Sometimes a closed question must be reopened as new evidence or new arguments based on old evidence come to light.In 1972 paleontologist Stephen Jay Gould and Niles Eldredge challenged conventional wisdom with an opposing viewpoint, the punctuated equilibrium hypothesis, which posits that species give rise to new species in relatively sudden bursts, without a lengthy transition period. These episodes of rapid evolution are separated by relatively long static spans during which a species may hardly change at all. (TPO30-2 The Pace of Evolutionary Change)

In 1972 paleontologist Stephen Jay Gould and Niles Eldredge challenged conventional wisdom with an opposing viewpoint, the punctuated equilibrium hypothesis, which posits that species give rise to new species in relatively sudden bursts, without a lengthy transition period.

In 1972 paleontologist Stephen Jay Gould and Niles Eldredge challenged conventional wisdom. They used an opposing view point. This opposing view point is the punctuated equilibrium hypothesis. This hypothesis posits that species give rise to new species in relatively sudden bursts. They give rise to new species without a lengthy transition.

In 1972 paleontologist Stephen Jay Gould and Niles Eldredge challenged conventional wisdom with an opposing viewpoint, the punctuated equilibrium hypothesis, which posits that species give rise to new species in relatively sudden bursts, without a lengthy transition period. (TPO30-2 The Pace of Evolutionary Change)

Greater productivity and rising demands provided entrepreneurs with profits that could be reinvested to take advantage of new technologies to further expand capacity, or to seek alternative investment opportunities. (TPO26-1The Industrial Revolution)

In view of this behavior, it has been suggested that chemicals present in fresh buck rubs may help physiologically induce and synchronize fertility in females that visit these rubs. (TPO28-3 Buck Rubs and Buck Scrapes)

Spartina establishes itself on substrates ranging from sand and silt to gravel and cobble and is tolerant of salinities ranging from that of near freshwater (0.05 percent) to that of salt water (3.5 percent). (TPO22-1 Spartina)

The rapid technical development of photography—the introduction of lighter and simpler equipment, and of new emulsions that coated photographic plates, film, and paper and enabled images to be made at much faster speeds—had some unanticipated consequences. (TPO22-2 The Birth of Photography)