Photosynthesis, prebiotic origin

Folsome s idea can be seen as an argument for setting the origin of photosynthesis at a much earlier stage, in fact, in the prebiotic era. The purpose of this intervention is to present some evidence that may support such a prebiotic origin of photosynthesis. 

Fig. 2. An evolution diagram illustrating a suggestion of common ancestry of some present-day organisms. The essential features of present-day photosynthesis may have originated in the prebiotic era and is preserved in its most primitive form in (at least some) present-day phototrophs. The heterotrophs may have developed parallel with the aerobic nonphotosynthetic bacteria, some l to 1.5 x 109 years after the emergence of the cyanobacteria. The eukaryotic photosynthetic organisms developed much later, perhaps some 1.5 to 0.5 x 109 years ago. The archaebacteria are primitive organisms that seem to have no evolutionary relation with the present prokaryotes.21 Little is known about their energy metabolism. Tentatively, they are considered as a very early form of cellular life.

We have discussed various theories of life origin in the Earth, however, irrespective of its origin, the advent of life contribnted significant alterations to existing prebiotic geochemical cycles. Aside from the colonization of terrestrial surfaces, perhaps the most important changes happened as a result of evolution of oxygenie photosynthesis and respiration. 

---