Ancient Species

Cyanobacteria

Cyanobacteria, or "blue-green algae", are bacteria which live in water. They often grow in colonies large enough to be seen. Cyanobacteria are photosynthetic, that is, they "capture" energy from sunlight and release oxygen. They are responsible for generating the oxygen-rich atmosphere on which all animal life depends.

At the beginning of the Cambrian Period (about 590 million years ago), some cyanobacteria began to take up residence within certain eukaryote cells. This eventually led to the development of plants - the chloroplast with which plants make food for themselves is actually a cyanobacteria living within the plant's cells.

Cyanobacteria sometimes form a mat which traps sediment and secretions of calcium carbonate. These mats can form into large layered structures called stomatolites, if they are dome-shaped, or ancolites, if they are round.

Fossil stromatolites have been found dating far back into the Archaean Period (3,800 to 2,600 years ago). The oldest known fossils are microfossils of cyanobacteria, dating from 3,500 million years ago, found in Western Australia. Stromatolites are still being formed today at Shark Bay in Western Australia.