Re: Colors of alien plants -- Scientific American

Aqua
> > Green chlorophyll was then a secondary pigment, to
> > mop up the red and blue wavelengths the primary
> > pigment wasn't getting - perhaps a niche organism.

Brian Davis
> So... evolution eliminated the pigments that could
> capture most of the energy, while preserving the
> pigment that doesn't? That seems a strange adaptation
> on the surface.

Probably those pigments were carefully optimized to
match hydrogen sulfide as the electron donor, and
therefore could not evolve to match water as an electron
donor.  Other pigments, being only marginally useful,
were free to evolve additional capabilities. 


--
  ----------------------
We have the right to defend ourselves and our property, because 
of the kind of animals that we are. True law derives from this 
right, not from the arbitrary power of the omnipotent state.

http://www.jim.com/
     James A. Donald