The oldest life on earth lived anaerobically, using no oxygen and relying on sulfates of possibly methane for their energy needs. These life forms were very, very simple and simply existed. The Archean is the eon in which the last common ancestor of all living things existed. Fossils of archebacteria (a type of life which still exists today) have been found from this time. The time between the first life and the end of the Archean is occasionally called the 'Boring Billion' by scientists, because very little actually happened.
Cyanobacteria are the most important form of Archean life. They were the first life to photosynthesize, perhaps as early as 3.5 billion years ago. They were the first life to create oxygen, and were the ones responsible for the oxygenation of the Earth. However, much of the early oxygen produced by cyanobacteria actually sunk into the Earth and became part of oxygen-rich iron settlements. Colonies of cyanobacteria, also called stromatolites, became widespread in the Paleoarchean.
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| Thank this for being able to breathe. Image courtesy of : http://www.globalhealingcenter.com/media/algae_closeup.jpg |
So, what are stromatolites, anyway? Spelled STRO-MA-TO-LITES, they are formations of colonies of photosynthesizing cyanobacteria (blue-green algae). They are small, cylindrical layered structures made of blue-green algae cells. Stromatolies were extremely common in the Archean eon that formed in shallow waters. These stromatolites helped create oxygen in the atmosphere and make more oxygen.
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| An artistic rendering of stromatolites (based on modern photographs). |
The Archean shows the oldest fossils of Apex chert and stromatolites as old as 3.5 MA although the oldest chemical markers of life are from 3.8 MA. Life was very simple and cyanobacteria were the first to photosynthesize, producing oxygen in colonies of stromatolites (cylinders of blue-green algae).
ReplyDeleteThe Archean have some of the oldest fossils such as the Apex chert and Stromatolites. They are as old as 3.5 billion years. Stromatolites are formations of colonies of photosynthesizing cyanobacteria.
ReplyDeleteThe earliest fossils can be found in the Archean Eon, dating around 3.43 Ga. The first life was very simple and consumed no oxygen. It existed simply to exist. Cyanobacteria developed during the Archean, and it was the first bacteria to produce significant quantities of oxygen. It developed cylindrical colonies called stromatolites, which greatly increased the air's oxygen.
ReplyDeleteThis period shows the oldest fossils coming from the Apex cert and stroamatolites, but they are hard to date because of how old they are, but are assumed it date back to 3.43 Ga. The first life lived off of sulfate from the methane for energy, not oxygen. Cyanobacteria existed, and one they photosynthesized they would create large amounts of oxygen, as well as come together in cylinder looking shapes called stromatolites.
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