Plant biology is a science of plant life and a branch of biology. The course includes two parts- origin and diversity; and functions and their environment. First part deals with the origin of life on this planet, the organization of cell and progressive organization of tissue and organs. It is followed by the diversity of plants and their relatives, the evolutionary relationship between plant groups and how each group may have arisen. The second part deals with physiology or day to day functioning of the most complex groups of plants, growth, reproduction, heredity and plants and their environment.