1 A MICROSCOPIC WORLD MICROBES THE FACTORY OF EVERYTHING Do you study microbiology in your school? According to what you have studied, are microbes useful, useless or harmful? Microbes were the first forms of life on our planet and have survived by adapting to ever-changing environments, from simple one-celled life forms to intelligent, decision-making, life-sustaining species in charge of many primary functions in biochemical and biological balances. Do you know what nitrogen is? If you need more information about it and its usefulness, surf the Net and find out. What are microbes? Microbes, or microorganisms, are tiny creatures that individually are too small to be seen by the naked eye. They are the oldest form of life on Earth and, by weight, represent 60% of the biomass of all life on Earth. They live everywhere: in the soil, water and air, in animal intestines, and in extreme settings such as rocks, glaciers, hot springs, and deep sea. The wide variety of microbial habitats reflects an enormous diversity of biochemical and metabolic traits. Disadvantages of microbes Microorganisms can be both very harmful and very useful: some of them are pathogens as they can cause serious diseases, such as malaria, poliomyelitis, diphtheria and typhoid fever. Some may contaminate food and cause food spoilage or even food poisoning. breathe. They are the foundation of the food chain that feeds all life on earth. They have been used for thousands of years to make fermented foods such as bread, cheese and yoghurt. Some soil microbes release nitrogen that plants need for growth and emit gases that maintain the precarious composition of the Earth s atmosphere. They are also at work in agriculture, industry, pollution control and medicine. In our bodies, different microbes help to digest food, ward off invasive organisms and engage in battles with the human immune system. Microbes are a source of new genes and organisms of value in biotechnology and energy production. Microbial genomes are relatively easy to study, so understanding their genomes helps understand how more complex genomes developed. Advantages of microbes However, the majority of microbes contribute to the quality of human life. They make about half the oxygen we Groups of microbes There are five basic groups of microbes: bacteria, fungi (yeasts and moulds), protozoa, microalgae and viruses. ONLINE RESOURCES Microbes and man to feed: to give food to naked: (here) without using a microscope setting: location spoilage: deterioration spring: water source tiny: extremely small trait: characteristic to ward off: to defend against 98 MICROBES AND BIOTECHNOLOGY The human microbiome is the genetic material of all the microbes that live on and inside the human body