Author's Name - Ruhul Kuddus

Introduction

Welcome to microbiology- the scientific study of microorganisms, or simply, microbes. Microbes are among the most abundant and widely distributed life forms. Microbes can be found in the atmosphere, essentially anywhere on the soil surface, inside rock layers, in the polar ice caps, in hot springs with boiling water, at the top of the tallest mountains and at the bottom of the deepest trenches of the oceans. In fact, microbes may be found virtually anywhere in the biosphere where there is water, whether in solid, liquid or gaseous form. Microbes evolved before other organisms, and they created and sustained the biosphere. The molecular oxygen and nitrogen gases in the atmosphere, two of the most important life-supporting elements, are there partly due to the microbial activities of photosynthesis and denitrification. Soil, the most important resource on the earth, after water, is also in part a product of microbial activities. Other complex life forms evolved from the first microbes. Microbes are used to produce many food items, drinks, medicines and industrial chemicals. A significant portion of the gross domestic product of any given nation is directly or indirectly microbial in nature. However, some microbes infect other organisms such as animals and plants, and some microbes destroy non-living objects that are important to human beings. Consequently, microbiology has become one of the major areas of instruction offered in most institutions of higher education.