evolution of oxygenic photosynthesis ..
There is suggestive evidence that photosynthetic organisms were present approximately 3.2 to 3.5 billion years ago, in the form of stromatolites, layered structures similar to forms that are produced by some modern cyanobacteria, as well as numerous microfossils that have been interpreted as arising from phototrophs ( Des Marais, 2000 ).
Origin and early evolution of photosynthesis. | Docphin
The evolution of life from its beginning through the development of the metazoa (primitive multicellular organisms) took billions of years. The earth's atmosphere did not contain oxygen when the earth formed 4.6 billion years ago. This reducing environment provided favorable conditions for the natural synthesis of the first organic compounds. The first phospholipid bilayer membranes formed along with primitive RNA and DNA genetic molecules. The membranes adsorbed proteins and the hereditary DNA/RNA material. From these organic molecules, the first primitive prokaryote (simple single cell organism lacking a nucleus) arose. Natural selection began.
For example, speciation patterns in the native flax snails of Northland can be related to changes in sea level. Originally 2-3 species were widespread at a time of low sea levels. Rising seas at the end of the glacial period isolated these as populations on offshore islands, where differential natural selection pressures led to the evolution of a greater number of separate species.
Early evolution of photosynthesis: clues from …
The are puzzling in that there is little or no evidence of any skeletal hard parts i.e. they were soft-bodied organisms, and while some of them may have belonged to groups that survive today others don't seem to bear any relationship to animals we know. Although many of the Ediacaran organisms have been compared to modern-day jellyfish or worms, they have also been described as resembling a mattress, with tough outer walls around fluid-filled internal cavities - rather like a sponge.
Evolution: Change: Deep Time - PBS
The Ediacaran animals disappear from the fossil record at the end of the Vendian (544 million years ago). In their place we find representatives of almost all the modern phyla recognised today: sponges, jellyfish and corals, flatworms, molluscs, worms, insects, echinoderms and chordates, plus many "lesser" phyla such as nemertean worms. These "modern" organisms appear relatively quickly in the geological time scale, and their abrupt appearance is often described as the "Cambrian explosion" however, bear in mind that the fossil record of the "explosion" is spread over about 30 million years. I keep taking things out of brackets because it is interesting relevant and memorable
Chronology of the universe - Wikipedia
Cardona, who was not involved in the recent study but has begun interpreting its results, thinks he may have found a hint in the heliobacterium reaction center. According to him, the complex seems to have structural elements that would have later lent themselves to the production of oxygen during photosynthesis, even if that wasn’t their initial purpose. He found that a particular binding site for calcium in the heliobacteria’s structure was identical to the position of the manganese cluster in photosystem II, which made it possible to oxidize water and produce oxygen.
Evolution of mammals - Wikipedia
That timing would have been early enough to predate the cyanobacteria typically credited as the first organisms to perform oxygenic photosynthesis. According to Cardona, it may be the case that a lot of bacteria could do it, but that after mutations, divergences and other events, only cyanobacteria retained the ability. (Cardona published a citing other molecular evidence for this hypothesis. He has not yet formally presented arguments about the potential link involving calcium for peer review, but he has written about the idea in and on a , and he recently began working on a paper about it.)