Exam 23: Species and Their Formation

Ginkgo trees (Ginkgo biloba) are "living fossils." Although ginkgos are native to China, they are now commonly planted in cities in the United States. Keeping in mind the principles of allopatric speciation, what might happen over time to the two populations of ginkgos?

A common means of sympatric speciation is

Which of the following species concepts would have great difficulty with the classification of cryptic species?

Suppose that members of two populations are separated by a geographic barrier and begin to diverge genetically. Many generations later, when the barrier is removed, the two populations can interbreed, but the hybrid offspring do not survive and reproduce well. Explain how natural selection might lead to the evolution of more effective prezygotic barriers in these species.

The sperm of one species of sea urchin is chemically incompatible with the eggs of a closely related species. This type of reproductive isolating barrier is called

Geographic isolation

Which of the following statements about Darwin's finches is true?

Linnaeus

Darwin's finches on the Galápagos Islands

It is difficult to apply the biological species concept to groups of organisms that

Narrow hybrid zones may persist for long times because

The _______ species concept holds that "species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups."

Which of the following observations would constitute conclusive evidence that two overlapping populations that had been geographically separated have not diverged into distinct species?

Carolus Linnaeus

Which of the following is often associated with higher rates of speciation?

Which of the following statements about allopatric speciation is false?

The _______ model explains the evolution of reproductive isolation as a consequence of interactions of alleles at different genetic loci.

Speciation rates in plants are _______ in animal-pollinated plants than in wind-pollinated plants.

Discuss the conditions on the Galápagos Islands that led to the evolution of the birds known as Darwin's finches.

The yellow-rumped warbler was formerly split into two species (myrtle and Audubon's warblers), but in 1973 it was reclassified as a single species. "Myrtle" and "Audubon's" warblers have largely allopatric ranges but hybridize where they are sympatric in the Canadian Rockies. They are similar in appearance but are readily distinguished by experienced birders. What further data about these two forms should ornithologists collect and analyze in order to decide whether they should continue to be classified as a single species?