We like to think of the human family tree looking
like, I mean, a tree, or, like, this linear progression
from monkey to great ape to ancient human to modern human.
But I'm here to say it's wrong, actually.
Our family tree is less of a tree and more of a bush.
Lots of ancient humans came out of Africa in waves.
And we went back into Africa and we came out of Africa again.
Then went back into Africa, and came out of Africa again.
Went back into Africa.
Came out of Africa again.
And we did this over hundreds of thousands of years,
if not millions.
Humans intermingled, intermixed, some bred with others.
It's what we mean as sex, obviously.
Rebecca has it exactly right.
And over hundreds of thousands of years,
all of that mixing and adaptation
to climates and terrains and survival
created this single amazing species that remains today.
[LAUGHS] Not a single line, but like paint
splattered on an ancient wall, Homo sapiens
came out of the splatters that mixed, creating new colors.
Lots of these ancient people, of course, died.
It's not clean.
It's not perfect.
It's actually very human when you think about it this way.
So this is episode two out of five in our origin series,
and I'm going to track humans from ape to us.
Let's kick into it.
[MUSIC PLAYING]
What's up, internet?
I am Trace.
Thank you for tuning in.
Humans are now on every continent.
Every nook and cranny of this planet
has some kind of human on it, or human influence over it.
Under the surface, under the ocean, in space--
there are humans everywhere.
But this massive lineage that got us here is complicated.
And I'm not an expert, so I called Dr. Rick Potts, the head
of the Human Origins Project at the Smithsonian,
I think it's what it's called.
I think-- Smithsonian.
Right, right, right, right, right.
You've definitely heard of them.
So anyway, Rick?
And we can see that over the course of human evolution
that there have been anywhere from 20 to 25 different species
of early humans that have been discovered so far.
All life evolves, and it either adapts or moves or becomes
extinct and bites the dust, and sometimes even
gets buried in the dust.
So we have fossils that really tell us a lot of this story.
Those species can be grouped together in, sort of,
four major groups.
One is the group to which we belong--
So the four groups Rick is talking about
are Homo-- that is us, the human.
And then there's Australopithecus, Paranthropus,
and Ardipithecus.
They're all on earth, some of them at the same time.
And some of us left Africa, but not all
of these different groups did.
And within each group, there are subgroups and species.
The earth was positively teeming with humans and human cousins.
Look at this chart I put together.
Each of these lines is one human genus
that existed at the same time, in some cases.
Look at that.
There is so much overlap.
And this is just the genus Homo.
There's also Australopithecus and Paranthropus.
They had multiple species already,
we don't know that much about, but that's OK.
Look at all of these different people.
And the big question is, why did we dominate?
It's kind of the mystery of human evolution.
It goes from about six or seven million years
ago up to about four million years ago.
And those species took the first steps
in becoming upright walking, and they probably
experimented a lot in different styles of walking upright
on two legs, based on the anatomy
that we see in the fossils.
Sorry if you thought that it was a simple, clean family
tree, or a simple, clean line from here
to there, from this to human.
That's not how it went.
And actually, today it's even more complicated.
We had already become, anatomically,
something that was looking almost like us
300,000 years ago in Africa.
But certainly by 150,000 years ago,
we were basically looking very similar to what we are now.
And we had already been dispersing out of Africa
by that point.
So the oldest fossils that look like they could well
be Homo sapiens are in the near east,
and they're about 180,000 years, whereas we
used to think that this encounter with Neanderthals
only happened very late, around 40,000 years ago, when
they disappear.
So the chronology for potential contact and interactions
has got massive compared to what it used to be.
Somewhere, over 200,000 years ago,
there seems to be an a movement out
of Africa [INAUDIBLE] sapiens.
And at that point, in terms of who
was where and what's going on and who was, like, interacting
with each other, it's so much more complex, but much more
interesting as well.
At one point, Homo heidelbergensis
was a common ancestor of us and the Neanderthal.
That's right.
There were hundreds of thousands of years
of overlap between our different groups,
and we were not running this race alone.
We just beat the next racers at the end,
assuming you want to characterize it
as a race at all.
It was a geological photo finish.
Neanderthals are like our cousins.
We would recognize ourselves in them
if we saw them face to face.
And at some point, we split off from them,
at a time when we were spread thin,
like a one little tub of cream cheese for a whole huge bagel.
Why do they do that?
Give me, like, four of those things.
And then we met up again.
We saw each other on either side of a river,
and we said, hey, what's up, man?
How you doing?
I mean, I'm guessing, of course.
But we can only guess.
So I asked the expert, Dr. Teresa Steele.
Well, I guess maybe four options that I can imagine.
So one, you just mentioned, the fighting, that people are like,
ah, there's another human.
We're going to fight and try to kill each other.
And given that those modern humans had spear throwers
and Neanderthals at that point probably
only had thrusting or short range spears,
I think it's pretty clear who would win that battle,
unfortunately.
Well, and we know because we're here.
The four options, as I characterize them here,
are the four F's.
There's fight, food, filth, and [BLEEP]..
You had these modern humans coming
in who are just able to be more successful hunters,
or populations are growing up.
They're just kind of edging the Neanderthals out cave site
by cave site by cave site.
Then, you have modern humans taking over.
And then there are some people who,
in fact, what we know from more recent human expansions,
would argue that disease might have--
so no real direct conflict, but modern humans came in.
They were an invasive species, bringing
all their modern diseases, modern human diseases
with them.
And of course, [BLEEP].
I got to beep it out.
Not just for the kids, but because it's funnier
to [BLEEP] it out all the [BLEEP] time,
you know what I'm saying?
I couldn't swear on [INAUDIBLE].
It actually feels super good, but I just
don't want to be that guy.
Just like the fourth proven thing
that the Neanderthals had.
[BLEEP]
Well, there's evidence of interbreeding,
so there's the run up in love each other, hopefully
in a friendly way.
That would be an option.
And we do have evidence of interbreeding.
Overall, Neanderthals appear much more
like bonobos than chimpanzees.
Chimpanzees are very aggressive and territorial,
and they do not like strangers.
Bonobos are a lot more open to, sort of, friendly relations.
And everything we see about Neanderthal behavior
suggests that they could well have been more like that.
So there's no reason to assume that meetings between us
and them always had to have some sort of conflict and aggression
going on.
When you are talking about genetic exchange and hybrid
babies, in order for there to be the Neanderthal genes still
in us today visible, those hybrid babies,
they had to have been able to grow up in whichever group
they were in to adapt, to understand
that cultural context, and be successful enough to then have
their own children.
So all of these people, according to our experts,
were flung all over the planet, and most would never ever meet.
1.9 million years ago, the genus Homo
was spread from Africa all the way through Asia.
And again, we found Neanderthals in Western Europe
all the way up into Siberia.
These human species were everywhere.
There was multiple migrations out of Africa,
and probably even more than what we can pick up
in the archeological record.
One of the traditional things we say
is that it's possible that the use of fire
allowed us to have another wave of leaving
Africa to move into more seasonal environments.
Unfortunately, the evidence for that is sparse.
We hit Europe about 46,000 years ago,
we being humans, Homo sapiens.
When we got there, we met Neanderthals, and, of course,
then ancient human sexy time happened--
AHST.
Bow chicka bow ba bow.
Anyway, the thing is, we're hopping in and out
of the African cradle, if you will,
and that's kind of strange to me.
So I asked Teresa, is it like a suburb, a slow crawl,
or is it just like one group decided to go and start
walking, and they stopped sometimes and had another group
go in the [AUDIO OUT].
It's really hard to know.
Looks like expansion may have actually gone first
into more the Asian part of Eurasia,
and people are speculating it may
be that it's Neanderthals that are limiting movement
going west because the Neanderthals are there.
And a lot of dense research into trying
to figure out the paths of migrations within Europe
and where Neanderthals and modern humans
might have interacted.
As a tropical evolved organism, we
weren't adapted to mountainous, cooler environments of Europe
and elsewhere.
We were not used to the desert.
We had some grasslands, but we had to learn new ways
to find food.
This didn't happen with just one individual.
It wasn't just one dude out there,
you know, the Steve Jobs of ancient humans being like,
I have discovered how to market this bow and arrow
very well to everyone, so now we should be able to find food.
It's called the iBow because you have to pull--
you have to pull it, so iBow.
No.
It was over generations.
And we had to learn about warmer clothing, again,
over generations.
You had to hunt animals, and then you
realized you could put the animal fur over you.
And then over time, you would get
used to having the animal fur over you.
And then you'd realize, maybe we should bring the animal fur
with us so we can, you know, wrap it around ourselves.
And, again, generations before we
figured out that we could sew it into the shapes of our bodies.
Lots and lots of people did not succeed at this.
Lots and lots of dead humans over these hundreds
of thousands of years.
Then, around 13,000 years ago, in North and South America,
we had humans because they lived in the land bridge that
existed between the Russian Asian area
to where we are in the North American area,
as we know them now.
And they lived on a land bridge between the two.
The Bering Strait land bridge was so huge
that people could live there.
And they didn't just live there for a couple days.
They lived there for generations,
slowly moving from this valley to the next,
from this forest to that, from this grassland to that marsh.
And those people became genetic cousins to the people in Asia.
It wasn't direct.
And again, it didn't happen cleanly.
It all happened amidst a crazy earth.
Not crazy like now.
Now, we're in the super rapid heating change,
but Earth had lots of swings in temperature from warm to cold.
Let me give you an example.
Two million years ago, there were 40,000 year climate
cycles.
We can see them in ice cores that we have dug out
of the ancient ground.
And those warm cold periods correlate
with one cycle of the tilt and wobble of the planet.
That tilt changes the amount of sunlight
about 10% that reaches the ground, which
is enough to end ice ages.
But then 800,000 years ago, it changed from 40,000 year cycles
to 100,000 year cycles.
We're not really sure why, but humans
are coming up in that period.
Literally, they were actually breathing, literally,
the same air, if you really think about it.
And, of course, the air mix has changed in the last 200 years.
There's more CO2.
There's more heat.
There's more rapid warming than we've
seen for almost a million years-- even more than that,
but we'll come back to that later.
Ancient humans had a lot to deal with.
Not to mention, there was no delivery,
no cars to get around, no one to cook and clean for you.
Actually, clean, you know, might be relative,
considering I guess they are ancient humans.
They lived in caves and outside.
We could spend months exploring the migration
patterns of ancient humans, you know, what ancient people ate,
the first Europeans, how Neanderthals and cavemen lived,
and the evolutionary leaps that happened over time.
Seriously, we could spend months on that.
Or you could hit up Curiosity Stream.
Curiosity Stream has big budget documentaries
that cover literally all of the topics that I just mentioned,
and so much more.
And once you sort of get full up on ancient humans,
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They have it all.
And right now, with my promo code
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Nebula has dozens of creators uploading new stuff
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But enough about streaming.
Let's get back to ancient humankind.
You know, back over here.
So over the next few 100,000 years,
humans were busy spreading out and taking over.
They jumped out of Africa.
They moved into Europe.
They met the Neanderthals.
They met other ancient human species,
some of which they would hang out with,
some of which they wouldn't.
But sometime around 74,000 to 70,000 years ago, we almost
went extinct.
We, humans, the superior supreme being, multi-pass.
We almost went extinct.
Scientists think that this might have
been a result of extreme climate change,
or, as one controversial hypothesis suggested,
the devastating after effects of the eruption of the Toba Super
Volcano in Indonesia.
We're not sure.
But at this time, there may have been
as few as 10,000 reproductive age adults in the world.
We would consider those people endangered.
That species would be on the endangered species list today.
That was us.
Fortunately, though, humans came back from the brink,
even as one of our relatives, Homo erectus,
did not, and went extinct.
We've learned more and more over the past decades.
We've done more fieldwork, both archaeological fieldwork
and palaeontological fieldwork.
We're appreciating how very bushy
our family tree is, that at many points in time
there's a lot of homonids, which are kind of bipedal apes,
out there on the landscape.
And this process of how it is that we
became the one that persists now is really important.
Our understanding of the deeper homonid evolutionary context
over the past three decades has really transformed,
and it looks a lot busier than it used to.
And that's also reflected in the genetics now.
The more samples of Neanderthals that we've looked at,
the more evidence we find for there
having been multiple phases of contact and interbreeding,
going back, potentially, over 200,000 years.
And we don't know where that happened.
So this whole long tale is to say
we went from ape to human through slow change,
and as humans started to spread out into the world,
we met these other people.
And once there were only a few species left,
spread around the world, there was a point
when we, the Homo sapiens, started to spread and win,
and continued to spread and win.
We were the victors, the last lonely humans
left on this planet.
And for many thousands of years, we
thought we were the only ones.
Now, we know our families were here with us.
We came up with others, right?
We came up with neanderthalensis.
We came up with all of these other Homos.
We are their legacy.
But still, like anyone with a survivor legacy asking, why us?
Why did we live and they didn't?
That's a question we can answer next time.
So make sure you come back for the next episode.
Thank you so much for tuning into this one.
I am Trace.
You can subscribe, please, and join us here on my channel.
You can also come and find me on Patreon.
You can find me, literally, all over
the internet @tracedominguez.
I really hope that you appreciate this.
Special thanks to all of the guests we've had so far.
And there's going to be more, so please come back.
Thanks again.
I'll see you in the future.