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Crash Course: Human Evolution
Crash Course: Human Evolution
What connects you to other species? DNA, for one thing. Hank and John Greene will tell you about a whole lot more.
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Key Ideas
As this video progresses, key ideas will be introduced to invoke discussion.
Think about the following questions as you watch the video
- Why is it wrong to say that humans evolved from monkeys or chimps?
- What are some common characteristics shared by humans and other primates like chimpanzees?
- Why did our primate ancestors begin to move out of the trees and become bipedal?
- Australopithecines come before the genus Homo in our evolutionary tree. What are some characteristics of australopithecines?
- Homo habilis, also known as “handy man,” had larger brains and made tools, but evidence has shown no signs of a substantial increase in collective learning. Why not?
- What new things did Homo ergaster (erectus) do?
- What is collective learning? Why is it important to the story of human evolution
- What were some advantages foragers had in comparison to peasant farmers or modern office workers?
: Hi, I'm John Green.
: Welcome to Crash Course Big History
: 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.
: So we're about halfway through our series,
: and after five episodes involving no humans whatsoever,
: today we are finally going to 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 the last, like, 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 the animated GIF
: and we inventedDr. 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.
: Primate 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, about 100,000 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 40 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 25 million to 30 million years ago,
: the line of the apes diverged from the Old 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 7 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 on to 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 cortexes too small
: and adrenal glands maybe too big.
: Aggression and bloodlust 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 a group gets a bit pushy,
: the females are prone to gang up and teach him a lesson.
: When it comes to intergroup 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 the chimpanzees
: around 7 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
: in wide-open savannah.
: Life in the savannah meant our ancestors needed to run
: from predators rather than climbing trees,
: so our lines 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 4 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 over three and a half 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,
: kind of like me before 6:00 a.m.
: By 2.3 million years ago,Homo habilisarrived 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 habilisis known to have hit flakes off
: of stones to use them for cutting.
: Now, lots of species used tools.
: For instance, chimpanzees use sticks
: for fishing termites out of the ground,
: and 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 a hundred years,
: chimpanzees are owners of highly efficient
: and wealthy termite-fishing corporations.
: Similarly, as impressive asHomo habilis'
: stone-working abilities are, we see very little sign
: of technological improvement over the thousands and thousands
: of years thathabilisexisted.
: Same goes for Homo ergaster erectus,
: who was around 1.9 million years ago.
: Homo ergaster erectushad 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 seeHomo ergaster
: creating a wide range of tear-drop hand axes in Kenya.
: By 1.5 million years ago,
: these tear drop 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.
: Archeologists see this as:
: 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 the Xbox 1 was just invented
: out of the blue one day, it was an improvement
: upon the Xbox 360, which was an improvement
: upon earlier consoles, arcade machines,
: and 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:
: This is what has taken us in a few thousand years
: from stone tools to rocket engines to being able
: to have theCrash Coursetheme song as your ringtone.
: Progress.
: If there was collective learning inHomo 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 and hearth,
: the first blade tools, the earliest wooden spears,
: the earliest use of composite tools
: where stone was fastened to wood,
: all beforeHomo sapiens were every 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 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-similarHomo sapienshave been around
: for about 250,000 years and throughout that time,
: we've been expanding our tool kit 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 innovators
: to pass their ideas on to others,
: you're likely to have some technological progress.
: These mechanisms are still working today.
: We've got over 7 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 workday for a forager
: was about six-and-a-half hours.
: When you compare that to an average of nine-and-a-half 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 30 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, dance, sing, tell stories.
: And foragers were also always on the move,
: which made it less likely that they'd contaminate their water
: or sit around waiting for a plague to develop.
: And with their constant walking and their varied diet,
: foragers were in many ways healthier
: than the peasants of ancient civilizations.
: They were also in some ways healthier than us,
: but we have antibiotics for now, so we live longer, for now.
: The classical view of foraging life is best expressed
: by Thomas Hobbes who wrote, "No arts, no letters,
: "no society, and, which is worst of all, continual fear
: "and danger of violent death, and the life of man,
: solitary, poor, nasty, brutish, and short."
: Except not really.
: I mean, life for the average person
: in 12th century France was also a smidge nasty,
: brutish, and short.
: And the lack of wealth disparity in foraging cultures
: may imply greater equality between social rankings
: and even between the genders, since female gatherers appear
: to be responsible for the majority of food collected
: rather than the hunting males.
: And from that perspective, life was kind of ruined
: by the advent of agriculture and then, later, with states.
: As Jean-Jacques Rousseau said, "The first person who,
: "having enclosed a plot of land, took it into his head to say,
: "'This is mine' and found people simple enough
: "to believe him was the true founder of civil society.
: "Do not listen to this imposter.
: "You are lost if you forget that the fruits
: of the earth belong to all and the earth to no one."
: And thus summarizes one of the great debates
: in the world of political science.
: Man, Big History discusses everything.
: Now it's possible that neither Rousseau nor Hobbes
: was completely correct and that, like, private property
: and agriculture didn't create the glory days or end them.
: Like, as previously mentioned,
: all primates have a dominance hierarchy of some kind.
: Also, you don't need a wealth disparity
: to drive human beings to hurt each other.
: Like, surveys of excavated remains
: from the Paleolithic indicate a murder rate
: that was possibly as high as 10%.
: Now, those statistics are still disputed,
: but despite the relatively short work day,
: life in the Paleolithic sounds a lot less appealing
: when you consider the high murder rate
: and also the occasional infanticide.
: That's not even to mention the older disabled people,
: who, when they couldn't keep up anymore,
: were abandoned to die in the wild.
: I can't help but feel that I might not have thrived
: in the Paleolithic what with my visual impairment
: and general lack of interest in hunting.
: Anyway, we call this the Hobbes versus Rousseau debate
: and it's still unresolved.
: I mean, humans may have been corrupted
: in many ways by society.
: On the other hand, it's possible a lot of the crimes and follies
: of human history may just be symptoms of our coping
: with the bad wiring left to us by evolution.
: You know, humans are a bit of an obsolete machine.
: We aren't particularly well-suited
: to the many lifestyle changes that have happened
: in the past few thousand years faster
: than our genes can keep pace with.
: But how you interpret the lives
: of early human foragers largely determines your view
: of history and also the fundamental nature
: of the human character.
: Ask yourself which side you sit on.
: Is humanity fundamentally good and corrupted by technology
: and modern social orders, or are we fundamentally flawed
: and in need of some sort of structure and authority?
: Or is there some kind of both/and way
: addressing the question?
: Here atCrash Course, we don't have answers,
: but we are grateful that you're pondering these questions
: with us.
: In any case, collective learning was really good
: for our survival, but then, 74,000 years ago,
: disaster struck.
: A super-eruption at Mount Toba on the island of Sumatra
: in present-day Indonesia clouded the skies
: with ash and cooled the climate.
: Plants and animals-- a.k.a. food--
: died off, and genetic studies show
: that this reduced the human population
: to a few thousand people.
: So as a result of this, we aren't exactly inbred,
: but there's more genetic diversity between two
: of the major groups of chimpanzees in Africa
: than there is in all of humanity.
: So this small group heroically recovered and spread out
: of Africa 64,000 years ago, colonizing diverse environments
: and continuing to innovate.
: For 13.8 billion years since the beginning of the universe,
: complexity had been rising in a powerful crescendo,
: but in the space of a few millennia,
: collective learning was about to make things really bonkers.
: Welcome to Crash Course Big History
: 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.
: So we're about halfway through our series,
: and after five episodes involving no humans whatsoever,
: today we are finally going to 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 the last, like, 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 the animated GIF
: and we inventedDr. 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.
: Primate 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, about 100,000 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 40 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 25 million to 30 million years ago,
: the line of the apes diverged from the Old 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 7 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 on to 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 cortexes too small
: and adrenal glands maybe too big.
: Aggression and bloodlust 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 a group gets a bit pushy,
: the females are prone to gang up and teach him a lesson.
: When it comes to intergroup 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 the chimpanzees
: around 7 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
: in wide-open savannah.
: Life in the savannah meant our ancestors needed to run
: from predators rather than climbing trees,
: so our lines 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 4 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 over three and a half 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,
: kind of like me before 6:00 a.m.
: By 2.3 million years ago,Homo habilisarrived 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 habilisis known to have hit flakes off
: of stones to use them for cutting.
: Now, lots of species used tools.
: For instance, chimpanzees use sticks
: for fishing termites out of the ground,
: and 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 a hundred years,
: chimpanzees are owners of highly efficient
: and wealthy termite-fishing corporations.
: Similarly, as impressive asHomo habilis'
: stone-working abilities are, we see very little sign
: of technological improvement over the thousands and thousands
: of years thathabilisexisted.
: Same goes for Homo ergaster erectus,
: who was around 1.9 million years ago.
: Homo ergaster erectushad 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 seeHomo ergaster
: creating a wide range of tear-drop hand axes in Kenya.
: By 1.5 million years ago,
: these tear drop 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.
: Archeologists see this as:
: 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 the Xbox 1 was just invented
: out of the blue one day, it was an improvement
: upon the Xbox 360, which was an improvement
: upon earlier consoles, arcade machines,
: and 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:
: This is what has taken us in a few thousand years
: from stone tools to rocket engines to being able
: to have theCrash Coursetheme song as your ringtone.
: Progress.
: If there was collective learning inHomo 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 and hearth,
: the first blade tools, the earliest wooden spears,
: the earliest use of composite tools
: where stone was fastened to wood,
: all beforeHomo sapiens were every 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 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-similarHomo sapienshave been around
: for about 250,000 years and throughout that time,
: we've been expanding our tool kit 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 innovators
: to pass their ideas on to others,
: you're likely to have some technological progress.
: These mechanisms are still working today.
: We've got over 7 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 workday for a forager
: was about six-and-a-half hours.
: When you compare that to an average of nine-and-a-half 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 30 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, dance, sing, tell stories.
: And foragers were also always on the move,
: which made it less likely that they'd contaminate their water
: or sit around waiting for a plague to develop.
: And with their constant walking and their varied diet,
: foragers were in many ways healthier
: than the peasants of ancient civilizations.
: They were also in some ways healthier than us,
: but we have antibiotics for now, so we live longer, for now.
: The classical view of foraging life is best expressed
: by Thomas Hobbes who wrote, "No arts, no letters,
: "no society, and, which is worst of all, continual fear
: "and danger of violent death, and the life of man,
: solitary, poor, nasty, brutish, and short."
: Except not really.
: I mean, life for the average person
: in 12th century France was also a smidge nasty,
: brutish, and short.
: And the lack of wealth disparity in foraging cultures
: may imply greater equality between social rankings
: and even between the genders, since female gatherers appear
: to be responsible for the majority of food collected
: rather than the hunting males.
: And from that perspective, life was kind of ruined
: by the advent of agriculture and then, later, with states.
: As Jean-Jacques Rousseau said, "The first person who,
: "having enclosed a plot of land, took it into his head to say,
: "'This is mine' and found people simple enough
: "to believe him was the true founder of civil society.
: "Do not listen to this imposter.
: "You are lost if you forget that the fruits
: of the earth belong to all and the earth to no one."
: And thus summarizes one of the great debates
: in the world of political science.
: Man, Big History discusses everything.
: Now it's possible that neither Rousseau nor Hobbes
: was completely correct and that, like, private property
: and agriculture didn't create the glory days or end them.
: Like, as previously mentioned,
: all primates have a dominance hierarchy of some kind.
: Also, you don't need a wealth disparity
: to drive human beings to hurt each other.
: Like, surveys of excavated remains
: from the Paleolithic indicate a murder rate
: that was possibly as high as 10%.
: Now, those statistics are still disputed,
: but despite the relatively short work day,
: life in the Paleolithic sounds a lot less appealing
: when you consider the high murder rate
: and also the occasional infanticide.
: That's not even to mention the older disabled people,
: who, when they couldn't keep up anymore,
: were abandoned to die in the wild.
: I can't help but feel that I might not have thrived
: in the Paleolithic what with my visual impairment
: and general lack of interest in hunting.
: Anyway, we call this the Hobbes versus Rousseau debate
: and it's still unresolved.
: I mean, humans may have been corrupted
: in many ways by society.
: On the other hand, it's possible a lot of the crimes and follies
: of human history may just be symptoms of our coping
: with the bad wiring left to us by evolution.
: You know, humans are a bit of an obsolete machine.
: We aren't particularly well-suited
: to the many lifestyle changes that have happened
: in the past few thousand years faster
: than our genes can keep pace with.
: But how you interpret the lives
: of early human foragers largely determines your view
: of history and also the fundamental nature
: of the human character.
: Ask yourself which side you sit on.
: Is humanity fundamentally good and corrupted by technology
: and modern social orders, or are we fundamentally flawed
: and in need of some sort of structure and authority?
: Or is there some kind of both/and way
: addressing the question?
: Here atCrash Course, we don't have answers,
: but we are grateful that you're pondering these questions
: with us.
: In any case, collective learning was really good
: for our survival, but then, 74,000 years ago,
: disaster struck.
: A super-eruption at Mount Toba on the island of Sumatra
: in present-day Indonesia clouded the skies
: with ash and cooled the climate.
: Plants and animals-- a.k.a. food--
: died off, and genetic studies show
: that this reduced the human population
: to a few thousand people.
: So as a result of this, we aren't exactly inbred,
: but there's more genetic diversity between two
: of the major groups of chimpanzees in Africa
: than there is in all of humanity.
: So this small group heroically recovered and spread out
: of Africa 64,000 years ago, colonizing diverse environments
: and continuing to innovate.
: For 13.8 billion years since the beginning of the universe,
: complexity had been rising in a powerful crescendo,
: but in the space of a few millennia,
: collective learning was about to make things really bonkers.