I agree with the others, if your goal is to control for size/mass then I don’t
see how the “residuals” from an intercept only model will be useful.
If the relationship between your trait and size is almost isometric, ratios are
the simplest way to go.
For ANOVAs, I will simply use size as a
Aloha Gabriel,
Joe and Graham have given you very good advice. I just wanted to chime in
to reinforce the point that you should not apply a "phylogenetic
correction" twice on the same set of data! If youʻve removed the expected
covariance, it is good for an ordinary ANOVA. If you do a
I might well be missing something but I think, Gabriel, that you do not
need to compute any residuals to do what you want to do. In your tail
length example, you perform a phylogenetic regression to get a
size-standardized tail length - in this case, the residuals of your pgls
model. That all
Gabriel Ferreira explained:
> I will try to better explain my problem, and I really appreciate your time
> to help me with this issue.
> My study is a conventional ecomorph with linear and univariate
> measurements
>
> So... Some of my traits are linear measures that can and must be
>
Hello Sr,
I will try to better explain my problem, and I really appreciate your time
to help me with this issue.
My study is a conventional ecomorph with linear and univariate
measurements
So... Some of my traits are linear measures that can and must be
"corrected" by body size, such as tail
If wants residuals of values of a trait in each species, taking into
account within-species variation and phylogeny, what does it mean if those
residuals correlate with those of some other character, or with an
environmental variable?
Just asking which R machinery to use might wait until it is
Hello Gabriel,
If I understand it correctly you're looking for an 'intercept only' model
(e.g., gls(x~1,...)). The rationale for doing so would be to assess the
'phylogenetic signal' in your trait 'x'. It will be somehow similar to using
functions such as, for instance, fitContinuous in
