Tristan,
There is no problem using shape variables in comparative method
analyses, so long as one uses the entire set of partial warp scores and
uniform shape. The Phylogenetic Generalized Least Squares (PGLS)
approach allows one to perform comparative analyses using such
multivariate data, and Felsenstein's independent contrasts is a special
case of this approach (see Rohlf, 2001 and references therein for
discussion). So procedurally, what you want to do is possible.
With respect to application papers, Rohlf (2002) discusses
fitting shape data to a phylogeny, and Ruber and Adams (2001) used PGLS
for a comparative analysis of cichlid body shape and trophic morphology.
I am certain that other application papers of this sort are out there,
but off the top of my head I cannot point you to them.
Hope this helps.
Regards,
Dean
Rohlf, F. J. 2001. Comparative methods for the anlaysis of continuous
variables: geometric interpretations. Evolution. 55:2143-2160.
Rohlf, F. J. 2002. Geometric morphometrics and phylogeny. pp. 175-193
in Morphology, shape, and phylogeny (N. MacLeod and P. L. Forey eds.).
Taylor & Francis. London.
Ruber, L., and D. C. Adams. 2001. Evolutionary convergence of body shape
and trophic morphology in cichlids from Lake Tanganyika. Journal
of Evolutionary Biology. 14:325-332.
At 07:34 AM 1/21/2004, you wrote:
>Dear Morphmeters,
>
>Are there any problems (statistical, procedural, philosophical) with
>using shape variables (such as relative warps scores) as input
variables
>in comparative analyses (such as independent contrasts) to examine the
>correlation of certain aspects of shape, with other variables? If this
>has been addressed before, are there references for articles where this
>was discussed? I haven't been able to find anything in the morphmet
>archives (but I'm not sure if I was using them correctly).
>
>Thanks in advance,
>
>C. Tristan Stayton
>==
>Replies will be sent to list.
>For more information see
http://life.bio.sunysb.edu/morph/morphmet.html.
Dean C. Adams, Ph.D.
Assistant Professor
Department of Ecology, Evolution, and Organismal Biology
Department of Statistics
Iowa State University
Ames, IA 50011
tel: (515) 294-3834
fax: (515) 294-8457
web: http://www.public.iastate.edu/~dcadams
==
Replies will be sent to list.
For more information see http://life.bio.sunysb.edu/morph/morphmet.html.
