¶ … Origin of Life
When Watson and Crick discovered DNA, double nucleotide chains containing the "language" of life, scientists had new information on which to base further research about the way living cells function and, in turn, the origins of life. In a 2007 article for Scientific American, Robert Shapiro explains why Watson and Crick's discovery did not provide the definitive answer to one of science's most provocative questions, as scientists had hoped.
One of the major problems to be resolved in discovering the origin of life is akin to the age-old question about which came first, the chicken or the egg. The discovery of RNA seemed to provide a plausible explanation. RNA, a class of molecules, carries information from DNA to cell structures. Scientists were poised to accept that RNA was the self-replicating molecule providing the catalyst for life. The question still remained: how did the first RNA arise? The spontaneity required for self-replication to suddenly take place goes well beyond scientific inquiry, some argue, and into the realm of improbability....
The group of scientists who believe in the replicator model have yet to show how a complex molecule could have formed initially. There are theories that certain compounds joined together by chance to form a molecule that could somehow self-replicate. Through an evolutionary process, the molecules mutated and adapted, eventually forming more complex organisms in which different parts performed different functions. The diagram provided by Shapiro shows, disorganized molecules organize into chains that mutate, surviving a selection process, and eventually organizing into organisms with compartments. As stated, this scenario is still considered theoretical; scientists have not established proof.
Likewise, proof does not exist the alternative theory of metabolism first, which holds that "compartmentalized" organisms formed spontaneously; particular compartments were capable of the kind of functions necessary to generate reaction networks leading to growth and evolution.
Shapiro outlines five truths that must be accommodated in any explanation about…
