Bio - Ch. 24

Feathers either play a role, or may have played a role, in _____. flight courtship gliding extended hops all of these

_____ is rapid speciation under conditions in which there is little competition. Microevolution Gene flow Paedomorphosis Adaptive radiation Genetic drift

Mass extinctions create conditions that promote _____. paedomorphosis genetic drift adaptive radiation microevolution gene flow

The appearance of an evolutionary novelty promotes _____. adaptive radiation gene flow mutation mass extinction paedomorphosis

The different finch species found on the Galápagos Islands probably arose as a result of _____. artificial selection paedomorphosis mass extinction gene flow adaptive radiation

Part A What is genetic drift? The physical splitting of a habitat The motion of continental plates over time A change in allele frequencies caused by random events The production of an evolutionarily independent group of organisms

Why are the large finches now living on the Galápagos Islands different from the original source population from a nearby island? Genetic drift occurred in the two populations. Natural selection favored individuals that were more fit in the new environment. The separation of habitats reduced gene flow between the populations. All three answers are correct.

True or false? The last ice age produced many different species mainly because populations dispersed and colonized new habitats. True False

Which of the following statements about reinforcement is true? Reinforcement is a type of natural selection. Reinforcement increases the number of intermediate phenotypes. Reinforcement decreases the morphological difference between two incipient species. Reinforcement is also called dispersive selection.

A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. The birds, after a period of time, become reproductively isolated. The island sinks and the population of birds that lived on the island returns to its original habitat. Which of the following statements about these bird populations is true? The populations were sympatric while they diverged. The populations will not be able to interbreed because they are different species. The birds were separated by a vicariance event. The populations will be able to interbreed even though they are different species.

A population of birds colonizes an area in which the insects upon which they feed live inside trees. Which of the following events accounts for an observed increase in average beak size in the bird population over time? Decreased fitness of the insects, allowing the birds to catch them more easily Decreased fitness of small-beaked birds, creating a new species Increased fitness of large-beaked birds, leading to natural selection Increased fitness of the large-beaked birds, creating a new species

True or false? A flood that separates a population of frogs onto opposite sides of a lake is an example of a vicariance event that may result in allopatric speciation. True False

Of the 59 matings in the experimental groups, how many were between like-adapted flies (flies adapted to the same medium)? 17 22 30 42

Which of the following statements is best supported by the data on matings in the experimental groups? There is no evidence of reproductive isolation between the starch-adapted flies and maltose-adapted flies. The starch-adapted flies and maltose-adapted flies appear to now be separate species as defined by the biological species concept. The starch-adapted flies and maltose-adapted flies are not different species, but a reproductive barrier is forming between the populations.

Which of the following statements is supported by the data from the control group matings? Flies were about as likely to mate with flies from different starch-adapted populations as with flies from their own starch-adapted population. Female starch flies from population #2 were more likely to mate with male flies from their own population than with flies from a different starch population. Male starch-adapted flies were less likely to mate with female starch-adapted flies than with female maltose-adapted flies.

A similar control experiment was performed with flies adapted to maltose, and similar results were obtained. What were these control experiments testing? These control experiments tested whether in the process of becoming adapted to different food sources, the flies had lost the ability to reproduce. These control experiments tested whether the starch-adapted flies had a greater preference for like-adapted flies than did the maltose-adapted flies. These control experiments tested whether flies were more likely to choose mates from their own population than from another population adapted to the same medium.

In Europe, there is a long narrow hybrid zone, shown in red on the map, between the high-altitude habitat of the yellow-bellied toad and the lowland habitat of the fire-bellied toad. Despite this, there is little gene flow between the two species. Select the correct explanation. Yellow-bellied toads and fire-bellied toads are two different species. Hybrids have poor survival and reproduction and thus produce few viable offspring with members of either parent species. Toads mate only with their own kind in order to avoid producing unhealthy hybrid young.

The original habitat of the North American maggot fly, Rhagoletis pomonella, was native hawthorn trees. About 200 years ago, some populations colonized newly introduced apple trees. The two populations are still classified as subspecies, but sympatric speciation is under way. What has contributed to incipient speciation in the maggot fly? Because apples mature more quickly than hawthorn fruit, the apple-feeding flies have been selected for more rapid development. Apple maggot flies try to avoid mating with hawthorn maggot flies. Maggot flies that feed and lay eggs on apples have gradually become adapted to this fruit.

Adaptive radiations on archipelagos (island chains) represent some of the best-understood speciation events. Why is an ancestral species more likely to give rise to multiple descendent species on an archipelago than on an equal-sized area of mainland? Populations on nearby islands are more likely to be genetically isolated than populations that are equally close to one another on the mainland. Favorable mutations are more likely to arise on an archipelago as populations try to adapt to conditions on their specific island. By chance, different species will colonize different islands in a chain.

Select the correct statement describing sympatric speciation. Sympatric speciation can occur in a single generation. Sympatric speciation is always initiated by geographic isolation of two populations. Sympatric speciation has never been observed in nature.

How long does it take new species to form on Earth? millions of years Speciation no longer takes place on Earth. The time required varies considerably.

Suppose that a group of male pied flycatchers migrated from a region where there were no collared flycatchers to a region where both species were present (see Figure 24.15 in your textbook). Assuming events like this are very rare, which of the following scenarios is least likely? Pied females would rarely mate with collared males. Migrant males would mate with collared females more often than with pied females. The frequency of hybrid offspring would decrease. The frequency of hybrid offspring would increase. Migrant pied males would produce fewer offspring than would resident pied males.

Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be 56. 12. 14. 28. 16.

Which of the following factors would not contribute to allopatric speciation? Gene flow between the two populations is extensive. The separated population is small, and genetic drift occurs. The isolated population is exposed to different selection pressures than the ancestral population. Different mutations begin to distinguish the gene pools of the separated populations. A population becomes geographically isolated from the parent population.

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification? The two forms are very similar in coloration. The two forms live in similar habitats. The two forms have similar food requirements. The two forms interbreed often in nature, and their offspring have good survival and reproduction. The two forms have many genes in common.

According to the punctuated equilibria model, given enough time, most existing species will branch gradually into new species. most evolution occurs in sympatric populations. most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. natural selection is unimportant as a mechanism of evolution. speciation is usually due to a single mutation.

Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent? gametic isolation habitat isolation temporal isolation behavioral isolation postzygotic barriers

The largest unit within which gene flow can readily occur is a hybrid. phylum. genus. population. species.

Which of these five species is the extant (i.e., not extinct) species that is most closely related to species X, and why is this so? Y; arose in the same fashion (i.e., at the same tempo) as X V; shared a common ancestor with X most recently W; shared a common ancestor with X most recently Z; shared a common ancestor with X most recently, and arose in the same fashion as X This tree does not provide enough information to answer this question.

Which species is most closely related to species W? X is most closely related to species W. Y and Z are equally closely related to W. V is most closely related to species W. It is not possible to say from this tree.

According to the _____ model, evolution occurs in spurts; species evolve relatively rapidly then remain unchanged for long periods. adaptive radiation nondisjunction punctuated equilibrium geographic isolation gradualist

Which of these is an example of temporal isolation? One species is found only in New York, the other only in London. The average weight of the individuals in one species is 45 kg; in the other species the average is 290 kg. One species performs a specific courtship dance. the other species does not. One species is nocturnal, and the other species is not. One is a type of primate, the other is a type of marsupial.

Sympatric speciation is _____. the emergence of many species from a single ancestor the process by which most animal species have evolved initiated by the appearance of a geographic barrier the appearance of a new species in the same area as the parent population especially important in the evolution of island species

Which of the following is the first step in allopatric speciation? geographic isolation hybridization polyploidy genetic drift formation of a reproductive barrier

Two animals are considered members of different species if they _____. cannot mate and produce viable, fertile offspring look different live in different habitats are members of different populations are geographically isolated

What is the most important factor that holds a gene pool of a species together and prevents speciation? sexual selection gene flow behavioral isolation hybridization prezygotic barriers