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Re: "Wonderful Life" - repeated.



{Not to divert too much attention from dinosaurs, but I thought I should
clear up something here...}

At 02:04 PM 11/13/96 -0500, you wrote:
>     I hope I'm not too late on this, but a couple of weeks ago
>on this list a writer solicited advice on (something like) the
>likelihood of there being a Cretaceous on an alternate planet.
>Mickey Rowe told him (rather peremptorily I thought) that this
>was unlikely and referred him to S.J. Gould's _Wonderful Life_.
>
>     Gould wrote, in his book about the fossils of the Burgess
>shale, that if you could rewind the "tape" of evolutionary
>history, erase it and start re-recording, that you would have a
>very different result on the second "recording".

[discussion of symbiosis deleted]

>     On page 317  and 318 Gould seems to be saying it was a
>miracle that vertebrates made it onto land.  Wind back the tape,
>he says, and "expunge the rhipidistians by extinction, and our
>lands become the unchallenged domain of insects and flowers."
>
>     By saying that only the lobe-finned fish were capable of
>developing walking appendages he is truly a slave to his thesis.
>Nearly every other group put representatives on land: arthropods,
>molluscs, worms.

Hardly!!  In fact, the three groups mentioned are just about the ONLY
representatives of the vast diversity of marine animal life which made it
onto land:  Several branches of arthropoda, pulmonate gastropods alone among
the molluscs (no fully terrestrial prosobranch or opisthobranch gastropods,
bivalves, cephalopods, scaphopods, chitons, etc.), only a few branches of
the annelids, a few other "worms", and that is just about it (other than
tetrapods).  Where are the land cnidarians? Ctenophores? Sponges? Bryozoans?
Brachipods?  These are all very common (some less so now than in earlier
periods), but (for various reasons) they never made it onto land.

However, because most people are unaware of the vast diversity of marine
inverts, they may misinterpret the record and think that most groups have
representatives on land.  Terrestrial life is tough, and only a handful of
lineages have managed to make it onto land (but these tend to be very
diverse when they get there).

Thomas R. Holtz, Jr.
Vertebrate Paleontologist     Webpage: http://www.geol.umd.edu
Dept. of Geology              Email:th81@umail.umd.edu
University of Maryland        Phone:301-405-4084
College Park, MD  20742       Fax:  301-314-9661

"To trace that life in its manifold changes through past ages to the present
is a ... difficult task, but one from which modern science does not shrink.
In this wide field, every earnest effort will meet with some degree of
success; every year will add new and important facts; and every generation
will bring to light some law, in accordance with which ancient life has been
changed into life as we see it around us to-day."
        --O.C. Marsh, Vice Presidential Address, AAAS, August 30, 1877