Lecture 10: factors driving development of aerobic cells: Life first appeared 4 billion years ago in the form of anaerobic prokaryotic cells. Anaerobic bacteria don"t need oxygen to do respiration. There wasn"t much oxygen at the time. 2. 2 bya we get cyanobacteria, which can do oxygenic photosynthesis. They led to bacteria that can do aerobic respiration aerobic respiration. Identify the paradox for why prokaryotes are biochemically complex but don"t develop morphological complexity: All evolution is slow and stepwise, so why haven"t prokaryotes evolved to be more complex since they"re so old. Biochemically, bacteria and archaea are remarkably diverse. They can make compounds that eukaryotic cells can"t and can live in extreme environments: relationship between surface area and volume as cells get larger: As a cell gets bigger, the volume of the cell gets bigger faster than the surface area of the cell.