Homo sapiens appeared in the south of the continent about 300,000 years agoback, and climate change helped it to settle,
What happened?
Climate change over the past 2 million years is thought to have played an important role in the evolution of our species.The authors of the new work modeled changes in the Earth's climate and linked habitable areas to known archaeological finds and fossils.Researchers suggest that our species evolved in a region in southern Africa for 300,000 yearsBack.
But there is another theory that disputes thisidea. To deal with this contradiction, a group of researchers from South Korea and Europe modeled the Earth's climatic history for 2 million years and compared it with the places where ancient human bones and tools were found.
Lead study author Axel Timmermann of the Institute of Basic Sciences at Busan University said this is the first study linking archaeological evidence to climate change.This will help piece together the history of how humans moved and evolved.
Ian Moffat, a geoarchaeologist at Flinders University, said the study looked at the main places where early human evolution took place - Africa, Europe and parts of Asia.
What do we know about the evolution of early man?
The genealogical tree of the human species isan intricate scheme with a huge number of branches, among which there are many forks, branches and dead ends - with some branches joining several times over the millennia, when different species interbreed and migrate.
Scientists believe that our ancestors began activelymove and populate new territories due to climate change. For example, when the familiar region ceased to be comfortable and suitable for life, in comparison with the neighboring one. But it is not easy to determine what the climate used to be in a particular area inhabited by people.
Researchers have several methods: dating sediments and analyzing particles, such as pollen, that are left in soil and rocks.In this way, you can find out what plants grew in this place, and on the basis of this, you can already draw conclusions about the climate.But caves in the climate have less information, as they are usually sheltered, dry and less likely to be affectedExternal environment.
How did the authors model the weather?
In a new study to study climatechanges, the authors used a computer model, the same type of model used by the intergovernmental panel of experts in their report on climate change. Previously, it was used to predict future climate changes, and now to learn about events that took place 2 million years ago.
The climate cycles the team modeled were different from today's climate changes. The situation today is associated with an increase in carbon emissions into the atmosphere.
Why has the climate changed in the past?
Climate change 2 million years ago occurred due to astronomical climate cycles.They are also called Milankovitch cycles: they are named after the Serbian explorer who is believed to have first claimed their existence in the 1920s.
There are several types of Milankovitch cycles −one of them is related to the distance from the Earth to the Sun. Our planet revolves around the sun, but it does not move in a perfect circle. There is a gravitational pull from Jupiter and Saturn that causes the trajectory to become oval. This means that the Earth is further away from the Sun for some time and receives less heat.
Another Milankovitch cycle arises from the fact thatthe gravitational attraction of the moon and sun affects the shape of the planet and flattens it a little closer to the poles. When the Earth rotates around its inclined axis, then one of the hemispheres receives more radiation from the Sun, and the other less. The authors of the new work note that changes in the tilt of the Earth also affect the climate, but to a lesser extent. Milankovitch cycles warm and cool the planet over tens of thousands to hundreds of thousands of years, but they cannot explain the current warming of the Earth.
What have we learned from climate modeling?
The team modeled the Earth's climate formost of the geological epoch called the Pleistocene. At the beginning of the Pleistocene, about 2 million years ago, a cool cycle began. Around the same time, the first waves of early human migration out of Africa started. Probably one of the first migratory species was an ancient relative of modern humans - Homo erectus.
The researchers found that their climaticthe predictions agree fairly well with real evidence of migration, such as ice drilled deep into the polar ice sheets. Based on their modeling, the team created maps that show which areas were habitable for human life. The data was based on rainfall and food availability.
Then more than 3,200archeological finds from six human species, including our species, Neanderthals, and H. heidelbergensis, which is thought to have originated in Africa about 800,000 years ago.
So the researchers saw how differentthe environment in which each human species preferred to live. They found, for example, that early humans lived in regions with stable climates, while later humans, such as H. heidelbergensis, were nomadic and settled in harsher, arid environments.
The maps also showed where one form had disappeared.early man and another appeared. It tells how one species evolved into another. For example, this happened to H. heidelbergensis in two places at the same time. Approximately half a million years ago, H. heidelbergensis spread from southern Africa throughout Europe and possibly also into Asia. About 400,000 years ago, H. heidelbergensis declined and the Neanderthals appeared. Then 300,000 years ago H. sapiens. began to displace H. heidelbergensis from southern Africa.
What was the main influence of climate on the life of an ancient person?
According to the authors, around the time that H.Africa was becoming very dry, and the environment was becoming less habitable.The team stated that H. sapiens dispersed from just one region in Africa.
But there is another theory - H. sapiens did not evolve from one area, but arose from many divided populations throughout the African continent that interbred with each other.
Climate models from a new studyshowed that suitable habitats for humans were in both eastern and southern Africa. But archaeological and fossil evidence confirms that our species originated from the southern region.
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