700 – 600 million years ago

Year forty
The earliest fossilised, multicelled animals

The earliest fossilised, multicelled animals

So far, all living things were made of just a single cell and almost all organisms lived in the sea. However, organisms constructed of more than one cell eventually began to evolve. Some members of the protist kingdom evolved into organisms with more than one cell (a familiar example where this has happened are the sea weeds, or algae, which are protists and not plants). Animals must have evolved in this way, although exactly when this took place is not known.

Animals made of many cells must have looked very simple at first, but just before Earth's 40th birthday (between 700 and 600 million years ago) they evolved into several different soft bodied creatures. Sea pens were attached to the shallow sea floor where they waited for the water currents to wash food to them. There were animals that looked a little like sea urchins that crawled about on the sea bed, worms that burrowed into it, and creatures resembling jellyfish that swam in the waters above.

It is very rare to find fossils of soft bodied creatures, but they are found scattered all over the world, including Britain. Fossilised sea pens found at Charnwood, near Loughborough, are similar to those in Australia. The sea pen is called Charnia masoni; the name 'Charnia' comes from Charnwood and 'masoni' comes from the name of the schoolboy who first found it, Roger Mason. This is one of Britain's oldest fossils and one of the oldest known animals.


Back to the beginning of the timelineBack to the beginning of the timeline

The timeline is interactive. You can move forward or back in time, exploring at your own pace. When you reach the end, test yourself with the timeline quiz.