[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: Radiation of species at late mid-Triassic
> Can anyone explain the extraordinary radiation of new orders of animal life
> late in the mid-Triassic. This fruitful period spawned the earliest
> dinosaurs, therapsids, thecodonts, pterosaurs, and perhaps even birds.
The main cause was probably the depauperation of the fauna after the
P-Tr extinctions. This left many open ecological opportunities
to be filled in by new forms. Such adaptive radiations are fairly
normal when an 'empty' ecological zone is avialble to exploit.
> remarkable diversification of higher life forms has not been
> matched since.
Well, the radiation of mammals and advanced birds in the Paleocene and
early Eocene comes close. To the extent it falls short fo the
mid-Triassic radiation, this is probably due to the fact that the
P-Tr extinctions were *far* more extensive than the K-T extinctions
(despite the latter being more famous).
> What environmental factors contributed to this, other than the
> Permain-Triassic extinctions?
I doubt there were any others.
The shear magnitude of the P-Tr extinctions is probably enough.
After all, the P-Tr extinctions were the largest since the end
of the Precambrian.
The peace of God be with you.