From: John Conway <john_conway@mac.com>
Reply-To: john_conway@mac.com
To: dinosaur@usc.edu
Subject: Re: How Did Hadrosaurs Survive?
Date: Tue, 29 Oct 2002 22:54:35 +1100
On Tuesday, October 29, 2002, at 10:26 PM, Tim Donovan wrote:
Newly introducd predators have devastated some ecosystems. The brown
tree snake wiped out nearly all of the native birds on Guam. New species,
including predators, are said to evolve in isolation, then spread.
Essentially there may be little difference between the effects of a newly
evolved predator and a newly introduced one. The advent of Tyrannosaurus
apparently resulted in the extinction of various Edmontonian taxa least
able to fight it or evade it e.g. Euoplocephalus, which was replaced by a
larger Lancian defender.
There is a BIG difference between the effects of a "newly evolved" predator
and a newly introduced one. Evolution of a predator gives time for an
evolutionary response from prey. Predators do not evolve in a vacuum. For
this reason I take exception to the line "advent of Tyrannosaurus", as if
Tyrannosaurus just "arrived". Tyrannosaurus evolved alongside hadrosaurids,
and hadrosaurids with it - show me the fauna with tyrannosaurids but no
hadrosaurids.