two gene copies at a neutral locus to coalesce?
400 generations 2N = 400
Suppose that species 1, 2, and 3 are closely related to one another. If you sequence a gene and find 10 nucleotides where these species differ from each other, you can use such data to estimate the distance between them. The nucleotide bases at these sites are (Species 1) GCTGATGAGT (Species 2) ATCAATGAGT (Species 3) GTCAATGACA. Estimate the distance between these three species and select one of the following answers.The molecular distance between species 1 and 2 is __________ and between species 1 and 3 is __________.
4; 5 compare DNA data, such as the data presented here, and to simply count the number of base pair differences. We can use this tally as the distance between the two species. In this problem, there are four differences between species 1 and 2, and five between species 1 and 3
Texas longhorn cattle have been bred to increase the tip-to-tip width of their horns, and the heritability of this trait has been well studied by Professor David Hillis at the University of Texas, Austin. In the current generation, the mean horn length is 52 inches. If only a subset of this population, with a mean horn length of 61 inches, is allowed to reproduce, and the narrow-sense heritability of this trait = 0.2, what approximately is the expected horn length in the offspring generation? Use the breeder's equation and the equations for R and S given in Figure 9.42 for your calculations.
54 inches h2 = R/S = 0.2.
The figure shows the genealogical history of gene copies in a population. How many generations back do these gene copies coalesce?
7
Based on the following picture, if evolution in one or more clades proceeds at a faster rate, the parsimony method will not result in a correct phylogeny. If the "True tree" is correct and the "Inferred tree" is wrong, which clades must be evolving faster?
A and C
Consider three loci experiencing different selective conditions. Assuming the same initial number of gene copies and constant population size, which locus will have the longest time to coalescence?
A locus under balancing selection
Sir Ronald A. Fisher's mathematical model of sex ratio was tested in nature on blue moon butterflies (Hypolimnas bolina), a species of butterfly from the Samoan islands, where the sex ratio deviated strongly from one to one (99% females). Which of the following is TRUE regarding this test?
A new mutant butterfly arose on one of the islands and the sex ratio among the blue moon butterflies on the island returned to approximately 1:1, supporting Fisher's mathematical model.
In competition within a genome, one of the interesting evolutionary interactions at the gene level is caused by the segregation distorters, or meiotic drive alleles. This has been observed in Drosophila, mice, and some other species. Meiotic drive may be observed when which of the following occurs?
A particular allele somehow distorts the process of segregation in its own favor, meaning it increases its representation in the gametes and thus becomes favored by selection. We expect that, on average, half the gametes produced by a heterozygote at a given locus will contain one allele at that locus and half the gametes will contain the other allele. But if a particular allele could somehow distort the process of segregation in its own favor (that is, if it could increase its representation to more than half the gametes produced by an individual), all else being equal, that allele would be favored by selection.
The voyage on HMS Beagle took place more than 20 years before Charles Darwin's publication of On the Origin of Species. Darwin was greatly inspired by his travels and wrote about them in his book. Where did the Beagle sail on Darwin's voyage?
Across the Southern Hemisphere
Itay Budin and Jack Szostak sought to understand how cell membranes composed of single-chain lipid molecules could possibly evolve to the more complex phospholipids seen in modern cell membranes (Budin and Szostak 2009). Which statement best summarizes their results?
Adding a small fraction of phospholipid molecules resulted in vesicles with higher phospholipid content; these cells tended to grow in size conferring a selective advantage.
Lice are often obligate parasites on specific hosts and because of such close associations, they are often used in studies of species interaction and coevolution. One such example involves lice on pigeons and doves, where phylogenetic studies uncovered eight cospeciation events. What drove their coevolution in this host-parasite system?
After a speciation event occurs in a pigeon or dove, lice are constrained to remain on their host species because they often fare poorly when switching hosts.
The idea of spontaneous generation has existed in human thought ever since the earliest written history. Such thoughts prevailed until the seventeenth century, when an Italian physician, Francesco Redi, tested the question on whether flies spontaneously generate from spoiled meat. Which of the following statements is FALSE regarding this experiment?
After the jars were covered with a mesh net, eggs and maggots were found in the meat.
The concept of inclusive fitness is essential in our understanding of the evolution of eusociality. Which of the following statements is FALSE regarding eusociality?
All members of the population reproduce, and they all cooperatively care for the young.
If the idea of natural selection was Charles Darwin's first insight on evolution, which of the following would best describe Darwin's second insight?
All species have descended from one or a few common ancestors; species that share a recent common ancestor tend to resemble one another in many respects.
Which statement is FALSE regarding populations that have experienced a bottleneck?
Allele frequencies in a population are almost always very similar before and after a bottleneck.
The figure shows the relationships among vertebrates. Which of the following is true based on this phylogeny?
Amphibians are more closely related to birds than they are to lobe-finned fishes.
Woolly mammoths (Mammuthus primigenius) once lived in the Northern Hemisphere and were a contemporary of modern humans. Due to various factors including human hunting, the mammoth became extinct approximately 10,000 years ago. According to the following phylogeny, which species is the closest relative of the woolly mammoth?
Asian elephant (Elephas maximus)
Suppose that you collected genotype frequency data from a natural population. If you found that the expected genotype frequencies differed significantly from your observed genotype frequencies, which of the following could you conclude?
At least one evolutionary process is operating in this population.
In their experiment in 1943 using E. coli, Salvador Luria and Max Delbrück tested two alternative hypotheses. The random mutation hypothesis and the acquired inherited resistance hypothesis make different predictions about the distribution of resistant mutants that will be observed upon exposure to bacteriophage (viruses that can infect and kill E. coli). Which of the following predictions, if proven, would support the acquired inherited resistance hypothesis?
At the time of exposure to the phage, all E. coli cells will be phage-sensitive. The process of exposure to the phage will induce phage resistance in a small fraction of the bacterial cells.
Which is correct regarding the sources of data for testing models of evolution?
Behavioral data often are used in evolutionary studies
Patrick Matthew published a theory very similar to Charles Darwin's theory in his obscure work On Naval Timber and Arboriculture, although he was not widely recognized for his ideas. What did the theories of Matthew and Darwin share and what was different?
Both theories recognized natural selection, but Matthew did not discuss common descent.
The modern theory of evolution, with natural selection as the mechanism for biological change, came from which of the following thinkers?
Charles Darwin and Alfred Russel Wallace
From the late Middle Ages up to the seventeenth century, the written records of the Bible provided a starting place for mathematically estimating the age of Earth. Scientists began to understand the age of Earth was far greater than calculations based on the Bible. Which of the following scientists had the most influence on Charles Darwin regarding the ancient age of Earth?
Charles Lyell
Which of the following best describes the difference between humans and modern chimps?
Chimp and human genomes differ by only 1.3%, yet patterns of gene expression may differ.
The oldfield mouse study is a textbook example of hypothesis testing among natural selection (adaptation) studies. Which of the following is NOT correct regarding the main findings of this study?
Coat color in the oldfield mouse does not seem to have any adaptive value.
Linda Vaughn and her colleagues wanted to find out if an ectothermic vertebrate, the desert iguana, could respond to infection with behavioral fever. They constructed environmental chambers with regions that were kept at two different temperatures—one below the thermal optimum for the lizards, and one above the thermal optimum. They injected the experimental group with heat-killed bacteria and the control group with saline solution. Which of the following best describes their findings?
Compared to the controls, lizards injected with bacteria stayed on the warm side of the enclosure until reaching a higher body temperature.
Although scientists widely accepted Charles Darwin's theory of evolution and common descent, one of the major problems proposed and discussed was how to account for complex structures and multiple, intricate parts. Why was this seen as a problem?
Critics argued that Darwin's view of natural selection acting in gradual increments could not be responsible for forming complex structures and multiple, intricate parts because they had no value until fully formed.
For many years in the United Kingdom, people with urinary tract infections have been treated with sulfonamide antibiotics. These antibiotics used to be very effective against the common pathogen of the urinary tract, E. coli, but in the late 1990s, increased resistance among the E. coli strains was documented. In the meantime, worrisome side effects of these drugs were documented as well, so doctors curtailed their use. Which of the following statements is TRUE about the evolution of resistance to the sulfonamides in the last decade?
Despite the reduced use of sulfonamides, there was little reduction in frequency of resistance among the bacteria.
In his scientific writings, Erasmus Darwin, grandfather of Charles Darwin, came up with a theory of evolution and argued that all life developed from what he called a "single living filament," which was modified in endless ways, over millions of years (Darwin 1796). What was one of the missing concepts in his work that Charles Darwin later fully addressed?
E. Darwin failed to connect the struggle for existence to the evolutionary changes that such a struggle would produce.
Evolution of complex traits, such as the production of milk in mammals and parental care, has been one of the difficult questions, both in theory and experimental studies. Which of the following best explains the evolution of complex traits?
Each intermediate step on the way toward the evolution of a complex trait was itself adaptive.
Charles Darwin's voyage across the Southern Hemisphere gave him an important insight to his theory that came from finding certain species and some fossils of their extinct predecessors in certain geographic regions. Which of the following was Darwin's conclusion that was essential in his theory and came from these biogeography evidences?
Each species arises only a single time in a single place, by descent with modification from a closely related species.
The Greek philosopher __________ was among the first to propose a theory that attempted to explain the diversity of living forms, as well as some aspects of adaptation.
Empedocles
In a species of water flea (Daphnia magna), females appear to respond to cues that environmental change is occurring or about to occur with a shift from asexual to sexual reproduction. Which of the following is NOT true for cyclical parthenogenesis in this species?
Environmental fluctuations tend to not significantly affect reproductive pathways in water fleas.
The figure shows the relationships among featherless and feathered dinosaurs and birds. Based on this phylogeny, what can you say about the evolution of feathers?
Feathers are an exaptation for flight.
Which of the following is NOT a possible reason why fever is widespread across animals despite its costs?
Fever decreases the ability of the immune system to detect pathogens.
Following an intense drought in 2000 to 2004, descendant populations of Brassica rapa flowered much earlier in the season than those from predrought populations. Researchers agreed that this could be a result of strong selection during these four years. For natural selection to act on flowering time in B. rapa, all of the following must be true, except
Flowering times must differ depending on the environment in which a plant is grown.
Using the method of independent contrasts, Dylan Schwilk and David Ackerly studied branch retention and serotiny in 38 species of pine trees (Schwilk and Ackerly 2001). Which statement is correct about their study?
For the traits of branch retention and serotiny, they calculated each of the independent contrasts for the 38 species and found a statistically significant positive correlation between the two.
Galápagos lava lizards inhabit dry rocky areas and are found on numerous islands in this archipelago. Mark Jordan and Howard Snell (Jordan and Snell 2008) assessed the genetic diversity of 17 populations of lava lizards. They reasoned that in the absence of gene flow between populations, genetic drift should strongly influence the patterns of diversity at the 11 microsatellite markers that they sequenced. The figure summarizes their findings. Which of the following is the best interpretation of this graph?
Genetic drift has been operating more strongly in smaller populations.
Which of the following is a definition of evolution from the perspective of population genetics?
Genotype frequencies change over time.
The evolution of eusociality is occasionally observed in diploid species, such as mole rats or shrimp. Which of the following statements is TRUE regarding haplodiploid mating systems and eusociality?
Haplodiploidy alone is neither necessary nor sufficient for the evolution of eusociality, but it does partly explain why eusociality evolved in many lineages of hymenopterans.
In 1977, Sidney Fox tried a different approach to testing the prebiotic synthesis of biological molecules. He mixed a number of different amino acids together at a high temperature (120°C) in an environment lacking water. When he subsequently placed the mixture into water to investigate what the amino acids would form, what happened next?
He found some peptide-like structures, but the bonds between the amino acids were weak and unstable
Although Charles Darwin formulated most of his ideas on evolution and natural selection while on his voyage on the HMS Beagle, it was 23 years after his return until he published On the Origin of Species. Why did it take so long for Darwin to present his work?
He realized that his ideas were revolutionary and worked to build evidence to present the strongest case possible for his theory of evolution by natural selection.
What are vestigial traits?
Homologous traits that were functional in some ancestral taxon but lack function in the taxon of interest.
Why are homoplasies problematic in phylogenetic reconstruction?
Homoplasies can result in species with a common trait despite the fact that they are not closely related to each other.
When we compare primate karyotypes (chromosome sets), interesting evidence of our genetic relatedness is revealed. What is the main difference between the human karyotype and the karyotypes of the great apes?
Humans have one fewer pair of chromosomes as a result of the fusion of chromosomes 2p and 2q in chimpanzees.
The textbook provides an example for the use of statistical methods in phylogeny inference in mammals. According to the Theria hypothesis, placental mammals (Eutheria) and marsupials (Metatheria) are sister groups, with monotremes (Prototheria) more distantly related. By contrast, the Marsupionta hypothesis places the marsupials and monotremes as sister groups, with the eutherian mammals more distantly related. Keith Killian and his coworkers used the DNA sequence data to test these hypotheses (Killian et al. 2001). What was their reasoning?
If the Marsupionta hypothesis was correct, the marsupials and monotremes would form a monophyletic clade in the phylogeny produced using the DNA sequence data.
The figure shows a phylogeny of snakes and their relatives. Based on the information in this figure about which taxa are known to be venomous, why did Bryan Fry and his colleagues hypothesize that monitor lizards and iguanas would also be venomous?
If venomousness is homologous in snakes and Gila monsters, then others in the monophyletic group that includes these species also may have inherited this trait from their common ancestor.
Interactions between the herbaceous plant Lithophragma parviflorum (also known as the woodland star) and the moth Greya politella serve as a good example of mosaic coevolution in nature. The moth lays its eggs into developing flowers of the woodland star, but the plant pays a cost for this because moth larvae eat some of the woodland star's seeds. In addition, this moth is the sole pollinator of the woodland star's flowers in some geographic locations, while in other locations, the woodland star has additional pollinators. Which of the following statements is NOT true regarding mosaic coevolution in this example?
In all studied locations, the woodland star rarely aborted flower capsules that contained moth eggs, compared to capsules that had no moth eggs.
Elizabeth Tibbetts has demonstrated that paper wasps (Polistes dominulus) use a type of conventional signal to communicate their fighting abilities. Which of the following is FALSE about the social communication of these wasps?
In paper wasps, increased "brokenness" of the black patterning on the face is a conventional signal associated with poor fighting ability. As the experiment showed, these signals are kept honest by social punishment. If a paper wasp exhibits facial patterns indicating dominance (and high fighting ability) but in reality is not a fighting type, the other wasps will react with increased aggression toward that wasp.
Which of the following statements would best describe a variational process, proposed in Charles Darwin's innovative concept of evolution by natural selection?
In this process, the group changes because some factor sorts among the variants in the original group of members.
According to the figure, which of the following statements regarding base substitution mutation rates is FALSE?
In viruses, base substitution mutation rates increase with increasing genome size.
What is methodological naturalism?
It is a strategy that provides a method or procedure for seeking scientific explanations of the world.
When we want to use a distance method or any other phylogenetic method that relies on DNA and/or amino acid sequence data, there may be a problem with sequence alignment. The following statements explain this problem and offer some solutions. Which of the following statements is FALSE?
It is impossible for scientists to align sequences manually.
Jean-Baptiste Lamarck was likely the first to propose a process for evolutionary change, and connected that process to environmental fit. However, he is most famous for his process being wrong. What was this process he proposed?
Lamarck proposed that characteristics were acquired during the lifetime of an organism as a result of the organism's habits and these acquired traits were passed down to their offspring.
Aristotle proposed a taxonomy of nature—a classification system of life that later would be called "the great chain of being," or scala naturae. This long-accepted view of nature was missing a couple of concepts necessary for the development of evolutionary biology. Identify the missing concepts below.
Links in the chain could have shared degrees of complexity and the potential to change.
The modern, or evolutionary, synthesis of Charles Darwin's theory is a result of our modern understanding of genetics. During the 1930s and 1940s, which two groups of scientists resolved their differences, ultimately resulting in the modern evolutionary synthesis?
Mendelians and biometricians
Fossil evidence is very important in reconstructing phylogenies. One example in the textbook of such a phylogeny is the evolution of horses (Equidae). Which of the following statements is FALSE regarding the evolution of horses?
Most of the species in this phylogeny are extant (currently living).
The figure shows the ratio of nonsynonymous to synonymous polymorphism in humans and the ratio of nonsynonymous to synonymous substitutions between humans and chimpanzees. What do these data demonstrate about the nature of variation in human populations?
Much of the variation in humans is under purifying selection and therefore due to deleterious mutations.
The textbook examines in detail a study of the natural populations of guppies (Poecilia reticulata) in the waterfalls of Trinidad and Tobago. Upstream of such waterfalls, guppies typically face only mild predation pressure from one small species of fish. Downstream of the waterfalls, however, populations of guppies often are under severe predation pressure from voracious predators such as the pike cichlid. What life history strategy would be favored by natural selection upstream of the waterfalls?
Natural selection should favor females that can produce offspring that are relatively large and grow quickly.
In the guppies (Poecilia reticulata) of Trinidad and Tobago, natural selection may act differently in different locations of the waterfalls. Upstream of such waterfalls, guppies typically face only mild predation pressure from one small species of fish. Downstream of the waterfalls, however, populations of guppies often are under severe predation pressure from voracious predators such as the pike cichlid. What life history strategy would be favored by natural selection downstream of the waterfalls?
Natural selection should favor females that produce as many offspring as possible, rather than producing larger but fewer offspring.
The origin of cell structures might be hypothesized to have involved a hypercycle, based on mutualism at the molecular level. Which of the following is correct regarding the hypercycle model?
Natural selection will favor a hypercycle that is enclosed in a membrane.
Genetic drift tends to increase the homozygosity of a population, and if it were the only evolutionary process operating, any finite population would eventually become entirely homozygous. In practice, however, populations do not become entirely homozygous. Why not?
New mutations provide a continual supply of new genetic variation.
The graph shows the number of nucleotide substitutions in several protein-coding genes and the divergence times for pairs of mammalian species. These data demonstrate which of the following?
Nucleotide substitution rates are approximately constant in these species.
One important consequence of genetic drift is that it decreases the heterozygosity in a population from what is expected under Hardy-Weinberg equilibrium.What are the observed and expected heterozygosities in a population that has three genotypes with the following frequencies f(A1A1) = 100, f(A1A2) = 25, f(A2A2) = 100.
Observed = 0.1; Expected = 0.5
Which two scientists elaborated on Darwin's idea of the "warm little pond" and formulated the "prebiotic soup hypothesis" as the first hypothesis for the abiotic origin of life on Earth?
Oparin and Haldane
The figure illustrates an evolutionary trade-off in binocular vision in birds. Which of the following is NOT true regarding the trade-off in this case?
Ostriches have better binocular vision than owls because their eyes are set on opposite sides of their head.
Which of the following statements regarding parsimony methods is FALSE?
Parsimony is the only phylogenetic approach that bootstrap resampling can be used with.
Penicillin once was considered a miracle drug that would permanently eradicate tuberculosis and many other bacterially caused diseases. Today, we encounter resistance to this and many other antibiotics in numerous bacterial species. What could we have done differently to slow the evolution of penicillin resistance?
Penicillin should not have been prescribed unless necessary.
In an early study of black spruce trees in Canada's Hudson Bay area, researchers studying nuclear DNA found no reduction of genetic diversity in post-ice-age populations, and thus no evidence of founder effects. Why did a recent study, using mitochondrial DNA (mtDNA), show different results regarding the founder effects in black spruce?
Pollen, which carries nuclear DNA but not mtDNA, can disperse far in the wind, but seeds, which carry both nuclear and mtDNA, cannot disperse as far.
Which of the following is true of the nearly neutral theory of molecular evolution?
Population size plays an important role in determining the outcome of drift and selection.
Which of the following genotypes of the pathogenic E. coli would you expect to find as the most common today in the United Kingdom following the curtailment of the sulfonamide prescriptions, keeping in mind the evidence that sulfonamide resistance did not decrease? Refer to the figure showing evolution and fitness effects of resistance and compensation in E. coli.
RC
The first genetic material on Earth was most likely __________.
RNA
Jeff Galef and his colleagues have studied the role of cultural transmission in the scavenging behavior of Norway rats (Rattus norvegicus). They wanted to find out if cultural transmission through social learning plays a role in rat foraging, so they developed an experiment with observers (rats that did not have previous exposure to some foods) and demonstrators (rats that had experienced a new addition to their diet). Which of the following is NOT true about this study?
Rats routinely chose the food that was not given to their tutors as a means to monopolize a food source that was not being exploited.
Vertebrate adaptive immune systems use clonal selection to recognize and deal with viral infection of a cell. Which of the following best describes the process of clonal selection?
Recombination generates a diversity of immune cells; cells that react with self proteins are deleted, and cells that bind to an antigen from a pathogen proliferate rapidly.
The Scottish author __________ presented a well-developed and widely influential theory on how new species originate from existing species in his 1845 book, Vestiges of the Natural History of Creation. He also thought about populations evolving rather than individuals.
Robert Chambers
The following figure shows two possible groups of species on which to focus conservation efforts. Why might you choose a conservation strategy that would save the two species in blue rather than the three species in red?
Saving the blue species preserves more phylogenetic diversity.
The figure shows the effect of late-acting and early-acting deleterious mutations on survivorship curves. What do the differences in these curves mean for the evolution of senescence?
Selection acts more weakly on late-acting mutations, which are less likely to get eliminated from the population.
Soybean, which are legumes (Glycine max), are involved in a mutualistic relationship with rhizobial bacteria (Bradyrhizobium japonicum) in which the bacteria convert inorganic nitrogen in the root nodules of the plant into an organic form of nitrogen that the plant uses as a resource for its own growth and synthesis. In experiments within a nitrogen-free atmosphere, the bacteria are forced to be "the cheaters." Which of the following was NOT a finding of these experiments?
Soybean plants did not have an ability to respond to reduced nitrogen fixation by the rhizobial bacterium in a way that would reduce cheating.
Suppose that you need to construct a phylogeny from the distance matrix data in the following table. Which species are most likely to be grouped in sister clades?
Species 3 and 4
Many mammals prefer mates that differ from themselves at the immune locus MHC. Why might this preference be advantageous for the offspring?
Such mating results in higher heterozygosity at the MHC locus, and therefore greater diversity in immune function.
Charles and Mary Brown found, in more than 30 years of studying cliff swallows (Petrochelidon pyrrhonota), that the number of swallow roadkill had significantly decreased and the average wing length of swallows in the population at large had decreased as well (Brown and Brown 2013). Which of the following scenarios could have resulted in these changes?
Swallows with shorter wings are more likely to survive in the face of oncoming vehicles, resulting in the population evolving shorter wings on average and dying less often as the result of road kill
Which of the following is a valid conclusion based on the phylogeny of proteobacteria shown in the figure?
The C. violaceum population is more recent than the population at node B.
In 1999, a group of medical workers was accused of a serious crime—infecting hospitalized children with the human immunodeficiency virus (HIV). Years later, in 2006, Tulio de Oliveira and a team of researchers used genetic sequence data from the HIV strains infecting these 44 Libyan children to reconstruct a phylogeny (de Oliveira et al. 2006). Which of the following statements is FALSE regarding the researchers' findings?
The HIV lineages in the children did not originate from a single strain, but instead were the result of several independent introductions.
Taxonomy has long been an important field of biological science, with the goal of classifying organismal diversity. What has changed over the past 50 years in the way that biologists approach classification?
The Linnaean system of classification has been placed in a modern evolutionary framework by Willi Henning.
Consider two populations of fish that live in separate ponds and differ in the frequency of alleles at a locus. After a flood, the two ponds become connected by a stream and some fish are able to move between the ponds. What will happen to allele frequencies at this locus in the two populations?
The allele frequencies in the two ponds will become more similar to each other.
The imperial blue butterfly (Jalmenus evagoras) and a species of ant Iridomyrmex anceps have a mutualistic relationship that is costly to both species but also provides benefits to both. Which of the following statements correctly describes the investment by both parties?
The butterfly larvae spend their resources on production of nectar, which leads to slower development and lower reproductive success. The ants have an increased risk of detection by predators and metabolic costs associated with defense of the butterfly larvae.
Richard Lenski and his colleagues have been tracking evolutionary change for more than 60,000 generations in the bacterium Escherichia coli (Le Gac et al. 2012; Wiser et al. 2012). According to the figure, which statement is NOT correct regarding their results?
The cell volume and fitness of the E. coli lines increased over time, but none of the lines experienced natural selection.
In a New Zealand snail species, both sexual and asexual populations can be found in the same geographic region. Some field observations indicated that sexually reproducing individuals are more common in the areas infested with parasites, and the reverse is also true. Curt Lively and Mark Dybdahl raised uninfected snails from many different asexual clonal lineages and then exposed them to parasites from the wild. What was their finding regarding the proportion of infected individuals, and did the results support the Red Queen hypothesis?
The clonal lineages that were rare in nature had a lower proportion of infected individuals, as predicted by the Red Queen hypothesis.
Peter and Rosemary Grant have studied the gene-culture transmission of birdsong in Charles Darwin's finches, Geospiza fortis and Geospiza scandens. What evidence from their studies illustrates the "culture" part of the transmission and what evidence illustrates the "gene" part of this coevolutionary relationship?
The cultural part of the transmission occurs when the son learns the song from the father. The gene part is a result of females mating only with males who sing the song typically produced by males of their own species, greatly reducing between-species mating.
The phylogeny in this figure shows the evolution of visual opsins in tetrapods. Each colored triangle represents a different opsin. Which of the following accurately describes the opsins in these species?
The green opsin is a synapomorphy in baboons and humans, and the light blue opsin is symplesiomorphy in squamate reptiles and birds.
In the 1850s and 1860s, Gregor Mendel bred pea plants and examined the way that traits were passed down across generations. His conclusions, although not accepted during his lifetime, established the foundation for the field of genetics. Of the choices listed, what is the most relevant summary of Mendel's conclusions?
The hereditary factors responsible for traits such as seed shape and flower color are inherited as discrete units.
If an mRNA sequence in the 5'-3' direction usually begins UGG AUG UCG CCC AUA, what would you expect to happen if the guanine in the third position is deleted from the mRNA sequence?
The mRNA will not be translated into a protein at all.
Fever may be an adaptation in mammals and some other animal groups. High fever is very dangerous to humans, and yet a number of studies of human patients have shown that fever may be correlated with better patient outcomes. Which of the following statements about fever and human disease is FALSE?
The observed correlation between fever and survival or recovery provides direct evidence that fever is the cause of the outcomes, good or bad.
Charles Darwin believed that cranial sutures present in modern birds, reptiles, and mammals evolved prior to the evolutionary split between these three groups (see Figure 3.26). What is the best explanation for the evolution of this complex trait?
The original selective advantage of cranial sutures was probably to allow the rigid protective cranium to expand with a growing brain, and this function is retained.
The placenta is one of the defining features in mammal evolution, providing a way to carry young in utero to full-term development. Examine the following figure and choose the correct statement based on this phylogeny of the mammals.
The placenta is found in some mammals (Eutheria) and is a homologous trait with origins at the split from the common ancestor with Metatheria.
The graph shows the changes in allele frequencies in simulations of 10 replicate populations. Which of the following is a reasonable explanation for what happened to these populations around generation 100 (highlighted in blue)?
The population size decreased.
Use the following rooted tree to decide which of the following is TRUE in the phylogeography of the magpie species. The Korean and Eurasian magpies originated in Asia, while the Black-billed and Yellow-billed magpies are currently found in North America.
The rooted tree shows that although magpies arose first in Asia, the Eurasian magpie diverged from the Korean magpie and subsequently invaded North America in a single migration. Later, their descendant lineages branched into the black-billed and yellow-billed magpie species found in North America today.
Which of the following statements about the Lincoln and Joyce experiment on self-replicating ribozymes is most likely correct?
The self-replicating ribozymes that had more efficient catalytic activities would soon begin to dominate their populations.
As demonstrated in this phylogeny, how many domains of life are there?
The three domains of life pictured in this phylogeny correspond to the three main branches of the tree of life—Bacteria, Archaea, and Eukaryotes. The tree of life represents all of the species that live or ever have lived, illustrating the branching network of relationships between living organisms.
The following unrooted tree shows the phylogeny of several magpie subspecies. This phylogeny is based on a maximum parsimony phylogeny derived using mitochondrial DNA (mtDNA) sequences. Suppose that we find an outgroup, the azure-winged magpie (Cyanopica cyana). What would be the best approach in constructing a rooted tree for these five magpie subspecies?
The tree will be rooted prior to the split from the azure-winged magpie.
Which of the following is a disadvantage to using genetic distance methods?
The use of distance methods is a phenetic approach, meaning that taxa are grouped together based on similarity, without reflection on the underlying historical relationships.
We often see pesticide resistance evolve in insects that feed on crop plants. Which of the following statements best describes how these changes occur?
The variants in the treated population that already have mutations that confer resistance to the pesticide treatment will survive and proliferate.
The graph shows the distribution of fitness effects of Bacteriophage f1 mutants. Note that values greater than 1.0 indicate beneficial mutations, whereas values less than 1.0 indicate deleterious mutations. What is the best conclusion from this study?
The vast majority of the mutations had a deleterious effect, but some were beneficial.
How do theory and experiment work together in evolutionary biology?
Theory and experiments can each provide feedback to the other.
Endothermic (warm-blooded) animals, such as birds and mammals, often produce a fever in order to combat an invading pathogen. Which of the following is TRUE of fever in other animals?
There are many ectothermic (cold-blooded) vertebrates with the ability to induce a behavioral fever, including a wide range of reptiles, fish, and amphibians.
The figure illustrates correlations by twin type and sex in a study of the influence of genetics on depression. Monozygotic twins (MZ) develop from one fertilized egg, whereas dizygotic twins (DZ) develop from two independent zygotes. Choose the correct statement based on the data.
There is a higher correlation for depression in monozygotic twins than in dizygotic twins, and therefore, depression may have a genetic component
In 1997, François Lutzoni and Marc Pagel compared the rate of nucleotide substitution in free-living versus mutualistic fungi in order to test a hypothesis that coevolution could promote the rate of molecular evolution in participating species. Which of the following was NOT supported by their results?
There was a more rapid rate of molecular evolution in the free-living fungi (related to the species that lives in lichens) than in the mutualistic species.
In the case of California salamanders, we can see how traits in one species (coloration of the toxic newts) influence selection on another (coloration of a nontoxic salamander). The figure describes the actions of a predator, the Western scrub jay, which was provided with the opportunity to feed on live salamanders. Note that Ensatina eschscholtzii oregonensis is a nontoxic and plain-colored subspecies, a close relative of the mimic Ensatina eschscholtzii xanthoptica. Which of the following is NOT true about the behavior of the Western scrub jays?
There was no significant difference in the behavior of the jays after being exposed to either the nontoxic salamander or the toxic newt. hawn Kuchta and his team of researchers first presented a Western scrub jay with a toxic California newt (Taricha torosa), and then they presented the jay with either the mimic salamander Ensatina eschscholtzii xanthoptica, or an individual from the closely related subspecies Ensatina eschscholtzii oregonensis, which is visibly similar to E. e. xanthoptica except that it lacks orange and yellow coloration (Kuchta et al. 2008). After experience with the toxic California newts, some of which the jays attacked, the jays took more time to approach E. e. xanthoptica than E. e. oregonensis individuals.
Steve Austad studied life history traits in an island and a mainland population of opossums (a marsupial species that lives in North America). In his 1993 article, he showed that opossums from the island population outlived those from the mainland, but the mortality rate increased with age in both populations. Given that the island he studied did not have any of the opossum's natural predators while the mainland did, choose the best explanation for these results.
These results provide evidence for an evolutionary explanation of senescence since natural selection is expected to favor slower rates of senescence in the island population.
n his famous book Principles of Geology, Being an Attempt to Explain the Former Changes of the Earth's Surface, Charles Lyell stated that Earth's geological features were formed by the same currently observable processes taking place. Charles Darwin was greatly influenced by Lyell's work and proposed that the current diversity of life can also be explained by mechanisms that are in operation today, acting over very long periods of time. Why was this a critical understanding for both scientists?
They both understood that if currently observable processes acted in the same manner in the distant past, those processes could then be scientifically tested.
Charles Darwin and his colleague Thomas Henry Huxley proposed that humans share a common ancestor with the great apes (chimpanzees, gorillas, and orangutans). How did they come up with such a hypothesis?
They looked at the morphological characteristics of living primate species.
The leaf-cutter ant (Acromyrmex octospinosus) is one species of ant that participates in a beneficial mutualism with a fungal species. The female workers as well as the reproductive females in the colony are often covered with a thick whitish-gray coating, which turns out to be bacteria that produce antibiotics. Which of the following is TRUE regarding the function of these bacteria?
They produce antibiotics that kill parasites that grow in the fungal gardens.
Do the phylogenies in the figure show the same or different relationships between taxa 1 through 4?
They show the same relationships because rotating the nodes in a phylogeny does not change the evolutionary relationships that they represent.
What did David Reznick and his coworkers do to test whether the life history strategies of the guppies (Poecilia reticulata) were indeed adaptations to their selection pressures in the upstream and downstream waterfalls of Trinidad and Tobago?
They transplanted guppies from high-predation sites below a waterfall to low-predation sites above a waterfall to test whether descendants of transplanted individuals evolved adaptations to their new selection.
When comparing the gene for elongation factor 1 between two species of rotifers, you find that the rate of nonsynonymous substitution is 0.026 and the rate of synonymous substitution is 0.81. Which of the following can you conclude from these data?
This gene has experienced strong purifying selection.
What is an important difference between transmission genetics and population genetics
Transmission genetics deals with genotypes of individuals, while population genetics deals with genotype frequencies in a population. Transmission genetics characterizes the way the genotype of an individual offspring is related to the genotype of its parents. Population genetics deals with how genotype frequencies in a population are related to those of the parental population. Both types of genetics use quantitative models, molecular biology, and information about inheritance.
Which of the two phylogenetic trees shown in the figure offers a more parsimonious explanation for the observed character states?
Tree B
Presume that phylogenetic trees of five species (A, B, C, D, and E) contain information about one important morphological characteristic, X. This characteristic is found only in species A and species C. "Loss" indicates the loss of characteristic X in one or more branches, while "gain" indicates independent occurrences of characteristic X (convergent evolution). Use parsimony logic to choose the tree that best represents this hypothetical situation.
Tree C
The following tree is a chronogram of five orchid subfamilies, where the relative size of each subfamily's clade is proportional to the number of genera in it. Which of the following can you infer from this tree?
Two subfamilies of orchids underwent rapid diversification beginning about 60 million years ago.
The following figure is an overview of a bootstrap analysis. If we have some characteristic data (A) and we construct an estimated phylogeny (B) using these data sets, we could apply bootstrapping resampling to create multiple bootstrap replicate data sets (C). How do we assess the support for any feature of the original tree?
We should count the percentage of replicate trees that also display this feature.
Which of the following helps explain why most species display an even sex ratio?
When males are rare, a parent that produces more males will have more grandchildren on average.
What does Hamilton's rule (rb − c > 0) tell us?
When relatedness is high, benefit to the recipient is high, and cost to the actor is low, then natural selection should strongly favor individuals that help their kin. Hamilton's rule shows that selection to assist family members is a function of how related individuals are and how high or low the associated costs and benefits turn out to be. If the coefficient of relatedness (r) and benefit to the recipient (b) are high, they can overcome the cost to the benefactor. However, if the cost is high, selection may not favor the behavior or action.
Many models of the evolutionary consequences of mutation assume that the rate of back mutation is negligible. When is this a reasonable assumption?
When we are considering a protein where forward mutation leads to a nonfunctional protein and back mutation leads to a functional protein.
Gorillas and orangutans have single-male breeding systems, where females mate with only one male. Chimps, in contrast, have a multi-male breeding system, where females mate with multiple males. Evolutionary biologists hypothesize that multi-male breeding systems will favor the evolution of large testes size. Do the data in the figure shown support this hypothesis?
Yes. Testes size increases with body weight, but in multi-male systems, testes size is disproportionately larger.
A phylogeny is __________.
a figure that shows the branching relationships among populations over evolutionary time
What do interior nodes on a phylogenetic tree represent?
a population that was the common ancestor of two or more descendant taxa
With trees based on a parsimony analysis, the most popular method to evaluate trees is known as "bootstrapping." Which of the following is the best definition for this method?
a technique that evaluates which clades on a particular tree are best supported by the data sets
In a recent study on fitness consequences of antipredatory behavior and coloration pattern in garter snakes (Thamnophis ordinoides), the phenotype space was depicted as a three-dimensional graph where the highest points represent combinations of traits associated with the greatest fitness values. For such situations, we could use Sewall Wright's metaphor of the __________.
adaptive landscape
In order to understand the origin of life on Earth, evolutionary biologists collaborate with__________.
all of the answer options are correct
Stanley Miller and Harold Urey developed and conducted experimental tests for a "prebiotic soup" model of the origin of life, which had been proposed a few decades earlier by Aleksandr Oparin and J.B.S. Haldane. What did Miller and Urey show could be synthesized abiotically?
amino acids
The figure shown is a phylogram—a phylogenic tree in which the branch lengths represent the __________.
amount of evolutionary change along each branch branch lengths represent the amount of change in the DNA sequences during evolution of lentiviruses. The amount of evolutionary change may correlate with the time since divergence, but this is not what is directly shown in a phylogram; in a chronogram, branch lengths represent time.
Nick Barton and Brian Charlesworth defined sexual reproduction as the process that involves the joining together of genetic material from two parents to produce an offspring that has genes from each parent (Barton and Charlesworth 1998). More specifically, such a process, which involves meiosis and gamete fusion, is called__________.
amphimixis
In the interaction between predators and prey, we frequently observe prey becoming increasingly good at escaping predators, and predators increasingly good at capturing prey. This is an example of __________.
an evolutionary arms race
Artificial selection could be described as all of the following, EXCEPT
an increase in the frequency of traits that are associated with increased survival and increased reproductive frequency in the wild
Which of the following is a phylogenetic method that can distinguish between asexual and sexual lineages of eukaryotic organisms?
analysis of nDNA- and mtDNA-based trees Evolutionary biologists can use the degree of phylogenetic incongruity between nDNA- and mtDNA-based trees to infer the mode of reproduction. Since mitochondrial DNA (mtDNA) is inherited only through females whereas nuclear DNA (nDNA) is inherited through both parents, phylogenetic trees based on mtDNA and nDNA in asexual species should be fairly congruent (similar to one another). In sexual species, we expect less congruent trees.
Suppose that in wild rose plants, the A locus controls pigmentation of the flower petals. The A allele (for red flower coloration) is completely dominant to the a allele (for pale pink flower coloration). If purebred red-flowered plants were crossed with purebred pink-flowered plants, and their heterozygous offspring (the F1 generation) were grown so that such hybrids might be crossed among themselves, which of the following flower phenotypes might you expect in the F2 generation?
both red and pale pink roses (in a ratio of 3:1, respectively)
Gene expression in eukaryotes is strongly influenced by the local structure of the chromosome. In which of the following regions of a DNA molecule would you expect to find the highest levels of gene expression?
decondensed chromatin
One of the important facts learned from experiments in molecular genetics is that most amino acids can be encoded by more than one nucleotide triplet. For this reason, we say that the genetic code is __________.
degenerate
A mutation resulting in deletion of a protein-coding gene will most likely have a ___________ effect on fitness.
deleterious
Traits are critical in the study of phylogeny for all of the following reasons, except to __________.
determine the immediate ancestor of an individual
Panic grass (Dichanthelium lanuginosum) can live in geothermally heated soils only when the fungus Curvularia protuberata is present. In order for Curvularia protuberata to colonize the soil, the Curvularia thermal tolerance virus (CThTV) must also be present. This web of coevolutionary interactions between multiple species is referred to as __________.
diffuse coevolution
Female hanging-flies, Hylobittacus apicalis, prefer males that bring them "nuptial gifts" of large prey items during courtship. This is an example of which evolutionary model of female mate choice?
direct benefits model he direct benefits model explains why females choose mates that provide them with resources. These additional resources increase their fecundity and survival; therefore males who provide these resources have greater access to females and are more fit than males that do not. Read the subsection titled "Direct Benefits" in Section 16.5 and see Figure 16.22.
In mice that are homozygous for the dark-color Agouti allele (D), the effects of the Mc1R locus are entirely masked so that, irrespective of the genotype at Mc1R, the mice have fully dark coloration. However, if at least one copy of the light-color Agouti allele (L) is expressed, the different shades of brown Mc1R locus are revealed (with the particular shade depending on the number of copies of L). This is an example of __________.
epistatic effects of the two genes
The gray tree frog, Hyla versicolor, is well known for the singing that male frogs use to attract a female. Studies have shown that male tree frogs that have more prolonged and frequent calls are more attractive to females. In the right weather conditions, males can chorus for hours in their attempt to attract a female. This is an example of __________.
expenditure of time and energy to attract a potential mate
Which of the following molecules involved in membrane structure was likely favored by natural selection in the evolution of early cells?
fatty acids
An addition or deletion of one or two base pairs in a gene sequence results in a __________ mutation.
frameshift
Which statement best describes the phenomenon of "antagonistic pleiotropy" in evolution?
genes that affect more than one characteristic and have a negative effect on fitness in one context, but a positive effect in another
In selection experiments on quantitative traits, we often measure a value of the response to selection (R). What is R equal to?
h2S
What does the shaded area between dashed lines in the figure represent?
he zone of conflict A parent can either allocate resources to a "focal" offspring or redirect those resources to other current or future offspring. The x axis represents the amount of resources that the parent invests in the focal offspring, and the y axis represents fitness costs (c) to the parent (blue and orange lines) or benefits (b) to the offspring for that investment (green line). Benefits refer to increases in the fitness of the focal offspring, and costs are quantified in terms of decreases in fitness of other offspring. The more resources that a parent invests in the focal offspring, the greater the benefits to that offspring—albeit with decreasing returns—but the greater the costs as well. The parent is equally related to all of its offspring, and so it is selected to maximize the difference between benefit and cost. But the offspring is only half as related to its full siblings as it is to itself, and thus by the logic of inclusive fitness, it is selected to maximize the difference between benefit and cost divided by 2. As a result, parent and offspring prefer different amounts of resource allocation. This zone of conflict is shaded in the figure.
An adaptation refers to a __________.
hereditary trait that makes organisms more fit in their environment and that has arisen as a result of the action of natural selection
Which of the following animal lineages has the most eusocial species?
hymenopterans
As the early Greeks moved away from supernatural explanations to explanations based on natural phenomena, they would propose explanations of phenomena based solely on natural processes. As the basis of the modern scientific method, this is called a(n) _
hypothesis
Richard Lenski's experimental E. coli populations have been used, among other things, to study constraints on what natural selection can achieve. In one set of experiments, the researchers found that the rate of adaptation was proportional to the supply of new variation available. This result highlights what type of constraint on natural selection?
limited genetic variation in a population
The major genetic effect of inbreeding in a population is to increase the number of__________.
loci at which the average individual is homozygous
In sickle cell anemia, a point mutation leads to a replacement of one amino acid in a hemoglobin molecule, in a unit responsible for transportation of oxygen. This and any other mutation in a gene that causes a change in the amino acid sequence in a polypeptide chain is known as a __________ mutation.
missense
The proportion of phenotypic variance that results from additive genetic variance alone is called the __________ heritability.
narrow-sense
The evolution of antibiotic resistance is the result of __________.
natural selection
In the southern European plains, a species of flower comes in two colors, purple and pink. When pink flowers are most common in a field, bees visit and pollinate the purple flowers more often, and vice versa. This switching of pollinator preference will result in __________.
negative frequency-dependent selection
Which of the following processes results in the maintenance of genetic variation within a population?
negative frequency-dependent selection
The height of a yarrow plant (Achillea millefolium) depends on its genotype and the altitude at which it is raised. Suppose that one of the genotypes produces plants that are tall at low and high elevations and short at medium elevations. In this case, we would say that the genotype codes for the __________ in the yarrow plant.
norm of reaction for height
Empirical research is very important in evolutionary biology. There are two main types of such research, which could be classified as __________.
observation and manipulation
What allele frequencies result in the highest frequency of heterozygotes in a population at Hardy-Weinberg equilibrium?
p = q = 0.5
Evolutionary biologists have developed a number of different phylogenetic methods. Which of the following methods, when applied to phylogenetic inference, points to a "preferred tree" that minimizes the total amount of evolutionary change that has occurred?
parsimony Parsimony is a logical method to distinguish between reliable synapomorphy and misleading homoplasy. Therefore, parsimony would infer a tree with the minimum number of evolutionary changes and, along with some other statistical methods, help construct the best t
In quantitative genetics theory, the value of a quantitative trait is sometimes given by the equation P = G + E. We could define P as the _________ of the continuous trait that we are studying.
phenotypic value
At the molecular level, gene duplication often produces novelty in a lineage. This process provides another evolutionary pathway by which a protein can switch functions, without loss of the original function. What analytical approach helped the most to answer the question of evolution in the aldosterone-M receptor pair in the study by Jamie Bridgham and her colleagues?
phylogenetic study
The figure shows the relationship between femur diameter and body mass for a wide range of animals. This figure highlights the surprising finding that there are no organisms with large bodies and thin legs. What type of constraint has caused this?
physical constraint on bone strength
Sometimes the relationships between taxa remain unresolved due to missing or conflicting data. For example, a node in the phylogeny of mammals might have three branches arising from it, leaving the evolutionary history of the placentals, marsupials, and monotremes uncertain. A nodes with more than two branches arising from it is called a
polytomy
Natural selection is a process by which the characteristics of a(n) __________ will change over time.
population
In an analysis of a human disease and its pathology, researchers may apply different explanations, depending on the disease. If their interest is in the immediate mechanisms that cause the pathology, they will use __________ explanations.
proximate
The purple flower of the F1 offspring of Gregor Mendel's parental generation crosses indicated that __________.
purple color in flowers is dominant to white color
One of the basic ideas in the theory of evolution is that the more closely related two species are, the more __________.
recently they shared a common ancestor
Conflict is also widely studied in the evolution of sociality. Conflict manifests itself in many ways in nature. Which of the following is NOT a manifestation of conflict that evolutionary biologists study?
reciprocal altruism
One example of studying natural selection in the field comes from decades of work on life history strategies in the guppy, Poecilia reticulata. A species' life history strategy refers to the __________
schedule and manner of investment in survivorship and reproduction over the lifetime of an individual
It is well known that both our fertility and our athletic abilities significantly decline as we age. What is the term for this decline in physical functioning with age?
senescence
The type of selection for traits that increases mating success rather than survival is called __________.
sexual selection
When narrow-sense heritability is calculated using similarities between parents and offspring, it will correspond to the __________.
slope of linear regression between the average phenotype of the two parents and the phenotype of the offspring
Reciprocal altruism can be best explained with a model proposed by Robert Trivers in 1971. Trivers hypothesized that if one individual (A) pays some cost to help another individual (B), but the cost is recovered at some point in the future (when B helps A), then natural selection might favor behaviors that lead to this type of reciprocity. In which of the following situations is reciprocal altruism likely to occur?
stable groups, with ongoing interactions with the same set of partners
According to the neutral theory, most mutations are deleterious and most observed _______________ are __________.
substitutions; neutral
All of the following can help resolve a polytomy in a phylogeny, except more __________.
symplesiomorphies
All of the following differ between phylogenies and pedigrees, except_________
that they represent patterns of ancestry over time
Charles Darwin was the first to propose that __________.
the changes that have occurred in species are primarily a result of natural selection
Inbreeding depression is a reduction in the fitness of inbred individuals caused by__________.
the expression of recessive deleterious phenotypes due to increased homozygosity
Sunflower hybrids resulting from crosses between wild sunflowers and their domesticated relatives have high rates of survival. This would seem to suggest that the hybrids have a high fitness. However, before reaching this conclusion, you should next examine __________.
the number of offspring produced by hybrids.
All of the following are true regarding Sol Spiegelman's experiment on the origins of life, except that __________.
there was no selection for any of the variations in length
Which position in a codon shows the greatest degeneracy? In other words, if a change occurs in this codon position, it is less likely to change the amino acid that is specified relative to the other positions.
third position
A mutation that results in a replacement of a purine with a pyrimidine is known as a __________ mutation.
transversion
The figure shown demonstrates a type of equilibrium in which the marble __________.
will remain at its present location if it is not perturbed, but if it is perturbed, it will move even further from that location