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Re: Theories on the extinction of dinosaurs




On Sat, 13 Nov 1999, Larry Febo wrote:
> 
> 1)large bolide strikes, and kicks up enough dust particles to block out
> photosynthesis for a few months.

> 2) all herbivores die off for lack of food.

Condylarthran mammals--some of them at least--were likely herbivorous.

> 3)all large warm-blooded carnivores die off
> 4) insects survive
> 5)insectivores (ie. small birds, small mammals, cold-blooded lizards)
> survive

Mammal species which had dentition unsuitable for insectivory survived
very well!  No evidence for the extinction (mass or otherwise) of any
birds.

> 6) some large cold-blooded predators that can survive a few months without a
> meal
> 7)plants grow again from seed
> 8)existing biosphere radiates genetically to fill unused niches, new
> herbivores develope, mammals get their chance, 

But mammals appear more poised to exploit rather than stumbling onto a
good thing.


> because the secondarily
> flightless birds are now toothless, and their wings have become too
> specialized to become very usefull as "mammal graspers"

Tell that to the victims of phorusrhacoids, eagles, etc. etc.

,...theropods loose
> their "reign of terror"...(at least on the scale of the Mesozoic...despite
> the presence of a few "terror birds" of the Paleocene).

But isn't that the point?  If birds remained fully competent predators of
mammals, they should have been able to continue their reign of terror
unless something else were repressing them.