Christian Vazquez - Geologic Timeline

Cambrian Period- 570 - 500 MYA

543 BCE

The first geological time period of the Paleozoic era. The "Cambrian Explosion" marked a burst of evolutionary changes in life on Earth. Trilobites were the dominate species during this time. This period gets its name from Cambria, the Roman name for whales.

Ordovician Period- 488.3 - 443.7 MYA

448 BCE

This period lasted 45 mya. During this time, the north area was almost all ocean and most of the world's land was collected into the supercontinent Gondwana. Throughout this time the supercontinent moved towards the south and was submerging underwater. shallow seas covering a large portion of Gondwana became breeding grounds for new forms of trilobites. Many of the species of Graptolites went extinct by the close of the period.

Silurian Period- 443 - 416 MYA

443 BCE

It was the third period in the Paleozoic era. It continued off from the Ordovician period and preceded the Devonian period. During this time period the sea level was rising and continental landmasses were low. Silurian fossils show evidence of reef building and the first signs that life was beginning to to colonize the new estuary, fresh water, and terrestrial ecosystems. Throughout this time and into Devonian, three northern continents collided forming a new super continent called Euramerica.

Devonian Period- 416 - 358 MYA

412 BCE

The fourth period of the Paleozoic Era. Its known as the "age of fishes." This time was a reef building in the shallow waters that surrounded each continent. The supercontinent Gondwana filled most of the southern hemisphere but it slowly began to drift north. The close of the Devonian period is considered the second of the "Big Five" mass extinction events.

Carboniferous Period- 359 - 299 MYA

318 BCE

This time period was known for its vast forests and can be also called the "coal age." The coal was produced by bark-bearing trees that grew in lowland swamp forests. The growth of these forests removed huge amounts of carbon dioxide, leading to a surplus of oxygen. The atmospheric oxygen levels were around 35%, compared with 21% today.

Permian Period- 299 251 MYA

297 BCE

In this period the two super continents, Gondwana and Euramerica, had collided to form the supergiant pangaea. It was shaped like a thick letter C.

Triassic Period- 251 - 199 MYA

199 BCE

The first period of the Mesozoic era. It had the early mammals and early reptiles roaming around. Most of the continents were formed in a thick C shape. The climate was generally very dry. This era was known as the "age of Reptiles." Only two groups of animals survived the Permian extinction: Therapsids, and Archosaurs. Therapsids were a mammal-like reptile. Archosaurs were more reptilian.

Jurassic Period- 199.6 - 145.5 MYA

145 BCE

The second segment of the Mesozoic era. During this period the supercontinent pangaea started to break apart. The northern half was splitting into landmasses that would eventually form North America and Eurasia. The southern half was transforming into what would be Antarctica, Madagascar, India, and Australia. And the western portion would soon form into Africa and South America. This period was the "age of dinosaurs." like it's name, dinosaurs were the dominant species in this period.

Cretaceous Period- 145 - 66 MYA

145 BCE

The last and longest segment of the Mesozoic era. It lasted approximately 79 million years ago. The continents were in different positions than they are today. The earliest birds came to be in this period.

Tertiary Period- 66 - 2.6 MYA

2 BCE

The first period of the Era that we live in today. Earliest placental mammals started to become in this period. Mammals were becoming the dominant species for this era. By now the earth's continents almost formed into what we see and live on today.

Quaternary Period- 2.6 - Present Day

2 BCE

The period we all live in today. By now we are in living on the continents that were formed for us in the past. Pangaea was now broken apart all over the earth. Life was forming from mammals and into humans. Us humans are now the dominant species of the earth. Although there were animals that are even right now extinct like the wooly mammoth, and others that I don't know about.