Bacteria – the most ancient group of living organisms. The first bacteria appeared on Earth more than 3.5 billion years ago. During nearly one billion years they were the only inhabitants on the planet.
Instruction
1. The body of the first bacteria had the primitive building. Over time the structure of microorganisms became complicated, but also now they are the most primitive unicells. At a part of the modern bacteria living in oxygen-free Ils at the bottom of reservoirs or in hot sulfuric springs lines of ancient ancestors remained.
2. Cages of bacteria nuclear-free therefore they are carried to prokariota. Unlike eukariot, they have no issued kernel separated from cytoplasm by a nuclear cover. The hereditary information presented in the form ring (is more rare – linear) molecules DNA, is located in the central part of a cage. Bacteria a mitosis – simple division in two breed.
3. Bacteria have no sexual process therefore on other mechanism, than at eukariot. It is supposed that in emergence of any devices the horizontal transfer of genes – transfer of genetic material from one organism to another, not being his descendant takes place. In particular, horizontal transfer promotes distribution at bacteria of resistance to antibiotics as "stability genes", having appeared at one bacterium, can quickly be transferred to other types.
4. Bacteria are of great importance in the nature and play a role of a powerful biotic factor. Thanks to the ability to transform humus and a humus to harmless inorganic substances they are irreplaceable in circulation of substances on the planet. Also bacteria perform soil-forming function.