From: me22over7@gmail.com   
      
   The following seems to be a significant challenge for the naturalistic   
   origin of life. Thoughts?   
      
   PROCESS   
      
   OoL assumes a progression from simple inorganic chemicals to a   
   population of protocells and then on to the first population of   
   free-living cells (pre-LUCA).   
      
   Protocells provide encapsulation, replication and heritable variation,   
   but are not "alive" in that they require feedstock supplies from the   
   environment. The feedstock dependence tapers from protocells to pre-LUCA.   
      
   ENVIRONMENT   
      
   This process of chemical evolution and then Darwinian evolution requires   
   the environment to supply nucleotides, lipids, sugars, amino acids,   
   polyphosphates, metal ions, etc, in certain concentrations, with   
   substantial homochirality, etc.   
      
   The environment must also provide sufficient temperature stability, pH,   
   mechanical agitation, structure (e.g. niche separation), wet/dry   
   cycling, feedstock recycling, waste removal, etc.   
      
   LINEAGE   
      
   OoL assumes countless locations working in parallel as described,   
   possibly with localised cross-pollination. However, there must be an   
   unbroken lineage (or lineages) to from start to finish. Which implies   
   the persistence and stability of the environmental requirements described.   
      
   TIME   
      
   How long would this lineage need? One million years? One thousand years?   
   100 million years?   
      
   PROBLEM   
      
   What geological situation on the early Earth could provide the   
   continuous, stable environment required for the duration needed? Even as   
   little as one thousand years is long for a suitable system of geothermal   
   ponds that is *uninterrupted* by any sterilisation/reset events.   
      
   Polymers such as RNA break down over hours to decades depending on   
   environment. Freezing or drying may extend lifetimes but also pause   
   evolution. In any case, when active, continuous replication is required   
   for renewal before decomposition.   
      
   1,000 years from chemicals to cells seems impossibly short. And 100,000   
   years for the nursery required seems impossibly long.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)