Chlorophyll, Bacteriochlorophyll, or Protochlorophyll

摘要

The question of which chlorophyll came first in the evolution of photosynthesis is discussed. It has been assumed that bacteriochlorophyll a came first, because the earliest photosynthetic organisms are thought to have been obligatory anaerobes. The writer proposes that the common ancestor of all photosynthetic prokaryotes and organelles contained protochlorophyll a, and that all green and purple photosynthetic bacteria are descended from a bacteriochlorophyll a - containing ancestor which diverged from the chlorophyll a line leading to blue-green algae and chloroplasts. (ERA citation 05:012582)