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Article: Evolutionary Origin of Bacteria and Viruses
- Article from:
- World of Microbiology and Immunology
CopyrightCOPYRIGHT 2003 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Evolutionary origin of bacteria and viruses
Earth formed between 4.5 and 6 billion years ago. Conditions initially remained inhospitable for the potential development of life. By about 3.0 billion years ago, however, an atmosphere that contained the appropriate blend of nitrogen, oxygen, carbon, and hydrogen allowed life to commence. The formation of proteins and nucleic acids led to the generation of the
genetic code
, contained in deoxyribonucleic and ribonucleic acids, and the protein machinery to translate the information into a tangible product.
Fossil evidence indicates that one of the first life forms to arise were
bacteria
. The planetary conditions that were the norm four to ...