Many protists reproduce sexually, as do the multicellular plants, animals, and fungi. In the eukaryotic fossil record, sexual reproduction first appeared by 1.2 billion years ago in the Proterozoic Eon.
All sexually reproducing eukaryotic organisms derive from a single-celled common ancestor. There are a few species which have secondarily lost this feature, such as Bdelloidea and some parthenocarpic plants - wikipedia 
Here we write about the Origins of Life, and the Cambrian Explosion in relation to Blockchain and the Singularity.
Animation of the small subunit of the Thermus thermophilus ribosome. RNA shown in orange, protein in blue. PDB 1FKA
- wikipedia 
Life started almost as soon as the planet was formed - somewhere between 3.8 and 4.1 billion years ago.
An extremophile is an organism adapted to extreme conditions.
Portion of the Cambrian Period during which life vastly diversified