Neil J. Fergusson wrote:
>To Dave Wright and all who are interested,
>In resoponse to Dave Wright's interesting posting on taxonomy and
>the species concept, I pose a couple of a little bit off
>the subject questions.
>Question 1: What is meant by a "monophyletic group" ? What about "Clade"


Someone forwarded that post from a "discussion" on birdchat (I wasn't
trying to start a brawl on tweeters...). The point was that species
concepts are arbitrary and which one is "correct" depends on what
properties you think a species should have.


A monophyletic group is a group of species or other taxa that share a
single common ancestor (and it includes all the descendants of that
ancestor). A clade is a monophyletic group.


>Question 2: The original definition of species, I believe, regards the
>ability to produce viable offspring. Two populations were considered to

There is no "original definition" of species (or did I miss something in
the Old Testament?) other than its ancient, general use which is roughly
synonymous with "kind" (cf. species of mineral).


David Wright
dwright at u.washington.edu