Stephen E. Jones wrote:
>Actually, according to my Biology lecturer, "speciation is" *hardly ever*
>"due to the gradual accumulation of small genetic changes" (i.e.
>anagenesis).
>
>These days it is recognised that, contrary to Darwin's theory, almost all
>speciation is due to branching (i.e. cladogenesis) due to isolation and
>genetic drift.
Darwin had a clear idea of lineages radiating into niches, and adapting
to those niches. This was the idea that he thought memorable enough
to remember the spot in the road where it occurred to him.
>As usual, the problem is in words having multiple meanings. In this case
>"gradual", which as a noun literally means "steps":
>...
>but which also, as an adjective, means: "1 : proceeding by steps or
>degrees"; and "2 : ...changing...by fine or often imperceptible degrees":
Clearly the secondary definition is the one Darwin had in mind. There
should be no confusion about what Darwinian gradualism is. It is
"imperceptible" change.
>Thus Dawkins' Neo-Darwinist idea of "gradual" is micromutations (i.e.
>microevolution) accumulating by "fine ... imperceptible degrees" into major
>changes (i.e. macroevolution); whereas Gould's punctuationist idea of
>"gradual" is "proceeding by steps or degrees" some of which are *big*
>steps (i.e. macromutations leading directly to macroevolution).
I was unaware that PE theory involved macromutations. My reading of
it is that it is about the irregular pace of evolution, the long periods of
stasis between evolutionary stages. But when change occurs, it is through
gradual Darwinian evolution.
>CL>Macroevolutionary events are saltations, real leaps in a single generation.
>
>This is *one* definition of "macroevolution". But, since the Latin
>macro="large" and micro= "small", they literally just mean large- and small-
>scale evolution:
Generally they're considered Greek words, but they are used in Latin.
'Macro' for example, would usually be 'magna' or 'magnus' in Latin.
It's fair to say that macroevolution has not had enough support to have
developed a standardized terminology.
>CL>Your loyalty to Darwinian gradualism ...
>
>Maybe Susan realises that it is only "Darwinian gradualism"
>which can (in theory at least) reliably craft complex designs?
Even irreducibly complex ones?
>It will be found that Cliff himself, despite all his symbiosis
>`hand-waving', falls back on "Darwinian gradualism" when he
>has to explain which symbiotic mergers, out of his imaginary
>"astronomical" numbers of them, actually survived.
No, that is due to natural selection; this is not a gradual mechanism
of evolution, gradualism is not involved.
>It is interesting to see how evolutionists use the fear of helping
>creationists to try to keep each other in line.
After all this time, anti-creationism still seems to be the major interest
of some evolutionists.
--Cliff Lundberg ~ San Francisco ~ 415-648-0208 ~ cliff@cab.com
This archive was generated by hypermail 2b29 : Wed Jun 14 2000 - 04:27:43 EDT