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Re: Copeing with mammals

On Sat, 27 Nov 2004, David Marjanovic wrote:

> Not in the least. In the first scenario, birds can actively push pterosaurs
> out of ecological niches; in the second, they can only evolve into empty
> niches.

OK...birds are better at evolving into empty niches.  Why?

> With that kind of fossil record next to nothing can be said about this.

Still, we manage quite well.

> Then why don't you take a look at precisely what those differences are, and
> use that knowledge to _base_ a hypothesis of competition upon it?

With warmth and feathers, birds can persist in colder climates.  This
might be especially important in incubation, etc.

Feathers are light, need less bone support, enable longer flight at less
energy expenditure.

Parental care enables longer period of development, therefore more brain
development, therefore better processing of environmental info relating to
predators and or prey.

Agility in flight allows a tighter turning circle, reverse of direction
for predator avoidance/prey capture

Nest building allows greater range of nesting habitats/concealment.

Communication between group members is facilitated by bigger brains and
longer chick-rearing (e.g., learning the song).

Better sensory equipment allows for better prey capture/predator

In many of these I am aware that while we know about birds, pterosaurs
abilities are not well known.

> > Unless you are hardline Etheridgian (one who says that
> > _all_ species distribution is a result of
> > past catastrophies and species taking advantage of open niches).
> I've never heard of this view, but I don't agree with it. When species
> split, their ecological niches usually split with them.

Oh, Geez.  It should be Eldridgian after Niles Eldridge, who said _all_
speciation follows catastrophies.