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Cyanobacteria are probably the most numerous taxon to have ever existed on Earth and the first organisms known to have produced oxygen, [10] having appeared in the middle Archean eon and apparently originated in a freshwater or terrestrial environment. [11]
Further chemical and isotopic analysis of ancient rock reveals that by the Siderian period, roughly 2.45 billion years ago, [5] oxygen had appeared. This indicates that oceanic, photosynthetic cyanobacteria evolved during this period because they were the first microbes to produce oxygen as a byproduct of their metabolic process. [6]
First photosynthetic bacteria appear 2.7 billion years ago Cyanobacteria become the first oxygen producers 2.4 – 2.3 billion years ago Earliest evidence (from rocks) that oxygen was in the atmosphere 1.2 billion years ago Red and brown algae become structurally more complex than bacteria 0.75 billion years ago
Bacteria develop primitive photosynthesis, which at first did not produce oxygen. [37] These organisms exploit a proton gradient to generate adenosine triphosphate (ATP), a mechanism used by virtually all subsequent organisms. [38] [39] [40] 3000 Ma Photosynthesizing cyanobacteria using water as a reducing agent and producing oxygen as a waste ...
The ability to generate oxygen via photosynthesis likely first appeared in the ancestors of cyanobacteria. [51] These organisms evolved at least 2.45–2.32 Ga [ 52 ] [ 53 ] and probably as early as 2.7 Ga or earlier.
Photosynthetic prokaryotic organisms that produced O 2 as a byproduct lived long before the first build-up of free oxygen in the atmosphere, [5] perhaps as early as 3.5 billion years ago. The oxygen cyanobacteria produced would have been rapidly removed from the oceans by weathering of reducing minerals, [citation needed] most notably ferrous ...
Cyanobacteria were the first organisms to evolve the ability to photosynthesize, introducing a steady supply of oxygen into the environment. [130] Initially, oxygen levels did not increase substantially in the atmosphere. [131] The oxygen quickly reacted with iron and other minerals in the surrounding rock and ocean water.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...