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

Re: the start



Stan wrote:


>For one thing, dinosaurs were not universally large.  They
>covered the whole range of sizes.  The large one probably evolved
>that size for much the same reason as large mammals evolved,
>escape from predation and/or access to new food resources
>(including the ability of carnivorous forms to eat the large
.herbivores).

However,  I believe only about 2% of modern land mammals reach or exceed the 
mean size of an adult dinosaur, and no dinosaurs are really small..

Those of us who are inclined towards the view of large dinosaurs as inertial
homeotherms would say that dinosaurs increased in size to gain thermal 
stability, whereas mammals were decreasing in size when they become endothermic
with an increased metabolic rate, quite possibly to exploit a nocturnal niche.

Tony Canning
tonyc@foe.co.uk