Microbiology Chapter 1: The Main Themes

Introduction to Microbiology

• Microbiology is the study of microorganisms, which are living organisms too small to be seen clearly with the naked eye.
• Microorganisms have a diameter of 1 mm or less and can only be seen with the aid of a microscope.
• Microbiology is one of the most applied of all the biological sciences and did not exist as a true science before the late 19th century.

Subdivisions of Microbiology

• Virology: the study of viruses
• Bacteriology: the study of bacteria
• Mycology: the study of fungi
• Phycology: the study of algae
• Protozoology: the study of protozoa

Occurrence of Microorganisms

• Microorganisms are present everywhere on earth, including humans, animals, plants, soil, water, and atmosphere.
• Microorganisms can multiply in all three habitats except in the atmosphere.

Economic Impacts of Microorganisms

• Microorganisms have both beneficial and detrimental influences on human life.
• Microorganisms are required for the production of various products, such as bread, cheese, yogurt, antibiotics, vaccines, and vitamins.
• Microorganisms play an important role in recycling organic and inorganic materials and maintaining the stability of the biosphere.
• Microorganisms are the source of nutrients at the base of all food chains and webs.

Negative Impacts of Microorganisms

• Microorganisms have harmed humans and disrupted societies over the millennia.
• Microbial diseases have played a major role in historical events, such as the decline of the Roman Empire and the conquest of the New World.
• The plague, also known as the "black death," struck Europe in 1347 and killed 25 million people, changing European culture and preparing the way for the Renaissance.

Microbes in Energy & Nutrient Flow

• Microorganisms are involved in the flow of energy and food through the earth's ecosystems.
• Photosynthesis is the light-fueled conversion of carbon dioxide to organic material.
• Decomposition is the breakdown of dead matter and wastes into simple compounds.

Human Use of Microorganisms

• Biotechnology: the production of foods, drugs, and vaccines using living organisms.
• Genetic engineering: manipulating the genes of organisms to make new products.
• Bioremediation: using living organisms to remedy an environmental problem.