Hi Pim, one definition of Neo Darwinism stated:
>>"The major tenets of the evolutionary synthesis, then, were that
>>populations contain genetic variation that arises by random (ie. not
>>adaptively directed) mutation and recombination;"
>>Bertvan: Since no on knows very much about how mutations arise, (everyone
>>admits most mutations are harmful and positive mutations are very rare) no
one >>can state with certainty that they are not adaptively directed.
Pim:
>Of course not, nothing is certain in science. But even if some mutations are
>"directed", it does not really matter.
Bertvan:
It matters to those who don't believe the universe is ruled by chance.
>>Bertvan: Up until now randomness has been such an important part of
the >>dogma that no one has investigated to see if they might be adaptively
directed.
>Pim:
>Why call it a "dogma"?
Bertvan:
I probably should apologize. The word has derogatory connotations. I don't
know what else to call a belief considered beyond question.
Definition of neo Darwinism:
>>"3.It postulates that speciation is (usually) due to the gradual
>>accumulation of small genetic changes. This is equivalent to saying that
>>macroevolution is simply a lot of microevolution."
Pim:
>So where lies the boundary between macro and micro-evolution? What forms
this >boundary?
Bertvan:
My personal definition is macro evolution involves mutations leading to the
addition of new organs, systems or body parts, whereas micro evolution is the
shuffling of traits already contained in the gene pool. Chris says such a
distinction is based upon an assumption, and he is correct. However, it is
also an assumption that macro evolution is merely lots of micro evolution.
No uncontested mutations of macro evolution have been observed. The holders
of both beliefs can interpret the evidence to support their positions. The
supporters of a difference between the two, can claim "random mutationa and
natural selection" appears to support stasis rather than novelty. The
supporters of no difference can point out that no alternative mechanism is
presently known. Myself, I consider it healthy that scientists of both views
are now working on the problem.
Bertvan