For example, it evolved to use water as a source of electrons instead of sulphur compounds. This meant that the green organisms were no longer confined to the sediments. They could now live in the surface waters or on land and had the whole visible spectrum for photosynthesis. They then evolved several accessory pigments that could absorb the newly available green wavelengths in the middle of the spectrum and pass their energy on to chlorophyll. Some plants are particularly good at this.
Many seaweeds absorb most of the spectrum and look almost black.
But most land plants, perhaps because they have more light to play with, don't have such good accessory pigments, so trees still look green. This destroys the CO2 acceptor molecule and generates unwanted phosphoglycollate, which has to be metabolised to regenerate the lost acceptor. The process is called photorespiration it needs oxygen, releases CO2, and uses about half the plant's photosynthetic energy. Photorespiration can be artificially inhibited by increasing the CO2 concentration so that it can compete better with oxygen. This is done commercially by enriching the air in greenhouses with CO2, when crop yield may be doubled.