- 12 minutes ago
Anthropologist Agustín Fuentes joins WIRED to answer the internet's burning questions about human evolution. Are humans still evolving? Was there a first human? What does the family tree leading to humans look like? Is monogamy in human relationships natural or something society imposes? Did early people really live in caves? Who invented kissing? Were the Neanderthals stronger than us? Why didn't other human-like species survive? Answers to these questions and many more await on Human Evolution Support.
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00:00I'm Anthropologist Agustin Fuentes.
00:02Let's answer your questions from the internet.
00:04This is Human Evolution Support.
00:10R at Ask Science asks,
00:13How long have humans been anatomically the same as humans today?
00:16What do we mean by anatomically the same?
00:18One could ask, well, what about our bodies is unique?
00:21What does nothing else have?
00:22Well, if you look at everything, it's pretty much just our chin,
00:25which is sort of ridiculous.
00:26We are the only species with a chin.
00:29But the chin doesn't make us human.
00:31How long have we had chins?
00:32It may be 300,000 years.
00:35How long have we had bodies that look like this?
00:37Maybe a little bit older.
00:38How long have bodies like this been the only thing around?
00:42About 40,000 or 50,000 years.
00:44When did anatomically modern humans, that is, other humans,
00:48fossils that look just like us, first show up?
00:50Around 300,000 years ago.
00:52But it doesn't mean that we poof emerged then.
00:57Toughwin2254 asks,
00:58Was there ever a first human?
00:59If not, then how do we become humans?
01:02It's important to realize that there wasn't some point where, you know,
01:05300,000 years ago, an archaic homo sapiens or a homo erectus, like, gave birth and
01:10it was a homo sapiens.
01:12That's not the way it works.
01:13What happens is there's a whole bunch of populations of homo erectus or homo erectus-like stuff
01:17that changed a little bit over time.
01:18And once they've changed enough, that is, whole populations, hundreds, thousands, tens of thousands of
01:23individuals. Once they changed enough, we're like, oh, you know, that's not like it was 100,000 years ago.
01:27It's different enough.
01:28We're going to call it homo sapiens now.
01:30That's the way evolution works.
01:31Gradually, over time, stuff changes.
01:34That's evolution.
01:36AshHuntyTheBee asks,
01:37Do y'all think monogamy is really natural or are we just forcing it?
01:42Okay, so let me give you the short answer.
01:44Humans are monogamish.
01:46When we say monogamy, we tend to think about marriage and law stuff and cultural ideologies.
01:51No.
01:52Deep in our past, humans didn't get married.
01:55Deep in our past, humans didn't make some kind of formal pronouncement of this one and this one
01:59come together.
02:00What they did do was come together frequently in pairs and really care for one another,
02:06and sometimes break up and find other pairs.
02:08Usually when people think about monogamy, though, they're talking about sex, right?
02:11Social mammals use sex not just for reproduction, but actually for social relationships.
02:16Primates, man, do they have sex a lot.
02:18Like, a lot of primates have more sex outside of reproduction than inside reproduction.
02:22And when it comes to humans, well, we're pretty much the sex champions of the primate world.
02:27Well, it turns out, in primates and in mammals in general, the more social you are,
02:31the more you rely on everyone else in your group and have interesting connections and relations to
02:35them, the more sex you have.
02:37Is monogamy the way we're naturally designed?
02:41No.
02:42Monogamy, in the sense of strong pair bonds between two individuals, happens a lot.
02:47It's very frequent for humans.
02:49But is attraction and sexual interaction exclusive within that pair bond?
02:53No.
02:53Everyone who's pair bonded knows they're attracted to other people too.
02:56That's part of the way we primates are.
02:59We love sociality.
03:00Sometimes we cluster together in throuples.
03:03Sometimes we have these extended families, which have great connections and really complex
03:08relationships.
03:09The bottom line is humans bond in incredibly powerful ways.
03:13And in fact, that might be part of the story of our success.
03:17D. Yvonne Marshall asks,
03:19If we really came from monkeys, then can someone please explain to me why there are still monkeys?
03:25We didn't come from monkeys.
03:26Okay, it turns out we're primates, monkeys are primates.
03:28About 35 million years ago, those living monkeys today and us shared a common ancestor.
03:33So deep in time, there was this ancestral primate.
03:36Monkeys emerged from one branch.
03:38We emerged from another branch.
03:39We did not come from monkeys.
03:41We and monkeys are cousins.
03:43Here's a question from the Debate Evolution subreddit.
03:46So, did we evolve from Neanderthals or what?
03:49Walk me through the family tree.
03:51I think we can do that.
03:52So, let's think about human evolution not so much as a family tree, but sort of a family shrub, right?
03:59So, down at the beginning here, those roots are, you know, let's say six, seven, eight million years ago.
04:05Ape-like things.
04:06From this, we get sort of this branch, and then this branch, and then this branch.
04:11We've got Australopithecus afarensis.
04:14Australopithecus afarensis, or Lucy, represents a cluster of hominids.
04:18And we think this is the sort of basal cluster to these three big lineages, right?
04:23These three parts of human evolution.
04:24So, one of the parts of human evolution that's not us, but closely related,
04:29are those that we call Paranthropus, or the robust Australopithecines.
04:33These relatives, ancestors slash relatives, had really big teeth, had bodies that were big and small,
04:39but were different enough that we're like, those are some branches of the family shrub that's not us.
04:44And then we've got this sort of other lineage over here, which, you know,
04:48is characterized by this thing we call Australopithecus africanus that looks a lot like Lucy,
04:53but, you know, has some changes, a little bit sort of more slender,
04:57maybe a little bit more like us, but it's not us yet.
04:59And then, 2.8 million years ago or so, Homo habilis, the murders of the genus Homo.
05:04Now, we think it might have come from this branch, probably didn't come from this branch,
05:08might have come straight up as a third branch from Australopithecus afarensis.
05:11Once we get up into this stuff, the genus Homo, us, we start to get some really cool, fascinating relatives.
05:20These are the Neanderthals, the Denisovans, and by the last million years or so,
05:25we get this large cluster of members of the genus Homo, our ancestors here.
05:29So, for example, we get Homo erectus or Homo ergaster by about 1.5 million years ago,
05:34which, really interestingly, is this individual right here.
05:37What's really fascinating is that we have this incredible diversity of ancestors,
05:41of populations, of relatives, and by about, let's say, 30,000, 20,000 years ago, just us.
05:50So, here's the human family shrub.
05:53Well, where are the lines? Like, exactly who connects to who?
05:56So, probably all of us connect back to Australopithecus afarensis or Kenyantippus.
06:01Anyway, something in this 3 to 4 million year period is probably the ancestor of all the rest of us.
06:05Then, we've got all of these different kinds of humans.
06:08So, which one of these different humans is directly the ancestor to us?
06:13All of them?
06:14So, it turns out that there's not one population, one species, or one of these that gave rise to humans.
06:20Humans look like we're a mixture genetically, behaviorally, culturally,
06:23of a number of different populations, groups, maybe even different species,
06:27that lived over the last million years.
06:29So, there's not one line from here to here or here to here.
06:31How can we be evolved from all these different things?
06:34Well, think of humans as a mutt, right?
06:37You can think of dogs as sort of a standard dog.
06:39You can actually mix together a whole bunch of dogs that look really different
06:42and pretty much get dog after a few generations.
06:44Humans are that way too.
06:46So, all of these different humans living 300,000, 200,000, 150,000, 50,000 years ago,
06:51different groups, moving around, mating, fighting, getting together, breaking apart,
06:55all of that has contributed to us today.
06:59That's why humans are sort of a composite species.
07:02We're a bit of our history, every one of us.
07:05Arsid asks, is it genetically possible for a mutation to occur that would give us superhuman
07:10properties, something like Spider-Man or the X-Men?
07:13Oh, that would be so cool, but it's not going to happen.
07:15That's not the way genetics and bodies work.
07:18So, I wish this X-Men thing was a possibility, like one change in the gene and like I could
07:21grow
07:22out, you know, Wolverine claws or something like that.
07:24It's not going to happen because development doesn't just poof happen.
07:27Like, as your bones develop, they develop in particular ways and they have constraints, right?
07:31So, you know, I might develop joined fingers, but I'm not going to develop an extra finger
07:36that has a titanium claw that sticks out or a bone claw or something like that.
07:40And you can't have one change that changes the whole game plan, right?
07:43It takes hundreds of thousands or millions of years.
07:46So, one might think, well, wasn't there a mutation in some ape-like ancestor that made him
07:50stand up and start walking?
07:51No.
07:52It turns out, like, early ape-like ancestors, 10, 14 million years ago, were already sort of
07:58standing on their hind limbs in the trees and moving around.
08:01And then a few million years later, started to use the ground a little more.
08:04And over millions of years, that slowly changed what bodies look like and hands and feet.
08:08The point is, there's no mutation that immediately changes you.
08:12Evolution takes time.
08:13Even if you get some really important genetic shifts, those genetic shifts could be invisible,
08:18nothing happens, or they could take years and generations before any change occurs.
08:23By the way, there is one interesting aside here about the X-Men.
08:26So, there's a species that's like us, but not us.
08:28Homo naledi, it's related to us.
08:30They lived about a quarter of a million years ago in this rising star cave system in South Africa.
08:34They're really fascinating.
08:36Well, one of the main researchers on that project was sitting next to someone very major in the
08:41comics world, and they began talking on a plane a number of years ago.
08:45And the result of that was a comic, and you can go check this out in X-Men Origins,
08:49that the X-Men actually didn't come from the same ancestors that we did.
08:53That in fact, something called Australopithecus sediba, lived about two million years ago,
08:57sort of emerged into a human, but a human with a slightly different ancestry.
09:02So in that argument, X-Men are not just that they have some mutation,
09:05but in fact, they have slightly different ancestors than we do.
09:08Next question.
09:10From the human evolution subreddit.
09:12Is the concept that meat caused the expansion of the human brain false?
09:15Yeah.
09:16Okay, what's really fascinating is this is what I was taught, as a student and as a scientist,
09:20and this is what I published and written about sometimes. It's changed now.
09:23We used to think that to get this big brain growth, you need a lot of protein.
09:27Early on, when our brains are really starting to first grow,
09:30that first big jump from the australopithecines or other things,
09:33it doesn't look like we're eating that much meat.
09:34And so we have to ask, well, where's that coming from?
09:37Well, carbohydrates, so roots and tubers, a lot of other small animals.
09:41The whole punchline that meat is why we got big brains and became human, that's not true.
09:47Meat's always been an important part of our diet. It's become more important in our diet,
09:52especially for children. But meat is not why we're human, it's not why our brains grew,
09:56and it's not why we're smart.
09:58At Dale Sparrow asks,
09:59Did ancient humans just eat a shitload of roots?
10:01Yes. Not just, but they did eat a lot of roots.
10:05Roots and tubers, the underground storage organs of plants, are really important in our evolution.
10:09But you know what else is important? Honey, right?
10:12It looks like insects and bees' honey might have really shaped our evolutionary history
10:16and gave us access to protein and things like that.
10:18You know what else is important?
10:20Lots of small animals, lots of small animals that we could catch and eat.
10:23You know what else is important?
10:24Big animals, when we finally figured out how to hunt big animals.
10:27All of that.
10:28At some point, not that long ago, right?
10:3110, 15,000 years ago, 8,000 years ago, humans went from gathering, hunting and killing things,
10:36catching fish, gathering whatever fruits or berries are out there,
10:39to messing with the plants, messing with the animals and creating new types of it.
10:43We call this domestication. Everything you are eating now is pretty much domesticated,
10:46is recreated over the last few thousand years to look like it does now.
10:50Is that better or worse? I don't know.
10:53What's really incredible about humans, and this is probably really old for our species,
10:57we don't just eat, right? We create diets, cuisines, and life.
11:03For humans, eating is not just about nutrition. It's also about culture and enjoyment.
11:09Cauliflower nice ass. At Adult Swim, Primal is a documentary about early humans!
11:14Exclamation point. Someone proved me wrong. At Primal.
11:17Okay, it's not a documentary about early humans, but Primal's cool.
11:20Yeah, it's wrong with dinosaurs and some other things like that,
11:23but what's cool about Primal is it puts us in touch with our ancestors.
11:26It puts us in touch with other ways to be human.
11:28And here we have a clip from Primal depicting the main character fishing.
11:32Fishing? How long have humans fished?
11:34Two million years ago, or almost two million years ago, in East Africa,
11:37we have one of the first evidences of butchering of an animal.
11:40And what is it? It's a giant catfish.
11:42How did they catch that giant catfish?
11:44They probably jumped into this river and grabbed this catfish and then processed it,
11:48chopped it up, and sliced it.
11:49We've been fishing a long time, and fishing matters to us.
11:54StandardAd868 asks,
11:55How did blue eyes spread if it was recessive?
11:57Well, it's not a simple dominant recessive.
11:59So there's a whole bunch of genes, 20 plus at least, that go into eye color.
12:03But you're right, blue eyes are pretty rare.
12:05Blue eyes can show up with particular genetic and developmental combinations.
12:10They've shown up in populations in Northern Europe, in populations in Australia,
12:14and populations actually in Africa, around the world.
12:16So blue eyes are rare, but they show up.
12:19But that gives to the bigger question.
12:20These little things that change about humans.
12:23Why?
12:23For example, many people today get their third molar taken out,
12:27because it's all crunched in the back there.
12:28That's not because there's a problem with the third molar.
12:30It's just that our jaw is starting to change.
12:32It's actually getting a little bit smaller as our heads got sort of globular and big, right?
12:36So there's only a limited amount of bone tissue there.
12:39And so as your jaw shrinks, you crowd that third molar.
12:43Viking Hair wants to know,
12:45Could Neanderthals and Homo sapiens talk with each other?
12:48Yes, they could.
12:49Clearly, Neanderthals and humans around that time could speak and they could interact.
12:54Well, if they could talk to each other, what do they sound like?
12:56Well, some people have argued that the Neanderthals had this high-pitched voice that is something like this, right?
13:02This skull, this shape had something about it.
13:06Maybe in the neck and the bones of the body that made it speak very high.
13:10Now, let's think about this for a minute.
13:12We would have to look at the bones in the neck and sort of the soft tissue of the larynx
13:16and a variety of other things.
13:18This is a Neanderthal, right?
13:19And this is a human.
13:22Actually, when we compare these, they're not huge differences.
13:24If you think about it, if you travel around the planet and talk to all of the eight billion humans,
13:30there's going to be a lot of voices and a lot of things going on.
13:33So, did they talk to each other?
13:35Probably.
13:35Maybe they used sign language.
13:37Maybe they grunted at each other.
13:39Maybe they spoke the same language.
13:41I don't know yet, but it probably wasn't one going,
13:43ah, and the other going, rah, rah.
13:45Xsoya asks,
13:46How did the first humans create tools when they didn't have tools to create tools with?
13:50Okay, the first tools are stone tools.
13:53Stone tools are made out of stones.
13:55So, what do you need to make a stone tool?
13:56Well, you need to be smart enough or have this insight that inside this stone is a tool.
14:01So, what do you need?
14:02You need one stone and another stone and you bring them together and you hit them together carefully
14:06and with foresight and you create a stone tool.
14:10So, what's really fascinating is not what tools did we use to make tools,
14:14but rather when did we figure out that inside a rock was a tool
14:18and figure out that picking up another rock and hitting that rock in particular ways
14:22and doing it again and again would get us something like this.
14:25That's the interesting question.
14:26These are called hand axes, right?
14:28Because you hold them with your hand and sort of cut or chop things.
14:31These are, you know, made in the last million years or so,
14:33750,000 years ago, 600,000 years ago.
14:36And what they are is a rock.
14:38So, Homo erectus, Homo heiderbergensis, one of those humans living around this time period,
14:42sat in a big rock and spent hours and hours knocking off little pieces on both sides
14:48to create a sharp edge and a beautiful form.
14:51They're way more symmetrical and way more work than is necessary to cut or chop or poke.
14:56Why did our ancestors not only learn how to make stone tools, right?
15:00But then make really beautiful ones, sometimes not even using them,
15:04just making them and putting them in big piles.
15:06Stone tools are not just tools.
15:08They're also social symbols.
15:11A million bucks asks,
15:13We are getting closer and closer to becoming the humans from WALL-E
15:16and I'm so scared, lol.
15:18No, we're not.
15:18WALL-E is an example of what happens to human bodies if, like in the movie,
15:22you know, you stop walking, you stop moving, you just start gorging your face.
15:26That's not evolution, right?
15:28That sort of getting immobile and gigantic and drooling.
15:31That's actually a capacity that human bodies have right now.
15:34Evolution works on existing variation slowly, usually.
15:38So what's going to change in humans?
15:40I don't know.
15:41Our genetic frequencies are changing right now and have been changing.
15:44You won't see any of that because that's all on the inside.
15:46Maybe our resistance to viruses is changing.
15:49We know that's true.
15:50So our head's going to get big or our eyes going to get gigantic.
15:53No, none of that's going to happen.
15:55WALL-E is not a threat, evolutionarily speaking.
15:58WALL-E is a threat if we don't change our ways,
16:02wisen up, and start taking care of ourselves and the planet.
16:05Axel17 asks, are hobbits real?
16:08Yes, they are.
16:09Not the Lord of the Rings hobbits.
16:10But it turns out, probably about 75 to 200,000 years ago,
16:15on the island of Flores in what is today Indonesia,
16:18a bunch of humans or human close ancestors or relatives called Homo floresiensis lived.
16:24Homo floresiensis was a hobbit. It was a very, very small little human with big feet,
16:29which is awesome, and they ran around and guess what they had to deal with?
16:32Komodo dragons!
16:33So there's a little teeny hobbit human fighting off gigantic lizards,
16:38hunting big rats and little mini elephants.
16:40It's like Middle Earth on the island of Flores.
16:43Homo floresiensis was only about three and a half, maybe four feet tall.
16:46They were really small.
16:47Why so small?
16:48Well, we think they're the product of something we call island dwarfism.
16:52So when you look at islands around the world,
16:54big animals show up on islands and get smaller.
16:57Like elephants get teeny.
16:58There's like little pony-sized elephants.
17:00There's other animals that are really small and they get to islands and they get bigger.
17:03Well, what we think happened is probably a million or more years ago,
17:07as humans moved around the planet, or actually human ancestors,
17:10some of them got to the island of Flores and they stayed there.
17:13And over time on that island, they shrunk down and got really small.
17:17And they did pretty well for, you know, more than 100,000 years.
17:19And, interestingly, humans show up on Flores around the same time that the hobbits disappear.
17:25Why? We don't know.
17:26Did they interact? We don't know.
17:28Mattia Sierra asks,
17:30Who invented kissing?
17:31Like, who was the first person to find out that touching lips could help spark chemistry?
17:35So humans are probably the only creature that kisses in association with sort of sexual arousal,
17:40the way we do.
17:41Other animals sort of put their lips together.
17:43For example, any of you watching this who have a dog,
17:46your dog is trying to get its tongue and its mouth on your mouth all the time.
17:50That's because that's a common exchange for canids, right?
17:52They love to lick each other in the mouth and share the microbiome.
17:55That's not kissing, right?
17:56We call it kissing, but for the dog, it's like,
17:58Hey, hello.
17:59Here's all the spit from my mouth so that we're part of the same pack.
18:01That's not what human kissing.
18:03We're not trying to exchange spit to be part of the same pack.
18:05We're actually kissing because it feels really good.
18:08So chimpanzees, right?
18:09Here's the skull.
18:10Chimpanzees have these big old lips, right?
18:12That are incredibly flexible.
18:14So they can smooch and move their lips and all kinds of things,
18:16but they don't have lips like ours that are sort of tight around our face and connected,
18:21and they don't have the same kind of nerve structures.
18:23So why did I just go around that?
18:25Because it turns out that part of the reason kissing is important for humans
18:28is the shape of our face, the shape of our mouths, and the shape of our lips.
18:33But why kiss?
18:33I mean, why do that?
18:34Well, it turns out humans love to look at each other, right?
18:37Face-to-face contact.
18:38When we meet someone, the first thing we do is look at their eyes.
18:41We look at their face.
18:42We're really interested in what's going on here.
18:44And then when you get close to someone, you love to touch them.
18:47And guess where on your face is one of the most filled with nerve endings
18:51and very sensitive sort of areas of tissue?
18:54The lips.
18:55So it turns out putting lips together,
18:57especially if you throw in tongue and other things like that,
19:00actually is really sensorily powerful.
19:03Like you really feel it.
19:04But then there's a problem.
19:05Not all people all over the planet, even today, kiss regularly.
19:08A lot of cultures kiss each other on greetings or kiss on the side of the mouth.
19:12Why do we kiss?
19:13We kiss because we can.
19:15Why is kissing fun?
19:16Kissing is fun because of the way our face and nerves are designed.
19:20Do all humans kiss?
19:21No.
19:22Do we need to kiss to spark chemistry?
19:24No.
19:24Does kissing spark chemistry?
19:26Yep.
19:28JustinAlphabet asks,
19:29The earliest human skeletons had spears in their rib cages.
19:31Do you think mankind will ever learn to get along peacefully?
19:34The earliest human ancestors did not have spears in their rib cages.
19:38Spears came a lot later.
19:39But what's really interesting is that we do find evidence throughout human history
19:43of one human ancestor hitting the other in the head and killing them, maybe.
19:47But it's not that common.
19:49We don't see one group attacking another group with regularity and lethality.
19:53Until between about 10 and 20,000 years ago.
19:55Then we start to see it more and more common.
19:57And in the last 8 or 7,000 years, warfare,
20:00two groups coming together and just trying to kill each other, does emerge.
20:05Clearly, fighting and aggression is deep in our history.
20:07It's part of our capacity.
20:08Warfare, however, is fairly recent.
20:11Humans have a capacity for incredible violence and aggression,
20:14and for incredible caretaking and collaborating.
20:18NotSoWinner57 asks,
20:19Why do we, as humans, look so different from one another compared to other animals?
20:23Good question!
20:25Because if you weren't a human, if you weren't in some culture today that makes a big deal about
20:29skin color or hair type or clothes, you wouldn't think humans look that different at all.
20:33If you came down from, you know, outer space and you looked, you'd be like,
20:35Ah, man, these are all the same.
20:37If you were to look just at human DNA, all humans are 99.9% identical.
20:42If you look at the DNA from a white-tailed deer in Michigan and that same deer in New Jersey,
20:48right, same species, not that far apart, those two deer would be more separate,
20:54more different from one another genetically than any two humans in the entire planet.
20:57It turns out contemporary humans, Homo sapiens sapiens, us around today,
21:01all eight billion of us are the last living human species.
21:05But if you take a look around 400,000 years ago, five, six, 700,000 years, a million years ago,
21:12there were multiple human populations, probably multiple human species,
21:16a lot more variation than there is today.
21:18So bottom line, yeah, there's a lot of variation in humans,
21:22but under the skin and as being human, we're all pretty much the same.
21:28Goltz2707 asks,
21:29Question for those knowledgeable in the field.
21:30Did early humans actually live in caves or were they special use spaces?
21:35And it's just that the artifacts left in caves are better preserved than those left out in the open.
21:38Yes, the answer is yes all the way around.
21:41It looks like some humans and human ancestors did in fact live in caves,
21:44that is, they spent a lot of time there.
21:46Most did not.
21:47And yes, something in a cave has a better chance of being preserved than something outside in the open.
21:51But given all of that, let me just tell you, like being in caves is fascinating.
21:56Because being in caves, especially if you have fire, you've got to think about smoke,
21:59you've got to think about wind patterns.
22:00Being in caves, you have to sort of deal with other things like cave bears and other things
22:04that want to live in those caves and you've got to keep them out.
22:06And also, when humans and human ancestors used caves, they didn't just like go sit in a cave.
22:11They actually manipulated those caves and changed them.
22:13For example, more than 200,000 years ago in this cave in France,
22:17you have to go way to the back of the cave.
22:18There's evidence that Neanderthals took a bunch of stalactites and stalagmites,
22:21you know, the ones from the bottom and the top,
22:23broke them and then laid them out in a circle
22:25and then built a fire in the middle of that circle and used this for generations.
22:29And cave paintings.
22:31Like for some reason, humans go all over the place and crawl into really difficult places
22:35and like paint on the walls.
22:37I've been in one cave in Portugal, we have to crawl through,
22:40turn upside down, get on your back and then look up like this
22:43and you see this beautiful horse up on the side.
22:46What? What's going on?
22:47So yeah, they were sacred spaces too.
22:50So humans lived there.
22:51Yeah, they were symbolic and sacred spaces.
22:53And yeah, stuff gets preserved better there.
22:55That's why caves are so important in human evolution.
22:58Vedit Srimali27 asks,
23:00If species like Homo neanderthalensis had larger brains than us,
23:03and Homo erectus survived for nearly two million years,
23:06why did they succumb to extinction while Homo sapiens thrived?
23:09There used to be a whole bunch of different kinds of humans.
23:13They're all dead.
23:14They all went extinct.
23:15Why?
23:15What's going on?
23:16Well, neanderthals did have bigger brains than us on average,
23:20but a normal human brain ranges from 1,000 cubic centimeters to 2,000 cubic centimeters.
23:25That's 100% variation.
23:26So having 100 cubic centimeters more or less on us for neanderthals really doesn't matter.
23:32So neanderthals did not really have bigger brains than us.
23:34They were just a little bit bigger body.
23:36Homo, our genus, shows up about 2.8 million years ago.
23:40In that time period, it divides and moves around into different sort of populations that look
23:45pretty different from one another in many ways.
23:47What's really interesting, though, is all this variation, all these different kinds of human,
23:52they all go extinct at some point.
23:54And we made it.
23:55Well, when I say we, that's not exactly right.
23:57Don't think of all these other humans as necessarily going extinct.
24:00Think about them as leaving us little gifts, little pieces of DNA, little bits of heritage that make us who
24:06we are today.
24:07So, I mean, a logical question to ask is how do we have genetics from different species, right?
24:11Species that aren't us.
24:12Well, first of all, species is a fuzzy category, right?
24:15We don't know exactly, you know, 120,000 years ago if a Homo sapiens and a Neanderthal walked by each
24:22other.
24:22Did they see each other as different species?
24:24We knew they could have sex.
24:26Clearly we're carrying some of those genes.
24:27So what we really should ask is not how do different species get together,
24:31but what does it mean to understand that we, humans, are this composite,
24:37we're this compilation of all these different populations, of all this different variation from the past,
24:42that somehow has made it to today.
24:45Not only made it, but there are 8 billion of us right now.
24:48That is pretty impressive.
24:49So whatever we did, we did okay.
24:51What was it about us?
24:52Sure, it's not the chin, right?
24:54It's not the chin.
24:54The chin did not make us survive.
24:56Maybe it was our unbelievable ability to communicate, to cooperate.
24:59Maybe it was our ability to create trading networks across hundreds of miles.
25:03Maybe it was our ability to care for one another a little bit more than others.
25:06Maybe it was our ability to imagine new possibilities and try to make them real.
25:10All of those things are things we do.
25:12But all of those things are probably things that some of these guys did too.
25:16Are we really that different?
25:18Or maybe are we just the luckiest hominin, not the best?
25:23Milky Women asks, how true is the idea of survival of the fittest?
25:26First off, it's important to point out that survival of the fittest we associate with Darwin.
25:29But Darwin didn't use that phrase in the first edition of On the Origin of Species.
25:34He did in the second edition in Moving Forward.
25:36Why?
25:36Well, he got sort of pushed to use it because it sounds cool, right?
25:39People love survival of the fittest because they think it means if you're bigger,
25:42or faster, or meaner, or fight more, you win.
25:44That is not how evolution works.
25:46Not usually.
25:47Some animals being faster is better.
25:49Other animals being smarter is better.
25:51Other animals being slower is better.
25:54One of the biggest problems with this idea of survival of the fittest
25:56is that we think about guys in that way, right?
25:59Like the alpha male, the guy who, you know, looks maxes and gets the women and does everything.
26:04Okay, let's actually deconstruct that for just one second.
26:08So alpha male comes from terms about wolves, a pack of wolves.
26:11There's not an alpha male.
26:12There's a male and a female who breed.
26:14They're the sort of like center of the group.
26:15And they breed and the other ones help them raise the young and they hang out
26:19and they're all together and they communicate and cooperate and collaborate.
26:22Basically, someone made up this notion of alpha male as this dude who's at the top of everything.
26:27It turns out for most of human evolution, and even today,
26:30if there's one dude who's really aggressive and bothering everyone and pushing them around,
26:34what happens?
26:34That dude gets tossed out of the group.
26:36There are eight billion humans on the planet right now.
26:38So we're definitely fit.
26:39Are we the fittest?
26:41That we'll have to wait and see.
26:43Peter Agro asks,
26:44Where did the first humans come from?
26:46How did they spread across the planet?
26:48We're homo sapiens.
26:48So genus homo species sapiens.
26:51The genus homo has about two and a half million,
26:53almost three million years of history.
26:54We originate in Africa,
26:56Sub-Saharan Africa,
26:57and over the last two and a half million years or so,
27:00have spread all around Africa and the rest of the world.
27:02If you want to say,
27:03well, where's the first fossil looks just like us?
27:05That we're going to call that the first human.
27:07That's probably around 300,000 years ago in North Africa,
27:10in what is today Morocco.
27:11It looks very similar to other stuff, but a little bit different.
27:13It has a chin and some other stuff.
27:15There's others about 180,000 years ago in East Africa,
27:17and then more recently we find them in Central Asia,
27:21Southeast Asia, Europe, and Australia.
27:23Humans do a lot of things,
27:25but what they really do well is move and mate and hang out.
27:29So, no easy answer, but there are two fun ones.
27:33One, humans begin in Africa and spread around the world over the last two million years.
27:39Two, humans begin in Africa and spread around the world about 300,000 years.
27:43Either one, totally good.
27:45From the explain like I'm five subreddit comes a question,
27:48why are human kids so useless for so long compared to almost every other animal?
27:52So, imagine, all of you have seen the wildlife show where a giraffe gives birth, right?
27:56This giraffe gives birth, the baby drops out, and then, you know, seven minutes later,
28:00it's running across the savannah. That's really impressive.
28:03Human babies, they, we give birth, you have the baby, what does the baby do?
28:07They can't even lift their head for weeks.
28:10What's going on there?
28:11That's actually part of the secret of being human.
28:15It turns out that humans have stretched out that infancy and childhood
28:19in a way that allows us extra time to grow.
28:22The human brain at birth is only 40% of its adult size.
28:26That's the smallest of any mammal.
28:28So, most of our brain grows outside, in the world, interacting with other humans.
28:33Why? Culture.
28:34It's hard to learn how to be human, and our bodies and our brains need to be in interaction,
28:39be together with others.
28:40And so, how do we extend out that childhood?
28:42We do a lot of caretaking, right?
28:45The story, it takes a village to raise a child, that is true.
28:47One person can do it, but it's really hard.
28:49Our bodies, our lives, whether you're male or female, young or old,
28:53our bodies are geared towards grabbing those kids, holding onto them, and taking care of them.
28:57Why do humans have this really long childhood?
29:00That's because it takes a long time to be human,
29:02and part of that is being together with others.
29:08ParkingBid9954 asks,
29:09Were the average Neanderthal man stronger than modern man?
29:12Maybe. Depends on which modern man you're talking about.
29:15Humans are incredibly variable.
29:17On average, Neanderthals were a little bit stockier than most humans today.
29:20But humans 15,000 years ago were a little bit stockier than most humans are today.
29:25Part of it is their overall lives were a little more stressed out.
29:28They had to use their bodies for a lot more things.
29:30More and more as humans require less body use, we get a little bit of reduction, right?
29:36That is so we can move the bone tissue around.
29:38For example, now that we pretty much pre-cook or pre-chew all of our food, right?
29:43Processed food, canned food, cooked food.
29:44Actually, we really don't need much power up here in the jaw.
29:47And what we've seen is our jaws and teeth have gotten a little bit smaller.
29:52Myrna Arroyodorf asks,
29:53Random thought of the day.
29:55Considering the amount of Neanderthal mitochondrial DNA we have,
29:58can it be that Neanderthal women just found homo sapien males cuter, leaner, more charming?
30:03Uh, no.
30:04We have no idea what happened when Neanderthals and humans got together,
30:08aside from the fact that sometimes they had sex and offspring.
30:12Did they find each other cuter?
30:13Were they repulsed by one another?
30:14Were they intrigued by one another?
30:16I don't know.
30:16I wish I had a time machine.
30:18But what we do know is that humans and Neanderthals somehow more than once got together and had a baby.
30:26Corey's Jill asks,
30:27In hunter-gatherer societies, were gender roles really as rigid as they are taught in textbooks
30:31and depicted in pop culture?
30:33First of all, when we look at even recent sort of societies, let's say 5,000 years ago,
30:37I can look at the bone chemistry, right?
30:39And I can show you that men and women on average as adults were eating slightly different foods.
30:43That suggests some kind of real different sort of patterns, right?
30:45Or we can show that like right arms and left arms are different in men, but not in women,
30:49which shows a different kind of sort of behavior around agriculture or something like that.
30:54But when we go back in time, we don't see that.
30:56When we look at male and female bodies, it's really hard to find identifiable differences.
31:00Well, people say men hunt.
31:01Well, we see in Neanderthals and in earlier humans, both males and females have the same kind of broken bones.
31:07They see them have the same kind of sort of stature and thick, strong muscles.
31:10So it's just not clear.
31:12The manosphere wants us to believe that evolution shows men are this way and women are this way.
31:17And you know what? It's just not true. It's a little more complicated and much more interesting.
31:22Eric Von Doom asks,
31:23Sometimes I think about how human beings have been around for 300,000 years,
31:27but recorded history only goes back 5,000 years.
31:30So there's 295,000 years that are just completely unaccounted for.
31:35Not true. We have great accounting. First of all, recorded history goes back more than 5,000 years.
31:40We have hundreds of thousands of years of evidence of humans building stuff, making things, creating things, and leaving them.
31:47500,000 years ago in East Africa, human ancestors, Homo erectus or one of the other species,
31:52carved up these big chunks of wood and put them together like Lincoln logs, right?
31:56Other ones, 128,000 years ago, made little perforated holes in shells and strung them around their necks.
32:02And 65,000 or 70,000 years ago, humans in the island of what is today Sulawesi, right?
32:08Climbed into a cave and painted a pig in a handprint.
32:12Humans decided to take pigments to add water and spit and other stuff to ochre to these mineral pigments
32:18and paint their bodies and paint the walls.
32:20So don't just hold on to writing. Writing is recent.
32:23The really interesting stuff, the amazing stuff is what our ancestors built and left for us to discover.
32:30So, those are all the questions for today. Thank you for watching.
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