But, a whole ecosystem has developed near these thermal vents. The single celled Archea are fed upon by other organisms and so on, right up through fish which live on the larger multicellular animals. The Archea seem to be related to the first single celled organisms. The origin of glycolysis. The development glycolysis permitted cells to regenerate ATP from ADP and inorganic phosphate by using the energy supplied by glucose and other carbohydrates.
Glycolysis requires no oxygen, which was in very low concentrations in the early atmosphere.
The origin of chemiosmosis. Eukaryotes pump hydrogen ions from the innermost compartment of mitochondria and chloroplasts outward. Probably the early cells, used pumps, powered by ATP, to remove hydrogen ions from the cell interior. It is hypothesized that electron transport chains which were powered by reduced molecules replaced the ATP powered pumps, probably because they were more efficient. The sizes of cells.