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  • Hi, I'm John Green. Welcome to Crash Course Big History Project where today we're going

  • to talk about the Planet of the Apes films. - What's that? Apparently, those were not documentaries.

  • But there was an evolutionary process that saw primates move out of East Africa and transform

  • the earth into an actual planet of the apes...but the apes are us.

  • And then we made the movie and then some prequels and some sequels and some reboots and now sequels to the reboots.

  • Man, I can't wait until I get to see the 2018 reboot of this episode of Crash Course Big

  • History I hear they get James Franco to play me.

  • [Theme Music]

  • So we're about halfway through our series and after five episodes involving no humans

  • whatsoever today we are finally gonna get some people.

  • Mr. Green, Mr. Green! Why are we already at humanity, I mean if we're covering 13.8 billion

  • years shouldn't humanity come in like, the last two seconds of the last episode? I mean

  • humans are totally insignificant compared to the vastness of the universe, like we should

  • be checking in on how Jupiter's doing.

  • Fair point, Me From the Past; Jupiter by the way, still giant and gassy.

  • There's two reasons why we focus a little more on humanity in Big History; the selfish

  • reason is that we care about humans in Big History because we are humans. We are naturally

  • curious to figure out where we belong in the huge sequence of events beginning with the big bang.

  • Secondly, humans represent a really weird change in the universe. I mean, so far as we

  • know, we are one of the most complex things in the cosmos.

  • Whether you measure complexity in terms of biological and cultural building blocks or

  • networks or connections, I mean, we're kind of amazing! Now I realize that many of our

  • viewers will be offended by our human-centric bias, but humans are amazing. I mean, we invented

  • the internet and we invented animated GIF and we invented Dr. Who and then we invented

  • Tumblr, a place where all of these things can come together!

  • So 65 million years ago, catastrophe wiped out the dinosaurs and we saw the adaptive

  • radiation of a tiny shrew-like ancestor of humans that would look more at home like,

  • next to a hamster wheel than in your family album. Let's set the stage in the Thought Bubble.

  • So the slow waltz of plate tectonics continued to pull Eurasia and the Americas apart expanding

  • the Atlantic Ocean, primates colonized the Americas, and separated by the vast Atlantic, continued

  • their separate evolution into the new world monkeys -- which is not a band name, although it should be.

  • Then around 45 million years ago, Australia split from Antarctica and while mammals out-competed

  • most marsupials in the Americas (except animals like possums), Australia saw an adaptive radiation

  • of marsupials. This, of course, meant that later, one-hundred thousand years ago when

  • the Americas were having their share of mammoths and saber-tooth tigers, Australia was having

  • a spell of gigantic kangaroos, marsupial lions, and wombats the size of hippos.

  • Then, somewhere around forty million years ago, India, which had been floating around

  • the southern oceans as an island, smashed into the Eurasian continent with such force

  • that it created the world's tallest mountain range, the Himalayas.

  • Meanwhile, in Africa, Primates continued to evolve and twenty-five to thirty million years

  • ago, the line of the apes diverged from theold-world monkeys and no, neither you, nor a chimp,

  • is a monkey, nor did we evolve from the monkeys that are around today - those are like our cousins.

  • Moreover, we did not evolve from chimpanzees, the chimpanzee is a cousin as well, not an

  • uncle. We are not more highly evolved than they are; Instead, our lines of descent split

  • off from a common ancestor with chimpanzees about seven million years ago. Then chimpanzees

  • further split into a separate species, the Bonobos. Knowing about this common ancestry

  • tells us a lot about our shared traits with other primates.

  • For instance, we all have fairly large brains, relative to our body mass, we have our eyes

  • in the front of our heads from the days when we hung out in trees and depth perception

  • was an excellent way of telling how far away the next tree branch was so as to prevent

  • us from plummeting to our deaths, and we also have grasping hands, to make sure, you know,

  • that you could hold onto the branch in question. Primates also have hierarchies, social orders

  • whether male or female led, that determine who gets primary access to food, mates, and other benefits.

  • Thanks Thought Bubble! So, our closest evolutionary cousins, the chimpanzees, can tell us a thing

  • or two about shared behaviors. For one thing, while all primates have a hierarchy of alphas

  • and betas, humans and chimps, who share 98.4% of their DNA, are the most prone to team up

  • together and launch a revolution against the alpha male. We're also both prone to ganging

  • up, roaming our territory, and beating up unsuspecting foreigners of the same species,

  • and not for direct survival reasons.

  • Chimpanzees have been observed finding a lone chimp male from another group and kicking,

  • hitting, and tearing off bits of his body and then leaving the helpless victim to die

  • of his wounds, and humans definitely bear this stamp of our lowly origin, where indeed,

  • the imperfect step-by-step process of evolution made us highly intelligent, but still, with

  • prefrontal cortex's too small, and adrenal glands maybe too big.

  • Aggression and blood lust are definitely part of our shared heritage, and, looking at more

  • recent human history, does that really surprise anyone? Contrast that behavior, for a moment,

  • with the more peaceful Bonobos, who are female-led, and when a male in her group gets a bit pushy,

  • the females are prone to gang up and teach him a lesson. When it comes to inter-group

  • encounters in the wild, the male Bonobos seem tense around strangers at first, until usually,

  • the females from each group cross over and just have sex with the newcomers, completely diffusing

  • the tension. Talk about make love, not war - Bonobos are hippies.

  • While our common ancestor with chimpanzees around seven million years ago was more suited

  • to living in forests and seeking refuge from danger by climbing trees, climate change in

  • East Africa made things colder and drier, and many forests were replaced by woodlands

  • and wide-open savanna. Life in the savanna meant our ancestors needed to run from predators

  • rather than climbing trees, so our line shifted away from the bow-legged stance reminiscent

  • of chimpanzees, and developed bipedalism, where our locomotion came from legs that were

  • straight and forward-facing.

  • There's still some debate about when bipedalism first began, but we know that by the first

  • australopithecines around four million years ago, our evolutionary line was bipedal, this

  • also freed up our hands.

  • Australopithecines were not very tall, standing only just above a meter, or just above 3.5

  • feet, and had brains only a little bigger than modern chimpanzees. They were largely

  • herbivores with teeth adapted for grinding tough fruits and leaves. Australopithecines

  • may have communicated through gestures and primitive sounds, but their higher larynx

  • meant that they couldn't make the range of sounds required for complex language. There

  • was probably a lot of pointing and grunting going on. Kinda like me, before 6 am.

  • By 2.3 million years ago, homo habilis arrived on the scene. They weren't much taller than

  • australopithecines, but they had significantly larger brains - though still a lot smaller

  • than later species. Excitingly, homo habilis is known to have hit flakes off of stones

  • to use them for cutting. Now, lots of species use tools, for instance chimpanzees use sticks

  • for fishing termites out of the ground, they use rock hammers and leaf sponges and branch

  • levers and banana leaf umbrellas. A lot of these skills don't seem to arise spontaneously,

  • just because of the intelligence of individuals, but, like in the case of termite fishing,

  • chimpanzees pass the information on by imitation - primate see, primate do.

  • In a way, this social learning is sort of cultural, yet, succeeding generations of chimpanzees

  • don't accumulate information, tinker with it, and improve upon it, so that after 100

  • years, chimpanzees are owners of highly efficient and wealthy termite fishing corporations.

  • Similarly, as impressive as homo habilis stone-working abilities are, we see very little sign of

  • technological improvement over the thousands and thousands of years that habilis existed.

  • Same goes for homo ergaster erectus, who was around 1.9 million years ago.

  • Homo ergaster erectus had an even bigger brain, was taller, and they even seemed intelligent

  • and adaptable enough to move into different environments across the old world. They may

  • have even begun our first clumsy attempts at fire, which is vital for cooking meat and

  • vegetables, opening up opportunities for more energy and even more brain growth.

  • But still, there's not much sign of technological improvement, their tools got the job done,

  • if it ain't broke, don't fix it.

  • Yet 1.78 million years ago, we do see homo ergaster creating a wide new range of teardrop

  • hand axes in Kenya. By one-point-five 1.5 million years ago, these teardrop axes had

  • rapidly become common, and had improved in quality and were shaped with a flat edge into

  • multi-purpose picks, cleavers, and so forth.

  • Archaeologists see this as the first possible sign of tinkering and improvement of technology

  • that may have been transmitted by social learning. A faint glimmer of something new. Why is this important?

  • Well, humans didn't get to where we are because we're super-geniuses. It's

  • not like invented the Xbox One out of the blue one day, it was an improvement upon the

  • Xbox 360 which was an improvement upon earlier consoles, arcade machines, computers, and

  • backward onto the dawn of video games. In the same way, we didn't just invent our

  • modern society by sudden inspiration, it's the result of 250,000 years of tinkering and

  • improvement. This is where accumulation matters - it's called collective learning, the ability

  • of a species to retain more information with one generation than is lost by the next. This

  • is what has taken us, in a few thousand years, from stone tools to rocket engines to being

  • able to have the Crash Course theme song as your ringtone. Progress!

  • If there was collective learning in homo ergaster, it was very slow and very slight. This may

  • have been due to limitations on communication, abstract thought, group size, or just plain

  • brain power. But over the next two million years, things started to pick up. Homo antecessor,

  • Homo Heidelbergensis and the Neanderthals developed the first systematically controlled

  • use of fire in hearths, the first blade tools, the earliest wooden spears, the earliest use

  • of composite tools, where stone was fastened to wood, all before homo sapiens were ever

  • heard of, around 250,000 years ago.

  • Neanderthals even moved into colder climates, where they were compelled to invent clothing,

  • they used complex tool-manufacture to produce sharp points and scrapers and hand-axes and

  • wood handles, and they improved their craft over time.

  • While evolution by natural selection is a sort of learning mechanism that allows a species

  • to adapt generation after generation, with a lot of trial and error, and death - collective

  • learning allows for tinkering, adaptation, and improvement on a much faster scale with

  • each generation and across generations without waiting for your genes to catch up.

  • Anatomically similar homo sapiens have been around for about 250,000 years, and throughout

  • that time, we've been expanding our toolkit from stone tools to shell fishing to trade

  • and actual fishing, mining, and by 40,000 years ago we had art, including cave images,

  • decorative beads and other forms of jewelry, and even the world's oldest known musical

  • instruments - flutes carved from mammoth ivory and bird bones.

  • All this stuff came about as a result of collective learning. As long as you have a population

  • of potential innovators, who can keep dreaming up new ideas and remembering old ones and an

  • opportunity for those old innovators to pass their ideas onto others, you're likely to

  • have some technological progress.

  • These mechanisms are still working today - we've got over seven billion potential innovators on

  • this planet, and almost instantaneous communication, allowing us to do so many marvelous things

  • including teach you about Big History on the internet.

  • So life for early humans was pretty good, like foraging didn't require particularly

  • long hours - the average work day for a forager was about 6.5 hours. When you compare that

  • to an average of 9.5 hours for a peasant farmer in medieval Europe, or the average of nine

  • hours for a typical office worker today, foraging seems downright leisurely.

  • Quick aside: I work thirty minutes a day less than a peasant farmer in medieval Europe?

  • That's not progress! Stan, I want more time off!

  • Stan just pointed out that I have a chair, something that peasant farmers in medieval

  • Europe did not enjoy, and I want to say that I'm very grateful for my chair.

  • Thank you for my chair, Stan.

  • Anyway, a forager would go out, hunt or gather, come home, eat, spend time with the family,