Earth's First Inhabitants

Crustaceans Ruled the Oceans Before Land Existed

by Leslye Hernandez, age 8

Some of the first creatures to make their home in the ocean were worms, trilobites, and sea scorpions.
One type of animal that lived in the ocean was worms. But unlike today’s earthworms, these worms did not live in the ground. These worms found food by burrowing in mud for small plants and animals.
Trilobites were born 550 million years ago. The name trilobite means three “lobes”, or parts. This animal was special because it had two grooves on its back, dividing the body into three parts. It also has a tough outer shell to keep it safe from predators.
Sea scorpions could grow to be seven feet long and some could be as big as lions. They lived 500 to 250 million years ago. The scorpions had big eyes. These scorpions did not shoot venom out of their tail like most scorpions today do. Instead, they tore apart their prey with their large claws.
Some of the first creatures that lived on earth were crustaceans.  These strange-looking animals lived in the ocean. Although they are very different from the animals we know today, they are still fascinating to learn about.

[Source: 100 Things You Should Know About Prehistoric Life ]