Speciation

Speciation is the formantion of new species. Over many generations favorable adaptations gradually appear, and unfavorable ones dissappear. Eventually the changes become so great that the result is a new species.

Speciation video



The Rate of Evolution
According to Darwin's theory, new species arise overtime. In other words evolution occurs slowly and continuosly over thousands and millions of years. People who believe gradualism occured, believe that transitional forms or lengths between species are missing from the fossil record. Thus, few of them are preserved. Some people have different opinions about evolution. Another view of evolutionary change is known as punctuated equilibrium. Punctuated equilibrium is when a species stays the same for extended periods of time. According to the fossil record, equilibrium is interupted by the appearance of a new species. In other words a long period of equilibrium is interupted or punctuated by a short period of rapid evolution.


Stanley_Speciation_A_&_B.gif


EXPLANATION OF PICTURE ABOVE
The gradualism model, right, is gradually evolving more steadily throughout time. The Punctuated equilibrium picture, left, shows bursts of species occuring in short periods of time.