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LET'S EXPLORE Prehistoric life

What were the first living things?

Soft-bodied sea creatures, 635 million years agoSoft-bodied sea creatures, 635 million years agoThe first living things probably appeared in the oceans about 3.8 billion years ago. They were tiny life-forms called bacteria. It took another 2.5 billion years before more advanced life-forms, types of seaweed, started to appear. The first animals appeared around 635 million years ago. They were soft-bodied sea creatures, such as jellyfish and worms.

Cambrian explosion

The first animals with hard parts—shells or bony skeletons—first appeared about 541 million years ago. This was at the beginning of a time in the Earth’s history that scientists call the Cambrian Period. A wide variety of living things appeared. It was like an “explosion” of life.
Creatures of the Cambrian seasCreatures of the Cambrian seas

These animals lived in warm, shallow seas. They included shellfish, corals, starfish, molluscs and sponges. Some very strange-looking animals swum in the Cambrian seas. One, Opabinia, had five mushroom-shaped eyes. The largest and fiercest of all Cambrian creatures was the 60-centimetre (24-inch) Anomalocaris. Its name means “odd shrimp”. It had two large eyes set on stalks and a pair of pincer-like arms.

The Cambrian Period is named after Cambria, the Latin name for Wales. Here there is a large expanse of Cambrian rocks at the surface.

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