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[N.MacLeod@nhm.ac.uk: Bolides and Paleo. History]



Again, my apologies to those that see this twice...  Michael Reese
sent his assertions about the demise of the dinosaurs to PaleoNet as
well as to the dinosaur list, and the following is a response that
didn't get sent here directly:

  Date: Tue, 2 Apr 96 23:13:22 PST
  From: N.MacLeod@nhm.ac.uk (N. MacLeod)
  To: Multiple recipients of list <paleonet@ucmp1.Berkeley.EDU>
  Subject: Bolides and Paleo. History

  So I see somebody out there isn't on Spring Break. It's about time
  someone roused PaleoNet from its annual Spring slumber.
  
  In response to Nathan Edel's comment on size and the K-T mass
  extinction, large animals tend to be somewhat more specialized than
  their smaller counterparts and so more prone to extinction by all
  mechanisms. The demise of large animals (e.g., dinosaurs) is as
  consistent with the climatic change model as it is with a bolide
  impact. I think what Mike Reese is getting at is that the
  environmental damage predictions offered as corollaries to the
  bolide impact hypothesis would seem to suggest that the resulting
  extinctions should have been much more severe (from a taxic point of
  view) than the available record seems to indicate. For example,
  today local extinctions of fish, amphibians, and lepidosaurs
  (lizards and snakes) are used as some our most sensitive ecological
  indicators of environmental damage. Yet these groups seem to have
  suffered no substantial extinctions through the Maastrichtian-Danian
  interval. You can argue, of course, that the record of these groups
  is not as dense as we would like. It's not. Then again, uppermost
  Maastrichtian dinosaurs are known (at best) from only a handful of
  localities and (at worst) from only a single area in western North
  America which (not coincidentally) is the same area from which our
  best data on some of these "lower" vertebrate groups originates.
  
  This recurring reference to extinctions as the hot paleo. topic of
  the day is interesting all by itself. It's been more than a dozen
  years since extinction studies more-or-less displaced punctuated
  equilibria-related topics in many technical and popular
  articles. [Note: I am convinced that the two debates are, at many
  fundamental levels, different faces of the same philosophical
  disagreement.]  In reading the pre-1972 paleo.  literature I don't
  get the impression that paleo. in the '50's and '60's was dominated
  by single issues in quite the same way. However, I must admit that
  my entire paleo. career has been spent in the shadow of these two
  controversies and so I may simply lack an appreciation for the
  detailed history and significance of older paleo. controversies.
  Did our science change into somewhat of a "single issue" discipline
  in the '70's? If so, why and has this been a good thing? If not,
  what were the burning questions of previous times and did they burn
  as brightly in the technical and popular literature?

  Norm MacLeod

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  Norman MacLeod
  Senior Scientific Officer
  N.MacLeod@nhm.ac.uk (Internet)
  N.MacLeod@uk.ac.nhm (Janet)

  Address: Dept. of Palaeontology, The Natural History Museum,
           Cromwell Road, London, SW7 5BD

  Office Phone: 0171-938-9006
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