Exam 24: The Origin of Species

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?

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

Other than predation by introduced Nile perch, the most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is ________.

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

Use the following description to answer the question. In the oceans on either side of the Isthmus of Panama are 30 species of snapping shrimp; some are shallow-water species, others are adapted to deep water. There are 15 species on the Pacific side and 15 different species on the Atlantic side. The Isthmus of Panama started rising about 10 million years ago. The oceans were completely separated by the isthmus about 3 million years ago. In the figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1-5), with 1 being the shallowest. Which of these habitats is likely to harbor the most recently diverged species?

How do hybrid zones slow reproductive isolation?

Which of the following statements describes mechanical isolation prezygotic barrier?

According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that ________.

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 ________.

What happens to the hybrid zone when gene flow is established?

Plant species A has a diploid chromosome 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

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

Use the following description to answer the question. On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands and is also found on the African mainland, located about two hundred miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago. The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea ________.

Speciation ________.

Use the following description to answer the question. On the volcanic, equatorial West African island of Sao Tomé, two species of fruit fly exist. Drosophila yakuba inhabits the island's lowlands and is also found on the African mainland, located about two hundred miles away. At higher elevations, and only on Sao Tomé, is found the very closely related Drosophila santomea. The two species can hybridize, though male hybrids are sterile. A hybrid zone exists at middle elevations, though hybrids there are greatly outnumbered by D. santomea. Studies of the two species' nuclear genomes reveal that D. yakuba on the island is more closely related to mainland D. yakuba than to D. santomea (2n = 4 in both species). Sao Tomé rose from the Atlantic Ocean about 14 million years ago. Using only the information provided in the paragraph, which of the following is the best initial hypothesis for how D. santomea descended from D. yakuba?

Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification?

Which postzygotic barriers prevent formation of hybrids beyond the first generations?

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?

Which statement describes unity within a species?

Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. These rituals involve fighting other males and making stylized movements that attract females. What type of reproductive isolation does this represent?