> Ok...let me summarize what I think I understand.
>
> A long time ago there were supercontinents...pangea and gondawondaland. These
> huge landmasses allowed for tremendous ranges supporting the evolution of
> extremely large animals.
>
> Also...very large critters are an evolutionary response to cooling
> enviromental cooling. Witness whales living in artic waters. The megafauna
> of the Ice Ages.
>
> That being the case the HUGE dinosaurs would seem to have been ice age
> critters also?
Not necessarily. Its a function of their cooling demands. If they spent a lot of
time in water, they would of course be cooled more efficiently than if they were
in open air all the time, so they would trend bigger without necessarily a cold
climate. However, there is some evidence that at least some dinosaurs were evolved
to live in rather chilly climates.
Additionally, another persons comments about the nutritional content of flora of
the jurassic period is also relevant, in that a) needing to eat much more food to
get equal nutritional content will tend to trend animals to larger sizes, as they
need to engage biological economies of scale to eat right, and that b) larger
animals tend to have slower metabolisms, and thus require a lower percentage of
their body weight in dead mass food intake. Small animals like small birds and
shrew must eat at least their entire body weight each day in food to survive,
while you and I only need around 5% of our body weight or less in food each day,
using todays highly nutritious food. This is also one reason why modern humans
tend toward the obese (besides the lack of exercise), as their bodies are evolved
for a much less nutritious diet.
Dinosaurs, which were cold blooded or semi-cold blooded, were evolved to eat a
much less nutritious diet than is presently available. I imagine that if any were
alive today, they would die early of obesity related health problems. THis could
also possibly be a contributing factor to their demise. Imagine that a much more
nutritious plant evolved, which was very sucessful at reproducing and spreading,
and became a staple diet for dinos. All of the herbifores would become fat and
easy for predators to catch, while the predators, now eating this 'cornfed' meat,
would start developing cholesterol problems, cardiopolumonary disease, etc....
>
>
> Hmmmmmmm.....Brontosaurs wading thru snowdrifts munching from the tops of
> then-equivalent pine forests? Stegasaurous being the equivalent to Bison?..
> Allasuraus being that peroids's dire wolves?
>
> Every critter fills a niche...
>
> How for wrong am I?
>
> But that leaves the question....64 million years ago when the dinokiller hit.
> Was it glacial? Was Gondawandaland (or pangea?) dispersed to be the map we
> are more familair with today? After all the dinoblaster is reputedly resting
> beneath the gulf waters near the Yucatan. Were the big dino's already gone
> then?
Its thought that most dinos in North America at least were killed off by the
blast, as the regolith from the blast settled mainly over north america, and the
large tidal flood reached far up the missisipi valley to canada. The amount of
dust blown into the sky would have been up long enough to kill off most plant life
for sufficient time for most of the remaining dinos to die off from starvation,
though I imagine that there were sufficient lizards species that survived that
they were around long enough to become todays modern birds and reptiles, while
creating an instinctual fear of reptiles in mammals.
-- TANSTAAFL!!! Michael Lorrey ------------------------------------------------------------ mailto:retroman@together.net Inventor of the Lorrey Drive MikeySoft: Graphic Design/Animation/Publishing/Engineering ------------------------------------------------------------ How many fnords did you see before breakfast today?