The Quaternary period has several geological divisions. Today we're going to focus on the first division of this period: the Pleistocene. This geological division was characterized primarily by low temperatures across the planet and the appearance of large mammals such as the mammoth. To fully understand everything involved in the temporal study of this geological division, it's essential to have a correct understanding of geological time.
In this article we are going to tell you everything you need to know about the Pleistocene.
Key features
This period is a key reference point for studying the evolution of the human species. It was during the Pleistocene that the first ancestors of modern humans appeared. It is one of the most studied geological periods and has the richest fossil record. This ensures that the information obtained is quite extensive and reliable.
The Pleistocene began approximately 2.6 million years ago and ended at the end of the last ice age, around 10.000 BC. During this time, there were hardly any major continental movements. The continents remained practically in the same position.
As we mentioned at the beginning of the article, this entire geological division has been characterized primarily by low temperatures globally. This has led to successive glacial cycles in which temperatures have risen and fallen. These are known as interglacial periods. Approximately 30% of the Earth's surface was permanently covered in ice during this time. The polar regions were the areas that remained continuously frozen.
As for the fauna, large mammals such as mammoths, mastodons, and giant ground sloths reached their peak. These animals practically dominated the planet due to their enormous size. There was also a development of the ancestors of modern humans: Homo erectus, Homo habilis, and Homo neanderthalensis. You can learn more about Homo neanderthalensis and its evolution during this period. You can also explore the Pleistocene fauna in greater depth.
Pleistocene geology
During this period of division, there wasn't much geological activity. Continental drift appears to have slowed down compared to previous eras. The tectonic plates on which the continents sit barely moved more than about 100 kilometers relative to each other. At this time, the continents were already in positions very similar to their current ones.
Ice ages were very frequent during this period, fueled by several cycles of significant increases and decreases in the planet's temperature. This led to several regions further south becoming completely covered in ice. As a consequence of the ice ages, the surface of the continents was affected by an erosive process. This is known as glacial landforms . It is important to understand how this glacial landforms affected the landscape in the boreal forest and glaciation.
Sea levels also dropped significantly, by approximately 100 meters . This is due to ice formation during the ice ages and the resulting climate changes. To better understand this, you can read about major climate changes throughout Earth's history.
Pleistocene climate
During this geological period, what is known as the Ice Age occurred . This is incorrect, as the Pleistocene was characterized by a series of glaciations, with periods of both higher and lower ambient temperatures. The climate and ambient temperatures fluctuated throughout the era, although they did not reach the extremes seen in other periods of Earth's geological history.
The climatic conditions are practically a continuation of the earlier Pliocene epoch. At this stage, the planet's temperatures dropped significantly. Stripes of land closer to the poles were observed, and during this stage Antarctica remained almost entirely covered in ice from the northern extremes of the American and European continents during the glaciation stages.
Throughout the Pleistocene epoch, there were four ice ages. To learn more about the region's climate, you can review the climate of Antarctica and how it influenced the Pleistocene.
Flora, fauna and human beings
During this period, life was quite diverse despite all the climatic limitations caused by the ice ages. During the Pleistocene, there were several types of biomes . In each biome, the plants best adapted to the most extreme environments developed. In the Northern Hemisphere, within the Arctic Circle, the biome we now know as the tundra developed. The main characteristics of the tundra are its small size; there are no large, leafy trees. Lichens are abundant in this type of ecosystem.
The taiga is another biome observed during the Pleistocene. It consists primarily of vegetation dominated by coniferous trees, which sometimes reach great heights. Information gleaned from the fossil record also indicates the presence of lichens, mosses, and some ferns in these biomes. Thus, the Pleistocene flora was very diverse, adapting to the climatic conditions. You can find more information about it here.
Within the continents, temperatures were not as low, allowing large plants to develop and forming vast forests. This is where thermophilic plants began to emerge. These plants exhibit adaptations necessary to survive extreme temperatures.
As for the fauna, mammals were the most dominant group. One of the most notable aspects of this fauna is that it is known as megafauna. That is, the predominant fauna were large in size and fully adapted to withstand the low temperatures of that time.
Furthermore, other animal groups continued to increase their diversity and evolve to adapt to new environments. These animals include birds, amphibians, and reptiles. The mammoth was the most interesting mammal of this era. These animals looked quite similar to the elephants we know today. They possessed long, sharp tusks, their main characteristic being the upward curve of their tusks. Depending on the region and its temperature, they were covered in varying amounts of fur and were herbivores.
Also, regarding humans, most of the species that preceded Homo sapiens evolved , but Homo sapiens also appeared. Its main characteristic was that it reached its maximum brain development. For more information, you can consult the article on Homo erectus.
