concentrations increased atmospheric methane converting hydrogen sulfide water sulfur compounds example h sub sub co sub sub h''v'' ch sub sub h sub sub early forms fermentation also increased levels atmospheric methane transition oxygen dominant atmosphere ''great oxidation'' begin approximately nbsp billion years ago photosynthetic processes started nbsp billion years prior ref name goldblatt ref name catling radiation heat temperature light biology life operates within certain range temperatures heat form energy regulates temperature heat affects growth rates activity behaviour
Natural science Biology Ecology