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Hi,
Something I wonder... There's a diversity of food
preference among our herbivores mammals (let's take Cervidae for
example).
So, was it possible that some species of
Sauropods prefered ferns, others, conifers or maybe some species of
conifers?
In this case, there were ecological niches not only
based on size of the food, but also on the nature of the food (species of
plants.)
Cheers,
Luc J. "Aspidel" BAILLY.
----- Original Message -----
Sent: Thursday, July 05, 2001 6:46
PM
Subject: Re: Morrison Sauropods\etc.
(long)
There is quite a
diversity of huge (= adult) plant eaters in the Morrisson
Formation with
Apatosaurus, Barosaurus, Brachiosaurus, Camarasaurus,
Diplodocus and
Haplocanthosaurus compared with todays eco-systems. Every
genus may have
filled a different ecological niche to evade direct competiton.
But
this is only the tip of the iceberg. There must have been an abundance of
sauropod babies and juveniles. According to Gregory Paul in "Dinosaur Eggs
and Babies" a sauropod could have produced between 500 - 4000 eggs in a
40-year interval.
For us humans to keep population size stable a
woman must have about 2.1
children on average. If we take , let's say, an
average of about 1000 eggs
per female sauropod for this, this would mean
that sauropods needed about 500
times more offspring to keep their numbers
stable.
This in turn would mean that there was a huge number of
juveniles (with a
very high mortality rate, what a carnage), which
contained the real genetic
variety needed for survival of a species. So
the total number of adult
animals needed for survival may have been very
much lower as in today's
mammals.
But the problem I see is that
juveniles of at least six different genera
competed for food and shelter.
And that with a basically identically bauplan.
At young age sauropods
genera must have been more similarily built than later
as adults.
Additionally there were an overlap in size. This means e.g. each
genera
reaching at some time of their growth food in a height of two meters.
And
this independently of their later adult sizes.
So the real competition
was in the kindergarten including theropods bigger
than these youngsters.
Any comments are welcome.
And now cheers from a sunny Germany
(time to go swimming)
Heinz Peter Bredow
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