∙ Charles Darwin proposed 'Theory of Natural Selection'. It states that organisms which are better adapted to their environment tend to survive and produce more offspring.
∙ Gregor Mendel proposed the 'Law of Inheritance'. It consists of law of dominance, law of segregation and of law of independent assortment.
∙ Jean Lamarck proposed the 'Theory of Inheritance by Acquired Characters'. It states that, the characters acquired during the lifetime of an organism are always passed on to the next generation.