Cambrian Ocean World: Ancient Sea Life of North America

Cambrian Ocean World: Ancient Sea Life of North America

Cambrian Ocean World: Ancient Sea Life of North America

Cambrian Ocean World: Ancient Sea Life of North America

Synopsis

The Cambrian is our origination story; the species fossilized in the rocks are our "founding fathers." We can follow their story (and ours) through more than half a billion years of time.

Excerpt

Somewhere in nearly every state or province in north America are Cambrian rocks recording the history of life in one of the most important time periods in Earth history. in Vermont, Washington, Virginia, Wisconsin, California, Alberta, British Columbia, Sonora, New Mexico; in Nevada, Utah, Colorado, Pennsylvania, South Dakota, Oklahoma, Idaho, Texas, Alabama, Wyoming – the list goes on. Rocks of Cambrian age are almost everywhere. and in them we find some of the earliest complex animals to appear on Earth. the diversification of animals in the Cambrian is astounding.

By any human measure, the Cambrian period was an incredibly long time ago, but in terms of the story of our planet it only began after most of Earth history so far had already unfolded. It would be another 315 million years before mammals or dinosaurs would appear on the scene – or nearly five times as many years as have passed since the dinosaurs (other than birds) disappeared and left the world to the mammals, in our chauvinistic view. From the perspective of the most diverse major animal group of the Cambrian (the arthropods), however, the world of the Cambrian was theirs then, and still is now, as today the number of insect species alone is nearly one million. the only major loss to them since the Cambrian is that of the trilobites, the proverbial fossils of the Paleozoic era. Even trilobites outstripped other famous fossil groups in terms of diversity. We know of around a thousand species of dinosaurs from the fossil record; modern mammals number around six thousand species; birds are all the way up around ten thousand. the lowly trilobites? Twenty thousand species! Although they may have inflated numbers due to high preservation potential, as fossils trilobites own the Paleozoic.

The Cambrian period on Earth might as well have been another planet, compared with what we are used to today. This is the story of a different time and place. the time is incredibly distant; the place, not so.

The Cambrian period was obviously a very long time ago, but why was it important? It was nowhere near “early” in Earth history; 80 percent of that history occurred before the first years of the Cambrian. the world of the Cambrian represented a time quite different from most before it in terms of environmental conditions. This parallels differences in the biotas. But the Cambrian was probably most important because it was, quite simply, the birth of our modern biological world. Whereas the previous 3 billion years were occupied almost exclusively by microbes, and only shortly before had multicellular animals appeared, almost all . . .

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