Charles Darwin (1809-1892) was a naturalist, who is best known for his theory of evolution which explains how new species of living organism develop and manage to survive better than than the other in a very slow and gradual process of evolution. As per this theory all different types of plants and animals existing in nature have evolved out of relatively limited numbers of common ancestors through a gradual process of evolution over thousands of millions of years. This theory is referred by many as Darwin's as theory of evolution. Darwin's ideas on the theory of evolution have been described in great detail in his book called On the Origin of Species by Means of Natural Selection, or the Preservation of favoured Races in the Struggle of Life, published in 1859.
As per this theory the primary mechanism of evolution is the process of natural selection. Some people also describe this process of natural selection as the process of survival of the fittest. Darwin stated that all species of organisms produce mare off springs than are necessary to replace themselves. Thus there is a tendency for the population of the species to increase. However there is limited amount of food and other necessities available in nature to support these increased numbers. Also some species are killed by prey by others for their food. Thus all the members of a species have to continuously struggle for their survival. Darwin's theory states that some members of the species have traits that help them in this struggle for survival. In comparison other members have traits that are not so helpful for survival. As a result the members of species with more suitable traits have greater chance of surviving and reproducing. As a result population of members with more favourable traits increase. On the other hand population of members with less favourable traits gradually reduces till it becomes totally extinct.
When this type of evolutionary process occurs in one species in two or more different geographical locations with different environments, members of population in each of the location may evolve differently because of the environmental factors. This type of differences in evolution, in many cases lead to development of so different varieties of a common species that each is considered a different species.
In the past there was major criticism of Darwin's theory because it conflicted with some religious beliefs regarding how this world and all the creatures living in it were created.
Another major criticism of Darwin's theory is on the grounds of some of the statistical impossibility of some of the sophisticated features of many organism developing as a result of random variations in basic traits of the less developed ancestors from which the more sophisticated species are supposed to have developed.
It is also important to note that Darwin's theory only explains how different multiple species develop from some common ancestors. This theory does not explain satisfactorily how the ancestor itself may have developed. In particular, Darwin's theory does no explain how the basic life form developed.
No comments:
Post a Comment