Micro-organisms affect every aspect of the life on Earth. It has a vital role in supporting and maintaining the nature and life.They are the oldest form of life on earth. Microbe fossils date back more than 3.5 billion years to a time when the Earth was covered with oceans that regularly reached the boiling point, hundreds of millions of years before dinosaurs roamed the earth.Understanding microbes is vital to understanding the past and the future of ourselves and our planet.Hence the study of microorganisms has become a major discipline in world today.
Microbes can be divided into five main groups: Archaea, Bacteria, Fungi, Protista and Virus. You might have heard of bacteria and fungi before. Archaea are bacteria-like creatures that have some traits not found in any true bacteria. Protists include primitive algae,amoebas , slime molds and protozoa . We can also include viruses as a major type of microbe, though there is a debate as to whether viruses can be considered living creatures or not. Since all these creatures are tiny and individually too small to be seen with unaided eye,microbiology is unusually dependent on a distinctive sets of methods ,which means that we cannot see them without microscopy and the fact that we cannot do the experiments with them with without pure culture techniques.These methods constitute core of techniques of cultivation common to all microbiology, in addition almost all microbiologists use wide variety of other techniques for identification of micro organisms, especially from biochemistry, genetics and molecular biology.
Microorganisms need access to a source of energy and the raw materials essential for the construction of their cellular components. A characteristic feature of the microorganisms is their ability to grow and form a population of organisms. One of the results of microbial metabolism is an increase in the size of the cell. The many requirements for successful growth include those both chemical and physical. An understanding of environmental influences also aids in the control of microbial growth and the study of the ecological distribution of microorganisms.