Classification of Organisms

All living organisms are grouped on the basis on their path of evolution and the characteristics they share with other organisms, this of known hierarchy. Hierarchy of classification is demonstrated below;

Groups .... Example; Man
Phylum: Chordata

Class: Mammalia

Order: Primate

Family: Hominidae

Genus: Homo

Species: Homo. sapiens

So what about dinosaurs ?

Dinosaurs are member of class Reptillia, Within the class dinosauria there are two orders; Saurischia: (Sauros - Lizard; ischia -- hip) Ornithischia:: (Ornith- Bird; ischia - hip).

Dinosaurs first emerged 228 Million years ago and died out 65 Ma . To put this in perspective, consider the Earth's life History as one year, the dinosaurs existed on Earth from December 11th to December 25th. Whereas humans only arrived on December 31 at approximately 11:50 pm.

Figure 1 : Doodle of December
Now look at how long each period, the Cretaceous, lasted for. Stratigraphic column

Late Cretaceous: dinosaurs were diverse and numerous. Splitting of the super-continent; Pangea created isolated continents of Gondwanaland and Laurasia:, so groups had to remain in one area, this is known as Endemism, rather than having a global distribution of all species.

Figure 2: How the world looked in the Cretaceous. Well not exactly but it's close.

Southern continents generally contained
sauropods, some ornithopods and theropods. Northern Continents : sauropods, ceratopsians and hadrosaurids and carnivores such as the infamous Tyrannosaurids.
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