Fundamental molecules of life are pigments which arose and co-evolved as a response to the thermodynamic imperative of dissipating the prevailing solar spectrum

[摘要] The driving force behind the origin and evolution of life has been thethermodynamic imperative of increasing the entropy production of thebiosphere through increasing the global solar photon dissipation rate. Inthe upper atmosphere of today, oxygen and ozone derived from life processesare performing the short-wavelength UV-C and UV-B dissipation. On Earth'ssurface, water and organic pigments in water facilitate the near-UV andvisible photon dissipation. The first organic pigments probably formed,absorbed, and dissipated at those photochemically active wavelengths in theUV-C and UV-B that could have reached Earth's surface during the Archean.Proliferation of these pigments can be understood as an autocatalyticphotochemical process obeying non-equilibrium thermodynamic directivesrelated to increasing solar photon dissipation rate. Under these directives,organic pigments would have evolved over time to increase the global photondissipation rate by (1) increasing the ratio of their effective photon crosssections to their physical size, (2) decreasing their electronic excitedstate lifetimes, (3) quenching radiative de-excitation channels (e.g.,fluorescence), (4) covering ever more completely the prevailing solarspectrum, and (5) proliferating and dispersing to cover an ever greatersurface area of Earth. From knowledge of the evolution of the spectrum ofG-type stars, and considering the most probable history of the transparencyof Earth's atmosphere, we construct the most probable Earth surface solarspectrum as a function of time and compare this with the history ofmolecular absorption maxima obtained from the available data in theliterature. This comparison supports the conjecture that many fundamentalmolecules of life are pigments which arose, proliferated, and co-evolved as aresponse to dissipating the solar spectrum, supports the thermodynamicdissipation theory for the origin of life, constrains models for Earth'searly atmosphere, and sheds some new light on the origin of photosynthesis.

[学科分类] 地球化学与岩石