He claims that the ancestors of mankind almost became extinct about 900 thousand years ago

Now there is only Homo sapiens left, but there were many other close relatives of humans – many of whom were around at the same time.

our closest human relatives, Denisovans And Neanderthals It disappeared between 30,000 and 40,000 years ago. By then, the different human races had existed in parallel for hundreds of thousands of years.

Homo sapiens may be over 300,000 years old, and you can read more about them at forskning.no.

But if we go back further, these three human species share a common ancestry. These ancestors of modern humans lived several hundred thousand years ago, and went through different evolutionary stages.

A new study estimates that at one time there were very few individuals of these ancestors.

Only 1,300 people remained

At some point during a period of about 120,000 years ago – starting around 930,000 years ago – there may have been as few as 1,300 of these ancestors left, according to one study. A new study in the scientific journal Sciences.

This is called a very serious evolutionary bottleneck by researchers.

– 1,300 people sounds pretty exciting, Torvin Orman tells forskning.no, after looking at the new research. He is a researcher at OsloMet and author of the book “Historien om Oss” on the origins of humanity.

But he also realizes that he can be credible. Why, we’ll come back later. But how could the researchers estimate that there were so few people?

“near extinction”

The researchers used a form of statistical analysis to look at human history. By looking at the genes of a relatively large sample of living people from many different places in Africa and beyond, they can build a picture of genetic diversity today.

With this knowledge, they can estimate genetic variation over time, while also estimating how many people have lived in different generations.

Using this computer model, they reached this potentially exciting genetic bottleneck from about 900,000 to 800,000 years ago.

But this does not mean that there are only 1,300 people left in the world, but there may have been at one time 1,300 individuals who are the direct ancestors of Neanderthals, Denisovans and Homo sapiens.

The researchers concluded that there are so few left that this entire human species is “on the brink of extinction,” according to the article.

But why there should be so few of these ancestors is not clear.

disaster?

The researchers behind the new study suggest that the potential population crash could be linked to the dramatic climate changes that occurred about 900,000 years ago.

This must have been a long period of low temperatures and great changes in plant and animal life.

Torfin Urmen suspects that this may have been decisive for the people at that time.

He asserts that there have been major changes at this time, but he thinks that perhaps relatively advanced human species could handle these changes without nearly going extinct.

But there is a lot unknown here. There are, for example, many archaeological sites of early humans dating from this time period, including those from Gopur in Ethiopia and several possible sites in China.

But it is not certain what kind of human race we are talking about in these places, says Torfin Urmen.

– The problem is separating the line that leads to us from other lines that existed at the same time, according to Ormin.

At this time there were several different races of humans. The researchers behind the new study point to a species that can be contextualised Homo heidelberg as the possible direct ancestor of Homo sapiens, Neanderthals, and Denisovans.

Some variants of Homo erectus—another line in the family tree—may have lived parallel to our direct ancestors, as you can see in the human family tree below.

new types?

This small group of just a few individuals may also be traces of an entirely new species that emerged among other hominins that lived about 900,000 to 800,000 years ago, according to the research paper.

Torfin Urmen thinks this could be a possible explanation, and points to fairly recent research findings showing a significant change that may have occurred in the same time period.

About a million years ago, a chromosomal mutation may have occurred, whereby two chromosomes joined together to form the large “chromosome 2” . This research paper is from 2022 It is likely that this mutation occurred about 900 thousand years ago.

Orman says that a mutation of this type can make it difficult to have healthy children with those who do not have the same type of mutation.

So this could be a possible explanation for how so few individuals survived. Of all the people who lived at that time, there was a small group of people with new mutations – who “started” the family line that led to modern humans.

Dramatic genetic bottleneck

Orman explains that this could be a sign of a new species occurrence, in which a new, stable human species is being created. But this could take a long time, and the researchers point to a period of more than 100,000 years.

– It could take a long time before speciation actually ends and becomes a new sedentary human species – which later gives rise to Neanderthals and Denisovans.

He points out that these three human species appear to have the same origin, and thus may all bear traces of this potentially dramatic genetic bottleneck.

If there was more DNA available from more Neanderthals, perhaps this bottleneck could be found again in their genetic material, Ormin suggests.

However, the researchers stress that more research needs to be done, both archaeological and genetic, before such a dramatic bottleneck can be proven to actually exist.

reference:

He et al.: Genomic inference of severe human bottleneck during the early to middle Pleistocene transition period. Sciences2023. Digital ID: 10.1126/science. abq7487

Stringer, Ashton: Did our ancestors almost die?? Science, 2023. DOI: 10.1126.science.adj9484