Timeline of life on Earth

4.6 Gya Earth Forms
4.5 Gya The moon forms after impact of a mars sized body
4.2 Gya-4.0 Gya Crust solidifies, oceans form.
4.2-3.5 Gya First life forms  bacteria (likely got energy from chemosynthesis and/or photochemosynthesis)
~2.8 Gya Oxygen releasing photosynthesis (oxygen was toxic to most life forms)
~2.7 Gya First Eukaryotes (Cells with a nucleus)

4.6 Gya Earth Forms