In previous posts, we've analyzed how geological time works and reviewed the most important events that took place in the Mesozoic Era and the Precambrian Eon . Today, we return to the Cenozoic Era, where we'll analyze what happens in the Quaternary Period . This is the last period of the Cenozoic Era and encompasses two of the most recent epochs: the Pleistocene and the Holocene.
Do you want to know the most important events that occurred in this period? Keep reading because we tell you everything.
The arrival of ice and man
After millions of years, we are approaching what we consider the "present day." The Quaternary, which began 2,59 million years ago , is the period in which we live today. The Quaternary not only includes the Pleistocene and Holocene epochs, but also, for the sake of consistency in understanding the changes that occurred on Earth, the Gelasian Age. During this age, there were very significant changes in life on the planet, the climate, and the oceans due to glacial periods.
The Quaternary period comprises two epochs: the Pleistocene and the Holocene. The Pleistocene is the longer of the two and includes centuries of glacial activity. It is known as the Ice Age , a concept closely linked to glaciation . Moving on to a more recent epoch, we have the Holocene, considered the post-glacial period and the one we are currently experiencing.
When discussing the Pleistocene, many people refer to it as "the age of man" because the genus Homo began to evolve during this period. It was during the Holocene that humans were able to develop organized life in social groups, which we now call civilization.
Pleistocene characteristics
We begin by describing the Quaternary period with its first epoch. 2,59 million years ago, the Pleistocene epoch began, ending just 12.000 years ago. During this time, ice spread in the form of glaciers, eventually covering more than a quarter of the Earth's surface . The ice reached areas never before seen. When we talk about glaciation or ice ages, we often imagine the entire world covered in ice, including the oceans. This is not the case. Almost 25% of the Earth covered in ice is incredibly unusual.
Due to the vast amount of ice around the world, sea levels dropped by up to 100 meters, and life on the planet had to adapt to the new environmental conditions or disappear. In areas where there was no ice, almost all the dominant flora and fauna were the same as in the previous period (Pliocene), which leads us to review the major extinctions in history.
There were large glacial systems scattered across the coldest and most icy regions. The first was a glacier in Scandinavia that stretched south and east across northern Germany and western Russia. It reached as far as the British Isles, so you can imagine the size of that glacier. You can also learn more about the ice cap and its importance during the Quaternary period.
On the other hand, we also find another enormous glacial system located across most of Siberia. Another glacial system stretched from Canada all the way to the United States , and many of these glacial systems were fundamental to Pleistocene geology . All these glacial formations, through their dynamic processes and formation, gave rise to the glacial features we can observe today in all these places.
Glaciations, flora and fauna
As you can guess, the Arctic and Antarctic regions were also covered with ice, as were most of the mountains around the planet. The snow level dropped to levels that have never been observed today. As I mentioned before, all the actions that glaciers and their subsequent melting entail can be seen even today in many parts of the world.
There wasn't just one ice age during the Pleistocene, but six. Between each one, there were periods of warmer climate and retreat. Currently, we are considered to be in one of those periods of glacial "rest."
Regarding the flora and fauna that had to adapt to the completely frozen areas, we find mammoths, reindeer, giant deer, and polar bears. The vegetation in this area consisted entirely of lichens and mosses. It was very similar to the current tundra, which has been one of the regions most affected by climate change . During interglacial periods, with warmer temperatures and less ice cover, horses, felines with large canines, and rhinoceroses were able to live there. For a more in-depth study of the fauna of that era, I recommend reading about Pleistocene fauna and how it influenced human development.
Several other animal species adapted well to the changing climate, allowing them to survive longer. These included bison, elk, foxes, and bobcats. In the colder regions of North America, species such as the camel, yak, llama, tapir, and horse became extinct . By the end of the Pleistocene, large mammal species like the mastodon, the famous saber-toothed tiger, and the giant deer had already disappeared from the entire planet.
Human and Holocene evolution
Now we talk about human evolution, starting with the Paleolithic period in the Pleistocene epoch, where Homo habilis began to gather and hunt. Later, Homo erectus crafted more sophisticated weapons and hunted in groups. Homo neanderthalensis was a species adapted to the cold that appeared 230.000 years ago.
We now turn to the most recent epoch of the Quaternary: the Holocene. This is where we are today. It began 12.000 years ago, and its transitional temperature changes triggered a period of global melting . This melting caused a thirty-meter rise in sea level, an interesting phenomenon in Earth's history. It is said that this interglacial period could end in a new ice age.
Extinctions have continued for 12.000 years and have accelerated even further in the last 100 years due to human presence and technological development. There have been five major extinctions on Earth. Therefore, the massacre occurring today is called the sixth extinction.
The nomadic life of the human being ended with the development of agriculture and livestock. Fishing also greatly favored human development. Finally, the Holocene is usually studied until the invention of writing, where what we call History begins to be studied.
I hope this post has let you know more about the last period of the Earth.