Exam 17: The Origin of Species

Eastern and Western meadowlarks look almost identical and sometimes inhabit the same areas of prairies. These birds recognize members of their own species by distinctive songs and thus do not breed with each other. This is an example of

Store- bought hybrid tomatoes are very popular with consumers. Suppose you buy a tomato from the grocery store, collect seeds from it, and plant the seeds. If the seeds do not germinate, the seedlings fail to thrive, or the plants die quickly after sprouting, what reproductive isolating mechanism might be responsible?

How do premating isolation mechanisms differ from postmating isolation mechanisms?

A European species of marsh grass called Spartina maritima has a diploid number (2n) of 60. A similar species native to North America, S. alterniflora, has 2n = 62. In 1835, the North American species was found growing near the European species in Southampton, England, after being accidentally imported. Occasional sterile hybrids were noted. In 1895 a new species, S. anglica, was first identified at Southampton and subsequently became common. The new species has been identified as a fertile hybrid of the original two species. What is the 2n chromosome number of the hybrids that formed from the original two species S. maritima and S. alterniflora?

Researchers believe that at least % of the species that have lived on Earth have become extinct.

If a hybrid is unable to produce sperm because meiosis does not proceed correctly, gene flow between the species is restricted by

One species of fish feeds in the muddy bottom of a lake. A second species eats insects that land on the water surface. This is an example of

The biological species concept is based on the idea that individuals in one group are be unable to breed with individuals outside their group. This phenomenon is referred to as .

Female blue- footed boobies of the Galápagos Islands will mate only after a specific courtship display on the part of the male. The male high- steps to advertise his bright blue feet. What mechanism describes why the females do not mate with other species of boobies?

From an evolutionary perspective, explain how three species of large, flightless birds (ostriches, rheas, and emus) came to occupy the widely separated landmasses of Africa, South America, and Australia.

Where would a researcher most likely find examples of allopatric speciation?

Hybrid inviability is an example of a(n) _ isolating mechanism.

Strong courtship displays like the one in the figure below can lead to

The immediate cause of most extinctions is

The elaborate courtship rituals of many bird species help to preserve their genetic isolation through

The origins of 300 or more species of cichlid fish in Lake Malawi can best be explained by

Explain why naming and describing species based only on their appearance can be problematic.

Before the modern era of science, organisms were assigned to species on the basis of

The organisms most likely to undergo sympatric speciation by polyploidy are

When two organisms reach sexual maturity at different times, it is an example of