Classification of Living Organisms

Introduction: As discussed in previous lecture, a large number of species exist on the earth. Human and its constant efforts to identify newer species and their potentials for food, cloth and shelter. In addition, human’s are also interest to explore the relationship between different species so that techniques developed for one species canbe used for distantly relared species without much efforts. For examples, experiments performed on monkeys and the results of these experiments can be applied to the human without much optimization. Since, it is difficult to draw the relationship between different species without comparing their properties and group them accordingly. This process of classification is known as taxonomy.

Classification of Living Organism: In earlier day when number of species were limited, Aristotle has used morphological differences as a criteria to group into plant and animals. But as number goesup this kind of classification didn’t hold and the organism were classified into two kingdom; plantae and animalia. This type of classification was easy to do but several organism are difficult to classify of either of these kingdoms. Later, R.H. Whittaker have grouped the organisms using five kingdom classification. The properties used to distinguish different kingdoms are given in Table 2.1. The basis of classification includes cellular structure, body organization, mode of nutrition, reproduction etc.