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Various topics

A few notes:

First on extinction:

I don't know anyone who would argue against the fact that an impact would
make a big impact on the Earth's ecosystem. However, whether one or all of
us agree with that, all it does is make a prediction about what we might
expect to see in the fossil record. Now, despite what some physicists would
like, this does not settle the question. The fossil record provides the
data necessary test for this idea - although it also provides great
difficulties in performing the test. Paleontologists may be last to accept
the theory en masse because they are best suited to know just how many
biases and obstacles there are to establishing diversity data and nailing
down times of mass extinction and the nature of that mass extinction. If the
record can be shown to be fully compatible with a world-wide extinction
in both terrestrial and marine ecosystems at the exact time of the
iridium layer and no other explanation for that layer can be found, then
it seems reasonable to me to accept the impact theory as the best
current explanation. Now correlating the extinctions and nature or
pattern of the terrestrial and marine extinctions is still not greatly
in place which is why many dinosaur experts were so amused by seeing
physicists proclaim they were documenting the dinosaur extinctions by
taking deep-water sediment samples around the layer. They were sampling
a very different signal that may or may not have represented what
was going on on land, or may have represented it in different ways.

Now I became a leaner toward the impact theory in the mid 80's and have
not wavered much at all - actually have become more and more so
monotonically. Before that, despite all the huffing and braying of Alvarez
and his group, there was relatively little supporting data, just a
hint of something with some supporting data. It took an awful lot of work
to get enough data assembled to make it the best explanation in my book.
Sheehan's paper was laudable and very interesting but is far from the
last word on diversity patterns worldwide or even locally through time
because of the nature of taphonomic sampling and how time-averaged samples
can include material from past samples into later samples. The diversity
they show is not large by any means anyway and there is a lot more
similar sampling, etc to be done looking at patterns leading up to the
K-T. We may never know the nature of terrestrial diversity leading up to
the extinction event, or know when it occurred and in what pattern relative
to the marine record. The Signor-Lipps effect is just one of many potential
road blocks that we have to struggle with on this.

The point is, we are involved in a long experiment testing out various
theories put forth by paleontologists and astrophysicists and geophys.
as to the history of the Earth and the history of its life. I have heard
many physicists lecture science fiction writers because they were so naive
about the subtleties of the processes they study and the way the writers
often ignore these in their writings. Well, this is one case where the
physicists and astrophysicists have to not be naive about the processes
they want to use to test their predictions of the effects of impacts
on the Earth. Taphonomic, biological, stratigraphic and sedimentological
bases all have to be covered and too many have shown vast amounts of their
own tendency to gloss over these details.

This is not a race to see who can be converted to the TRUTH the fastest. It
is a long testing process of predictions. What if detailed work shows
terrestrial systems to actually be unaffected? Or only affected on a single
continent? Or show the biggest effect 100K years after the marine realm?
These all have ramifications for honing the theories on the effects of
impacts and we need to do this testing. I think Pete is wrong about
paleontologists being slower about continental drift acceptance, there
were many converts and hold-outs in all disciplines, all this after
paleontologists many years earlier were asking about their organismal
distributions that supported continental connections that other geologists
poo-pooed directly.

2) Behavior can be genetically coded and is being used more and more by
researchers within phylogenetically contexts - frequently by superimposing
behavior data onto cladograms. We have an arachnologist who does this in
incredible detail for spiders including web building behavior and other
aspects. There is even a behavior pattern he calls Zuma Beach or something
like that because it looks like a weight-lifter flexing his biceps on the
California Beach. What that says about humans and fetching wolves, I have
no idea or much knowledge. Humans especially are tricky.

I have just picked up a book entitles something like the Bell Curve Debate -
basically papers discussing the Bell Curve book noting various parts of
the debate. Here is a case of being able to look at the scientific process
at work and being ignored (which by whom is a part of the debate) that
merits some observation.

Sorry its so long yet again - Ralph Chapman NMNH