The word dinosaur comes from
the Greek language. It means
‘terrible lizard’. People decided
that these creatures should be
called dinosaurs because they
were so big. They were not really
talking about how scary they
People believe that dinosaurs were
living on the earth until about 65
million years ago. Scientists think
that the dinosaurs became extinct
very quickly because of a big asteroid
that might have fallen on the earth
or because of a volcano erupting.
The asteroid theory
The volcano theory
There were two main types of
dinosaurs. The main difference in the
2 groups were the shape of their hip
joints. Dinosaurs that had hips like
lizards are called Saurischia. The
other group had hips more like birds
and they are called Ornithischia.
Saurischia are divided into two main groups.
1. Theropods - They are the only meat-eating
group of dinosaurs. They walked on three-toed
bird like feet with sharp claws. They had
powerful legs and short arms.
2. Sauropods – these were lizard footed
reptiles. They were the really large herbivores.
They walked on all four feet, had small heads
and long necks and tails.
A T-Rex is
of a theropod.
Ornithischia - bird hipped
All of the dinosaurs in this group were
herbivores. This means that they only ate
plants. There were 2 main groups. They
were the Thyreophora and the Cerapod
groups. The dinosaurs included in these
groups were plated, armoured, and horned