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Re: Climate change



Nick Pharris wrote

>On Thu, 4 Apr 1996, Christopher Nedin wrote:
>
>> Then, day/night temperature fluctuations were fairly small over
>> considerable areas of the globe, making gigantothermy a viable strategy.
>
>We'll see.
>
>> However, with the major climate shift towards the end of the Mesozoic (for
>> whatever reasons), the broad, ameliorated, global climatic zonations
>> collapsed, resulting in the expansion of the temperate zones - complete
>> with their more varied day/night, summer/winter temperature range.
>
>OK, what about the (reduced) temperate zones that *did* exist during the
>Mesozoic?  What of the dinosaurs there?  60 degrees is a ways up the
>earth, but it isn't all the way.  What of the dinos down there in
>Australia, where, someone recently posted, it may have gotten down to -4
>deg C?

None of the dinos found in these locations could be considered "giant". And
that temperature was probably seasonally adjustable.

>> it is hard to re-heat
>> - especially if metabolism is only partially aiding the heating process.
>> The result would be that the big dinos would be forced into the narrower
>> tropical/subtropical zones.  But the whole supporting ecosytem was in
>> collape by then.
>
>Bear in mind that this is all assuming the dinosaurs were gigantothermic,
>which has not been proven (although, alas, neither has endothermy).

Well, we have to start somewhere :-)

Chris

cnedin@geology.adelaide.edu.au                  nedin@ediacara.org
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Many say it was a mistake to come down from the trees, some say
the move out of the oceans was a bad idea. Me, I say the stiffening
of the notochord in the Cambrian was where it all went wrong,
it was all downhill from there.