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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]
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 ...
Earth forms 3.4 billion years ago 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
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 ...
Dinosaurs were initially cold-blooded, but global warming 180 million years ago may have triggered the evolution of warm-blooded species, a new study found.
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.