I think it’s more likely that chlorophyll and its related molecules were just the first photosynthetic pigments that came about, and new pigments couldn’t compete with it because they’d have to start from square one, whereas existing life is already built around the specifics of chlorophyll. And as Romashka said, perhaps chlorophyll is already as efficient as possible so a new pigment wouldn’t be beneficial anyway.
I’ve seen interesting work noting that the absorption spectrum of chlorophyll is very approximately the inverse of that of purple sulfur bacteria, which were most likely much more common in the early earth due to differences in geochemistry and atmospheric composition. Something taking the scraps that were left behind?
Photosynthesis has evolved many many times, but what has only evolved once in the cyanobacteria (and then been appropriated by blue green algae and countless other endosymbiosis events) is oxygen-producing photysynthesis. This allows the fixation of carbon at much higher efficiency since it can use water as the required electron donor instead of sulfur or metal salts or organic molecules and thus had a big advantage.
The choice of electron source is ultimately independent of the pigments used, but they are linked by evolutionary history.
I think it’s more likely that chlorophyll and its related molecules were just the first photosynthetic pigments that came about, and new pigments couldn’t compete with it because they’d have to start from square one, whereas existing life is already built around the specifics of chlorophyll. And as Romashka said, perhaps chlorophyll is already as efficient as possible so a new pigment wouldn’t be beneficial anyway.
I’ve seen interesting work noting that the absorption spectrum of chlorophyll is very approximately the inverse of that of purple sulfur bacteria, which were most likely much more common in the early earth due to differences in geochemistry and atmospheric composition. Something taking the scraps that were left behind?
Photosynthesis has evolved many many times, but what has only evolved once in the cyanobacteria (and then been appropriated by blue green algae and countless other endosymbiosis events) is oxygen-producing photysynthesis. This allows the fixation of carbon at much higher efficiency since it can use water as the required electron donor instead of sulfur or metal salts or organic molecules and thus had a big advantage.
The choice of electron source is ultimately independent of the pigments used, but they are linked by evolutionary history.