cH.24 GRADE A Q&A
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?
A)The two forms have many genes in common.
B)The two forms are very similar in coloration.
C)The two forms interbreed often in nature, and their offspring have good survival and
reproduction.
D)The two forms have similar food requirements.
E)The two forms live in similar habitats. - (correct answer)The two forms interbreed
often in nature, and their offspring have good survival and reproduction.
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?
A)Favorable mutations are more likely to arise on an archipelago as populations try to
adapt to conditions on their specific island.
B)By chance, different species will colonize different islands in a chain.
C)Populations on nearby islands are more likely to be genetically isolated than
populations that are equally close to one another on the mainland. - (correct
answer)Populations on nearby islands are more likely to be genetically isolated than
populations that are equally close to one another on the mainland.
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.
, A)Yellow-bellied toads and fire-bellied toads are two different species.
B)Hybrids have poor survival and reproduction and thus produce few viable offspring
with members of either parent species.
C)Toads mate only with their own kind in order to avoid producing unhealthy hybrid
young. - (correct answer)Hybrids have poor survival and reproduction and thus produce
few viable offspring with members of either parent species.
Which of the following is the first step in allopatric speciation?
A)polyploidy
B)formation of a reproductive barrier
C)geographic isolation
D)genetic drift
E)hybridization - (correct answer)geographic isolation
Three populations of crickets look very similar, but the males have courtship songs that
sound different. What function would this difference in song likely serve if the
populations came in contact?
A)a temporal reproductive isolating mechanism
B)a gametic reproductive isolating mechanism
C)a postzygotic isolating mechanism
D)a behavioral reproductive isolating mechanism - (correct answer)a behavioral
reproductive isolating mechanism
Many songbirds breed in North America in the spring and summer and then migrate to
Central and South America in the fall. They spend the winter in these warmer areas,
where they feed and prepare for the spring migration north and another breeding
season. Two hypothetical species of sparrow, A and B, overwinter together in mixed
flocks in Costa Rica. In spring, species A goes to the east coast of North America, and
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?
A)The two forms have many genes in common.
B)The two forms are very similar in coloration.
C)The two forms interbreed often in nature, and their offspring have good survival and
reproduction.
D)The two forms have similar food requirements.
E)The two forms live in similar habitats. - (correct answer)The two forms interbreed
often in nature, and their offspring have good survival and reproduction.
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?
A)Favorable mutations are more likely to arise on an archipelago as populations try to
adapt to conditions on their specific island.
B)By chance, different species will colonize different islands in a chain.
C)Populations on nearby islands are more likely to be genetically isolated than
populations that are equally close to one another on the mainland. - (correct
answer)Populations on nearby islands are more likely to be genetically isolated than
populations that are equally close to one another on the mainland.
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.
, A)Yellow-bellied toads and fire-bellied toads are two different species.
B)Hybrids have poor survival and reproduction and thus produce few viable offspring
with members of either parent species.
C)Toads mate only with their own kind in order to avoid producing unhealthy hybrid
young. - (correct answer)Hybrids have poor survival and reproduction and thus produce
few viable offspring with members of either parent species.
Which of the following is the first step in allopatric speciation?
A)polyploidy
B)formation of a reproductive barrier
C)geographic isolation
D)genetic drift
E)hybridization - (correct answer)geographic isolation
Three populations of crickets look very similar, but the males have courtship songs that
sound different. What function would this difference in song likely serve if the
populations came in contact?
A)a temporal reproductive isolating mechanism
B)a gametic reproductive isolating mechanism
C)a postzygotic isolating mechanism
D)a behavioral reproductive isolating mechanism - (correct answer)a behavioral
reproductive isolating mechanism
Many songbirds breed in North America in the spring and summer and then migrate to
Central and South America in the fall. They spend the winter in these warmer areas,
where they feed and prepare for the spring migration north and another breeding
season. Two hypothetical species of sparrow, A and B, overwinter together in mixed
flocks in Costa Rica. In spring, species A goes to the east coast of North America, and
