Warm/Cool/Cold blood

[Ralph Lindberg <dragonsl@hebron.connected.com>]

        One of the things that bothers me about the warm/cool/cold blood
arguments relates to the theory that nature does not like to invent the
same idea twice. 

        Baker's argument that dinos and birds are related, and that warm
bloodedness was in their common ancestor leaves one gaping hole to me. No
"family tree" I have even seen left any doubt that early mammals existed
before the dino/bird branch broke off the reptile. 
        Does this mean that warm bloodedness arose at least twice, Once
for the dino/bird and once for mammals. Or does it mean the theory is
correct and that dino/bird/mammals broke off of the reptile branch in
some, as yet, unknown way?
        Personally I think that some ancestor of the dinosaurs, birds and
early mammals evolved "cool" bloodedness. Then the various branches
evolved this in various ways, and to various degrees of "warm". This means
that the dino/bird/mammal ancestor broke off earlier then we normally
believe. But considering how "holey" the fossil record is this is very
possible. 

Ralph Lindberg email=>dragonsl@hebron.connected.com
more hobbies then time