About 440 millions years ago ,the first life appeared on land .It was simple plant life,similarly to today's mosses.Then ,about 400 millions years ago,the first land animals -worms,spiders, scorpions and insects- evolved as they moved on to the land . FACT. Are there any amphibians alive today?
Yes. There are many different amphibians
In the world today. Frogs,toads and salamanders are all amphibians.
Some fish began to live in shallow water,It was difficult to swin in the shallows.To help these fish move around they grew shorts legs.Some of them also grew lungs,which meant they could breath air.These animals could live in water and on land .
Fact. The lungfish is one of today's fish that can
Live out of water. It can breath.
An animal that can live in water and on land is called an amphibian.It means 'double life'. The first amphibians appeared by 350 millions years ago.Gradually ,they spent more and more time on land. About 30000 millions years ago,some amphibians changed into reptiles.They could
live on land all the time .Reptiles have backbones and scaly skin ,and most lay eggs.Many reptiles
such as crockodiles,spend lots of time in the water,but they can't brath underwater.They use the sun to keep their bodies warm. FACT. Dimetrodon had a skin 'sail' on it's back. It soaked up the sun's heat, and controlled the body temperature.
The first reptiles ,such as Hylonomus.were small lizard like animals that ate tiny creatures.
Reptiles learned how to run quickly so they could catch fast moving insects.As reptiles become
larger ,they caught and eat bigger prey,including others reptils.Some reptiles only ate plants.
FACT. A SMALL ANIMAL FOUND IN SCOTLAND,
ROCKS THAT ARE 350 MILLION YEARS OLD,
MIGHT BE ONE OF THE FIRST REPTILES. BUT SOME SCIENTISTS SAY IT WAS AN AMPHIBIAN.
Some prehistoric reptiles grew fur on their bodies to keep themselves warm.These were cynodonts.
They lived about 245 millions years ago.Over time they changed into a completely new group of animals,called mammals.