[Vision2020] John D your gradualism post

[Phil Nisbet]

John D

Excellent post and full of fairly interesting papers.

Every few years Jay Gould and a few of the relatively die hard Darwinists 
attempt to come up with a case for gradualism.  They are at last agreeing 
that punctuated equilibrium is a reality, but still will not give up the 
ghost that there might be a case of gradualism out there for them to find.

The best they have been able to do is make a claim that there must be a 
geological reason that gradual morphological change and the strata in which 
it occurs are less preservable than is the case for punctuated equilibrial 
events.  Why exactly long term stable areas with slow changes would not be 
better preserved is something they have yet to come up with a reason for.

What they are left doing is conceptual papers and you list many recent ones, 
but they are not based on hard field data.  I am reminded of Alverez’s 
initial work at Gubio for some of these papers trying to show forams tests 
changing upward in sequence.  Sampling error and over extension of data in 
these cases tends to show that the changes assumed to be gradual turn out 
most often to be punctuated equilibria rather than gradualism.

Gradualism assumes that speciation occurs at the center of a species range 
as a result of mutations that occur at a measured rate that will be selected 
as more viable through natural processes.  We can go to locations that had 
such environments and pale ecological conditions and in every case I am 
aware of, find that speciation either does not occur at all or that 
colonization from marginal populations is what has actually happened.

Intellectually, gradualism is very satisfying, which is why it keeps turning 
up like a bad penny.  Its is very easy to understand why evolutionary 
biologists would prefer it to dealing with punctuated equilibrium, which 
like life is far more messy and harder to follow.

Look at a thought problem.  A species with long legs eats and lives in water 
that is gradually rising.  What gradualists suggest is that generation to 
generation the legs of the creature will grow to accommodate the new 
condition in the habitat.  What really ends up happening is that some will 
adapt by simply migrating, a few by longer legs, a few by floating, a few by 
changing what they eat, a few by having longer necks and a host of clever 
and simple things.  Some will not cope at all and will simply become 
extinct.  The question is, when will one of these adaptive strategies become 
selected as speciation instead of being simply the normal range for 
creatures of that particular grouping?

If gradualism was to hold in this case, we would expect one hippo to become 
a whale and one to become a rhino and one to stay a hippo.  What actually 
happens on the ground is that the hippos stay range bound and moving to stay 
in their species comfort zone until stressed by events.  Its point events 
that destroy the center of the range that causes speciation.  If the event 
is either too small or to brief, the species will join back together in the 
center of its creeping range and not become distinct from the earlier 
adaptive methods it has used.

A lot of this is hugely important to remember, because it has consequences 
for how we cope with ecological systems and species in our current day and 
age.  If gradualism was the case, species that man impacts would slowly 
adapt to the changes that man imparts to habitat.  We know that not to be 
the case and have to treat our actions on the globe so as not to be an 
extinctive or speciational point of punctuation.

As a note to you, similar things have happened when dealing with things like 
continental drift and plate tectonics.  The old school refused to step down 
from their earlier ideas of a world created by synclines, 
http://www.mantleplumes.org/WebDocuments/Geomyths.pdf  I can still remember 
Dean of North Cascades Geology, Dr Peter Misch chewing us out for talking 
about such things on field trips and other people trying to accommodate both 
ideas to please the contending parties.

Phil Nisbet

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