Extinct human species evolved rapidly to survive a period of climate change 2 million years ago

A species of ancient human that lived two million years ago was forced to evolve and change its physical traits to survive climate change.

The emergence of Paranthropus robustus occurred around the same time that the more primitive hominid species Australopithecus went extinct.

This period of rapid change in South Africa is believed to have occurred due to significant climate changes that have forced the animals to adapt or die.

During this period, the first members of the genus Homo also emerged, from which modern humans descend.

Homo erectus and P. robustus have taken different approaches to the changing world, with the former developing a large brain to create tools in order to tackle the problem of hard and chewy food sources.

The latter, however, underwent physical changes and developed larger teeth and powerful chewing muscles for over 200,000 years, a rapid evolutionary intervention.

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“These two very different species, H. erectus with their relatively large brains and small teeth, and P. robustus with their relatively large teeth and small brains, represent divergent evolutionary experiments,” said Angeline Leece of La Trobe University. the other first author of the study.

“While we were the lineage that ultimately won, the fossil record suggests that P. robustus was much more common than H. erectus in the landscape two million years ago.”

Researchers found a new P. robustus fossil in the fossil-rich Drimolen cave system northwest of Johannesburg in the so-called Cradle of Humanity.

They compared this with others of the same species that had previously been found.

Existing theories stated that there was a great deal of variation in the size of the males and females of the species, a phenomenon known as sexual dimorphism observed in many living animals.

However, the new specimen, called DNH 155, which is clearly male and believed to be the best preserved example of its species, dispels this.

Researchers, from Washington University in St Louis and La Trobe University in Australia, now think it exemplifies how the species has changed physically.

One notable feature that has changed over time is its dentition.

Dr Leece states, ‘We now know that tooth sizes change over time in the species, which raises the question of why.

“There are reasons to believe that environmental changes have placed these populations under food stress, and this points to future research that will allow us to test this possibility.”

Existing fossils from the time this species existed show that mammals that relied on woodlands and scrub became extinct while other species associated with more arid and open environments appeared in the area for the first time.

P. robustus, which appeared in this period of flow, was built for arid conditions.

Professor David Strait, a professor of biological anthropology at Washington University, says he was consequently suited to eating hard foods that grew in this new climate.

“P. robustus is notable in that it has a number of features in the skull, jaws and teeth that indicate it was suitable for a diet consisting of very hard or very hard foods, “he said.

“We believe these adaptations allowed them to survive on foods that were mechanically difficult to eat as the environment changed to be cooler and drier, leading to changes in local vegetation.”

The researchers found that early members of this species had weaker chewing muscles than their descendants.

Over the course of 200,000 years, a dry climate has likely led to natural selection which has favored the evolution of a more efficient and powerful food system in the species, “says Professor Strait.

The results are published in the journal Nature Ecology & Evolution.