The Quaternary is a subdivision of geologic time. It is the Quaternary Period that covers almost the last 2.6 million years up to the present day of the earth. The Quaternary, as well as the Tertiary Periods both together, form the Cenozoic Era.
The quaternary meaning can be understood by the below-given image:
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The Quaternary is further subdivided into two epochs, the first is the Pleistocene which is up to about 11,700 years ago and the second is Holocene which is about 11,700 years ago to the present day. The Quaternary Period is one of the very extraordinary changes that took place in the global environment and also the period during which much of human evolution had taken place.
The Quaternary Period has also involved many dramatic climate changes in the planet, which has affected food resources and led to the extinction of many species. The period also saw the rise of a new predator that is known as man.
Climatic Conditions During the Quaternary Period
Scientists from all over the world have evidence of more than 60 periods of glacial expansion that was interspersed with briefer intervals of warmer temperatures. The entire Quaternary Period which also includes the present is referred to as an ice age because of the presence of at least one permanent ice sheet i.e. Antarctica. However, studies say that the Pleistocene Epoch was much drier and also colder as compared to the present time.
The glacial advancement varied between continents, but approximately 22,000 years ago, glaciers covered about 30 percent of the surface of the earth. In areas that are now Europe and North America, there existed huge grasslands known as the “mammoth steppes” and had a higher productivity rate with greater biomass than the modern grassland. The grasses were very dense and also highly nutritious. Whereas, winter snow cover was quite shallow.
Ascent of Man During the Quaternary Period
Homo erectus was the first-ever hominid species that widely used fire. There are two hypotheses about the species’ origin. The first hypothesis is that the species were initially originated in Africa and later dispersed throughout Eurasia, with the ability to exploit the colder regions using fire and tools. The second hypothesis claims that the Homo erectus migrated to Africa from the region of Eurasia. Excavations in Dmanisi, Republic of Georgia, have uncovered fossil evidence that Homo erectus species were successful hunters.
The existence of the Homo neanderthalensis was from about 200,000 years ago to about 30,000 years ago. Fossil evidence showed that the species lived in western Europe which also includes southern Great Britain, throughout central Europe and Ukraine, and as far south as Gibraltar and the Levant. However, Neanderthal fossils have not been found in Africa. Neanderthals were shorter as well as stockier than modern humans with longer, stronger hands and arms. They lived in shelters, made and wore clothing, and also used diverse tools made up of stone and bone.
According to the climatic conditions, there was a requirement for a heavy diet in animal protein so they were sophisticated hunters. A recent discovery indicates that they also cooked and ate plants. They buried their dead and made ornamental or symbolic objects. No earlier hominid species have been shown to practice any kind of behaviour that indicates the usage of language.
Evidence suggests that Homo sapiens originated in the continent of Africa and the oldest fossils of anatomically modern humans, found in Ethiopia which are approximately 195,000 years old. By 100,000 years ago they had dispersed as far north which is now known as modern Israel, but the oldest fossils of modern humans are also found farther north are only 40,000 to 60,000 years old. By this discovery, it is clear that Homo sapiens, as well as Homo neanderthalensis, were contemporaries for a time. Few dental evidence claims that H. sapiens matured later than Neanderthals. This suggests that a longer childhood led to more time for social development as well as transmission of knowledge and technology to new generations.
This might have led to the division of labour allowing all the females as well as the young to forage for more diverse food sources. Diversification in diet could have been a species advantage for the Homo sapiens when the climate cooled again. The most recent Neanderthal remains are approximately 28,000 years old. Homo sapiens weathered the drastic climate changes and continued to disperse throughout the Earth whereas the Neanderthals became extinct.
FAQs on Quaternary
1. Write a Short Note on Migration to America.
Ans: Approximately between 13,000 to 10,000 years ago, at the beginning of the Holocene Epoch, lowered sea levels exposed the Bering Land Bridge between Siberia and Alaska. Snowfall in this area was relatively light because of the rain shadow effects of the Alaska Range. Therefore, it was natural for Homo sapiens to follow migrating animals into the continent of North America.
About 12,000 years ago, nearly three-fourths of North America's large animals, which included woolly mammoths, horses as well as camels were wiped out. One explanation for their extinction is that the increase in global temperatures caused the glaciers to retreat. Increasing sea levels submerged the land bridge, and also the forests began to replace the mammoth steppes. After all, changes in habitat undoubtedly had put stress on animal populations.
The mass extinction also then coincided with the arrival of humans in that area. Some scientists claim that overhunting was a major contributor to mass extinctions. Another theory claims that a comet slammed into the glaciers of eastern Canada about 12,900 years ago, which led to a drastic effect on the climate and set off a new era of glacial conditions.
2. Write a Short Note on Animals During the Quaternary Period.
Ans: These steppes supported huge herbivorous animals such as mammoth, mastodon, giant bison, and woolly rhinoceros. They all were well adapted to the cold and were preyed upon by equally large carnivorous animals like the saber-toothed cats, cave bears, and dire wolves.
The latest glacial retreat began the Holocene Epoch. In the areas of Europe and North America, the mammoth steppes were replaced by vast forests. This drastic change in climate and food resources led to the extinction of the largest herbivores as well as their predators. However, the scientists say that climate change was not the only factor in their demise but also a new predator was making itself known.