Nature of the fossil record

[Doug Erwin <MNHPB028@xxxxxxxxxxx>]

to reinterate what Jere has said in a slightly different way - the point
of the Lipps(-Signor) Effect is that is establishes the correct null
hypothesis against which to measure the observed patterns in the fossil
record.  Contrary to Peter Harries comments, the L(-S) Effect is PRIMARILY
a preservational phenomenon.  The effect is exacerbated by collecting
bias and can be reduced by increased collecting effort.  However it cannot
be completely negated by increased collecting.  Correctly identifying the
null hypothesis is critical in all of this, and is all to infrequent in
paleontology.
Doug Erwin