Well, I have the gut that depends also on the adopted units of measure for the different traits. That is: having only averaged species data, is 1cm of wingspan increase a greater change than 1kg of bodymass increase?
A solution would be to compare on each tip the inferred traits directional change (approximated by the difference between the values at the phylogeny nodes) with their variance. This would allow to use the same scale for the evolution of every trait, i.e. variance units. I think that's the idea behind haldanes: see Gingerich 1993 http://earth.geology.yale.edu/~ajs/1993/11.1993.17Gingerich.pdf Giulio Valentino Dalla Riva PhD candidate @ Biomathematics Research Centre University of Canterbury Christchurch, NZ Phone: +64 3642987 ext 4869 On 17/07/2015, at 3:41 am, Theodore Garland Jr <theodore.garl...@ucr.edu<mailto:theodore.garl...@ucr.edu>> wrote: If everything is log-transformed then the variance of phylogenetically independent contrasts or, equivalently, the MSE (if I remember correctly) from a PGLS analysis is directly related to the rate of trait evolution. I'm not sure of the best way to test for statistical differences among traits, but I am sure you could do this with simulations. Cheers, Ted Theodore Garland, Jr., Professor Department of Biology University of California, Riverside Riverside, CA 92521 Office Phone: (951) 827-3524 Facsimile: (951) 827-4286 (not confidential) Email: tgarl...@ucr.edu<mailto:tgarl...@ucr.edu> http://www.biology.ucr.edu/people/faculty/Garland.html http://scholar.google.com/citations?hl=en&user=iSSbrhwAAAAJ Director, UCR Institute for the Development of Educational Applications Editor in Chief, Physiological and Biochemical Zoology Fail Lab: Episode One http://testtube.com/faillab/zoochosis-episode-one-evolution http://www.youtube.com/watch?v=c0msBWyTzU0 ________________________________________ From: R-sig-phylo [r-sig-phylo-boun...@r-project.org<mailto:r-sig-phylo-boun...@r-project.org>] on behalf of Karla Shikev [karlashi...@gmail.com<mailto:karlashi...@gmail.com>] Sent: Thursday, July 16, 2015 2:13 PM To: r-sig-phylo@r-project.org<mailto:r-sig-phylo@r-project.org> Subject: [R-sig-phylo] testing for variation in rates of evolution among traits Hi there, I've come across several methods to test for differences in the rate of evolution among branches in a tree, but I can't find methods to test for differences in rates of evolution of different traits on the same species (ex. if wing size evolution is faster than than overall body size evolution). Any suggestions? Thanks! Karla [[alternative HTML version deleted]] _______________________________________________ R-sig-phylo mailing list - R-sig-phylo@r-project.org<mailto:R-sig-phylo@r-project.org> https://stat.ethz.ch/mailman/listinfo/r-sig-phylo Searchable archive at http://www.mail-archive.com/r-sig-phylo@r-project.org/ _______________________________________________ R-sig-phylo mailing list - R-sig-phylo@r-project.org<mailto:R-sig-phylo@r-project.org> https://stat.ethz.ch/mailman/listinfo/r-sig-phylo Searchable archive at http://www.mail-archive.com/r-sig-phylo@r-project.org/ [[alternative HTML version deleted]] _______________________________________________ R-sig-phylo mailing list - R-sig-phylo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-phylo Searchable archive at http://www.mail-archive.com/r-sig-phylo@r-project.org/
