week 5 questions

In the animation, fish with less streamlined fins have a ____________ reproductive fitness than fish with more streamlined fins because ____________. A. lower; the increased fin size hinders mating B. lower; they are less able to escape predators C. higher; they swim more quickly D. higher; the increased fin size is more likely to attract a mate E. lower; their ability to acquire food is impaired

B. lower; they are less able to escape predators

Neutral mutations can increase in frequency to a maximum of what percentage of the population? A. 25% B. 50% C. 75% D. 99% E. 100%

E. 100%

Once a mutation is introduced into a population, it will eventually be passed on until it is found in 100% of the individuals in that population. A. True B. False

B. False

When individuals of a parent species are separated geographically, one population of separated individuals is more likely to acquire neutral mutations than the other. A. True B. False

B. False

Speciation has occurred when: A. mutations in a population reach 100% of the organisms in that population. B. divergent populations evolve to the point where interbreeding does not produce viable, fertile offspring. C. organisms from a single species are separated by a physical barrier. D. a DNA sequence is changed, resulting in an altered protein product. E. an alteration in an organism's genetic material is made permanent.

B. divergent populations evolve to the point where interbreeding does not produce viable, fertile offspring.

Why is it likely that MOST speciation is allopatric? Because gene flow between populations prevents genetic divergence in sympatry. Because related species are always found in allopatry rather than in sympatry. Because gene flow between diverging populations is strong in allopatry. Because disruptive selection between forms of traits in sympatric populations is always very strong. Because vicariance events are common.

Because gene flow between populations prevents genetic divergence in sympatry.

A neutral mutation is one that: A. increases survival and/or reproduction. B. decreases survival and/or reproduction. C. does not affect survival or reproduction.

C. does not affect survival or reproduction.

Indicate whether genetic drift, if it acted alone, could cause changes in the allele frequency(ies) of a population. Question 2 choices Choice A., Acting alone could change allele frequency. Choice B., Acting alone could not change allele frequency.

Choice A., Acting alone could change allele frequency.

Indicate whether natural selection, if it acted alone, could cause changes in the allele frequency(ies) of a population. Choice A., Acting alone could change allele frequency. Choice B., Acting alone could not change allele frequency.

Choice A., Acting alone could change allele frequency.

Seven species of snapping shrimp are found on either side of the Isthmus of Panama. What data provides good evidence that this is speciation by vicariance? Question 3 choices Choice A., That populations on opposite sides of the Isthmus are reproductively incompatible. Choice B., The DNA of each current species is most similar to that of a species found on the opposite side of the current Isthmus. Choice C., The rate of evolution can be calculated because the populations have been separated for about 3 million years. Choice D., That it takes about 3 million years for accumulation of enough mutations to result in new species of snapping shrimp.

Choice B., The DNA of each current species is most similar to that of a species found on the opposite side of the current Isthmus.

A geologic barrier betwen two populations of one species can contribute to speciation because of: Question 6 choices Choice A., similar environmental conditions in the two locations. Choice B., lack of gene flow between populations. , Choice C., increased mutation rates due to separation.

Choice B., lack of gene flow between populations. ,

Vicariance is defined as: Question 1 choices Choice A., variation in allele frequencies within a population of organisms. Choice B., variation in frequency of mutations among different genes in a population. Choice C., when a geographic barrier arises that isolates two populations. Choice D., migration to a distant, isolated island resulting in isolated populations.

Choice C., when a geographic barrier arises that isolates two populations.

Which phrase best describes how natural selection results in evolution? Question 3 choices Choice A., Weak individuals are eliminated by strong individuals. Choice B., Individuals adapt to their environment by undergoing mutations. Choice C., Individuals with particular traits survive better than individuals with other traits. Choice D., Individuals with particular traits leave behind more offspring than individuals with other traits.

Choice D., Individuals with particular traits leave behind more offspring than individuals with other traits.

Over time, in a population, new mutations of a given gene may: Question 5 choices Choice A., disappear from the population. Choice B., remain at relatively low levels in the population. Choice C., become fixed as the only form of the gene in the population. Choice D., disappear, remain at low levels, or become fixed.

Choice D., disappear, remain at low levels, or become fixed.

In order for the gene pools of two closely related species to remain distinct, there must be: Question 4 choices Choice A., a geographic barrier between them. Choice B., different mutation rates in each species. Choice C., different selection pressures on each species. Choice D., some form of reproductive isolation.

Choice D., some form of reproductive isolation.

In the animation, fish with a larger body size have a ____________ reproductive fitness than fish with a smaller body size because ____________. A. lower; they cannot access as many different environments B. higher; they are less susceptible to additional mutations C. higher; they can swim farther distances D. higher; they are less vulnerable to predators E. lower; they swim more slowly

D. higher; they are less vulnerable to predators

In animals with alleles for a given trait of A and a, if Hardy-Weinberg conditions are met, which one of the following is not a possible genotype frequency? For a hint, click on the check mark next to "Hardy-Weinberg" at the top. Click the x box to turn it off when you're done. A. p2 B. q2 C. 2pq D. p2q2 E. Each of the genotype frequencies provided is a possibility.

D. p2q2

Neutral changes in a physical trait of an organism are most commonly fixed in a population by: A. isolation. B. natural selection. C. predation. D. increasing population size. E. genetic drift.

E. genetic drift.

In general, allopatric species will evolve pre-zygotic isolating mechanisms more rapidly than sympatric species. False True

False

You would expect similar species with a different number of chromosomes to be genetically compatible and therefore able to reproduce. False True

False

When we look at islands across the planet (think the islands of the Galápagos and Hawaii) we see that there are a remarkable number of island endemic species, species that are found nowhere else. What is a possible explanation for this observation? Vicariance events are more common on islands than in mainland environments. Island isolation promotes allopatric speciation. Sympatric speciation on islands is easier than in mainland environments because levels of disruptive selection are higher on islands. Extinction rates are lower in islands so species that have gone extinct elsewhere persist on islands. Sympatric speciation on islands is easier than in mainland environments because rates of chromosomal evolution are higher on islands.

Island isolation promotes allopatric speciation.

_____ is the primary force responsible for changes in allelic frequency of deleterious mutations. _____ is the primary force responsible for changes in allelic frequency of neutral mutations. Natural selection; Genetic drift Genetic drift; Natural selection

Natural selection; Genetic drift

You are an experienced naturalist and biologist and you observe two birds mating that you do not believe to belong to the same species. The eggs from this breeding do not hatch, and when you obtain one of the eggs, you find embryonic development stopped not long after fertilization. Which of the following conclusions is supported by these observations? Post-zygotic factors prevented successful reproduction. Temporal isolation prevented successful reproduction. Behavioral isolation prevented successful reproduction. This is evidence to suggest the two types of birds are a single species. Pre-zygotic isolation prevented successful reproduction.

Post-zygotic factors prevented successful reproduction.

A large population of mice (2000 individuals) lives in an area dominated by small shrubs in the desert. 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 this area is 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 following would MOST account for the amount of genetic differences observed? Divergence between the two populations was caused solely by drift. The divergence between populations could only have been caused by stabilizing selection. Divergence between the two groups is high because of gene flow between them. Since the original dispersal event, the small population will have evolved more than the large population.

Since the original dispersal event, the small population will have evolved more than the large population.

Adaptive radiation is an acceleration of speciation and adaptation when there are a large number of ecological opportunities available. False True

True

Imagine that you had two populations of red-tailed hawks one with long tail feathers, the other with short tail feathers. Mating discrimination in this species could entail either hawks with long tail feathers preferentially mating with other hawks that have long tail feathers, or hawks with short tail feathers preferentially mating with other hawks that have short tail feathers. False True

True

In co-speciation, two groups of organisms speciate in response to each other and in a coordinated manner. True False

True

Speciation can occur in the absence of natural selection; for example, in speciation that results from instances of genetic drift. True False

True

The longer two species have been separated, the greater the number of genetic differences between them. True False

True

Different species of fruit flies occupy each of the islands in the Hawaiian island chain, a group of volcanic islands that formed one after the other. One hypothesis for how the different fruit fly species formed is that, after each new island was formed, fruit flies from existing islands colonized it and subsequently diverged. If this hypothesis is correct, it would be an example of: allopatric speciation by vicariance. peripatric speciation by vicariance. sympatric speciation by vicariance. sympatric speciation by dispersal. allopatric speciation by dispersal.

allopatric speciation by dispersal.

Two species of antelope ground squirrels are separated by the Grand Canyon. They are hypothesized to descend from a common ancestor, populations of which were separated as the canyon formed. If this hypothesis is correct, it would be an example of: allopatric speciation by vicariance. peripatric speciation by vicariance. sympatric speciation by dispersal. allopatric speciation by dispersal. sympatric speciation by vicariance.

allopatric speciation by vicariance.

You are a biologist on a trip to an island in the South Pacific. While on the island, you are allowed to collect DNA samples from a local species of rat that resembles a species seen on a nearby continent. If your DNA analysis also indicates the two species are closely related, you might conclude that the evolution of the two separate species was an example of _____ speciation through _____. sympatric; vicariance sympatric; dispersal allopatric; dispersal allopatric; vicariance

allopatric; dispersal

In general, sympatric speciation requires the action of _____ selection acting against hybrids. ecological disruptive stabilizing artificial directional

disruptive

The reason that lions (which live in Africa) and tigers (which live in Asia) don't produce ligers (infertile offspring of lions and tigers) in the wild is likely the result of: behavioral isolation of tigers and lions. temporal separation of lions and tigers. both temporal and ecological separation of lions and tigers. an incompatible lock-and-key mechanism between the species. ecological separation of lions and tigers.

ecological separation of lions and tigers.

Which of the following species concepts might differentiate species on the basis of specific dietary requirements? evolutionary species ring species ecological species

ecological species

The accumulation of different mutations in genetically separated populations is known as _____ and is the key to speciation. genetic divergence reproductive fitness intersexual selection reinforcement

genetic divergence

New species can form through allopatric or sympatric speciation. Which of the following mechanisms will act more strongly on populations that are initially separated in allopatry than on those initially separated in sympatry? disruptive selection gene flow genetic drift reinforcement

genetic drift

In some large groups of plants, including dandelions, oaks, and willows, the biological species concept is complicated because the process of _____ allows gene flow to occur between good _____ that can be easily distinguished based on appearance. hybridization; ecological species polyploidy; evolutionary species polyploidy; ring species allopatric speciation; ring species hybridization; morphospecies

hybridization; morphospecies

Imagine a scenario in which a common population of animals is separated into two groups by a natural event. Over time, you might expect the two populations to become _____ genetically similar. This process is known as _____ speciation. more; sympatric less; sympatric less; allopatric more; allopatric

less; allopatric

The process by which sympatric speciation might occur would MOST likely be the result of: natural selection. vicariance. convergent evolution. adaptive radiation.

natural selection.

Unlike the biological species concept, the morphospecies concept relies on: phenotype. offspring. behavior. physiology.

phenotype.

In the southwestern desert of the United States there are temporary ponds that form only after heavy summer rains. As a naturalist, you visit these ponds and notice that female frogs mate with males of their own species based only on their calls. The lack of mating between different species would be an example of _____ and _____. pre-zygotic isolation; behavioral isolation pre-zygotic isolation; temporal separation post-zygotic isolation; temporal separation post-zygotic isolation; behavioral isolation

pre-zygotic isolation; behavioral 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? pre-zygotic, temporal separation post-zygotic, ecological separation post-zygotic, temporal separation pre-zygotic, ecological separation pre-zygotic, behavioral isolation

pre-zygotic, temporal separation

or many species, hybridization results in sterile offspring, a process known as reinforcement of isolation. An alternate way of viewing the process of reinforcement is: behavioral isolation. selection for hybrid individuals. ecological isolation. selection against individuals that hybridize.

selection against individuals that hybridize.

All else being equal, selection should more strongly favor reinforcement of reproductive isolation among related species in: peripatric populations over sympatric populations. allopatric populations over peripatric populations. peripatric populations over allopatric populations. sympatric populations over allopatric populations. allopatric populations over sympatric populations.

sympatric populations over allopatric populations.

Sympatric speciation: only occurs in bacteria. occurs whenever a physical barrier between two species is removed (i.e., a river dries up) and the two species start to interbreed. whenever hybrids mate with parental species. can occur instantaneously through formation of polyploid offspring.

can occur instantaneously through formation of polyploid offspring

For many species, hybridization results in sterile offspring, a process known as reinforcement of isolation. An alternate way of viewing the process of reinforcement is: behavioral isolation. selection for hybrid individuals. ecological isolation. selection against individuals that hybridize.

selection against individuals that hybridize.

Neutral mutations can decrease in frequency to a minimum of what percentage of the population? A. 0% B. 5% C. 10% D. 25% E. 50%

A. 0%

Mutations always result in either an increase or a decrease in an organism's reproductive fitness. A. True B. False

B. False

Which of the following factors would be least likely to affect the mutation rate in a population? A. age of the males reproducing in a sexual population B. the presence of mutagens in the environment C. the level of recombination in a population D. generation time of the species

C. the level of recombination in a population

A good example of vicariance is a: Question 2 choices Choice A., change in allele frequencies in two closely related populations that are isolated from each other by a geographic barrier. Choice B., rise in sea level floods a coastal area and breaks it up into several small islands distant from each other

Choice A., change in allele frequencies in two closely related populations that are isolated from each other by a geographic barrier.

Evidence indicates that a number of finches from Ecuador dispersed to the Galapagos Islands more than 300 miles away and ultimately gave rise to the different species of Galapagos finches that exist today. This is good evidence of speciation by vicariance. Question 4 choices Choice A., true Choice B., false

Choice B., false

While in South America, you come across what you think are two groups of birds in the same location. They are nearly identical aside from their color. After years of observation, you conclude that the birds eat similar diets and share similar behaviors but do not reproduce with each other. These groups of birds appear to be an example of: two different species on the basis of the ecological niche occupied. two different species on the basis of reproductive behavior. a single ecological species. a single biological species. ring species.

two different species on the basis of reproductive behavior.

An allele that has acquired a mutation at a particular nucleotide position is just as likely to acquire a subsequent mutation as an allele which has not been previously mutated. A. True B. False

A. True

If the frequency of the blue trait changes randomly in the population from generation to generation, the most likely cause for this is: A. genetic drift. B. natural or artificial selection. C. mutation. D. epigenetic inheritance.

A. genetic drift.

If the environmental conditions change, a neutral mutation can become advantageous or disadvantageous. A. true B. false

A. true

Speciation is said to occur when: (For a hint, reset the map and click on the purple double-headed arrow. Click on the arrows again when you are done.) A. two populations become completely reproductively isolated from one another. B. any two mutations become fixed differences between the populations. C. partial reproductive isolation between two populations is achieved. D. two populations become permanently physically separated from each other.

A. two populations become completely reproductively isolated from one another.

_____ is a special case of explosive speciation in which new species form rapidly in response to numerous "open" ecological niches. Sympatric speciation Adaptive radiation Co-speciation Allopatric speciation Peripatric speciation

Adaptive radiation

Which of the following statements is TRUE regarding hybridization? Hybridization involves the transfer of genetic material between members of similar species. Hybridization can result in fertile offspring. Natural selection sometimes acts against progeny that result from hybridization. All of these choices are correct. Hybridization occurs in plants more often than in animals.

All of these choices are correct.

_____ is the gradual emergence of two or more species as a result of the geographic separation of two or more groups of animals of the same species. Instantaneous speciation Sympatric speciation Adaptive speciation Allopatric Co-speciation

Allopatric