Cambrian Era Research Paper

Ian McCafferty
Geology 101
Cambrian Period

The Cambrian period, part of the Paleozoic era, started around 543 million years ago and ended about 490 million years ago. This period is known to have produced the most intense burst of evolution ever known, and that’s how it got its nickname “Cambrian Explosion” because of a dramatic burst of evolutionary changes in life on Earth. The Cambrian period is known as period, which is the most basic unit of geologic time. The name “Cambrian” got its name from a place in Wales where the first fossils of this type of ancient life were found. (Live Science, National Geographic). No one quite yet knows what sparked this biological revolution. Some scientist think that it had something to do with the …show more content…
Evidence shows that there was a single supercontinent, named Pannotia, that broke apart to form four other supercontinents. One, Gondwana, which was the biggest of the four, formed much of the land that is now modern Africa, Australia, South America, Antarctica, and India. Another supercontinent, Laurentia, was located more near the equator and composed of modern North America. The other two, Siberia and Baltica, were smaller than Laurentia and Gondwan, and they composed of modern day Europe. Because of a warming climate, the melting of glaciers caused rising sea levels which led too flooding and low-lying landmasses to create shallow, marine habitats ideal for the evolution of new life forms. At the beginning of the Cambrian period, no life existed on land; all life was aquatic. Photosynthesis and the primary production of bacteria and algal is what led to the population of the worlds shallow seas. The chordates, animals with a dorsal nerve cord; also animals known as brachiopods, which …show more content…
But the process did not happen with just the blink of an eye. It took millions of years of evolution during the Precambrian eon. Animal fossils have been found from roughly 575 million years ago, an interesting animals lived in the oceans, known as Ediacarans. Even though we don’t know much about this interesting group of animals, they might have included ancestors of the families that we can identify from the Cambrian explosion. Right now there are two main accepted hypothesis for the Cambrian extinction; the Glacial Cooling Hypothesis and the Oxygen Depletion Hypothesis. The first hypothesis, the Glacial Cooling Hypothesis, was developed by James F. Miller of Southwest Missouri State University. In Miller’s hypothesis he states that he has found evidence of early Ordovician sediment of glacial origin in South America. He suggests that this evidence of continental glaciation at the boundary of the Cambrian-Ordovician periods’ is responsible for the decrease in global climates. Because the animals that lived during the Cambrian period were used to living in a warmer climate, they could not survive the colder conditions. He also suggests that continental glaciation would bring large amounts of water onto the the surface in the form of glacial ice. Because of this frozen water on the surface, a decrease in ocean water happened, reducing the amount of shallow seas. And because of this, Miller

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