Microbiology Introduction, Nonliving Matter, Familiar Plants and Animals, Inhabitants Earth, Carbon dioxide

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Microbiology Microbiology Introduction Landmarks in the History of Microbiology Discovery of Microscope Discovery of Microbial Life Abiogenesis Versus Biogenesis / Microbes and the Origin of Life Spontaneous Generation Doctrine or Abiogenesis Controversy over Spontaneous Generation End of the Debate Fermentation / A Biological Process - Pasteurization / Heating Destroys Microbes Germ Theory of Disease Koch's Postulates: The Pathogenesity Test Pure Culture Concept and Other Microbial Techniques Robert Koch 1843-1910 The Father of Microbial Techniques Growth of Medical Microbiology Causation of Diseases Bacterial Diseases and Their Discoverer Immunization Surgical Antisepsis Rise of Chemotherapy Growth of Plant Pathology Discovery of Viruses Soil Microbiology Other Important Contributions Development of Microbiology Since 1590-2000 in Chronological Form and Investors

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Your Ad Here	Introduction The discipline of science dealing with the laws of life and development of organisms particularly microscopic or submicroscopic forms of life, which are usually invisible to the naked eye, is called microbiology (Gr. mikro = small, bios = life, logos = science); it is also associated with the changes which such forms bring about in other organisms and in nonliving matter. The first thing we learn in the study of microbiology is the existence of what may be called the world of microscopic or submicroscopic forms of life. We must realize that the familiar plants and animals are not the only living forms on earth but, on the contrary, there are many a great number of very tiny life forms all about us everywhere too small to be seen usually by the naked eye. We are ordinarily quite unconscious of their presence. If we wish to see and study them, it is necessary to use a normal compound microscope or even more advance forms of microscopes. If an object has a diameter less than 0.1 mm, our eye fails perceiving it at all, and very little detail can be perceived in an object with a diameter of 1.0 mm. Roughly speaking, therefore organisms with a diameter upto 1.0 mm (1000 μ) are designated as microorganisms and are studied under the broad realm of microbiology.
However, according to our present knowledge, we may put archaebacteria, bacteria, cyanobacteria, microalgae, protozoans, microfungi, viruses, viroids, prions etc. under the domain of such forms of life. Two different words are in common use as inclusive designations for these forms; the first being "microorganism" and the other the "microbe". The latter word has been derived from French and was introduced in 1878 by a French surgeon, C.E. Sedillot. Sometimes the term "germ" is also employed, but it has so many meanings that its use may lead to ambiguity. Microorganisms (bacteria) were undoubtedly the first living inhabitants on the Earth, and they were anaerobic as molecular oxygen was either absent or present only in trace amounts. The oldest fossil records of plants and animals are only 0.6-0.7 million years old, but we now have credible evidence that microbial life existed more than 3.5 billion years ago, that is, just I billion years after the formation of the Earth and almost 3 billion years before the plants and animals appeared on Earth.
How Microbes Evolved on Earth? The Earth was still in the process of developing and had a reduced atmosphere before life originated on it. It is thought that the reduced atmosphere of earth consisted largely of gaseous forms of nitrogen, hydrogen, carbon dioxide and water vapour; with smaller amounts of ammonia, carbon monoxide and hydrogen sulphide. Oxygen was either absent or present only in trace amounts and, therefore, the atmosphere was anaerobic (oxygen-free). Torrential rains poured over the developing Earth for centuries forming large masses of water in which the original gaseous raw materials of atmosphere gradually dissolved forming "ocean".	Your Ad Here
The oceans were like a 'broth' and, with the aid of energy from ultraviolet rays and electrical discharges (lightening), variety of organic compounds were synthesized progressively in them by abiotic (nonliving) reactions and these organic compounds slowly evolved into larger and more complex organic molecules (macromolecules). The macromolecules had inherent tendency to aggregate in various combinations and appeared as distinct bodies (the microspheres) in the surrounding water medium. These microspheres are postulated to be the first step toward cellular organization and referred to as progenotes or protobionts. Acquisition and use of nucleic acids, development of enzymatic capabilities and membrane organization further led the progenotes or protobionts to create eugenotes or primitive version of prokaryotic cell (bacterial cell).
Your Ad Here	The microorganisms are almost omnipresent and are characterized with a very high degree of adaptability. They constitute a world of their own; full of uniqueness from different biological standpoints. The microbial world is spread over the entire biosphere-the lithosphere, the hydrosphere and the atmosphere; the latter being their temporary abode. The lithosphere comprises the solid components i.e. the rocky substances of the continents and the hydrosphere includes all the liquid components i.e. water in oceans, lakes, rivers and on land. The atmosphere is the gaseous mantle which envelops the lithosphere and hydrosphere. Apart their presence in these components of biosphere, the microorganisms are also found in the living as well as dead bodies of the organisms.

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