Classification of Living Organisms
Imagine a bacteria, neem tree and toad. All of them are living things and their basic unit is a cell. However, one major difference is that the cells in neem tree and toad have nucleus, whereas the bacterium has no nucleus. Thus all life can be divided into two major categories Prokaryotes and Eukaryotes. Among the eukaryotes like pond algae, fern and a rabbit, the pond algae is a single celled organism, whereas rest are multicellular organisms. On the basis of significant characteristic features like the presence or absence of cell wall and the photosynthetic activity, the organisms (living beings) are divided into major groups as shown in Figure 1 and 2.