Aristotle was a Greek philosopher who classified the living organisms on a scientific basis for the first time. He classified the plants as herbs, shrubs and trees and animals were categorized into two groups, animals with red blood and animals without red blood. The need for a higher and a better classification was always felt. Linnaeus was responsible for the two kingdom classification (Plantae and Animalia) and R.H.Whittaker introduced the five-kingdom classification whose main basis was the mode of nutrition. Theophrastus was a successor to Aristotle and was known for classifying plants and how they reproduced.