[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Triceratops

Christopher Ott wrote:
As far as the number of characters goes, what is a good number?<
From my far from perfect understanding of cladistics, it seems that a good
rule for a minimum number of characters is about one and a half times the number of taxa. So, if I was to run an analysis of four animals, I'd want 6 characters at least. And the more characters, the stronger your phylogeny will be.

If you have too many, why not call them a different genus?<
Well, if you have 20 characters, and most or all of your taxa have them, that wouldn't seem to me like reason to separate the taxa. :) Really, I think that the point of having a multitude of characters is not to say that many characters will separate taxa, but instead to be able to draw conclusions based on what the characters tell you. The more characters (shared or derived) that you have, the more faith you can have in the data (theoretically).

When you think about the biological concept of species, would the two types interbreed in the wild? Interesting thought to ponder.<
Indeed, quite interesting! I think about this a lot, actually. I can understand (maybe) more than one species of the same genera inhabiting the same temporal and geographic area, but when you get to theropods (dealing with dinosaurs), it becomes less likely. If you know that there are at least four carnivores (let's take the Kayenta here, for example) in the area (Shake-And-Bake, _"Syntarsus" kayentakatae_, _Dilophosaurus_ and the Morales and Bulkey ichnotheropod), I find it very hard to believe that there would be two species of any of those taxa, especially competing in such a non-prey rich environment such as the Kayenta. Anyways, getting off on my own rant now. Time to stop.

Student of Geology
Northern Arizona University
P.O. Box 20840
Flagstaff, Az. 86011
AIM: TarryAGoat
"A _Coelophysis_ with feathers?"

Get your FREE download of MSN Explorer at http://explorer.msn.com