Geologists divide Earth’s history into eons. Currently, we are in the Quaternary era, where the Tertiary, the Secondary and, of course, the Primary ones previously existed. Each era is divided into periods. Within the Quaternary era there are two periods: the Holocene , which dates back 10,000 years ago, and the Pleistocene, which began 2 million years ago.
As for the term Pleistocene, it is a neologism that literally means “the most recent”.
It is worth remembering two data that frame the geological ages: it is estimated that the Earth is 4500 million years old and that the first forms of life appeared 3500 million years ago. In this general scheme , the human species is only 200,000 years old.
What happened in the Pleistocene?
During this geological period, the continents already had the same appearance as they do today, since continental drift did not cause significant changes.
In the Pleistocene, ice extended over a quarter of the Earth’s surface (in our time, ice occupies approximately 10%). Also, several glaciations occurred within warmer interglacial periods.
As the glaciations progressed, the animals moved to other regions without ice.
The migrations produced triggered natural selection processes (many species did not adapt to climatic fluctuations and ended up becoming extinct, as is the case of the mammoth and the smilodon or saber tiger).
During colder periods, grasslands developed in regions closer to the poles and during warmer periods they extended to coniferous forests and deciduous trees.
At the end of the Pleistocene appeared the first hominids on the planet and for this reason there is talk of a new period, the Holocene (current period within the Quaternary period).
In the Pleistocene the ancestors of human beings managed to master fire
It was in the Tertiary era that the first primates appeared. Over time, they evolved into two orders: the prosimians and the apes. Two million years ago a new species appeared, Homo erectus. His great contribution was the invention of fire, one of the greatest revolutions in history.
Homo erectus was fragile compared to the large predators in its habitat, but it had a more developed brain . With a better intelligence, he was able to master fire for different purposes: to keep himself warm, to cook and to protect himself from the wildest beasts.