Re: AAT Questions...

Ralph L Holloway (
Wed, 2 Aug 1995 11:32:26 -0400

On Tue, 1 Aug 1995, Elaine Morgan wrote:

> Convergent evolution is a respectable scientific concept. The examples
> most commonly given are the way the dolphin acquired a fish-like
> silhouette, and the way the aardvark and the pangolin became
> look-alikes. It is usually a suite of changes in behaviour and
> morphology which is so described, and there is a fixed and perfectly
> natural expectation that an animal will be currently occupyin the niche
> for which the convergence has specialised it.
It might be useful to canvass positions among leading evolutionary
writers with regards to convergent and parallel evolution. I'm
admitterdly behind the times, but when I teach introctory students
regarding convergent evolution, and use some of the examples that Elaine
has mentioned, I also add that convergent evolution happened between
animals FAR removed from each other, taxonomically. As I learned it
(mostly from reading G.G. Simpsons bookS) one used parallel evolution to
talk about similarities when the animals were of close genetic
relationships (e.g., new world and old world monkeys) and convergent
evolution for those forms where the convergence for an adaptation to an
environmental similarity between forms that were far genetically removed
from each other. (i.e., Cetaceans vs Fish...)
(Perhaps Guy Hoelzer can come in here?)
This, I hope, explains some of my inital irritation (too strong a word,
Elaine) with Elaine's use of convergence when discussing pongids,
hominids, and AAH.
Ralph Holloway