The _____ species concept is the most applicable to classifying species from the fossil record.
Two species of clams inhabit the same marine habitat along the Atlantic coast. One releases gametes into the water in early spring, and the second species releases gametes into the water in late summer. Which type of reproductive barrier is at work between these species?
Two rodent populations become separated when a large canyon develops in a previously unbroken forest. When is allopatric speciation between the two populations complete?
When the two populations evolve to be different enough that they are incapable of interbreeding successfully when given the opportunity to do so under natural conditions, allopatric speciation is complete.
Which population would be most likely to undergo relatively rapid allopatric speciation?
A group of wild horses is transported from Wyoming to a small desert island, previously without horses, off the coast of California. No additional horses reach the island thereafter.
Which of the following statements about reproductive barriers and speciation is true?
Speciation can occur with even a single gene mutation if that mutation involves reproductive barriers.
Which type of organism is most likely to undergo sympatric speciation by polyploidy?
plant species that are capable of self-pollination and some degree of asexual reproduction
How is modern bread wheat related to wheat found in mideastern farms 10,000 years ago?
Modern bread wheat is the product of several instances of hybridization of wheat species including wheat found in mideastern farms 10,000 years ago. Development of modern wheat also involved errors in cell division and self fertilization.
The two species of finches studied by the Grants on Daphne Major are known to hybridize. What is their status?
They hybridize occasionally when the behavioral barrier separating the species fails. The fitness of hybrids fluctuates depending on the weather: Some succeed, but most do not. The result over the long term is a stable hybrid zone.
When populations of closely related pied flycatchers and collared flycatchers live in different geographic areas, the males of both species look a lot alike. However, when populations of the two species share a common geographic area, there are significant differences in the appearance of the two species. What conclusions might you draw from this situation?
This is a case where hybrid offspring of the two species are less fit than either of the parent species. In the geographic areas where the populations overlap, natural selection has reinforced color differences that serve as reproductive barriers between the two species.