1. Dinosaurs
Dinosaurs, one of the most successful groups of animals (in terms of longevity) that have
ever lived, evolved into many diverse size and shapes, with many aqually diverse modes of
living. The term “Dinosauria” was invented by Sir Richard Owen in 1842 to describe these
“feafully great reptiles, “specially megalosaurus, lguanodon, and Hylaeosaurus, the only three
dinosaurs known at the time. The creatures that we normally think of as dinosaurs lived during
the Mesozoic Era, from late in the Triassic period (about 225 million years ago) until the end of
the Cretaceous (about 65 million years ago). But we now know that they actually live on today as
birds.
Some things to keep in mind about dinosaurs :
Not everything big and dead is a dinosaurs. All to often, books written (or movies made)
for a popular audience include animals such as mammoths, mastodons, pterosaur, plesiosaurus,
ichthyosaurs,and the sail-backed.
Dimetrodon. Dinosaurs are a specific subgroub of the archosaurs, a group that also
includes crocodiles, pterosaurs, and birds, although pterosaurs are close relations, they are not
true dinosaurs. Even more distantly related to dinosaurs are the marines reptiles, which include
the plesiosaurs and chhthyosaurs. Mammoths and mastodons are mammals and did not appear
until many millions of years after the close of the Creatoceaous period. Dimetrodon is neither a
reptile nor a mammal, but a basal synapsid, i.e., an early relatives of the ancestors of mammals.
(Was invented by Sir Richard Owen in 1842)