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Re: dino extinction?
On Tue, 6 Oct 1998 11:20:37 -0400 Allan Edels writes:
> However, we don't know which if any, we don't know which way the
selection might >have leaned (i.e. too warm => all males, too cool => all
females - or vice versa!)
It's even more complex than that. Reptiles which do exhibit
temperature-based sex determination (TBSD) often show a varying selection
over a range of temperatures. That is, of a given clutch of eggs, almost
all might be male at the lowest safe temperature range of incubation;
mixed male/female at mid range; almost all female a little higher; mixed
at slightly temperatures; and almost all male at the highest range of
safe incubation temperatures. This can be a real headache when you're
trying to breed reptiles for the pet trade (which I don't do, but
communicate with some people who do).
Also, TBSD sometimes depends on ambient temperatures at a certain stage
of development. I highly suspect that this is true for all TBSD cases,
but have no data to prove this idea. Sort of thing that can be written
up for a herpetological journal. This stuff can be a real headache.
Anyway, finding TBSD in dinosaurs is highly problematical, given these
If one says a vacuum cleaner "sucks", does that mean it doesn't?
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