Claim CB300:
Complex organs and biological functions could not have evolved.
Source:
Response:
-  This is an example of the argument from
 incredulity.  In fact,
   several complex organs, which have previously been claimed unevolvable,
   have plausible means of evolving, including the eye, the
   bombardier beetle defense mechanism, the woodpecker
   tongue, and more.
 -  Evolutionary mechanisms do account for the evolution of complexity,
   since non-lethal mutations tend to add more components to simple
   systems than they remove (Soyer and Bonhoeffer 2006).
   The abstract of Lenski et al. (2003, 139) is worth quoting in full:
     A long-standing challenge to evolutionary theory has been whether it
      can explain the origin of complex organismal features. We examined
      this issue using digital organisms -- computer programs that
      self-replicate, mutate, compete and evolve. Populations of digital
      organisms often evolved the ability to perform complex logic
      functions requiring the coordinated execution of many genomic
      instructions. Complex functions evolved by building on simpler
      functions that had evolved earlier, provided that these were also
      selectively favoured. However, no particular intermediate stage was
      essential for evolving complex functions. The first genotypes able
      to perform complex functions differed from their non-performing
      parents by only one or two mutations, but differed from the ancestor
      by many mutations that were also crucial to the new functions. In
      some cases, mutations that were deleterious when they appeared
      served as stepping-stones in the evolution of complex
      features. These findings show how complex functions can originate by
      random mutation and natural selection.
 
Links:
National Science Foundation, 2003.  Artificial life experiments show how
 complex functions can evolve.
 http://www.sciencedaily.com/releases/2003/05/030508075843.htm
References:
-  Lenski, Richard E., Charles Ofria, Robert T. Pennock and Christoph
   Adami. 2003.  The evolutionary origin of complex features Nature
 423:
   139-144.  http://myxo.css.msu.edu/papers/nature2003/
 (See also NSF,
   2003, above.)
 -  Soyer, Orkun S. and Sebastian Bonhoeffer. 2006.  Evolution of
   complexity in signaling pathways.  Proceedings of the National Academy of
 Science USA 103: 16337-16342.
 
 
created  2003-5-8, modified  2006-11-2