The punctuated equilibrium model of evolution suggests that new species appear

A. gradually over very short periods of time so that intermediate species are often observed in the fossil record.
B. gradually; as groups become isolated, they slowly evolve through their own individual pathways.
C. gradually after long periods of time with little to no change; as groups become isolated, they slowly evolve through their own individual pathways.
D. suddenly after long periods of time with little to no change.
E. only after older species disappear from the fossil record.


Ans: D. suddenly after long periods of time with little to no change.

Biology & Microbiology

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Biology & Microbiology

The Hadley effect is

A. why water in a toilet bowl spins counter clockwise. B. an explanation for climate patterns that links solar radiation and the spin of the Earth. C. one of the reasons for the extinction of the Panamanian golden frog. D. why water in a toilet bowl spins counter clockwise and an explanation for climate patterns that links solar radiation and the spin of the Earth. E. Only important in southern hemisphere forests on the western sides of mountains.

Biology & Microbiology

Studies of snapping shrimp on either side of the Isthmus of Panama have shown that each Caribbean shrimp species is more closely related to a Pacific shrimp species than it is to any other Caribbean shrimp species. The most likely explanation for this result is

A. snapping shrimp species in each ocean diverged prior to the formation of the Isthmus of Panama. B. creation of the Panama Canal allowed interbreeding between populations of shrimp. C. snapping shrimp in the Caribbean and the Pacific were never part of the same population. D. snapping shrimp species in each ocean diverged after the formation of the Isthmus of Panama.

Biology & Microbiology

A researcher follows the mutation rates in the nematode Caenorhabditis elegans in five different tissue types across 300 generations. One would expect mutation rates to be ________ across the different tissue types

a. equal b. approximately equal c. different d. deleterious e. None of the above

Biology & Microbiology