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Re: Phylogeny and Distance





George,
In addition to what I just posted about the Darwin quote, I would also encourage anyone to read anything written by Peter Ashlock on the subject of phyletic trees and cladistic analysis.
His methodology (of incorporating morphological distance, as well as branching order) is practiced by many systematists-----particularly in botany and entomology. The systematics textbook by Mayr and Ashlock (Principles of Systematic Zoology, 1991) is a good place to start for anyone wanting to know more about Ashlock's views.
------Ken
********************************************************
From: Dinogeorge@aol.com
Reply-To: Dinogeorge@aol.com
To: dinosaur@usc.edu
Subject: Re: Phylogeny and Distance
Date: Thu, 11 Jan 2001 23:55:22 EST

In a message dated 1/10/01 3:05:51 AM EST, kinman@hotmail.com writes:

<< ****What is not being recognized here is that "relationship" is not the
 same thing as "relatedness", and therefore neither are the degrees of
 relationship and relatedness.   Siblings may share a common relationship,
 but the number of genes they share in common can vary from 100% (in
 identitical twins) to extremely low percentages in rare instances (the
 disparity in relatedness can be enormous even among the closest of
 relatives). >>

You are stretching the analogy of a phyletic tree as a family tree too far.
Phyletic trees are not based on morphological distance, only on branch
topology. There is no analogue to "relatedness" as you describe in a phyletic
tree.
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