Biology Chapter 24 practice

Rank the following in order from most general to most specific. 1. gametic isolation 2. reproductive isolating mechanism 3. sperm-egg incompatibility in sea urchins 4. prezygotic isolating mechanism

2, 4, 1, 3

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 ________.

28

Which of these habitats is likely to harbor the most recently diverged species?

A1

The Panama Canal was completed in 1914, and its depth is about 50 feet. After 1914, snapping shrimp species from which habitats should be most likely to form hybrids as the result of the canal?

A1 and B1

In which habitat should one find snapping shrimp most closely related to shrimp that live in habitat A4?

B4

Which statement describes unity within a species?

Members have the potential to interbreed in nature and produce viable, fertile offspring.

The common edible frog of Europe is a hybrid between two species, Rana lessonae and Rana ridibunda. The hybrids were first described in 1758 and have a wide distribution, from France across central Europe to Russia. Both male and female hybrids exist, but when they mate among themselves, they are rarely successful in producing offspring. What can you infer from this information?

Postzygotic isolation exists between the two frog species.

Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

They have been geographically isolated from each other for a longer time.

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 behavioral reproductive isolating mechanism

The largest unit within which gene flow can readily occur is ________.

a species

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 ________.

allopatric speciation

How are two different species most likely to evolve from one ancestral species?

allopatrically, after the ancestral species has split into two populations

Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?

biological

Macroevolution is ________.

evolution above the species level

Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by ________.

gametic isolation

What does the biological species concept use as the primary criterion for determining species boundaries?

gene flow

If the isthmus formed gradually rather than suddenly, what pattern of genetic divergence would you expect to find in these species pairs?

greater percentage of difference in DNA sequence between species that inhabit deep water than between species that inhabit shallow water

Use the following information to answer the question. Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees. What keeps the two populations separate?

habitat isolation

You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?

morphological

The production of sterile mules by interbreeding between female horses (mares) and male donkeys (jacks) is an example of ________.

reduced hybrid fertility

Two species of frogs belonging to the same genus occasionally mate, but the embryos stop developing after a day and then die. These two frog species separate by ________.

reduced hybrid viability

If biological species are defined in terms of reproductive compatibility, the formation of a new species hinges on ________.

reproductive isolation

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of ________.

sympatric speciation and habitat isolation

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven it?

sympatric speciation; habitat differentiation

Which of the following statements describes a prezygotic mechanical isolation barrier?

two snails have shells that spiral in different directions