Janelle Sawers, Age 8, Of Ottawa, Ont.,For Canada, question:

Is a lobster related to a trilobite?

The trilobite said goodbye to our world millions of years ago. This was long before the crusty lobsters eame to live in our seas. The trilobites and the lobsters have never met each other. Nevertheless, we can say that they are related to each other.

The lobster came to live in our salty seas about 180 million years ago. This was the age of reptiles, when the clumsy dinosaurs ruled the world. The last of the trilobites disappeared perhaps 100 million years before the lobsters and the dinosaurs arrived. But some scientists say that the lobster sprang from the family tree of the trilobite.

The earliest fossils date back some 500 million years. They are the remains of ancient animals preserved in stone, and some of the earliest fossils we have are of the trilobites. Some 500 million years ago, these flat and crusty creatures swarmed on the floors of the ancient seas. This was the age of the trilobites.

Fossil records tell us that there were more than 2000 different trilobites, and for millions of years they outnumbered all the other creatures in the world on land or sea. They were flat, crawling creatures. Their bodies were in three sections, somewhat like the insects. They were covered with crusty shells and wore antennae. Most of them were one or two inches long, but some of the giants measured 12 inches.

Through millions of years, the early trilobites changed and improved. There were trilobites that could curl their crusty bodies around to protect their softer undersides. Some of the children of the trilobites appeared with legs and other outstanding ehanges. They no longer qualified as trilobites, though they descended

The ancestor trilobites had all disappeared 200 million years ago. But the family tree did not come to an end. The different descendants of the ancient trilobites lived on and kept improving themselves. Some became the scorpions, the first animals to leave the seas and brave life on the dry land. Another branch of the tree deve1oped long after their ancestors, the trilobites, had all disappeared. They are the lobsters and the crayfish, the shrimps and the prawns.

The lobsters belong in the crusty shelled class of animals called crustaceans. The class crustacea is part of a subdivision of a larger group of animals caued a phylum. The crustaceans and the scorpions, the spiders and all the insects belong in the phylum arthropoda, the jointed footed animals. All of them are arthropods, and the trilobites were arthropods who once swarmed in the ancient seas.