How do we know about life in the past

We find out about life in the past by looking for evidence. Fossils are one kind of evidence. They are the remains of living things that have been preserved. Objects made by humans, such as stone tools, are another kind of evidence.


Is it true?

Plants can’t be fossilised.


  1. Plants can become fossils, in the same way that animals can. By studying them we learn about the plants that once grew on Earth.


How is a fossil made?

It takes millions of years to make a fossil. The pictures on the left show how it happens.

(1)     An animal dies. Its body sinks to the bottom of a lake.

(2)     Sand and silt cover its body.

(3)     The flesh rots away. Minerals seep into the bones and turn them to stone. The animal is now a fossil

(4)     The fossil is found.



Who Looks for prehistoric life?

People who look for remains of prehistoric animals, such as dinosaurs, are called palaeontologists. People who look for ancient humans are archaeologists. They find great things, such as bones, tools, buildings, jewellery and weapons.


Palaeontologists excavating fossilised dinosaur bones



A sticky resin that oozed from pine trees trapped insects that landed on it. It hardened into a substance called amber. Prehistoric insects are perfectly preserved inside it.



Which were the biggest dinosaurs?

In the Jurassic age, giant plant eaters called sauropods became the largest animals to walk on Earth. One of them, Ultrasauros, may have been up to 30 metres long and about 18 metres high, which is as tall as a six-storey building!


How do we know that dinosaurs existed?

Scientists called palaeontologists examine dinosaur bones and piece them together. They also study fossilised footprints, nests and eggs, dung and even tooth marks on bones.


Which were the smallest dinosaurs?

Compsognathus was the size of a turkey and weighed about three kilograms. It hunted insects and lizards. Heterodontosaurus and Lesothosaurus, both plant-eating dinosaurs, were just as small.



Which were the heaviest dinosaurs?

Ultrasauros may have weighed as much as 50 tonnes, but scientists have recently found evidence of an even bigger dinosaur in Argentina. The gigantic Argentinosaurus may have weighed as much as 100 tonnes. Most sauropods were smaller, weighing between 30 and 80 tonnes.



The neck of Mamenchisaurus was 15 metres long, strengthened by a system of spines. It could not have been lifted very high. Mamenchisaurus probably fed on low-growing

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