Micro-organisms may be classified in the following large biological groups: AlgaeProtozoaSlime mouldsFungiBacteriaArchaeaViruses. Full Study material is given below: Related Share your love Previous Post 1. INTRODUCTION TO THE SCIENCE OF MICROBIOLOGY. MAJOR DIVISIONS OF MICROBIAL WORLD AND RELATIONSHIP AMONG THEM Next Post 3. Nutritional requirements, growth and cultivation of bacteria and virus.