WHAT MAKES A DINOSAUR?
During the Cretaceous period, dinosaurs were at their peak in size, variety and numbers, dominating every continent and land mass. The first dinosaurs were probably two-legged hunters no bigger than a dog. However they would soon evolve into a huge variety of shapes and sizes that spread around the world. Palaeontologists can tell a dinosaur apart from other kinds of fossilised animals, by the details in the bones of its skull, shoulders, vertebrae, hands, hips and hind limbs. These show that dinosaurs walked with limbs erect and on their toes, not flat-footed like bears today. Without living specimens to study, we cannot know for sure how their bodies worked. Dinosaurs came in a variety of different shapes and sizes
BIRDS
Several features allow birds to be distinguished from their closest relatives- the dinosaurs. Skeletal features such as a reduced tail and distinctive feet set birds apart from other animals. Although all species of birds pocess feathers, this is not a characteristic that set them apart from other early types of animals as some dinosaurs also had feathers. The first birds developed in the Late Jurassic.
EARLY BIRDS
Their tail, hand and chest bones were much like those of today. Speculation remains whether flight in birds originated from running or climbing dinosaurs. Primitive birds pocessed features associated with flight, but some may have lived on the ground. The loss of serrations on teeth and the shortening of a tail are trends that reflect the move towards a lighter skeleton for more agile flying abilities. The evolution of the alula, the part of a bird's wing that corresponds to a thumb, allowed birds to become better flyers. Later birds developed stronger wing and chest bones, and had more flexible necks.
The oldest known bird is Archaeopteryx (right) that lived 150 million years ago. |
ANCIENT WINGSCIENTIFIC NAME: Archaeopteryx
SIZE: 60 cm long DIET: Small animals HABITAT: Tropical desert islands DESTINATION FOUND: Western Europe TIME: Late Jurassic period |
CONFUCIUS BIRDSCIENTIFIC NAME: Confuciusornis
SIZE: 60 cm long DIET: Plants and seeds HABITAT: Lakeside forest DESTINATION FOUND: East Asia TIME: Early Certaceous period |
HESPERORNISSCIENTIFIC NAME: N/A
SIZE: 1.8 m long DIET: Fish, small sea animals HABITAT: Coastal areas DESTINATION FOUND: North America TIME: Late Cretaeous period |
NEW BIRDS
Althought the dinosaurs died out about 65 million years ago, their decendants the birds survived the mass extinction. Throughout the Cenozoic, they evolved into many different species suited for life in almost all parts of the world. Today birds flourish with more than 9000 species outnumbering mamal species nearly two to one. But Cenozoic bird species didn't suvive to the present day.
SCIENTIFIC NAME: Titanis
SIZE: 2.5 m tall DIET: (Carnivore) Meat HABITAT: Grassland DESTINATION FOUND: North America TIME: Tertiary and Quaternary periods |
GIANT BIRD |