Exam 24: The Origin of Species

Polyploidy can be best described as

In a hypothetical situation, the National Park Service, which administers Grand Canyon National Park in Arizona, builds a footbridge over the Colorado River at the bottom of the canyon. The footbridge permits interspersal of two closely related antelope squirrels. Previously, one type of squirrel had been restricted to the terrain south of the river, and the other type had been restricted to terrain on the north side of the river. Immediately before and ten years after the bridge's completion, researchers collected ten antelope squirrels from both sides of the river, took blood samples, and collected frequencies of alleles unique to the two types of antelope squirrels (see the following graphs). -The data in the previous graphs indicate that

Which of the following factors would not contribute to allopatric speciation?

The next few questions refer to the following description. 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 320 kilometres 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

Theoretically, the production of sterile mules by interbreeding between female horses (mares)and male donkeys (jacks)should

Rocky Mountain juniper (Juniperus scopulorum)and one-seeded juniper (J. monosperma)have overlapping ranges. If 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, then which of these terms are applicable? 1. sympatric species 2. prezygotic isolation 3. postzygotic isolation 4. allopatric species 5. habitat isolation 6. reduced hybrid fertility

Which of the following statements about species, as defined by the biological species concept, is (are)correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. The biological species is the largest unit of population in which successful interbreeding is possible.

Speciation

The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is

The next few questions refer to the following description. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. -Which two of the following have operated to increase divergence between mosquitofish populations on Andros? 1. improved gene flow 2. bottleneck effect 3. sexual selection 4. founder effect 5. natural selection

The next few questions refer to the following evolutionary tree, whose horizontal axis represents time (present time is on the far right) and whose vertical axis represents morphological change. -Which species is most closely related to species W?

The next few questions refer to the following description. On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences. -If one builds a canal linking a predator-rich pond to a predator-poor pond, then what type(s)of selection should subsequently be most expected among the mosquitofish in the original predator-rich pond, and what type(s)should be most expected among the mosquitofish in the formerly predator-poor pond?

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?

The difference between geographic isolation and habitat differentiation is the

A hybrid zone is properly defined as

The next few questions refer to the following description. 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 320 kilometres 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. -If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, these conditions will most likely lead to

There are currently two large, permanent bridges that span the Panama Canal. The bridges are about 13 kilometres apart. If snapping shrimp avoid swimming at night and avoid swimming under shadows, then what do these bridges represent for the snapping shrimp?

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

The next few questions refer to the following description. In the ocean, 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. In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The sea water on either side of the isthmus is separated into five depth habitats (1-5), with 1 being the shallowest. -Which habitats should harbour snapping shrimp species with the greatest degree of genetic divergence from each other?

Rocky Mountain juniper (Juniperus scopulorum)and one-seeded juniper (J. monosperma)have overlapping ranges. If 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, then which of these terms is applicable?