2007-02-28 08:31:03 · 3 answers · asked by : ) 2 in Science & Mathematics ➔ Biology
Aerobic Respiration (i.e. Krebs Cycle /TCAC) must have evolved after anaerobic respiration (i.e. glycolysis), as the aerobic pathways rely on the anaerobic pathways for the first step.
2007-02-28 09:37:11 · answer #1 · answered by blastedsand 2 · 0⤊ 0⤋
Respiration must have developed first. Cells needed energy, so they needed some kind of respiration from the beginning of cell history. However, oxygen wasn't available for aerobic respiration until the cyanobacteria began carrying on photosynthesis.
2007-02-28 16:51:01 · answer #2 · answered by ecolink 7 · 0⤊ 0⤋
probably before, as bacteria commonly respire anaerobically, and they are usually the first organisms to evolve in the earths early atmosphere, which had methane co2 etc but no o2.
2007-02-28 16:38:25 · answer #3 · answered by Anonymous · 0⤊ 0⤋