Human Evolution

 Overview

Humans as a species have evolved over thousand of years to be one of the most developed ones on Earth. The famous Theory of Evolution was proposed by Charles Darwin, an English scientist. The theory was later renamed as "Theory of Natural Selection" based on what the theory suggests, it is also commonly called Darwinism.
History
For many years it was believed that the Earth and all that is present on it were spontaneously created by God. The implications of this belief was that all the species present on the Earth had been there from beginning and unchanging.
However, according to the ' autogenesis theory ' of the origin of life, the origin of life itself lies in non-living organic matter. Over years, various theories have been put forward to explain this theory, only two of them being widely accepted due to their more logical approach. These two are the 'Theory of Acquired Characters' and 'Theory of Natural Selection'. 

Theories of Human Evolution

French biologist Jean Baptise de Lamarck proposed that the driving force behind evolution of humans was/is inheritance of acquired characters and put forward the 'Theory of Acquired Characters' based on this concept. According to this theory, organisms might change physically to meet the demands of the environment in which they attempt to survive. These changes can then be passed on to the next generation for the betterment of their life and thereby evolve to survive better in tough conditions. He supported this theory with the example of evolution of giraffe. He wrote that "... take for giraffe, it has evolved to it's long neck for the lack of fresh grass and henceforth in desire of tree leaves...".