3.25 billion years ago, cyanobacterium may have been present.

[PB666]

http://www.upi.com/Science_News/2015/10/07/Ancient-rocks-reveal-earliest-instance-of-photosynthesis/4561444168335/

While the article is not click bait, there are some click- baity popups so you can ditch these by locating the microscopic x in the top right corner.

We talk about life on mars but one advantage of earth is the availability of light, more so now than in the past, as well can be said about mars. The importance of light and evolution is key, is phototrophs appear quickly after the first cell it provides leverage for the importance of oxygen.

Edited October 8, 2015 by PB666

[baggers]

loosely related:

2.2 billions years ago: lichens-like.

https://en.wikipedia.org/wiki/Diskagma

http://www.sci-news.com/paleontology/science-fossils-early-terrestrial-life-01249.html

2.1 billions years ago: multicellulars macroscopic things.

https://en.wikipedia.org/wiki/Francevillian_biota

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0099438

Edited October 8, 2015 by baggers

[KerikBalm]

I don't think you can conclude those 2.1 bya things are multicellular, Eukaryotic, or even life.... It sort of looks like a mineral percipitate.