Re: A Little Brain Teaser

[Robert.J.Meyerson@uwrf.edu (Rob Meyerson)]

>Okay, here's a fun question for all of you to ponder: Name one carnivore
>(extant/extinct) that can be confidently said to be derived from an
>herbivorous ancestor. Omnivores don't count - this must be a bona fide
>carnivore (I'm not sure if insectivores count). Some graduate students here
>at Cal were talking about it yesterday and largely were stumped. All I
>could think up was that possibly carnivorous mid-Tertiary kangaroo
>(featured in Paleoworld once). I guess there's also that one
>desert-dwelling mouse that hunts voraciously (the one that howls). Any
>dinosaur examples that anyone can think of (I'm asking for good examples
>here, not wishy-washy possibilities)?

I'm not sure that we can.  Dinosaurs evolved from thecodonts, a largely=
 predatory group.  If anything, there seems to be a popular trend for=
 animals to go the other way (modern seed eating birds, for example).

Ecologically speaking, it makes more sense to go from a predatory trophic=
 level to a herbiverous trophic level, simply because there is more energy=
 available for consumption.  It is when there is a great deal of energy on=
 the herbivory level that carnivory becomes reasonable (it takes a great=
 deal more to support a second carnivore level).

Rob

***
Q. Why is structural geology like a card game?

A. They both have folds.