  The most important thermodynamic work performed by life today is the
dissipation of the solar photon flux into heat through organic pigments in
water. From this thermodynamic perspective, biological evolution is thus just
the dispersal of organic pigments and water throughout Earth's surface, while
adjusting the gases of Earth's atmosphere to allow the most intense part of the
solar spectrum to penetrate the atmosphere and reach the surface to be
intercepted by these pigments. The covalent bonding of atoms in organic
pigments provides excited levels compatible with the energies of these photons.
Internal conversion through vibrational relaxation to the ground state of these
excited molecules when in water leads to rapid dissipation of the solar photons
into heat, and this is the major source of entropy production on Earth. A
non-linear irreversible thermodynamic analysis shows that the proliferation of
organic pigments on Earth is a direct consequence of the pigments catalytic
properties in dissipating the solar photon flux. A small part of the energy of
the photon goes into the production of more organic pigments and supporting
biomass, while most of the energy is dissipated and channeled into the
hydrological cycle through the latent heat of vaporization of surface water. By
dissipating the surface to atmosphere temperature gradient, the hydrological
cycle further increases the entropy production of Earth. This thermodynamic
perspective of solar photon dissipation by life has implications to the
possibility of finding extra-terrestrial life in our solar system and the
Universe.
