Charles Darwin in 1859 explained the mechanism of organic evolution based on the principle of natural selection. Darwin encountered with a wide range of variation among organisms in the Galopagos islands during his voyage. On returning, Darwin authored his famous book ‘Origin of species’ by means of Natural selection to describe the process of evolution.
The Darwinian view of evolution is based on following observations and their deductions–
(1) Enormous fertility among organisms causes struggle for existence. Organisms possess enormous potentiality of reproduction and this results in struggle among them for limited natural resources (food and space).
(2) Members of a population differ from each other and most variations are hereditary. The organisms, that possess variations which make them best adapted to existing environmental conditions, can make better use of resources. Organisms with such variations are, therefore, more likely to survive and leave descendants.
(3) This differential reproductive success of organisms is the consequence of a process called natural selection. Herbert Spencer used the term “survival of the fittest” to describe this weeding out of less perfect ones.
(4) After a certain ** of time, continuous changes in specificities due to changing environmental conditions lead to emergence of new phenotypes and ultimately cause origin of a new species.
