BLY 121 Module 11: Evolution, Speciation & Phylogenetics

You are studying a gene with three distinct alleles found in Daphnia magna, a water flea. Your sample reveals the following genotype proportions: AA = 10 AB = 5 AC = 15 BB = 30 BC = 15 CC = 25 The allele frequencies of all alleles at a given are equal to 1. The frequency of allele A is: >unable to be determined from these data. >0.4. >0.3. >0.2. >0.1.

0.2

If the frequency of allele A is 0.7 in a population that is in Hardy-Weinberg equilibrium, what would the frequency of the heterozygous Aa genotype be? The genotype frequency cannot be calculated from the information provided. 0.42 0.3 0.09 0.49

0.42

Imagine these genotype frequencies in a population: p2 = 0.49, 2pq = 0.42, q2 = 0.09. Now assume that there is nonrandom mating where individuals with one genotype will only mate with individuals that also have their genotype. Assume this pattern of mating goes on until the frequency of heterozygotes is effectively zero. What will the frequency of allele p be in the population? 0.49 0.3 0.7 0.91 1.0

0.7

In a population of Mendel's garden peas, the frequency of dominant yellow-flowered plants is 50%. The population is in Hardy-Weinberg equilibrium. What is the frequency of the recessive allele in the population? 0.5 The frequency cannot be determined from the data provided. 0.71 0.05 0.25

0.71

A researcher is studying the color of grasshopper exoskeletons. Assume that this phenotype is caused by the action of two alleles. Green grasshoppers have the genotype AA and brown grasshoppers have the genotype aa. If the frequency of the A allele in this population is 0.2, what is the frequency of the a allele? 0.6 0.8 0.4 0.2 0.1

0.8

If a gene has two alleles, and allele A has a frequency of 83 percent, then allele a has a frequency of: 41.5 percent. 7 percent. 166 percent. 117 percent. 17 percent.

17%

Consider the phylogenetic tree shown in the figure. Within the tetrapods, if mammals are excluded, how many different sister groups can be defined? 3 4 6 7 5

6

You find a fossil that you think is about 350 million years old. You decide to use 235U to date a volcanic ash bed just below the key specimen. The half-life of 235U is 700 million years. If you are correct, what approximate percentage of the original 235U would you expect to remain in your sample? 0 percent 25 percent 50 percent 75 percent 100 percent

75%

Which of the answer choices is a benefit of reconstructing evolutionary history from living organisms? A range of features can be used to generate phylogenetic hypotheses. The time dimension of speciation events can be calculated with greater certainty. Evolutionary links running through extinct species can be inferred easily. The environmental context is more easily observable. None of the other answer options is correct.

A range of features can be used to generate phylogenetic hypotheses.

Which of the statements is true regarding adaptive radiation? Adaptive radiation tends to occur at a slower pace than genetic drift between two similar populations on the mainland. Adaptive radiation is more likely to occur in a population produced by a dispersal event than in a long-established population on a continent. Adaptive radiation is more likely to occur when there are a variety of similar and competing species. Adaptive radiation is more likely to occur within a mainland population than in a smaller population that underwent dispersal.

Adaptive radiation is more likely to occur in a population produced by a dispersal event than in a long-established population on a continent.

According to the figure, a mass extinction occurred at or near the end of the _____ Period. Ordovician Permian Devonian Triassic All of these choices are correct.

All of these choices are correct.

Which research question would a population geneticist be most likely to ask? How much genetic variability is found in sperm whales? All of these choices are correct. How can scientists explain the amount of genetic diversity in Adelie penguins? Why do some species have more genetic diversity than others?

All of these choices are correct.

If Archaeopteryx was instead a sister taxon to Oviraptosaurs, how would this change our conclusions about the evolution of birds? Birds would have toothless beaks as a synapomorphy for the group. The closest living relative to birds would be crocodiles. Birds would be most closely related to the group Oviraptosaurs. Birds would no longer be considered living dinosaurs.

Birds would be most closely related to the group Oviraptosaurs.

The fossil record is often used to infer phylogenetic history. Which of the statements accurately supports this assumption? Events that occur early in the fossil record are represented by branching events nearer to the tips of a phylogenetic tree. There is a one-to-one correlation between each branch of the phylogenetic tree and fossil specimens. There are fossil representatives of every organism in the tree of life. Fossil record events are too old to be represented on phylogenetic trees, which reconstruct the more recent past. Events that occur early in the fossil record are represented by branching events nearer to the root of a phylogenetic tree.

Events that occur early in the fossil record are represented by branching events nearer to the root of a phylogenetic tree.

T or F? And why? If the position of birds and turtles are switched, the tree will still reflect the accurate evolutionary relationships between these three taxa. False. Now there are three sister groups in the phylogeny. False. Turtles are now a sister group to crocodiles and alligators. True. Birds are still being shown as a sister group to crocodiles and alligators. True. All three taxa still share the same most recent common ancestor.

False. Turtles are now a sister group to crocodiles and alligators.

If you wanted to use a molecular clock to date a relatively recent divergence event - one that occurred in the last 100 million years or so - which of the four types of genes would make the BEST clock? Why? Fibrinopeptides, because they have changed the most over that time period. A histone gene, because it has changed relatively little over that time. Hemoglobin, because of its steady rate of change. Cytochrome c, because it has changed relatively little over that time. A histone gene, because it has changed the most over that time period.

Fibrinopeptides, because they have changed the most over that time period.

Constructing a phylogeny that shows an equivalent branching pattern using either morphologic or molecular data sets strongly suggests that the phylogeny is an accurate representation of the evolutionary history of the group being studied. Why does additional data from fossils give increased support to our understanding of the evolutionary history for certain groups? Fossils are one way to calibrate the timing of events on a phylogeny. Phylogenies can't be accurate without fossil data. Fossils show the entire evolutionary history of a group of organisms.

Fossils are one way to calibrate the timing of events on a phylogeny.

How do fossils provide evidence of evolutionary history? Fossils provide a record of extinct species. Fossils provide complete information on extinct species. Older fossils are an excellent source of DNA from which we can construct molecular phylogenies. Fossils provide an accurate account of the number of species that exist at any particular time.

Fossils provide a record of extinct species.

Which of the statements is the most accurate in reflecting levels of genetic divergence between different species of lice? G. cherriei and G. costaricensis will have the same number of genetic differences from G. chapini because speciation could not occur in the lice without genetic differences. G. cherriei and G. costaricensis will have accumulated the most genetic differences between them relative to the other Geomydoecus species because they share the most recent common ancestor. G. cherriei and G. costaricensis will have the same number of genetic differences as O. cherrieri and O. heterodus because they coevolved together. G. cherriei and G. costaricensis will have accumulated the fewest genetic differences between them relative to the other Geomydoecus species because they share the most recent common ancestor.

G. cherriei and G. costaricensis will have accumulated the fewest genetic differences between them relative to the other Geomydoecus species because they share the most recent common ancestor.

How does gel electrophoresis allow researchers to observe genetic variation? Gel electrophoresis enables a scientist to distinguish dominant and recessive traits. Gel electrophoresis enables scientists to distinguish allele variants of a gene. Gel electrophoresis enables scientists to replicate a strand of DNA. Gel electrophoresis enables a scientist to link phenotype to genotype.

Gel electrophoresis enables scientists to distinguish allele variants of a gene.

Which of the statements are true regarding hybridization? Select all that apply. Hybridization can result in fertile offspring. Hybridization involves the transfer of genetic material between members of similar species. Hybridization occurs in plants more often than in animals. Natural selection sometimes acts against progeny that result from hybridization. Hybridization cannot result in the formation of new species.

Hybridization can result in fertile offspring. Hybridization involves the transfer of genetic material between members of similar species. Hybridization occurs in plants more often than in animals. Natural selection sometimes acts against progeny that result from hybridization.

Which of the answer choices is not a condition of the Hardy-Weinberg equilibrium? The size of a population must be large. Mating within a population must be random. Individuals can migrate in and out of a population as long as the population size remains constant. Individuals of any genotype must have the same reproductive success as individuals of any other genotype.

Individuals can migrate in and out of a population as long as the population size remains constant.

How could our understanding of tetrapod evolution be altered if the fossil from Tiktaalik had been found in sediments that were aged at 380 million years ago? It could indicate that there is another transitional form that is even less tetrapod-like but has not been found. All of these answer choices are correct. It could indicate that tetrapods evolved much earlier than 360 million years ago. It could indicate that Tiktaalik and tetrapods evolved due to convergent evolution.

It could indicate that tetrapods evolved much earlier than 360 million years ago.

Why is agreement between the fossil record and phylogenies constructed from living organisms considered strong evidence of evolution? It is unlikely that two independent methods of investigation would result in the same pattern by chance alone. All living organisms will eventually become fossils, so evidence of their evolution will be recorded in the fossil record. Phylogenetic methods based on DNA sequences can suggest that two species are closely related, but only fossils can show direct evidence of an evolutionary relationship between species. Evolutionary processes cannot be studied directly in the laboratory alone, so it is necessary to compare living and extinct species to see evidence of evolutionary change. All of these choices are correct.

It is unlikely that two independent methods of investigation would result in the same pattern by chance alone.

Ligers (hybrid offspring from lions and tigers) and tigons (hybrid offspring from tigers and lions) do exist, and mating that produces the hybrid offspring has occurred at conservation sanctuaries where both species are kept in common areas. Yet, we consider tigers and lions to be separate species according to the biological species concept. Which of the statements reflects how the BSC can still be used to categorize these species? > Under the BSC, the hybrids from lion/tiger mating would also be considered a separate species. > Lions and tigers represent separate evolutionary lineages, so would be considered separate species under the BSC. > Lions and tigers can be considered separate species under the BSC because they do not look alike. > Lions and tigers can be considered separate species under the BSC because they are not typically in the same place, so breeding does not normally occur.

Lions and tigers can be considered separate species under the BSC because they are not typically in the same place, so breeding does not normally occur.

In April of 1986, there was a nuclear reactor meltdown at the Chernobyl Nuclear Reactor site in Ukraine. Individuals that responded to the disaster were exposed to high levels of ionizing radiation and showed mutation rates up to 6 times higher than rates found in individuals not exposed to the radiation. When researchers sequenced the genomes of the offspring of these individuals, they found that many of the offspring had the same mutations, even though they had never been to the site of the nuclear accident. Which statement could explain these data? > The responders have a naturally higher mutation rate than other surrounding populations, and the mutations are inherited by their offspring. > Many of the mutations occurred in reproductive cells and were inherited by the offspring. > The responders and their families live close enough to Chernobyl that many generations were exposed to high levels of ionizing radiation. > DNA repair mechanisms are deficient in the offspring, so they have higher rates of mutation.

Many of the mutations occurred in reproductive cells and were inherited by the offspring.

Why can't we measure genetic variation in a population using observable traits (phenotypes)? Select all that apply. All traits are encoded by a single gene. Phenotypes are not determined by genes. Many traits are encoded by multiple genes. The environment can also affect phenotype.

Many traits are encoded by multiple genes. The environment can also affect phenotype.

In a study of genetic variation of the Graceland gene, a researcher finds that there are two alleles in a population. In a large sample (500 individuals), the frequency of heterozygotes is 0.63. Is the population in Hardy-Weinberg equilibrium? > No. There would be no heterozygotes if the population were in Hardy-Weinberg equilibrium. > No. The highest frequency of heterozygotes under Hardy-Weinberg equilibrium is 0.5. > No. The frequency of heterozygotes would be 1 if the population was in Hardy-Weinberg equilibrium. > No. The frequency of each genotype would be equal if the population were in Hardy-Weinberg equilibrium.

No. The highest frequency of heterozygotes under Hardy-Weinberg equilibrium is 0.5.

The graph shown illustrates that the extent of the adaptive radiation of the Galápagos finches is correlated with the number of islands present in the archipelago. What can be concluded from the graph? Rates of speciation are correlated with the net total land area available. The balance between rates of sympatric and allopatric speciation is governed by mutation rates. Opportunities for geographic isolation are a key component of the speciation process. Each island hosts sympatrically speciating populations. Allopatric speciation tends not to occur on islands.

Opportunities for geographic isolation are a key component of the speciation process.

The largest mass extinction occurred at the end of which period? Cretaceous Triassic Permian Devonian Ordovician

Permian

What is a possible explanation for why a population may not be in Hardy-Weinberg equilibrium? There are more than two alleles for a trait. The alleles for a trait being examined exhibit incomplete dominance. One allele for a trait is fixed in the population. Selection is favoring a particular trait in the population. The Hardy-Weinberg equilibrium cannot be achieved by all types of traits.

Selection is favoring a particular trait in the population.

A large population of mice (2000 individuals) lived in an area in the desert dominated by small shrubs. When the population size got too high, a small group of 6 individuals left and colonized an area adjacent to the original population's home, but the adjacent area was primarily dominated by trees instead of shrubs. There is no gene flow between the dispersers and the original population. A researcher sequenced the genomes of representative individuals from both populations and found substantial genetic differences between them. Which of the statements would most account for the amount of genetic differences observed? > The divergence between populations could only have been caused by stabilizing selection. > Divergence between the two groups is high because of gene flow. > Since the original dispersal event, the small population could have accumulated more mutations than the original population. > Divergence between the two populations was caused solely by drift.

Since the original dispersal event, the small population could have accumulated more mutations than the original population.

Imagine you are at the top of a mountain looking down. As you hike from the highest elevation to the lowest elevation, you find three different species of related mice. None of them are found at the same elevation, and the vegetation changes at each elevation level. Using species C as a reference, you find that there are more genetic differences between species A and species C than between species A and species B. Which of the statements would best reflect the mode of speciation in these mice? Speciation was allopatric or peripatric, but would depend on the number of individuals that dispersed from the original population. Only genetic drift is responsible for the differences observed. Species C arose from species A later than species B.

Speciation was allopatric or peripatric, but would depend on the number of individuals that dispersed from the original population.

You sequence the DNA of chromosome 12 from reproductive cells of 40 individuals in a population. You find that 10 individuals each have the same neutral, reproductive cell mutation. The following year, you sequence the same chromosome in all the offspring from those 12 individuals, but find that none of the offspring has the mutation. Which statement reflects how this could occur? The copy of chromosome 12 with the mutation was deleted during meiotic division. The copy of chromosome 12 with the mutation was not in the gametes involved in fertilization producing the offspring. The mutation is neutral, so it is not inherited by the next generation. The mutation is neutral, so it is lost during meiotic divisions.

The copy of chromosome 12 with the mutation was not in the gametes involved in fertilization producing the offspring.

Consider the two phylogenies showing the relationship between five related species of moths and five species of related flowers that hold nectar as a reward for their pollinators. The similar pattern of the phylogenies suggests the characteristics co‑speciated with one another. Which of the descriptions is an accurate statement reflecting the figure shown? This is not an example of co-speciation. Each phylogeny represents the variation present in each population of the flower and the moth. The flowers and moths cannot co-speciate because co-speciation only occurs in host-parasite relationships. The flowers and moths coevolved, so that spur-length and tongue-length each evolved because of changes in the other. The flowers and moths experienced the same allopatric speciation events during their history.

The flowers and moths coevolved, so that spur-length and tongue-length each evolved because of changes in the other.

Consider the figure, which shows the rates of the molecular clock for different genes. You are estimating the time since the divergence of two species and used hemoglobin for your molecular clock. You would like to get independent support for your estimate. If you also use cytochrome c, which result do you expect? The number of amino acid differences between the two species will be fewer for cytochrome c than for hemoglobin. The number of amino acid differences between the two species will be fewer for hemoglobin than for cytochrome c. The number of amino acid differences between the two species will be the same for both genes.

The number of amino acid differences between the two species will be fewer for cytochrome c than for hemoglobin.

Why do histone genes have a very slow molecular clock? >The structure of the histone gene must be conserved for DNA to function properly. >Histone genes do not have the same rate of mutations. >DNA-correcting mechanisms function more readily with histone genes. >Histone genes normally have self-correcting mechanisms. >Cells have more histone genes than any other kind of gene.

The structure of the histone gene must be conserved for DNA to function properly.

As a population geneticist, you find a species of snails with more genetic diversity than humans. What does this mean? The snails have more DNA than humans. There is more variation in the gene pool of snails than humans. The snails have more genes on their chromosomes than humans. The snails have more mutations occurring than humans. The snails have a larger population size than humans.

There is more variation in the gene pool of snails than humans.

Which statement describes populations that are genetically isolated? They do not live in the same areas. They do not evolve. They do not share the same mutations. They do not originate from the same population. They do not exchange genetic material.

They do not exchange genetic material.

At some fish markets the fish are sold only as fillets, with no identifying morphological characters showing for each fish sample. Some evolutionary biologists are a bit suspect of some of the fish being sold there and think the market may be engaging in false advertising. The biologists hypothesize that the very expensive halibut fillets are actually a cheaper fish. The biologists buy fillets of the halibut, cod, scrod, and monkfish and sequence their DNA. Since the samples are all from bony fish, they use a known sequence from a cartilaginous fish as the outgroup to build a phylogeny. Which answer option supports their hypothesis that the halibut is actually a cheaper fish (cod, scrod, or monkfish)? The monkfish is a sister taxon to the cartilaginous fish, and the other three fish all have the same sequence. All four bony fish have the same sequence. Three branches are present besides the outgroup. One branch each for cod, scrod, and monkfish. Two sister groups of bony fish are shown in the phylogeny. In one, halibut and monkfish are a sister group, and in the other, cod and scrod are a sister group.

Three branches are present besides the outgroup. One branch each for cod, scrod, and monkfish.

Using distance-based methods to construct a phylogenetic tree requires: many independent mutations in each taxon. at least 10% of the genome sequence for each taxon. a constant evolutionary rate of change in the DNA of the taxa. a large number of DNA differences between all taxa.

a constant evolutionary rate of change in the DNA of the taxa.

You sequence a region of the genome in every individual in a population. You find a mutation that is present in 30% of the population. You then sequence the same region after four generations have passed and find the mutation is present in 82% of the population. Based on these data, you might conclude that the mutation is a(n) _____ mutation. deleterious neutral advantageous somatic

advantageous

If two populations are thought to be diverging from one another, what would you expect to observe? an accumulation of different mutations in different populations the same genotypes, but different phenotypes more shared mutations in different populations an increase in similarity of alleles coding for proteins

an accumulation of different mutations in different populations

Streamlined bodies are common in many aquatic organisms. Dolphins, tuna, penguins, and sharks are all organisms with streamlined bodies that reduce friction and drag. Body shape in each of these organisms would be considered: a similar character. a homologous character. an analogous character. a natural character.

an analogous character.

Wings in birds and bats arose independently in the two groups. This means that wings are a(n) _____ trait and the forelimbs are a(n) _____ trait in the two groups. homologous; homologous analogous; analogous analogous; homologous homologous; analogous

analogous; homologous

Phylogenetic trees can be built using: anatomical data only. molecular data only. anatomical data or molecular data. visible characteristics only.

anatomical data or molecular data

You are near a lake and notice a lot of frogs. They all look very similar to one another. You sit down and start to listen to the calls of the frogs and note that there are three distinct calls. Moreover, you see that females are only mating with male frogs that make one type of call and ignoring males making a different call. This is an example of: gametic isolation. ecological isolation. temporal isolation. behavioral isolation.

behavioral isolation

What is the first event in the fossilization process? hardening of sediments into rock burial of the organism by sediments erosion of soils around the organism conversion of organic tissue to minerals (rock)

burial of the organism by sediments

Mutation and recombination are the only processes that can increase genetic variation because they are also the only processes that: can produce new genotypes. can change allele frequency. cannot be influenced by artificial selection. are not random. can produce deleterious results.

can produce new genotypes.

When calculating the allele frequency of allele A in a population, you multiply the frequency of individuals who are homozygous for A by 2 because: each individual who is homozygous for A has two copies of the allele. if A is dominant, it will show up twice as much. there are always twice as many homozygous individuals as heterozygous individuals. individuals homozygous for A will produce twice as many offspring. individuals homozygous for A will be twice as likely to survive.

each individual who is homozygous for A has two copies of the allele.

T or F? According to the phylogenetic tree shown in the figure, lizards and snakes are more closely related to caecilians than they are to mammals.

false

T or F? An advantageous mutation is more likely to get fixed in a population through genetic drift than is a deleterious mutation.

false

T or F? Frogs and salamanders share the same most recent common ancestor as mammals and sauropsids.

false

T or F? If two populations are reproductively isolated from one another, they must be genetically isolated from each other and, therefore, cannot belong to the same species.

false

T or F? Imagine that the first fossil tetrapod was found in sediments aged at 400 million years ago. This would be direct evidence against the branching pattern shown in the phylogeny.

false

T or F? Traits favored by sexual selection are the same traits favored by natural selection.

false

While we can use molecular clocks based on molecular sequence data to estimate the times at which various lineages diverged, we ultimately need the _____ to calibrate the clocks. transitional forms DNA sequences character states fossil record sister groups

fossil record

Many aquatic species release their sperm and eggs into the water, often at the same time as other local species. As the gametes mix in the water, fertilization occurs. Which answer option most likely inhibits fertilization of gametes from one species by a different species? gametic isolation temporal isolation ecological isolation behavioral isolation

gametic isolation

A researcher studying two species (species 1 and species 2) sequences a short stretch of eight codons from the same gene, gene A, in each and compares them. Species 1 and species 2 had a most recent common ancestor 50 million years ago. Species 1: ATC GGG CGG GAC TTA TTA TAT GCC Species 2: AAC GGG CGA GAC TAA CTA TAT GCA Given the differences between the sequences of the two species' genes shown here, what evolutionary force can you predict is in operation on gene A? positive selection directional selection balancing selection genetic drift disruptive selection stabilizing selection negative selection

genetic drift

Imagine a single interbreeding population has been split into two. Initially they are still able to interbreed, but the two populations continue to diverge from each other genetically. Which answer option contributes the most to divergence immediately after the two populations are separated? gene flow mutation natural selection genetic drift

genetic drift

What term describes changes in allele frequency due to random inheritance of alleles from one generation to the next? genetic drift mutation selection non-random mating immigration

genetic drift

Frogs, birds, rabbits, and lizards all have different forelimbs, which makes sense when you consider their different lifestyles. Interestingly, all of their forelimbs share the same set of bones: the ulna, the radius, and the humerus. These same bones are also seen in fossils of the extinct animal Eusthenopteron, which demonstrates common ancestry among these four groups of animals. Hence, these forelimbs are an example of: homilies. homologies. analogies. similes.

homologies.

The figure shown represents a phylogenetic tree of vertebrate animals. According to this tree, what is the sister group to the tetrapods? mammals amphibians coelacanths lungfish sauropsids

lungfish

The phylogeny shown represents a hypothesis for the evolutionary relationships among major groups of plants. If it is correct, in what order should we predict to find the fossils of these groups, in order from oldest to youngest? moss group, ferns, conifer group, flower group ferns, moss group, conifer group, flower group conifer group, ferns, moss group, flower group ferns, conifer group, moss group, flower group flower group, conifer group, ferns, moss group

moss group, ferns, conifer group, flower group

Some proteins have a slower molecular clock due to ______ selection, which eliminates harmful alleles. beneficial neutral positive disruptive negative

negative

Based on the diagram shown, you predict that the earliest fossil gorilla (which may not resemble modern-day gorillas) would be _____ than the earliest fossil _____. None of the other answer options is correct. older; orangutan younger; chimp older; bonobo younger; bonobo

older; bonobo

Consider the phylogenetic tree shown in the figure. The groups identified as "fish" would be considered a: polyphyletic group because each group of "fish" has a different common ancestor. paraphyletic group because tetrapods are not included in the group "fish". monophyletic group because they are all grouped together in the phylogeny. monophyletic group because they all share the same most recent common ancestor.

paraphyletic group because tetrapods are not included in the group "fish".

Based on the matrix, which tree represents the most parsimonious explanation of relatedness among these species? phylogeny 3 phylogeny 1 phylogeny 2

phylogeny 2

Some recent discoveries of fossils surprisingly retain some coloration of feathers and skin. This is the result of the preservation of: proteins. DNA in the nucleus of a cell. lipids such as cholesterol. pigment molecules.

pigment molecules.

Horses and donkeys can interbreed, but their offspring (mules) are infertile. This is an example of what kind of reproductive isolating mechanism? post‑zygotic, genetic incompatibility post‑zygotic, behavioral isolation pre‑zygotic, temporal separation post‑zygotic, ecological separation pre‑zygotic, behavioral isolation

post‑zygotic, genetic incompatibility

If two individuals from different species attempt to mate, but fertilization fails to occur, this is likely the result of _____. However, if such a mating produces a zygote that fails to form a viable embryo, this is likely the result of _____. post-zygotic factors; pre-zygotic factors behavioral factors; pre-zygotic factors pre-zygotic factors; behavioral factors post-zygotic factors; lock-and-key factors pre-zygotic factors; post-zygotic factors

pre-zygotic factors; post-zygotic factors

Ring species are a series of related populations that occur in the shape of a ring. Adjacent populations can hybridize, but populations at the ends of the ring cannot. The figure shows a ring species complex for seven populations of salamander. The seven populations are arranged around a low valley that the salamanders cannot cross. E. e. crocreator has a very specific mating "dance" that E. e. klauberi does not recognize, so they do not hybridize. This is an example of: temporal isolation. pre‑zygotic isolation. post‑zygotic isolation. ecological isolation.

pre‑zygotic isolation.

Two species of frog mate in the same pond. One breeds in early summer and one in late summer. This is an example of what kind of reproductive isolation? post‑zygotic, ecological separation pre‑zygotic, behavioral isolation pre‑zygotic, ecological separation pre‑zygotic, temporal separation post‑zygotic, temporal separation

pre‑zygotic, temporal separation

Genetic variation has two sources: mutation and: recombination. natural selection. genetic drift. non-random mating. cell division

recombination

Competition among members of one sex for access to the other sex results in _____ selection. directional disruptive stabilizing sexual

sexual

_____ is the process by which two populations of the same species living in the same habitat diverge into separate species. Adaptive radiation Co-speciation Peripatric speciation Sympatric speciation Allopatric speciation

sympatric speciation

The specific types of homologies used to develop phylogenies are shared derived characters or: convergent characteristics. sister groups. parsimonious branches. synapomorphies.

synapomorphies.

Imagine that a researcher discovers two new similar species of bats in the same geographic area. Amazingly, one of these species preys upon insects during the day. The other species, as one would expect, is nocturnal and only feeds during the night. These two bat species would be considered: peripatrically isolated. energetically isolated. allopatrically isolated. temporally isolated.

temporarily isolated

Data from both phylogenies and the fossil record show all of the answer choices except: the earliest animals appeared more recently than the earliest land plants. microorganisms diverged early in evolutionary history. flowering plants diverged more recently than algae. primates diverged more recently than tetrapod vertebrates. diversity has accumulated over time.

the earliest animals appeared more recently than the earliest land plants.

What is the eventual long-term result of different mutations accumulating in different populations? decreased genetic isolation the evolution of different species the extinction of one population merging the populations through migration fixation of the same alleles in both populations

the evolution of different species

When considering the extinctions at the ends of the Permian Period and the Cretaceous Period, which had a more rapid increase in the number of genera in the first 65 million years after the extinction event? the extinction at the end of the Permian Period the extinction at the end of the Cretaceous Period

the extinction at the end of the Cretaceous Period

Asian elephants and African elephants are separate species. Within African elephants, there are populations that live in forested areas and populations that live in savannah areas. Elephants in each region are considered separate species. They both fill a similar ecological niche where they live. There is some evidence that forest and savannah elephants can hybridize on occasion. Based on this information, which species concept best applies to forest and savannah elephants? the phylogenetic species concept the biological species concept the morphospecies concept the ecological species concept

the phylogenetic species concept

A single species of fish, the three‑spined stickleback, once inhabited a large lake. At some point in the lake's history, lava flowed from a nearby volcano into the lake cutting it into three completely isolated mini‑lakes. Despite the heat from the lava, a few individuals from the original population of stickleback survived in each mini‑lake. Three million years later, a researcher finds that each mini‑lake is inhabited by its own species of stickleback. Which of the figures most closely reflects how the three species of spiny back are related to one another? tree L tree M tree H tree K

tree H

T or F? All mutations in a population—both harmful and beneficial—contribute to the evolution of that population.

true

T or F? As you move from right to left on the tree, you would expect to find the fossils of the first fish buried in deeper strata than the fossils of the first mammal.

true

T or F? Imagine that a taxonomist is provided with several flashcards that contain the names of different species. She would like to organize these flashcards to construct a phylogenetic tree. To do this, she would pay attention to which species belongs to which genus or class.

true

T or F? In a given population, all humans have the same blood type O. If no other alleles for blood type exist in this population, this population is "fixed" for the O allele.

true

T or F? In co-speciation, two groups of organisms speciate in response to each other and in a coordinated manner.

true

T or F? In general, males and females of the same species can produce fertile offspring.

true

T or F? Migration, genetic drift, and mutation are all mechanisms of evolutionary change.

true

T or F? Mutation increases genetic variation.

true

T or F? Phylogenetic methods based on DNA sequences and data from the fossil record show that the evolutionary link between birds and crocodiles runs through dinosaurs.

true

T or F? Sexual reproduction of diploid individuals is one of the conditions of the Hardy-Weinberg equilibrium.

true

T or F? Some species of plants are isolated pre-zygotically from one another due to gamete recognition proteins. It is possible that if the genomes were sequenced for these two species, they could show very little genetic divergence from one another.

true

T or F? When two populations have undergone divergence in allopatry long enough to be unable to produce fertile offspring, they are different enough to be considered two different species.

true

The graph shows the relationship between allele frequencies of two possible alleles for a gene in a population of a diploid organism. T or F? For any given point on the line in the graph, there is only one possible set of genotype frequencies for a population that is in Hardy-Weinberg equilibrium.

true

A new mutation arises in the intron of a gene in a somatic cell. This mutation contributes to _____ in the population _____ by individuals in the next generation. variation; but will not be inherited variation; and will be inherited adaptation; and will be inherited adaptation; but will not be inherited

variation; but will not be inherited

Male northern elephant seals (Mirounga angustirostris) compete with one another for territories along the beach and defend these territories throughout the breeding season. The males that win the male-male competitions defend the "best" territories and have access to females that stay in that territory of the beach. The females land on the beach during mating season, chose which territory of the beach to join, and then disproportionately breed with the male that defends that area of the beach. At what point may intersexual selection occur in these elephant seals? when the female leaves the beach after mating with a male when the male mates with a female within his group when the female lands on the beach and chooses her resting location when the male defends his group of females against a different male when the female is swimming to the beach

when the female lands on the beach and chooses her resting location