A model explaining the mechanism of evolution that represents an updating of the original ideas set forth by Charles Darwin. According to this model, those individuals with hereditary traits that best adapt them to their habitat are most likely to survive and to transmit these adaptive genes to their offspring. As a result, with the passage of time the frequencies of beneficial genes rise in the population, and when the composition of the gene pool of the evolving population becomes sufficiently different from that of the original population, a new species will have arisen. Since a beneficial mutation must spread through an entire population to produce detectable evolutionary changes, speciation will be a gradual and continuous process. Contrast with punctuated equilibrium.
Subjects: Genetics and Genomics.