Introduction
- Bacteria are unicellular micro-organisms. These are Prokaryotic in cellular organisation and placed under the kingdom Monera in a single Class Schizomycetes.
- Bacteria were not known until the invention of the microscope.
- Bacteria were discovered by Anton van Leeuwenhoek in Delft, Holland in 1676.
- Leeuwenhoek with the help high power lenses observed his own teeth scrapping and found that it contained millions of living creatures or organisms and he named them Animalcules.
- Ehrenberg first called these creatures as Bacteria.
- Later researches were carried out by Louis Pasteur and Robert Koch which highlighted the importance of bacteria.
- But at present a lot of information is available regarding bacteria and viruses.
Characters of Bacteria
- Bacteria are found in soil, water, air and also inside the body of living organisms.
- These can withstand extreme drought, cold and heat.
- Some bacteria live as parasites on other living organisms and plants.
- Some plants live in symbiotic association. For example., Rhizobium forms root nodules of legumes and fixes atmospheric nitrogen, Escherichia coli commonly called E.coli lives in the intestine of man.
- Bacteria are found in different shapes such as rod shape, spherical shape, comma shape, and spiral shape.
- Bacteria that change their shape according to the environment and nutrients available are called pleomorphic bacteria. For example., Acetobacter.
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