biol5c final (everything else :'))

What happens to the hybrid zone when gene flow is established? A) A population merges with another population. B) Hybrids cease to be formed. C) weakening of reproductive barriers D) continued production of hybrids

B

How do hybrid zones slow reproductive isolation? A) species with incomplete mating barriers B) decreased embryonic mortality C) increased gene flow D) morphologic abnormalities

A

How can reproductive barriers form sympatric populations while their members remain in the same geographic area? A) increased gene flow B) polyploidy C) decreased sexual selection D) habitat sharing

B

If biological species are defined in terms of reproductive compatibility, the formation of a new species hinges on ________. A) gene flow B) reproductive isolation C) hybrid formation D) gene pool expansion

B

Reinforcement is most likely to occur when ________. A) the environment is changing B) hybrids have lower fitness than either parent population C) prezygotic isolating mechanisms are in place D) gene flow is low

B

A small number of birds arrive on an island from a neighboring larger island. This small population begins to adapt to the new food plants available on the island, and their beaks begin to change. About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ________. A) speed up the process of speciation B) tend to promote adaptation to the new food plants C) tend to slow adaptation to the new food plants D) represent a colonizing event response

C

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ________. A) prezygotic isolation B) reinforcement C) allopatric speciation D) sympatric speciation

C

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 species B goes to the west coast. What can you say about the isolating mechanisms of these two species? A) They must have strong postzygotic isolating mechanisms to spend winter in such close proximity. B) They must have strong prezygotic isolating mechanisms to spend winter in such close proximity. C) These two species mate in different climates. D) Reinforcement must be occurring when they winter together.

C

Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools? A) genetic B) ecological C) biological D) morphological

C

According to the biological species concept, for speciation to occur, ________. A) the number of chromosomes in the gene pool must change B) changes to centromere location or chromosome size must occur C) large numbers of genes that affect numerous phenotypic traits must change D) at least one gene, affecting one reproductive barrier, must change

D

Among known plant species, which of these have been the two most commonly occurring phenomena that have led to the origin of new species A) allopatric speciation and sexual selection B) allopatric speciation and polyploidy C) sympatric speciation and sexual selection D) sympatric speciation and polyploidy

D

How are two different species most likely to evolve from one ancestral species? A) sympatrically, by a point mutation affecting morphology or behavior B) sympatrically, due to extensive inbreeding C) allopatrically, due to extensive inbreeding D) allopatrically, after the ancestral species has split into two populations

D

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. Assuming events like this are very rare, which of the following scenarios is least likely? A) Migrant pied males would produce fewer offspring than would resident pied males. B) Pied females would rarely mate with collared males. C) Migrant males would mate with collared females more often than with pied females. D) The frequency of hybrid offspring would decrease.

D

There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept describing species relationship between modern humans and Neanderthals is most applicable in these observations? A) genetic B) ecological C) morphological D) biological

D

Which of the following describes the most likely order of events in allopatric speciation? A) genetic drift, genetic isolation, divergence B) genetic isolation, divergence, genetic drift C) divergence, genetic drift, genetic isolation D) genetic isolation, genetic drift, divergence

D

Which of these animals could overcome the geographic barrier of water that causes allopatric speciation? A) birds B) pollen C) small rodents D) mountain lions

D

You want to study divergence of populations, and you need to maximize the rate of divergence to see results within the period of your grant funding. You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed. What combination of characteristics would maximize your chance of seeing divergence in this study? 1. Choose a random sample of individuals to form the new population. 2. Choose individuals from one extreme to form the new population. 3. Choose a species to study that produces many offspring. 4. Choose a species to study that produces a few, large offspring. 5. Place the new population in the same type of environment as the source population. 6.7Place the new population in a novel environment compared to that of the source population. A) 1, 3, and 6 B) 1, 4, and 6 C) 2, 3, and 5 D) 2, 3, and 6

D