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. It¹s 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 Earth¹s 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.

Category: Science