In his monograph "29 Evidences for Macroevloution", Dr. Douglass Theobald
) goes to great length to support
common descent due to the fact that all life on earth uses the same 22 amino
acids, and that all DNA uses the same basic components. This suggests that all
life on earth arose from a single organism. To qoute Dr. Theobald "Common
Descent is the hypothesis that all living organisms are the lineal descendants
of one original living species". In other words, all the variations of life
on this world can traced to a single starting point. It seems that Dr. Theobald
does not show any surprise at this. His monograph doesn't deal with the subject
of abiogenesis (the theory that life originally arouse from non-living matter).
given the proper conditions on the early earth). He states "Abiogenesis is not
a part of evolutionary theory, it is an independent hypothesis". However at the
same web site (www.talkorigins.org...
), you can find a short dissertation
on the theory of abiogenesis which contends that simple life will result by random
coombinations of complex molecules over a period of time. Dr. Theobald stresses
that since all life on earth uses to same basic proteins in the same manner that is
a evidence of common descent since some other form of portein could be used for the
same process. He talks about the phlyogenetic tree which is used to classify how
all life is genetically related. There is only one phylogenetic tree for all life
on this planet.
My question is: If life just occurs randomly or as a result of normal conditions
at the beginning of the earth), why don't we see several different types of life that
can be traced back to several different common ancestors? Why don't we see animals or
plants that use 22 amino acids different than ours? Why don't we see animals or plants
whose DNA structure is fundamently different than ours? I would expect that if life
ere to just arise out of the primordial ooze, then we should find all kinds of creatures
which would have celluar structures different than ours (not one phylogenetic tree, but
three or four or more). Can anyone hazard a response to this question.