The Tertiary Period In The Cenozoic Era (Essay Sample)

Before reading about the content of the tertiary you need to understand its structure first. The Cenozoic Tertiary area is divided into two-sub areas : Paleogene and the Neogene. The Paleogene itself is divided into the Paleocene, Eocene, Oligocene and the Neogene into the Miocene and Pliocene. 

The tertiary begins with the Paleocene area and the collision of a meteorite with our planet. This meteorite had an important impact on the biology of our earth. Indeed, the only dinosaurs left are the avian ones. Those avian dinosaurs evolve in “terror birds” and the lack of dinosaurs on the ground lets the mammals become the dominant group on land.

The flora reconstructs itself step by step and the angiosperms allow the first forests to grow.

In addition, new parts of land emerge from the water with the shrinkage of seas and the temperature of the earth at that time is around 9°C.  

Follows the Eocene where even more lands are emerging from seas. This period starts with the PETM, an important 5°C boost of temperature. The first primates appear at that time thanks to the first canopy forests that help them grow in a secure place. Those first primates will be evolving until becoming.. Homo Sapiens. 

After the Eocene there is the Oligocene which most important biological event is “the big cut”. Until then Europa and Asia were separated from each other with water. This junction between those two continents allows migratory flows from one continent to another. Furthermore, the Antarctic starts to cover in snow making the temperatures drop.

Then begins the second sub-period of the tertiary, the Neogene with the Miocene. The geology of earth during the Miocene is extremely similar to ours today with, however, two difference. Greenland isn’t covered in snow yet plus North America and South America aren’t divided yet. As for the temperature it is slightly warmer during the beginning of the Miocene then it drops. The cause of this cooling is the creation of several mountains thus changing atmospheric conditions. Moreover, we can find several species that are the same as today such as the beaver, wolf, crows and owls and during this area we can find every bird family that exist as of today. The cetaceans evolve greatly during that time and the Miocene is called the “area of cetacean” ! About the flora we can say that small moist forest existed in the Sahara were trees were growing.

Then comes the last sub-sub-area of the tertiary, the Pliocene. During this last period, the Alps and the Himalayas are created as well as the Isthmus of Panama. The latter is connecting North America from South America creating a migratory flow allowing     marsupials to go north and the placentals to go south. This Isthmus will also modify the ocean streams creating the well-known golf stream. During that time the earth will also cool down a little covering for example the Greenland of snow. Additionally to the cooling there was a drying. Thus, tropical forest are now only reduced to a small band around the equator and grassland became more common.