When did ammonites live?
Ammonites lived about 400 million years ago. They were sea animals with a hard spiral shell, and they probably floated rather slowly through the sea. Some ammonites were as big as juggernaut wheels. At this time, the oceans were full of sea animals with shells of many different shapes and sizes. Some creatures even had two shells.
What were trilobites?
Trilobites were ancient animals that looked like giant woodlice. Their bodies were divided into three parts, or segments, and they had armoured skin. They scurried across ocean floors, looking for food. About 400 million years ago, trilobites of all shapes and sizes roamed the seas. At the same time, other segmented animals, such as crabs and lobsters, developed. Trilobites died out about 250 million years ago.
Did you know? Nautiloids were the ancestors of modern squid and octopuses. They used jets of water to push themselves quickly through the sea after prey.
Which animals are called sea lilies?
The animals called sea lilies look rather like armour-plated starfish on tall stalks. They developed 500 million years ago and are still with us today. They got their name because they wave their tentacles in the water to trap food. This makes them look a bit like flowers. Sea lilies attach themselves to the seabed, and the largest are 20 meters long.
How did coral reefs form?
Coral reefs were formed by tiny animals known as polyps, which were a bit like sea anemones. The coral polyps lived together in large groups called colonies. Together, they formed hard external skeletons to support their bodies. The skeletons slowly built up into large mounds known as coral reefs. The reefs become underwater habitats for many ancient sea creatures.