One origin? (viral evolution)

Mon Jul 23 13:10:53 CDT 2001

Please excuse this rather basic question by a taxonomy neophyte. What
exactly is the difference between/def'n of a clade and a grade?

Eric Dunbar.

> From: Curtis Clark <jcclark at CSUPOMONA.EDU>
> Date: Fri, 20 Jul 2001 09:54:13 -0700
> Subject: Re: One origin? (viral evolution)
>
> Snakes are tetrapods, even though they have no legs, because they are
> members of the tetrapod clade, descended from the first tetrapods.
> Likewise, eukaryotes are a clade, and eubacteria may be a clade (although I
> know that Ken disagrees), but "prokaryotes" are a grade.