00:00Hi, I'm John Green. Welcome to Crash Course Big History Project where today we're going
00:04to talk about the Planet of the Apes films. - What's that? Apparently, those were not documentaries.
00:10But there was an evolutionary process that saw primates move out of East Africa and transform
00:15the earth into an actual planet of the apes...but the apes are us.
00:19And then we made the movie and then some prequels and some sequels and some reboots and now sequels to the reboots.
00:25Man, I can't wait until I get to see the 2018 reboot of this episode of Crash Course Big
00:29History I hear they get James Franco to play me.
00:41So we're about halfway through our series and after five episodes involving no humans
00:45whatsoever today we are finally gonna get some people.
00:48Mr. Green, Mr. Green! Why are we already at humanity, I mean if we're covering 13.8 billion
00:53years shouldn't humanity come in like, the last two seconds of the last episode? I mean
00:57humans are totally insignificant compared to the vastness of the universe, like we should
01:01be checking in on how Jupiter's doing.
01:03Fair point, Me From the Past; Jupiter by the way, still giant and gassy.
01:06There's two reasons why we focus a little more on humanity in Big History; the selfish
01:10reason is that we care about humans in Big History because we are humans. We are naturally
01:15curious to figure out where we belong in the huge sequence of events beginning with the big bang.
01:20Secondly, humans represent a really weird change in the universe. I mean, so far as we
01:25know, we are one of the most complex things in the cosmos.
01:29Whether you measure complexity in terms of biological and cultural building blocks or
01:33networks or connections, I mean, we're kind of amazing! Now I realize that many of our
01:39viewers will be offended by our human-centric bias, but humans are amazing. I mean, we invented
01:44the internet and we invented animated GIF and we invented Dr. Who and then we invented
01:51Tumblr, a place where all of these things can come together!
01:53So 65 million years ago, catastrophe wiped out the dinosaurs and we saw the adaptive
01:58radiation of a tiny shrew-like ancestor of humans that would look more at home like,
02:04next to a hamster wheel than in your family album. Let's set the stage in the Thought Bubble.
02:08So the slow waltz of plate tectonics continued to pull Eurasia and the Americas apart expanding
02:14the Atlantic Ocean, primates colonized the Americas, and separated by the vast Atlantic, continued
02:20their separate evolution into the new world monkeys -- which is not a band name, although it should be.
02:25Then around 45 million years ago, Australia split from Antarctica and while mammals out-competed
02:31most marsupials in the Americas (except animals like possums), Australia saw an adaptive radiation
02:36of marsupials. This, of course, meant that later, one-hundred thousand years ago when
02:40the Americas were having their share of mammoths and saber-tooth tigers, Australia was having
02:44a spell of gigantic kangaroos, marsupial lions, and wombats the size of hippos.
02:50Then, somewhere around forty million years ago, India, which had been floating around
02:54the southern oceans as an island, smashed into the Eurasian continent with such force
02:58that it created the world's tallest mountain range, the Himalayas.
03:02Meanwhile, in Africa, Primates continued to evolve and twenty-five to thirty million years
03:06ago, the line of the apes diverged from theold-world monkeys and no, neither you, nor a chimp,
03:13is a monkey, nor did we evolve from the monkeys that are around today - those are like our cousins.
03:18Moreover, we did not evolve from chimpanzees, the chimpanzee is a cousin as well, not an
03:24uncle. We are not more highly evolved than they are; Instead, our lines of descent split
03:29off from a common ancestor with chimpanzees about seven million years ago. Then chimpanzees
03:34further split into a separate species, the Bonobos. Knowing about this common ancestry
03:39tells us a lot about our shared traits with other primates.
03:42For instance, we all have fairly large brains, relative to our body mass, we have our eyes
03:46in the front of our heads from the days when we hung out in trees and depth perception
03:50was an excellent way of telling how far away the next tree branch was so as to prevent
03:54us from plummeting to our deaths, and we also have grasping hands, to make sure, you know,
03:58that you could hold onto the branch in question. Primates also have hierarchies, social orders
04:02whether male or female led, that determine who gets primary access to food, mates, and other benefits.
04:09Thanks Thought Bubble! So, our closest evolutionary cousins, the chimpanzees, can tell us a thing
04:13or two about shared behaviors. For one thing, while all primates have a hierarchy of alphas
04:18and betas, humans and chimps, who share 98.4% of their DNA, are the most prone to team up
04:24together and launch a revolution against the alpha male. We're also both prone to ganging
04:29up, roaming our territory, and beating up unsuspecting foreigners of the same species,
04:33and not for direct survival reasons.
04:35Chimpanzees have been observed finding a lone chimp male from another group and kicking,
04:39hitting, and tearing off bits of his body and then leaving the helpless victim to die
04:44of his wounds, and humans definitely bear this stamp of our lowly origin, where indeed,
04:49the imperfect step-by-step process of evolution made us highly intelligent, but still, with
04:54prefrontal cortex's too small, and adrenal glands maybe too big.
04:57Aggression and blood lust are definitely part of our shared heritage, and, looking at more
05:01recent human history, does that really surprise anyone? Contrast that behavior, for a moment,
05:05with the more peaceful Bonobos, who are female-led, and when a male in her group gets a bit pushy,
05:09the females are prone to gang up and teach him a lesson. When it comes to inter-group
05:13encounters in the wild, the male Bonobos seem tense around strangers at first, until usually,
05:18the females from each group cross over and just have sex with the newcomers, completely diffusing
05:22the tension. Talk about make love, not war - Bonobos are hippies.
05:26While our common ancestor with chimpanzees around seven million years ago was more suited
05:30to living in forests and seeking refuge from danger by climbing trees, climate change in
05:35East Africa made things colder and drier, and many forests were replaced by woodlands
05:39and wide-open savanna. Life in the savanna meant our ancestors needed to run from predators
05:43rather than climbing trees, so our line shifted away from the bow-legged stance reminiscent
05:47of chimpanzees, and developed bipedalism, where our locomotion came from legs that were
05:51straight and forward-facing.
05:53There's still some debate about when bipedalism first began, but we know that by the first
05:56australopithecines around four million years ago, our evolutionary line was bipedal, this
06:01also freed up our hands.
06:02Australopithecines were not very tall, standing only just above a meter, or just above 3.5
06:07feet, and had brains only a little bigger than modern chimpanzees. They were largely
06:11herbivores with teeth adapted for grinding tough fruits and leaves. Australopithecines
06:15may have communicated through gestures and primitive sounds, but their higher larynx
06:19meant that they couldn't make the range of sounds required for complex language. There
06:22was probably a lot of pointing and grunting going on. Kinda like me, before 6 am.
06:27By 2.3 million years ago, homo habilis arrived on the scene. They weren't much taller than
06:31australopithecines, but they had significantly larger brains - though still a lot smaller
06:35than later species. Excitingly, homo habilis is known to have hit flakes off of stones
06:40to use them for cutting. Now, lots of species use tools, for instance chimpanzees use sticks
06:45for fishing termites out of the ground, they use rock hammers and leaf sponges and branch
06:49levers and banana leaf umbrellas. A lot of these skills don't seem to arise spontaneously,
06:53just because of the intelligence of individuals, but, like in the case of termite fishing,
06:57chimpanzees pass the information on by imitation - primate see, primate do.
07:02In a way, this social learning is sort of cultural, yet, succeeding generations of chimpanzees
07:06don't accumulate information, tinker with it, and improve upon it, so that after 100
07:10years, chimpanzees are owners of highly efficient and wealthy termite fishing corporations.
07:14Similarly, as impressive as homo habilis stone-working abilities are, we see very little sign of
07:19technological improvement over the thousands and thousands of years that habilis existed.
07:24Same goes for homo ergaster erectus, who was around 1.9 million years ago.
07:28Homo ergaster erectus had an even bigger brain, was taller, and they even seemed intelligent
07:33and adaptable enough to move into different environments across the old world. They may
07:37have even begun our first clumsy attempts at fire, which is vital for cooking meat and
07:41vegetables, opening up opportunities for more energy and even more brain growth.
07:45But still, there's not much sign of technological improvement, their tools got the job done,
07:49if it ain't broke, don't fix it.
07:50Yet 1.78 million years ago, we do see homo ergaster creating a wide new range of teardrop
07:55hand axes in Kenya. By one-point-five 1.5 million years ago, these teardrop axes had
08:00rapidly become common, and had improved in quality and were shaped with a flat edge into
08:04multi-purpose picks, cleavers, and so forth.
08:07Archaeologists see this as the first possible sign of tinkering and improvement of technology
08:11that may have been transmitted by social learning. A faint glimmer of something new. Why is this important?
08:17Well, humans didn't get to where we are because we're super-geniuses. It's
08:20not like invented the Xbox One out of the blue one day, it was an improvement upon the
08:24Xbox 360 which was an improvement upon earlier consoles, arcade machines, computers, and
08:29backward onto the dawn of video games. In the same way, we didn't just invent our
08:33modern society by sudden inspiration, it's the result of 250,000 years of tinkering and
08:39improvement. This is where accumulation matters - it's called collective learning, the ability
08:43of a species to retain more information with one generation than is lost by the next. This
08:48is what has taken us, in a few thousand years, from stone tools to rocket engines to being
08:53able to have the Crash Course theme song as your ringtone. Progress!
08:56If there was collective learning in homo ergaster, it was very slow and very slight. This may
09:01have been due to limitations on communication, abstract thought, group size, or just plain
09:05brain power. But over the next two million years, things started to pick up. Homo antecessor,
09:10Homo Heidelbergensis and the Neanderthals developed the first systematically controlled
09:14use of fire in hearths, the first blade tools, the earliest wooden spears, the earliest use
09:19of composite tools, where stone was fastened to wood, all before homo sapiens were ever
09:25heard of, around 250,000 years ago.
09:27Neanderthals even moved into colder climates, where they were compelled to invent clothing,
09:31they used complex tool-manufacture to produce sharp points and scrapers and hand-axes and
09:36wood handles, and they improved their craft over time.
09:39While evolution by natural selection is a sort of learning mechanism that allows a species
09:44to adapt generation after generation, with a lot of trial and error, and death - collective
09:49learning allows for tinkering, adaptation, and improvement on a much faster scale with
09:54each generation and across generations without waiting for your genes to catch up.
09:59Anatomically similar homo sapiens have been around for about 250,000 years, and throughout
10:03that time, we've been expanding our toolkit from stone tools to shell fishing to trade
10:08and actual fishing, mining, and by 40,000 years ago we had art, including cave images,
10:13decorative beads and other forms of jewelry, and even the world's oldest known musical
10:18instruments - flutes carved from mammoth ivory and bird bones.
10:21All this stuff came about as a result of collective learning. As long as you have a population
10:26of potential innovators, who can keep dreaming up new ideas and remembering old ones and an
10:30opportunity for those old innovators to pass their ideas onto others, you're likely to
10:35have some technological progress.
10:37These mechanisms are still working today - we've got over seven billion potential innovators on
10:42this planet, and almost instantaneous communication, allowing us to do so many marvelous things
10:47including teach you about Big History on the internet.
10:50So life for early humans was pretty good, like foraging didn't require particularly
10:55long hours - the average work day for a forager was about 6.5 hours. When you compare that
11:00to an average of 9.5 hours for a peasant farmer in medieval Europe, or the average of nine
11:04hours for a typical office worker today, foraging seems downright leisurely.
11:09Quick aside: I work thirty minutes a day less than a peasant farmer in medieval Europe?
11:14That's not progress! Stan, I want more time off!
11:17Stan just pointed out that I have a chair, something that peasant farmers in medieval
11:20Europe did not enjoy, and I want to say that I'm very grateful for my chair.
11:23Thank you for my chair, Stan.
11:24Anyway, a forager would go out, hunt or gather, come home, eat, spend time with the family,
11:29dance, sing, tell stories, and foragers were also always on the move, which made it less
11:34likely that they'd contaminate their water, or sit around waiting for a plague to develop.
11:39And with their constant walking and their varied diet, foragers were in many ways healthier
11:44than the peasants of ancient civilizations. There were also, in some ways, healthier than
11:47us, but we have antibiotics for now, so we live longer, for now.
11:52The classic view of foraging life is best described by Thomas Hobbes, who wrote:
11:56\"No arts, no letters, no society, and which is worst of all continual fear and danger
12:02of violent death and the life of man, solitary, poor, nasty, brutish, and short.\"
12:09Except, not really. I mean, life for the average person in twelfth century France was also
12:13a smidge nasty, brutish, and short, and the lack of wealth disparity in foraging cultures
12:18may imply greater equality between social rankings and even between the genders since
12:22female gatherers appear to be responsible for the majority of food collected, rather
12:26than the hunting males. And from that perspective, life was kind of ruined by the advent of agriculture
12:32and then, later, with states, as Jean-Jacques Rousseau said,
12:35\"The first person, who having enclosed a plot of land, took it into his head to say, 'this
12:40is mine' and found people simple enough to believe him, was the true founder of civil
12:45society. What crimes, wars, murders, what miseries and horrors would the human race
12:50have spared, had someone pulled up the stakes or filled in the ditch and cried out to his
12:55fellow men: 'do not listen to this imposter, you are lost if you forget that the fruits of the
13:00Earth belong to all, and the Earth to no one'\"
13:03and thus summarizes one of the great debates in the world of political science. Man, Big
13:06History discusses everything! Now, it's possible that neither Rousseau nor Hobbes was completely
13:11correct, and that, like, private property and agriculture didn't create the glory days or end them.
13:17Like, as previous mentioned, all primates have a dominance hierarchy of some kind. Also,
13:22you don't need a wealth disparity to drive human beings to hurt each other - like, surveys
13:26of excavated remains from the paleolithic indicate a murder rate that was possibly as
13:30high as ten percent. Now, those statistics are still disputed, but despite the relatively
13:34short work day, life in the paleolithic sounds a lot less appealing when you consider the
13:38high murder rate, and also, the occasional infanticide. That's not even to mention the
13:42old or disabled people who, when they couldn't keep up anymore, were abandoned to die in
13:46the wild. I can't help but feel that I might not have thrived in the paleolithic what with
13:49my visual impairment and general lack of interest in hunting.
13:53Anyway, we call this the Hobbes vs. Rousseau debate, and it's still unresolved. I mean,
13:57humans may have been corrupted in many ways by society, on the other hand, it's possible
14:02a lot of the crimes and follies of human history may just be symptoms of our coping with the
14:07bad wiring left to us by evolution.
14:10You know, humans are a bit of an obsolete machine, we aren't particularly well-suited
14:14to the many lifestyle changes that have happened in the past few thousand years - faster than
14:18our genes can keep pace with. But how you interpret the lives of early human foragers
14:22largely determines your view of history and also the fundamental nature of the human character.
14:27Ask yourself which side you sit on: Is humanity fundamentally good and corrupted by technology
14:34and modern social orders, or are we fundamentally flawed and in need of some sort of structure
14:38and authority? Or is there some kind of both/and way of addressing the question? Here at Crash Course,
14:43we don't have answers, but we are grateful that you're pondering these questions with us.
14:48In any case, collective learning was really good for our survival, but then, 74,000 years
14:53ago, disaster struck. A super-eruption at Mt. Toba on the island of Sumatra in present-day
14:58Indonesia clouded the skies with ash and cooled the climate. Plants and animals, a.k.a. food, died
15:04off and genetics studies showed that this reduced the human population to a few thousand
15:09people. So as a result of this, we aren't exactly inbred, but there's more genetic diversity
15:14between two of the major groups of chimpanzees in Africa than there is in all of humanity.
15:19So this small group heroically recovered and spread out of Africa 64,000 years ago, colonizing
15:25diverse environments and continuing to innovate. For 13.8 billion years since the beginning
15:30of the universe, complexity had been rising in a powerful crescendo, but in the space
15:34of a few millennia, collective learning was about to make things really bonkers.
15:39More on that next time.
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