Ariesfire-+The+Cambrian+Period

__ The Cambrian period __ In the beginning of time, there was the Big Bang, the earth formed and there was a time called the Pre-Cambrian. Then there was the [|Cambrian period], which lasted 544 million years ago to 505 million years ago. The Cambrian period was a busy time, called the “Age of Trilobites”, one of the many creatures that surfaced during the mass evolution and life explosion at the beginning of this period. During the Cambrian period, organism increased in variety, complexity, and quantity. The first vertebrates even appeared! The Cambrian period was also the beginning of the Paleozoic Era.

Before the Cambrian was the Pre-Cambrian time, where there were many important events. In this time, 4.6 billion years ago to 543 million years ago (88% of Earth’s history!), the earth formed, oxygen became present, and the first life forms became present. There was also the first mass extinction and ice age.
 * BEFORE **

After the Cambrian, there was the Ordovician Period, where plants invaded the land. Also, there was another ice age and mass extinction.
 * AFTER **

In the Cambrian period there were two super continents, Laurasia and Gondwana. Gondwana was what is now India, South America, Australia, and Antarctica. Laurasia was what is now North America, Asia, and Europe. During the Cambrian Period, the two super continents drifted toward the equator (0° latitude). A small part of Laurasia called Laurentia is now Massachusetts.The climate warmed and ice sheets melted, raising the sea level. The continents looked very different from they do today and from when they formed in the Pre-Cambrian.
 * PLATE TECTONICS & CLIMATE **

** ROCKS & LANDFORMS ** Most of the rocks from the Cambrian Period are now found in the U.S.A. and Canada. Back then, the continental margin was broad and flat, because the Greenville Mountains from the Pre-Cambrian were eroding. The sediments eroded from the mountains were deposited along the east of what would be New England. Later, the sand deposits were replaced with carbonates, which were widely deposited in a large, even shelf along what would be the east coast of North America. Because of ice sheets were melting, oceans were widening and sea level was rising. Warm, shallow seas covered the majority of the Earth.

** FOSSILS ** Because of the major life explosion in the beginning of the Cambrian, many [|fossils] from that period can be found. Scientists have identified over ten thousand types of trilobites, such as the // Phacops // and the // Agnostus //. Crustaceans, like // Brachiaris Pretiosa //, and Mollusks, // Shelbyocera // s for instance, were among the invertebrates fossils found. Also, the first definite vertebrate, // [|Haikouichthys] //, which was a fish, were found and identified as Cambrian fossils.

In the oceans of the Cambrian, a mass evolution took place. New species and subspecies popped up everywhere. Many new invertebrates emerged and even the first vertebrates made an appearance. Arthropod called trilobites ruled the Cambrian, with over 10,000 types, ranging from almost microscopic to almost a meter in diameter. They were among the most various and abundant Cambrian life forms. Mollusks, such as //Salterella//, and sponges, such as //Choia Utahensis//, were among the enormous amount of invertebrates living in this time period. Many more lived and flourished in the Cambrian oceans. A mass event took place in was the appearance of the first vertebrates, fish called [|Haikouichthys]. Its backbone and stiff armor allowed it to still have protection, but move swiftly and with much more control than its invertebrate ancestors. As creatures evolved, they developed more complex behavior. They actively hunted, tunneled deep in the ocean floors, dug burrows, and used chemicals from the water to create protective shells, all enabling them to better survive. Another abundant life form in the Cambrian period was one-celled algae. It is still one of the most common organisms in the world. Many species from the Cambrian are still around, such as jellies, sponges, and mollusks. Sadly, trilobites, the Cambrian’s most famous arthropod, went extinct.
 * LIFE **

Reflection This science project was an interesting mix of non-fiction writing, design and effective research. The topic, geologic time, was quite fascinating and each individual project is unlike the others in numerous ways, as we will see in the following presentations. I chose the Cambrian period, where evolution is a pivotal theme, because I have always been interested in the development of Earth’s organisms. I liked the writing in this and how we could be creative in our design. Finding pictures on Creative Commons proves to be pretty difficult for everybody, but that's the legal way. I also learned a lot about evolution and life. We don’t exactly know how life began, but we have seen evidence of its ever changing ways. In the time period I did my assignment on, a major evolutionary event took place. The first vertebrate swam in the oceans of the Cambrian. That is such an essential part of the evolution of many modern organisms and us. Those 3 cm fish are the beginning of all vertebrates on Earth and it has made me realize, and I hope it makes the readers of this realize, too, that many enormous, crucial things we take for granted have started from things as small as the Haikouichthys. Visit the bibliography for my research and links!

Visit the bibliography for my visuals!