Sharp climate change has affected human evolution
Last reviewed: 23.04.2024
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Specialists from the University of Pennsylvania came to the conclusion that the climatic changes that occurred in East Africa about two million years ago could affect the evolution of man.
The need to adapt to dramatically changing climatic conditions provoked the acceleration of the development of the brain of our ancestors.
The results of the research are published in the pages of the scientific journal Proceedings of the National Academy of Science.
For a long time, a group of paleoclimatologists, led by Katherine Freeman, conducted research on the territory of the Olduvai Gorge, the "cradle of humanity".
The scientists analyzed the sediments formed over a long period of time in the lakes of Olduvai Gorge. They studied changes in the chemical composition of the leaves of algae and plants that accumulated on the bottom of a lake that had dried up a very long time ago. According to experts, plants can be called a kind of mirror that can reflect the history of climate change.
Unlike organic compounds, the wax can be very well preserved in the thickness of the deposits, and by means of an analysis of the isotopic composition of the wax it is possible to find out which plants prevailed in one or another locality.
The expert found that the local ecosystem was constantly undergoing sharp climate changes, followed by periodic changes in the predominant vegetation in this area - Olduvai then turned into savannas, then it was covered with forests.
To find out what was causing these changes, the researchers used statistical and mathematical models to compare changes occurring in the environment with other processes that were taking place at that time, for example, changing the relief and tectonic processes.
"The orbit of Earth's rotation around the Sun changes over time," says Dr. Freeman. "These changes were tied to the local climate in the Olduvai Gorge due to changes in the monsoon system in Africa."
As a result, scientists counted five climatic changes, which were of a harsh nature - on average, the change of the savannah forest and vice versa occurred for one or two thousand years, which is by geological standards literally an instantaneous transition.
Researchers believe that it was a number of these climatic changes that served as an impetus for the settlement of our ancestors to different parts of Africa, and also caused the acceleration of evolutionary processes.
"This research makes it possible to shed light on the evolution of man. People had to work out certain mechanisms that helped them cope with the transition from one type of food to another, as well as with other resulting problems. These mechanisms may include the uprightness and more complex structure of the social society, "commented one of the authors of the work, Professor Clayton Megill of the University of Pennsylvania in the city of Philadelphia." We are able to find out that the unfavorable climate and its constant changes coincided with the appearance of the ancestors of modern man from Homo, who learned to create and use the first tools. "
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