The Cambrian Period

The Cambrian Period

Science 10/26/95

During the Cambrian Period a lot of things happened both geologically

and biologically. The Cambrian Period was the first period of the Paleozoic

Era, it lasted from 570 million years ago to 500 million years ago, 70 million

years. It?s very important because it corresponds with the firs t appearance of

abundant fossils especially Trilobites, which characterizes a succeeding point

in time. During the Cambrian Period the lapetus Ocean appeared, the

predecessor of the Atlantic Ocean, which separated the young North American and

Eurasian continents. Also Gondwanaland was in the final stages of development.

Gondwanaland was a very large continent made up of what is now South America,

Africa, Arabia, Madagascar, India, Australia, and Antarctica. Large shelled

organisms first emerged during the Cambrian. Also Earth?s atmosphere contained

the same amount of oxygen as it does now, enough to sustain the metabolic rate

of a complex organism. Running down the middle of the North American

continent was a large inland sea called the Saulk sea. Inhabiting this sea, and

the other seas of the primitive world, were Trilobites and Brachiopods .

Trilobites were three – lobed arthropods, unlike other arthropods Trilobites

had primitive ,unspecialized appendages. Brachiopods are simple bi- valve

shellfish that resemble clams. During the Cambrian corals and chrinoids

emerged. Chrinoids are sea animals of the class chrinoidea like the sea lily

and the feather star. The only plant life of the Cambrian period were

primitive algae.