Exam 22: The Origin of Species

In the ocean,on either side of the Isthmus of Panama,are 30 species of snapping shrimp;some are shallow-water species,and 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.Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

In a hypothetical situation,a certain species of flea feeds only on the blood of pronghorn antelopes.In rangelands of the western United States,pronghorns and cattle often associate with one another.If some of these pronghorn-feeding fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood,then over time which of these should occur,if the host mammal can be considered as the fleas' habitat? 1)reproductive isolation 2)sympatric speciation 3)habitat isolation 4)prezygotic barriers

If a speciation event occurred on Sao Tomé,producing D.santomea from a parent colony of D.yakuba,then which of the following terms applies (apply)? I.macroevolution II allopatric speciation III.sympatric speciation

Two species of frogs belonging to the same genus occasionally mate,but the offspring fail to develop and hatch.What is the mechanism for keeping the two frog species separate?

Sexual selection in cichlids occurs by female mate choice and results in reproductive isolation when

Please use the following information to answer the questions below. In the ocean,on either side of the Isthmus of Panama,are 30 species of snapping shrimp;some are shallow-water species,and 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 Figure 22.1,the isthmus separates the Pacific Ocean on the left (side from the Atlantic Ocean on the right (side B).The seawater on either side of the isthmus is separated into five depth habitats (15),with 1 being the shallowest. Figure 22.1 -In which habitat should you find snapping shrimp most closely related to shrimp that live in habitat A4?

Among known plant species,which of these are the two most commonly occurring phenomena that have led to the origin of new species? 1)allopatric speciation 2)sympatric speciation 3)sexual selection 4)polyploidy

You find a plant that is larger than others in your wheat field.When you examine the chromosomes of this plant during cell division,you observe that the cells have double chromosome numbers of the other wheat plants.You conclude this is an autopolyploid plant representing a new biological species in your wheat field when you observe

What is the best way to promote fusion between two related populations of mosquitofish,one of which lives in a predator-rich pond,and the other of which lives in a predator-poor pond?

"Conventional wisdom holds that the development of separate species happens quickly,most often when populations become separated by a geographical barrier." This is called ________ speciation."Even if these groups meet again and manage to mate before diverging too far from one another,their offspring will be unfit and die out." This is described as hybrid ________.

According to the punctuated equilibria model,

There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans or into a separate species of their own.Most DNA sequence data analyzed so far indicate that there was interbreeding between Neanderthals and humans;however,it appears to have been limited and mostly unidirectional (Neanderthal genes are present in Homo sapiens DNA,but there exists little to no evidence of the DNA of Homo sapiens in the small number of genomes sequenced from Neanderthal fossils.Which species concept is most applicable as a method of analysis in this example?

Which factor is most important for explaining why there are equal numbers of snapping shrimp species on either side of the isthmus?

Please use the following information to answer the questions below. 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 200 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. -Which of the following reduces gene flow between the gene pools of the two species on Sao Tomé,despite the existence of hybrids?

More species tend to be found in regions subdivided by rivers,canyons,mountains,or other human-induced barriers because of

Microevolution occurs

The predatory fish rely on visual cues and speed to capture mosquitofish.Mosquitofish rely on speed and visual cues to avoid the predatory fish.Which adaptation(s)might help the predators survive in ponds that are home to faster mosquitofish? 1)directional selection for increased speed 2)stabilizing selection for speed that matches that of the mosquitofish 3)change in hunting behavior that replaces reliance on visual cues with reliance on tactile cues 4)change in hunting behavior that eliminates speed in favor of better camouflage,which permits an ambush strategy

The mechanism of macroevolution occurs by

When the only evidence available for two extinct species is their fossil record,evaluation of reproductive isolation and the biological species concept is not useful.However,the phylogenetic species concept could potentially differentiate the species by using evolutionary history to describe

How can reproductive barriers form between sympatric populations while their members stay in contact with them?