Visit some of the dinosaurs that lived 220
million years ago.
When dinosaurs first appeared about 230 million years ago the world
was very different to as we know it. There were very few representatives
of any animal groups alive today - no mammals, birds or lizards
(although there were some lizard like reptiles).
What? No grass?
The difference was also apparent in the plant kingdom. There were
no flowering plants, which includes most of the common trees and
trees would not look very familiar to us today, although some
were relatives of modern day ferns and pines. Plant life would
have seemed very drab, just green and brown in colour. There
was no grass, instead, low ground cover would have been ferns
Triassic world was unusual for another reason. About 20 million years
before the appearance of the first dinosaurs, the biggest extinction
the world had ever known had occurred. Over 90% of all plant and animal
species then alive on land and in the sea had died out at this time.
Even in the Late Triassic the world was still recovering and there
was not the usual variety of life normally found on earth.
A giant desert
continents were configured differently to today. All the land
masses of the earth were joined together into one huge continent
called Pangaea. This stretched from pole to pole and its central
region was a vast inhospitable desert.
We can tell this,
as the type of rocks that were deposited at this time have sedimentary
features characteristic of a dry harsh climate. As all the continents
were connected, the animals and plants found in the fossil record
from that time are very similar all over the world.
It took more than 10 million years before ecosystems recovered and
complex systems and larger animals took even longer. Most of the dominant
land animals that were around when dinosaurs evolved were products
of long and established lines of descent.
The Late Triassic was an innovative time in the animal kingdom. By
the end of the period not only the dinosaurs had appeared but also
pterosaurs (flying reptiles), various kinds of marine reptiles, the
first crocodiles, turtles and the earliest true mammals.
Towards the end of the Triassic, 220 million years ago, there was
another extinction, which wiped out many of the non-dinosaurs including
the dicynodonts such as Placerias and primitive archosaurs
such as Postosuchus. It was after this that dinosaurs really
started to radiate and diversify.
Dinosaurs gain the edge
It is likely that dinosaurs did not out-compete other animals as has
often been assumed, due to their superior speed and agility, but that
they were fortunate in that they were not hit as hard by the extinctions.
Another extinction at the very end of the Triassic, wiped out the
remaining basal archosaurs and the dinosaurs were the only large land
A vicious little
carnivore, it's an
reptile will eat
its own young
An early pterosaur,
it catches insects
in its pin-like teeth.
A gentle herbivore,
ready to use its
tusks in defence.
and a beak
help it thrive.
Click the maps
to see how the Earth has changed in the last 220 million years.
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