Phyletic Gradualism versus Punctuated Equilibrium - Essay Example

Punctuated Equilibrium suggests that fossil records cannot give an account to the speciation process. For instance, if one records the existence of ancestral species in a certain place, there is a chance that new species are evolving in another place.

This evolution trend reduces the probability of the species being fossilized. Fossils from the new species are possible only if it happens to return to its ancestral range or be a different type that coexists with its relatives. Bryozoans, which are coral-like sea organisms, show evidence of punctuated equilibrium. The fossil record shows that the existence of one species 140 million years ago and no changes in the said species were found in the first 40 years. This pattern of diversification and stability then recurred in many years.

Nevertheless, the frequency of this evolution pattern remains an issue. Its occurrence is being questioned as a standard event or simply a rare phenomenon. Punctuated equilibrium is also challenged to conduct further studies as to the factors that affect rapid evolution or period of stability. (WGBH Educational Foundation and Clear Blue Sky Productions, Inc., 2001) There are eight processes that produce rapid evolution. These are stasis; isolation; strong selection and rapid change; no preservation; reintroduction; expansion and stasis; preservation; and the occurrence of evolution in sharp jumps with speciation events.

(University of California Museum of Paleontology, 2012) Stasis is where a population of species live, die, and become fossils in a hundred thousand years interval. The said fossils provide only insufficient evidence of evolution. Isolation is where a small number of certain species get separated from the entire population. After which, a rapid evolutionary change takes place caused by its new environment and small population. This new environment gives out selection pressures to the isolated population.

Hence, rapid evolutionary change begins among the isolated group of species. Due to the minute size of the isolated group of species, their rapid change, and their remote location, there is relatively no possibility of fossil preservation among them.