Lamarck's theory of inheritance of acquired characteristics states that the physical changes in the body parts of an organism are inherited to their off spring from generation to generation. During his study of physical appearance ( phenotype) of organism Lamarck said that the characters adopted according to the changes in environment by organism as a physical change in body are inheritable e.g giraffes long neck due to shortage of food the giraffes in order to reach to higher trees had to make their neck long so their neck length was increased and they had long necks so the new offspring when burn had long necks so on this basis he said that the physical changes are inherited. Giraffes with long neck had more chances of survival in the environment.
