The Quaternary is the third and last stage of the Cenozoic, which begins 2.6 million years ago and continues to the present day, that is, we live in the Quaternary Geological Age.
We can divide the Quaternary into two stages:
- It starts 2.6 million years ago and ends about 12,000 years ago.
- It begins approximately 12,000 years ago and continues until today.
At a global level, the continents were in almost the same positions as today, and the incoming glaciation would present cycles of 10,000-15,000 years of advances and retreats of frozen zones, reaching up to 30% of the planet.
The levels of the ocean waters increased to the present ones, and little by little the temperature would stabilize. Currently, we are ending the glaciation because there are ice in areas that are not mountain peaks such as the North Pole and Antarctica in the South Pole, in a cycle of retreat of the ice.
Along with the rapid cooling and advance of glaciers, the animals also had to adapt quickly to withstand the incoming cold weather.
During the Pleistocene, the so-called megafauna began to radiate, consisting of large land mammals such as woolly mammoths and rhinoceroses, bison, mastodons, and large wolves adapted to the cold climate.
During the Pleistocene, the so-called “mammoth steppes” became extensive, a series of grasslands with a large amount of herbaceous plants and very small bushes, with a large amount of nutrients, much more nutritious than the current steppes and grasslands.
With the 10,000-year cycles of freezing and retreating ice, bridges were created between the continents that encouraged the exchange of species, especially one that came to populate them all: the human species.
Homo habilis, originally from the African savannas, was the beginning of the rapid spread of the genus Homo around the globe, something that to this day still begs the question of why our ancestors left their ideal savannah habitat for colder territories where food was harder to find.
However, the fact that food was more difficult to find encouraged the development of the brain for the use of tools, manipulation of fire and creation of clothing.
The Holocene begins about 12,000 years ago, with the retreat of the planet’s freeze.
In the Holocene, part of the megafauna becomes extinct, either by human action or because they did not manage to adapt to a warmer climate, as happened to the large woolly mammals.
Although there are current descendants such as the Tibetan rhinoceros, very similar to the woolly rhinoceros of the Pleistocene, which migrated to colder regions to compensate for the increase in temperature of its previous area.
The Homo genus has undergone many changes: a more upright posture, more developed and strong legs, a specialization of the hands, and a much larger skull to house a growing brain.
It is thought that many of the species in the genus Homo lived together, such as Homo neanderthalensis with the early Homo sapiens, and that some of the features of H.nenaderthalensis remain in a small percentage of our genome, which would indicate that we are the result of a cross between two species in the same genus.
In the Holocene, the human species begins to develop some activities that make it sedentary and territorial, such as agriculture and livestock. Along with livestock farming, comes the domestication of animals such as dogs, which are close relatives of the Pleistocene steppe wolves.
Currently we can see the retreat of glaciers and ice sheets from both Poles of the planet, something natural but that by human action is being accelerated.
Humans have acted as a catalyst for global change, for the retreat of the ice, preventing animals from adapting to the new climates because they do not have time to evolve so quickly.
Due to this climate change by human action, some scientists indicate that we have entered a new Geological Stage called Anthropocene, within the Quaternary, which would begin with the Industrial Revolution, when a great amount of noxious gases began to be expelled by the boom of the industry.