Lamarcks theory of evolution was published in hilosophic zoologique in the year 1809. It is popularly known as The inheritance of Acquired characters in Organisms. According to this if an organ is used continuouly and constantly, it will tend to become highly developed whereas disuse results in its degeneration. Charles Darwin proposed theory of natural selection and survival of fittest and wrote the book Origin of Species in 1859. T. R. Malthus suggested that human population increases much faster than its food supply. Hugo de Vries proposed mutation theory of evolution. He worked on Oenothera lamarckiana (evening primrose).