1. Dinosaurs!
Dinosaurs

2. The first living creatures
About three billion years ago the Earth was very different from today. The continents were not yet formed and the only living things were a few simple plants. Later, tiny boneless animals began to live in the sea. After millions of years these first animals developed into more complicated creatures with shells and skeletons. Eventually certain fish developed organs that meant they could leave the water and breathe on land. They were called amphibians.

3. The first dinosaurs
Some amphibians developed into huge reptiles called dinosaurs. Just 200 million years ago some dinosaurs were the size of a truck. They had four legs, but some of them only used their two back legs for walking or running - rather like today's kangaroos.

4. Giant Dinosaurs
150 million years ago on earth there were plenty of plants and trees because the climate was so good. Perhaps this is why the plant-eating dinosaurs grew so big, almost as long as three buses put together. Their massive size meant that as well as having a brain in their head, they also needed brain cells in their tail to work their hindquarters. They were gentle creatures, but so huge that few animals ever dared attack them. All meat-eating dinosaurs, except the Allosaurus, were small by comparison and only about two meters long.

5. What was the biggest dinosaur
What was the biggest dinosaur? The largest complete dinosaur we know of was Brachiosaurus ("arm lizard"); it reached 23 m in length and 12 m in height (about the length of two large school buses and the height of a four-story building).

6. What was the smallest dinosaur that ever lived?
The smallest fully-grown fossil dinosaur is the little bird-hipped plant-eater like lesothosaurus, which was only the size of a chicken. Smaller fossilised examples have been found, but these are of baby dinosaurs

7. Thank you for listening
Mollie