who propounded the mutation theory of organic evolution
Hugo de Vries Hugo Marie de Vries ForMemRS[1] (Dutch pronunciation: [ˈɦyɣoː də ˈvris]; 16 February 1848 – 21 May 1935)[2] was a Dutch botanist and one of the first geneticists. He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation theory of evolution.
Spontaneous generation The doctrine of spontaneous generation was coherently synthesized by Aristotle,[2] who compiled and expanded the work of prior natural philosophers and the various ancient explanations of the appearance of organisms; it held sway for two millennia. Today it is generally accepted to have been decisively dispelled during the 19th century by the experiments of Louis Pasteur. He expanded upon the investigations of predecessors (such as Francesco Redi who, in the 17th century, had performed experiments based on the same principles). However, some experimental difficulties were still there and objections from persons holding the traditional views persisted. Many of these residual objections were dealt with by the work of John Tyndall, succeeding the work of Pasteur.[3]