The Cenozoic: The last and present era in the history of the Earth

The last and present era in the history of the Earth is the Cenozoic Era, which started around 66 million years ago, when a large-scale natural disaster occurred on the earth wiping out the dinosaurs.

This is commonly referred to as the Age of Mammals due to the fact that it is at this time that the mammals experienced tremendous advancement and took up the entire planet. This period is further separated into three great periods, namely the Paleogene, the Neogene, and the Quaternary, up to the present time.

The mammals had little to no presence at the start of the Cenozoic Era due to the fact that they were tiny, frail, and uncomplicated, but following the extinction of the dinosaurs, the mammals had a free pass in increased growth and development.

With time, there appeared countless varieties of mammals to adapt to various habitats, both on land, like elephants, horses, lions, bears, and rhinoceros; and in the air, like bats, and in water, like whales, dolphins, and seals. Later in this process, humans developed out of the apes, which had demonstrated superiority to all other living entities in terms of intellect and awareness.

At the beginning of the Cenozoic era, the climate of the Earth was hot and humid, and owing to this, the greater part of the world was covered by tropical dense forests. Having trees and flowers, which gave food and shelter to animals, were in abundance in these forests. The forests started to diminish in size in most of the areas as time went by, with the climate changing, and this gave way to large grasslands where grazing animals like horses, deer, and oxen thrived. The nature of most of the trees, grasses, and crops that we have today was developed during this time.

As far as the atmosphere and environment are concerned, drastic and long-term changes took place in the course of the Cenozoic era. To start with, the levels of carbon dioxide in the atmosphere were high, which is why it maintained the Earth's temperature warm; however, the level began to lower slowly, which led to the onset of cool weather.

In this century, there were a few ice ages, and the Quaternary period, being the latest,t was when massive ice sheets covered parts of the Earth, such as the north and south poles. These ice ages hada deep impact on the body structure, habits, and migration of animals, such as thick fur and layers of fat developed in most animals.

It is also true that the geographical arrangement of the Earth transformed significantly in the Cenozoic period. The continents gradually moved to their present positions, and due to the collision of India and Asia, great mountain ranges were formed, like the Himalayas.

The wind system and the rainfall patterns due to these mountains resulted in the creation of forests, deserts, and cold regions in the various regions. The sea level changed often and created new land-sea routes, enabling animals to be transferred between continents.

The Cenozoic Era led to the formation of ecosystems in a fully modern form, such as forests, deserts, grasslands, oceans, and polar systems. Numerous animal species appeared, and numerous became extinct species, which included mammoths and large mammals, whose extinction was caused by climate change, besides human hunting. The new stage started after the appearance of human beings in this epoch, since human beings quickly influenced nature through agriculture, cities, industry, and deforestation.

To sum up, one may state that the Cenozoic Era is the critical period in the history of the Earth, due to which the present-day animals, forests, climate, continents, and even human beings themselves were created. The Cenozoic Era is a significant study in terms of the biological, climatic, and geographical status of the world today, in that it is this period of time that provided the earth with its present shape.