Hello Everyone,
I am working with a comparative dataset using bat morphometrics. As part of
my analysis, I want to estimate the phylogenetic signal of my variables. I
understand how to do this using R. My question is more specifically about
what kind of data I should be using when calculating the
Dear Alyson.
There is no general rule about this; however, my suggestion would be to
use log-scaled values. This is because on a log-scale proportional
changes in the trait are equal, independent of the magnitude of the
trait. That is, a change of 1% in mass of whale is the same as a change
i
I agree with everything that Liam wrote -- right on.
Another point is that if you are looking at morphometric traits, then most
of them are probably highly positively correlated with body size. In that
case, testing for phylogenetic signal in, say, wing length, is going to be
largely redundant wi
Alyson-
Following off of what Liam said, one thing to consider is as most measures
of phylogenetic signal aren't relative to the units of the traits
considered, any transformation of the data should be about equally
interpretable. To take a spin with Liam's example, if , if the log-scale
trait had
Following on from what Ted just said about size-correction - one can use a
phylogenetic regression (GLS) with the trait of interest as the dependent
variable and size as the independent variable, while simultaneously
estimating lambda. The program BayesTraits can do this (
http://www.evolution.rdg.
Yes, certainly, but if you want something like the K statistic of Blomberg
et al. (2003), which will let you compare with a lot of other traits in
their database, then you need to do the univariate calculations on
size-corrected data. Also, if you are worried about saying "signal was
significant f
