Bio chap 14

Microevolution is _____.

1. changes in the gene pool of a population from one generation to the next
2.dramatic changes that take place over long periods of time
3.speciation
4.evolution on a molecular level

1

Speciation, or the formation of new species, is

1. necessary for natural selection and adaptation.
2. an event that has occurred only a few times in the history of the planet.
3. responsible for the diversity of life.
4. a form of microevolution.

3

When a horse and a donkey mate, they produce infertile hybrids called mules. According to the _____ species concept, horses and donkeys are _____.

1 biological … different species
2 biological … the same species
3 ecological … different species
4 ecological … the same species

1

Under the biological species concept, a species is a group of organisms that

1 have the potential to interbreed in nature and produce fertile offspring.
2 share a recent common ancestor.
3 are physically similar.
4 live together in a location and carry out identical ecological roles.

1

Which of the following types of reproductive barriers separates a pair of species that could interbreed except that one mates at dusk and the other at dawn?

1 mechanical isolation
2 temporal isolation
3 behavioral isolation
4 habitat isolation

2

Which of the following types of reproductive barriers separates a pair of moth species that could interbreed except that the females’ mating pheromones are not attractive to the males of the other species?

1 behavioral isolation
2 mechanical isolation
3 gametic isolation
4 temporal isolation

1

Which of the following types of reproductive barriers separates two species of sea cucumbers, whose sperm and eggs often bump into each other but do not cross-fertilize because of incompatible proteins on their surfaces?

1 habitat isolation
2 gametic isolation
3 mechanical isolation
4 temporal isolation

2

Frequently, a group of related species will each have a unique courtship ritual that must be performed correctly for both partners to be willing to mate. Such a ritual constitutes a ________, ________ reproductive barrier.

1 mechanical . . . postzygotic
2 behavioral . . . prezygotic
3 temporal . . . prezygotic
4 gametic . . . postzygotic

2

The geographic isolation of a population from other members of the species and the subsequent evolution of reproductive barriers between it and the parent species describes ________ speciation.

1 punctuated
2 sympatric
3 biogeographic
4 allopatric

4

In which of the following situations would speciation be most likely to occur?

1 Bighorn sheep occupy mountains from Canada through Death Valley in Southern California, interbreeding all the way. The populations at the two ends of the range live in very different environments.
2 Seven monkeys escape from an amusement park and zoo in South Florida. To everyone’s surprise, they establish a small but viable population, coexisting successfully with humans in a partly suburban environment very different from their native African habitat.
3 A population of juniper shrubs is split in two by a canyon. Every year, strong winds carry a small amount of the shrub’s pollen across the canyon.
4 A Japanese mollusk species whose larvae are often carried from port to port in ship bilge water now flourishes in San Francisco Bay, a busy commercial port.

2

Which type of organism is most likely to undergo sympatric speciation by polyploidy?

1 animal species with poor dispersal abilities whose populations exist in widely separated, small patches of habitat
2 plant species that are incapable of asexual reproduction and do not self-pollinate
3 plant species that are capable of self-pollination and some degree of asexual reproduction
4 animals, particularly those with highly selective females that select mates based on exaggerated traits

3

The emergence of many diverse species from a common ancestor is called

1 allopatric speciation.
2 gradualism.
3 hybridization.
4 adaptive radiation.

4

The ________ suggests that speciation occurs in brief spurts.

1 allopatric speciation model
2 punctuated equilibrium model
3 adaptive model of the origin of species
4 gradual model of the origin of species

2

The emergence of a new plant species over a brief period of time, followed by a long period of little change, is consistent with which of the following theories?

1 allopatric speciation
2 the gradual model of speciation
3 punctuated equilibrium
4 adaptive radiation

3

Each biological species is genetically isolated from other species. Why do the species evolve independently?

1 The species evolve independently because they live in different geographic areas.
2 The two species evolve independently because they do not exchange genes. Reproductive barriers keep them from successfully interbreeding.
3 The species evolve separately because they look different and have different morphologies.
4 The species evolve independently because they are free to interbreed and produce fertile hybrid offspring.

2

Which is a postzygotic reproductive barrier?

1 Two species of leopard frogs have different mating calls and do not mate with each other.
2 The hybrid offspring of two species of jimsonweeds always die before reproducing.
3 Mallard and pintail ducks mate at different times of the year.
4 One shrub lives on acid soil near bogs; another closely related species grows in basic soil on limestone cliffs. As a consequence, pollen is not carried between the two species.

2

Which of the following is an example of a postzygotic reproductive barrier?

1 One species of frog mates in April; another mates in May.
2 Two fruit flies of different species produce viable but sterile offspring.
3 The sperm of a marine worm penetrate eggs of the same species only.
4 One species of flower grows in forested areas, another in meadows.

2

What is the major evidence for the punctuated equilibrium model of evolution?

1 Big changes could never occur by a steady accumulation of smaller ones.
2 Transitional fossils are increasingly common as paleontologists continue to unearth new fossils.
3 Many fossil species appear suddenly in the fossil record, persist unchanged for long periods, and then disappear without transitional forms.
4 Populations do not adapt to the environment gradually.

3

What is the first step in allopatric speciation?

1 formation of a reproductive barrier
2 polyploidy
3 genetic drift
4 geographic isolation

4

The following options are all reproductive barriers. Which one is an example of a prezygotic barrier in which the two different species do mate?

1 Two crayfish species cannot interbreed because their genitalia do not engage properly with each other.
2 Hybrid mules produced by mating donkeys and horses are sterile.
3 One bird species lives in wetlands, the other in dry forests; hence, they do not encounter each other.
4 Two dragonfly species regularly mate, but their gametes are incompatible.

4