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Cambrian Period 570-500 MYA
In the Cambrian Period, organisms became more promininent on the planet. Through the Cambrian Explosion, the increase in diversity of lifeforms formed the beginning of the evolution into the creatures represented today. There were shallow seas of which contained relatively warm water, where the polar ice was absent for the majority of the era. -
Ordovician Period 500-435 MYA
Throughout this period, until the mass extinction events that occurred, the sea was cominated by conodants, graptolites, trilobites, brachiopods, bryozoans and echinoderms. There were also a large increase in plant population on the planet. -
Silurian Period 435-395 MYA
In this time, there was quite a few changes to the ocean life. Ice was melting, raising the sea levels significantly. More jawless fish species were starting to appear, along with the first jawed fish. There are also the earliest fossils of vascular plants and centipedes that date back to this period. -
Devonian Period 395-345 MYA
During the Devonian Period, ray finned and lobe-finned bony fish started appearing. The pectoral and pelvic fins started evolving into legs, which allowed them to start walking on land to gather food. There were also sharks starting to develop in the oceans. Seeded plants were also starting to be spread, creating vast and large forests. -
Carboniferous Period 345-280 MYA
The Carboniferous period was named because of all the coal that had been created in this time. There were swampy lands where the ground was comprised of plant matter and water. The moisture would keep the matter from decaying into the ground. Eventually, the matter would condense and be put under the right conditions to create coal. There was also a huge climate change throughout the middle of the period. -
Permian Period 280-225 MYA
The period was characterized from the land animals that existed. Trilobites and many types of marine animals had just become extinct. This happened to be the largest mass extinction in all of life. -
Triassic Period 225-195 MYA
During the Triassic Period, the first dinosaurs started to appear. Both the marine and land life evolved and the first flying vertebrates appeared. -
Jurassic Period 195-136 MYA
The Jurassic Period was the middle period of the Mesozoic Era, known as the Age of Reptiles. The supercontinent, Pangea, broke up early in this period. Earliest birds started appearing, along with mammals. There was also an abundance of dinosaurs. -
Cretaceous Period 136-65 MYA
This period was packed full of plants, which created a great supply of food for the dinosaurs. This was when the dinosaurs were at their peak, when they ruled the earth. The marine life was also very healthy, with an abundance of bony fish. The period ended with one of the largest mass extinctions, the K-T extinction. -
Tertiary Period 68-1.8 MYA
During this period, the world started to cool, resulting in moderate to warm temperatures which ended in a glaciation. Throughout the period, the first placental mammals started appearing, along with large running mammals, similar to elephants. -
Quaternary Period 1.8 MYA - Present
During the last glaciation, near the beginning of the Quaternary Period, a lot of changes occurred. Things such as the great lakes, Hudson Bay, amongst other things. At the time, the glaciers moved from the caps to about 40 degrees latitude. Also, a few new animals evolved, including mammoths, mastodons, saber-toothed cats and glyptodonts. Also, horses, american cheetahs and camels went extinct in America.
