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Re: Trying to falsify the bolide



Since you invoke me, and since most of these issues rest on observable or
commonsensical ideas:



On Fri, 21 Aug 1998, larryf wrote:

> I personally believe the
> very basic cause of the extinctions is the blocking of
> photosynthesis...period! 

Yes, I have a question regarding that, too.  Cloud cover can cause the
_Greenhouse Effect_.  How does anyone determine whether the dust cloud's
effects would be high or low temperatures?

> Nuclear winter, Acid rain, and all the other effects, if
> they occurred, were trivial (in degree). They don`t explain the facts, they
> only complicate the matter. As they don`t seem to fit, I just ignore them. 

But I don't think you can.  If enough light is blocked to stop
photosynthesis, there are bound to be other effects.  Regarding acid rain,
I read something (in Geology, I think), that initial estimates of sulphur
were significantly over the top.

> "This defoliation....would have much more serious effects on bird
> populations--many of today`s species...depend on it for predation
> protection."
> I`m not so sure of that,..I would think that the lack of foliation would
> prevent an ambush from predators. If the birds could more readily see the
> attacker, they could then just fly away.

Depending on the size of a bird, most seem to fly into the trees for
protection.  What many fear most is a sudden "ambush" while they are
in open space from the air in the
form of hawks, etc.  And when a hawk is in the trees it is advertized
loudly by many of the surrounding birds.  Small to medium-sized birds (not
all) seem to be in their element in a well-foliated canopy.

> " Without cover, mammals would be at the mercy of larger predators."
> 
> By these larger predators, I assume you mean theropods? Didn`t they hunt by
> day, and the mammals only come out at night?

While this information is hard to come by (we simply don't know), we
assume that some were nocturnal.  However, there is absolutely no reason
to say most were.  I believe they filled niches similar to mole-racoon (by
the way, has anyone here heard of sheep-sized, Perutherium?) sized mammals
of today.

> " No one is suggesting , I think, that with all the fruit, leaves, and prey
> gone there will now be a bumper crop of insects so that all can get by."
> 
> No, not all, just the insectivores.

But it was more than insectivores what survived--"various
species of Gypsonictops and
Purgatorius..." (_Mesozoic Mammals_ Kielan-Jaworowska et al) have been
interpreted as omnivores and frugivores.  And _Cimolestes magnus_ as a
possible carnivore on larger animals.  And Protoungulatum as probable
herbivore.  I believe these are accurate.  I will try and do some reading
today to check them.  This information is just so hard to find.  And yet,
it perhaps contains the potential to falsify the bolide-as-sufficient
idea.

> Will the discussion  end on this note??

I agree, a little closure is in order on at least the info above as is
_knowable_.