Name: When We Took Over the World
Uploaded: 2021-05-02T04:55:12.000Z
Duration: 12 min 43 s
Description: VoiceTubeの動画で発音を聞きながら英語表現を覚えよう！学べる英語：

Hi, it's Hank with news about some new benefits for our Patreon Patrons!

People pledging $15 or more now have access to a quarterly livestream with the Eons team!

様態の副詞

And if you pledge $100 a month, you can actually take part in the actual video stream and nerd

You can go to patreon.com/eons to find out more

But now, let's talk about some planetary domination.

Today, our species - Homo sapiens - lives on every continent on Earth.

There are more than seven billion of us, inhabiting almost every possible environment, and altering

them through our use of culture and technology to suit our needs.

We can survive harsh winters, irrigate deserts, and travel at will to reach the most remote

One of the defining features of our species is that we're behaviorally flexible.

We can use whatever resources are around in order to survive.

We've been like this for a long time, and it's a big part of the story of our success.

The early ancestors that we call the first anatomically modern humans were more like

us than any other member of the genus Homo, with more slender skeletons; smaller, less

protruding jaws and teeth; and really big brains.

These ancestors had to be able to adapt to all kinds of new environments as they spread

They encountered other hominin species, faced new predators and diseases, and found the

food and shelter they needed to thrive in new landscapes.

And we can actually trace the path they took, from our deepest origins in Africa all the

way to the Americas, by looking at the fossils and archaeological materials they left behind,

as well as in the genomes of their descendants: our genomes.

Now, we don't know all the details of this journey, but we can say for sure that it was

In the last 300,000 years or so, we've gone from inhabiting a single continent to all

Our story as a species is one of constant migration.

So, no discussion of human evolution would be complete without a deep look through that

short window of time when we took over the world.

Based on our current understanding of the evidence, the story of Homo sapiens begins

in Africa, between 300,000 and 350,000 years ago.

In 1961, miners working at a site called Jebel Irhoud in Morocco accidentally unearthed the

fossil remains of a hominin with facial features that were surprisingly like those of modern

But at the time, the remains couldn't be dated precisely.

And in the last few years, anthropologists have gone back to that site and found even

This new one had the same mix of modern facial features, like smaller brow ridges, and also

more basal traits, like a braincase that was longer and lower than the ones we have today.

And researchers were able to date these new finds to between 300,000 and 350,000 years

ago - a surprisingly early date for hominins with such modern-looking faces.

Before that find was made, the oldest known remains of modern humans were skulls from

two sites in Ethiopia, dated to 195,000 and 160,000 years ago, respectively -- more than

100,000 years younger than the material from Jebel Irhoud.

And while these younger skulls share some features with us -- like the same shape and

size of their braincase -- they've still got some fairly robust features, too -- like

heavy brow ridges -- which we associate with more archaic hominins.

So we've got fossil evidence of early Homo sapiens from northern and eastern Africa.

But the evidence in our genes paints a slightly more complicated picture.

Our genomes can be used to infer the history of our migrations, by comparing the DNA from

human populations in different places, and seeing how they differ.

Variations in our genomes are generally thought to correspond to how far apart certain populations

have been separated, in both distance and time.

Groups that live closer to each other are expected to be more similar, while groups

living farther apart are expected to be more different.

And older, more ancestral lineages typically have more genetic diversity than newer ones.

So based on the DNA we've studied of living peoples, there's evidence for modern human

origins all over Africa, not just the north and the east.

African populations turn out to have the greatest genetic diversity of any group of people in

So this suggests that their lineages are older.

Meanwhile, all of the populations outside of Africa have just a fraction of the diversity

found in Africa, suggesting that their variations are more recent.

But the pattern of genetic variation found within populations in sub-Saharan Africa points

to a complicated history of migration, genetic exchange, and selection.

And in the end, that makes it impossible to pinpoint a single place in Africa as the origin

In any case, we do know that, after arising in Africa, some groups of Homo sapiens started

Anthropologists usually draw these migrations as one-way arrows on a map, but that oversimplifies

Some populations expanded but then contracted again, and some moved back and forth between

So we're not sure who the first modern humans were to leave Africa,

or even how many times they made the journey.

We also have questions about what route these migrants took: Some fossil evidence suggests

that they went north, through that region of the eastern Mediterranean known as the

But there's genomic evidence of a possible southern route, which might have gone from

Ethiopia into the southern part of the Arabian peninsula and from there into Asia and Oceania.

If we follow the northern route first, we find fossil evidence at two sites in what's

In 2018, anthropologists published their discovery of half of an upper jaw with teeth that are

unmistakably human, along with evidence of hearths and well-developed stone tool technology.

Dated between 177,000 and 194,000 years ago, this site is considered by many to be the

earliest known evidence of modern humans outside of Africa.

Another site, called Skhūl, is part of the same complex as Misliya Cave, but it's more

recent, dated to 100,000 to 135,000 years ago.

Excavated in the early 1930s, it has yielded the remains of at least 10 adults, some of

which appeared to have been intentionally buried, providing early evidence of modern

Even further across the globe, there are two sites in southern China with modern humans

that overlap in time with those at Skhul.

And we don't know how these populations got there -- like, whether they came from

字幕リスト動画再生

When We Took Over the World

constant

demonstrate

evidence

journey