Article: Cell Evolution

Cell Evolution

Approximately 3.5 billion years ago, cellular life emerged on Earth in the form of primitive bacteria. Bacteria or "prokaryotes" organize their genes into a circular chromosome that lies exposed within the fluid environment of the cell. Within a billion years, bacterial cell types had flourished and diversified, evolving numerous ways of extracting energy from the environment. These types included first the fermenting anaerobic archaebacteria, then the oxygen-producing photosynthetic cyanobacteria, and finally respiring aerobic bacteria able to utilize the new oxygen-rich atmosphere. In addition some bacteria had become motile , such as the corkscrew-shaped wriggling ...



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