生命之旅第五集:人類生活 Human Life

[00:00.00] [00:19.40] [00:21.40]What if an alien biologist from outer space visited Earth? [00:26.13] [00:27.03]Imagine he was looking for the most intelligent of our planet's tens of millions of species. [00:32.80] [00:35.31]He'd probably start with the apes. [00:37.37] [00:40.31]They all seem pretty smart. [00:41.94] [00:42.58]A chimpanzee can do most of the things a two and a half year old human child can. [00:47.45] [00:56.30]If he compared their DNA, our alien investigator would discover they're almost identical. [01:02.76] [01:14.72]Biologically, he wouldn't hesitate to classify us humans as just another kind of chimp. [01:20.71] [01:25.16]But if he'd stayed and watched the way humans live and behave, [01:28.96] [01:29.33]he'd soon have seen a huge gulf between our capabilities [01:32.82] [01:33.03]and those of all the other apes. [01:35.13] [01:37.27]He'd have seen billions and billions of us dominating the Earth. [01:41.40] [01:43.64]How did that happen [01:45.01] [01:45.85]How did we, Homo sapiens, become so different? [01:49.54] [02:10.70]In this programme we're going to take a five million year journey [02:14.77] [02:15.01]from tree living apes to modern man. [02:17.50] [02:20.98]We're going to meet our closest living relatives and discover how we used our hands to get ahead. [02:26.98] [02:35.33]Following in our ancestors' footsteps, [02:37.49] [02:37.70]we're going to see how we came up against some very serious design flaws. [02:42.07] [02:45.21]Why giving birth is so hard for us. [02:47.54] [02:54.21]Why for so many years we could do little more than grunt [02:57.81] [03:01.66]and how talking is worth risking our lives for. [03:04.45] [03:07.73]When we open our mouths to speak there's a chance we could choke. [03:11.46] [03:23.88]We'll find out how the human race almost became extinct. [03:27.14] [03:29.98]...and what it was that saved us [03:32.38] [03:42.46]And we'll be looking into the future - [03:44.26] [03:44.77]when by taking control of our evolution we may be able to create perfect humans. [03:50.17] [03:50.50]And even defy the ageing process. [03:53.10] [04:03.28]Homo sapiens! [04:04.58] [04:04.92]Both man and animal. The hairless ape. [04:08.48] [04:09.79]Yet we're so different from all other animals on the planet. [04:12.88] [04:17.03]Where did we come from? [04:18.52] [04:30.44]For thousands of years we turned to the supernatural for the answer. [04:34.44] [04:39.25]But there is another scientific explanation - [04:42.22] [04:42.46]that we gradually evolved into what we are now over millions of years. [04:47.16] [04:53.10]The big clues to our past come from chimpanzees - [04:56.13] [04:56.34]our closest living relatives. [04:58.07] [05:04.21]All these chimps have been rescued from the bush-meat trade in Cameroon. [05:08.27] [05:13.79]They're now looked after by Dieudonne here - who has a very special relationship with them. [05:19.38] [05:29.87]The more we study chimps the more we realize just how much we have in common. [05:34.47] [05:41.42]The evidence that shows we really are descending from a chimp [05:45.85] [05:46.29]like ancestor is deep within the workings of our bodies. [05:48.41] [05:48.62]In our genes. 99% of our genes are exactly the same as theirs. [05:55.22] [05:56.76]What's the story in that 1% difference that's taken us from ape to man. [06:02.63] [06:07.51]In the beginning it had nothing to do with brainpower. [06:10.48] [06:15.15]Between 4 and 5 million years ago [06:17.45] [06:17.65]our ancestors started to spend more time on the ground. [06:20.71] [06:23.29]Two very different strategies emerged. [06:25.82] [06:29.10]Chimps evolved, [06:30.09] [06:30.30]walking on their knuckles as a way of getting around. [06:32.89] [06:36.27]Their hands stayed thick and solid to bear their weight. [06:39.60] [06:45.21]We took a more radical approach, the first step in our journey was just that. [06:50.58] [06:54.22]We stood up - on two legs. [06:56.31] [07:01.39]Since then we've never looked back. [07:03.59] [07:24.28]But our brains weren't as big as they are today. [07:27.05] [07:33.76]5 million years ago they were much smaller, the same size as the chimps. [07:38.60] [07:47.57]So why was walking upright such a crucial step? [07:50.51] [07:53.78]By putting all our weight on our feet we freed up our hands to do other things. [07:58.31] [08:02.02]The chimps here have been playing with Dieudonne's shoelaces for years. [08:06.25] [08:17.27]There seems to be an element of competition. [08:19.17] [08:25.25]The chimps never give up. [08:26.58] [08:31.28]They tie themselves in knots trying to get it right. [08:33.84] [08:41.63]However hard they practice though they can't compete with us. [08:45.12] [08:49.87]As we all know learning to tie your shoelaces is more complicated than it looks - [08:54.31] [08:54.77]and chimps just don't have what it takes, [08:57.30] [08:58.45]a delicate precision grip between finger and thumb. [09:02.40] [09:07.42]Our thumbs are longer and more flexible than those of chimps. [09:11.15] [09:11.83]So our hands have become precision instruments [09:14.12] [09:14.33]which we can use in an extraordinary variety of ways. [09:17.66] [09:41.22]Our ancestors didn't acquire this new anatomy overnight [09:44.38] [09:44.99]it also took an important change [09:46.39] [09:46.59]in the climate to make this evolutionary leap away from the chimps. [09:50.39] [09:54.33]It was then that we parted company. [09:56.30] [09:57.14]The chimps stayed in the trees. [09:58.60] [09:59.07]While we walked out onto the newly formed African savannah. [10:03.37] [10:06.71]The climate change suited our ancestors very well. [10:09.48] [10:10.58]Over the next few million years, it got drier and drier - [10:14.04] [10:14.29]completely transforming the landscape from thick forest into open plains. [10:19.16] [10:21.09]As our ancestors used their hands more and more for holding things [10:25.09] [10:25.40]it led us to the next big landmark on our journey. [10:29.06] [10:31.20]The creation of tools. [10:32.97] [10:34.31]Some of the earliest have been found in caves just like this. [10:38.24] [10:44.42]All these tools were very simple... [10:46.48] [10:47.05]and also very similar. [10:48.38] [10:53.13]This was state of the art technology 2 and a half million years ago. [10:57.26] [10:58.50]It's actually a kind of Ape mans' penknife. [11:00.90] [11:01.80]This cutting edge almost matches that of steel. [11:04.74] [11:07.21]The basic design didn't change for a million years, [11:10.14] [11:10.64]so around 5000 generations of hominids would have handled tools just like these. [11:16.51] [11:18.55]It's remarkable when you think how much modern technology, [11:21.85] [11:22.09]like the mobile phone has moved on in just the last 10 years. [11:26.12] [11:26.69]Today one person could have owned all these different types of phones. [11:30.60] [11:32.97]But that didn't mean that the ancient tool users were standing still. [11:36.63] [11:37.80]Once we'd left the trees for the plains, we had a new challenge to face. [11:41.74] [11:42.94]We were not alone. [11:44.60] [11:49.22]Taking a walk on the savannah on your own is asking for trouble, [11:53.35] [11:53.79]and it gets more dangerous the darker it becomes. [11:56.59] [12:02.26]Because this is the domain of the big cats. [12:05.63] [12:12.34]At night baboons try to find a hiding place. [12:15.17] [12:15.64]They stick close together and, if they can, take refuge in a tree. [12:19.70] [12:20.61]But when they hear a leopard coming they still panic- [12:23.61] [12:23.88]because they can't see well at night. [12:26.11] [12:29.56]The leopard aims to terrorize the troop into breaking ranks. [12:32.53] [12:33.76]Once separated from the rest, a baboon's a sitting target. [12:37.29] [13:01.19]Imagine what it would have been like for our ancestors out here, [13:04.28] [13:04.49]24 hours a day, trying to keep their families safe from wild animals. [13:08.69] [13:11.80]This is no place for a soft, defenseless human to be out late on their own. [13:15.67] [13:18.34]And there's solid evidence to show we humans really were under attack. [13:22.30] [13:23.74]Again the clues lie deep in ancient caves. [13:26.68] [13:35.22]Ape man skulls have been found with holes in them [13:38.62] [13:38.83]that exactly match the teeth of leopard, hyena and saber toothed tiger. [13:43.52] [13:55.98]One cave contained the remains of over 300 baboons and 150 ape men. [14:01.57] [14:02.65]Between one and three million years ago [14:04.58] [14:04.78]our ancestors were being torn apart and... [14:06.91] [14:07.12]eaten by big cats. [14:09.02] [14:24.37]Even by day, life here is no walk in the Park. [14:27.36] [14:27.87]But at least baboons like us can see much better in the daylight. [14:32.28] [14:38.28]They live in large troops, which means many pairs of eyes to spot a threat - [14:42.69] [14:42.99]and more combined force to fight off a predator. [14:45.96] [15:00.24]Safety in numbers gives baboons surprising confidence [15:03.57] [15:08.15]In fact they're downright cocky! [15:09.84] [15:20.29]For our ancestors too, [15:21.52] [15:21.73]sticking together was the best way to avoid ending up as cat food. [15:25.46] [15:27.13]The communal life created new challenges - [15:29.43] [15:29.64]and forced us to really start using our brains. [15:32.87] [15:34.91]Living together brings a whole new element - a social life. [15:38.67] [15:41.28]But the bigger your group, the bigger your social problems can be. [15:44.68] [15:50.09]You need a bigger brain to cope. [15:52.08] [15:55.73]In a group, working at friendships and alliances is crucial. [15:59.36] [15:59.93]You need to remember who's who and what's what? [16:02.49] [16:11.18]You need to be a diplomat [16:12.51] [16:12.81]so you don't get on the wrong side of those with more powerful weapons than you. [16:16.68] [16:22.19]A single social gaffe could be disastrous. [16:25.02] [17:04.16]As we too began to live in larger groups for safety, [17:07.29] [17:07.50]so our brains evolved to cope. [17:09.53] [17:10.10]And our brains continued to get bigger - almost four times bigger - [17:14.10] [17:14.31]so our skulls had to get larger too. [17:16.57] [17:20.15]And this gave us our next challenge. [17:22.11] [17:23.95]Because being the 2 legged brain boxes of the savannah [17:26.94] [17:27.22]now gave us a problem our four-legged friends didn't have. [17:30.38] [17:37.30]Take wildebeest. [17:38.42] [17:38.87]Because they walk on all fours, they can afford to have wide hips. [17:43.23] [17:46.97]That makes giving birth quick and easy, important with so many predators around. [17:51.91] [17:59.95]Although the baby wildebeest is big, [18:01.89] [18:02.09]its brain and skull are quite small in relation to its body size. [18:05.89] [18:06.19]So it can slip out easily. [18:07.63] [18:23.11]But for humans, birth is where we pay the price for our big brain. [18:27.24] [18:30.48]If we move from the Kenyan plains to the city of Nairobi [18:33.61] [18:33.85]and look at the physique of modern woman we can see why. [18:37.19] [18:44.23]The best design for walking upright is a slender body with narrow hips. [18:48.83] [18:52.34]But narrow hips are the worst possible design for giving birth to big brained humans. [18:57.30] [18:58.51]This was perhaps the biggest stumbling block we humans faced in our whole journey of life. [19:03.04] [19:03.65]We were stuck! [19:04.62] [19:07.35]Until evolution came up with a surprising solution. [19:10.72] [19:15.13]Unlike almost all other mammals, our skull isn't fully formed at birth. [19:20.00] [19:20.47]A human baby's head is soft and pliable [19:22.93] [19:23.20]allowing it to pass down the narrow birth canal. [19:25.83] [19:36.05]Woah, that's well done. [19:37.95] [19:38.15]During the first 12 months of life, [19:39.91] [19:40.12]the bony skull plates gradually fuse together to protect the brain, [19:44.25] [19:44.92]in effect we're all born premature! [19:47.55] [19:54.17]So for the first few months, a human baby is extremely vulnerable, [19:58.10] [19:58.30]requiring constant care. [19:59.79] [20:00.37]But the pay-off - a giant brain - [20:02.57] [20:02.81]far outweighs the risk - another biological problem solved. [20:08.54] [20:12.49]So 300,000 years ago big brained man, homo sapiens arrived. [20:17.92] [20:22.40]We can see the evidence f our greater intelligence in the new technology [20:26.20] [20:26.40]that early ape-men never had. [20:28.39] [20:33.17]A more sophisticated tool kit. [20:35.04] [20:40.18]Which includes spear points [20:41.84] [20:42.05]as well as a variety of scrapers and cutters for butchering meat. [20:45.98] [21:00.07]Found alongside those tools was a simple lump of rock [21:04.06] [21:04.34]that would lead to the great masterpieces of the future. [21:07.20] [21:14.25]It's ochre - crumbly iron oxide. [21:17.41] [21:18.08]This piece was found in Blombos Cave, [21:20.28] [21:20.49]near Cape Town in South Africa and is at least 70,000 years old. [21:25.19] [21:27.19]What's amazing is that it's engraved. [21:29.53] [21:29.96]This abstract etching is the first recorded work of art. [21:33.63] [21:34.57]It marks the roots of what we now call culture or civilization. [21:38.83] [21:41.37]And this pigs jaw bone might even offer a clue to when religion first began. [21:47.24] [21:47.88]It was discovered in the same grave as an early human [21:51.37] [21:51.72]and it's dated at more than a hundred thousand years old. [21:54.74] [21:55.62]It's the earliest evidence of ritual burial. [21:58.59] [22:00.49]The act of carefully burying a body with other objects suggests that [22:04.95] [22:05.20]those people believed that death wasn't the end. [22:08.19] [22:08.73]That the spirit lived on. [22:10.29] [22:12.44]Art and religion set us apart from the rest of the animal kingdom [22:16.14] [22:16.44]and led to our great civilizations. [22:19.24] [22:57.32]Many scientists believe that the trigger for these extraordinary breakthroughs [23:01.28] [23:01.55]was something we all take for granted. [23:03.61] [23:05.12]Language. [23:06.22] [23:07.16]This is where the main palm Sunday procession took place. [23:10.36] [23:10.73]From fossils scientists know that our voice box - or larynx - [23:15.10] [23:15.30]was much higher up in our ancestors than it is today. [23:18.67] [23:25.14]It's still in this position in the chimps and other apes. [23:28.55] [23:32.49]If this was still the same for us apart from the odd grunt [23:35.92] [23:36.12]or two we wouldn't have the power of speech. [23:38.75] [23:41.13]But around 200,000 years ago, [23:43.15] [23:43.36]our larynx dropped to where it is today, allowing us to make more complex sounds. [23:48.70] [23:51.47]This is when we started to talk. [23:53.30] [23:54.71]But why is talking so important to the story of the human race? [23:57.94] [24:03.55]You can find a clue back in West Africa. [24:06.04] [24:11.79]These chimps are collecting nuts to eat. [24:14.05] [24:28.11]They have to use a rock to crack open the shells. [24:30.67] [24:36.52]And they pick up these skills by copying. [24:39.04] [25:03.28]The young ones learn by watching their mothers closely. [25:05.97] [25:11.68]In Britain children also gather nuts, but not to eat, to play with. [25:16.55] [25:24.20]These are chestnuts or conkers. [25:26.29] [25:31.30]Like the chimps, [25:32.13] [25:32.34]the younger children learn by copying the older ones, [25:35.00] [25:35.34]handing down skills across the generations. [25:37.90] [25:46.55]The difference is, that it can take a young chimp [25:48.88] [25:49.09]six years to perfect its nut-cracking technique. [25:52.35] [26:09.14]We humans on the other hand can use a short cut. [26:11.67] [26:12.98]That's a nice little conker. [26:14.14] [26:14.35]Don't eat it though. [26:15.18] [26:15.38]Go and put it in the pile. [26:17.04] [26:20.15]We can teach even very young children simply by talking to them. [26:24.05] [26:25.59]- Are you opening them with your heels. - Yes [26:27.86] [26:28.06]Are you. Much easier to do it like that isn't it. [26:30.82] [26:34.30]So they can learn a new technique for opening the conkers instantly. [26:38.20] [26:47.95]And with language we continue to learn new tricks all our lives. [26:51.97] [26:55.59]By a hundred thousand years ago we were solving problems by talking together. [27:00.08] [27:00.76]We were using our big brains to communicate with each other as never before. [27:04.89] [27:08.80]But talking gave us another biological problem, and this one still hasn't been solved. [27:13.86] [27:15.57]Let's look at the chimps in Cameroon again. [27:17.77] [27:30.19]Chimps breathe mostly through their nose and hardly ever through their mouth. [27:34.39] [27:34.96]They use their mouths almost entirely for feeding. [27:37.29] [27:37.83]So air goes down one way, food another. [27:40.80] [27:47.21]For humans though it's a different story. [27:49.07] [27:54.31]Remember how as a child you were told not to talk with your mouth full? [27:57.84] [27:58.25]Well, there's a very good reason for this. [27:59.98] [28:07.63]To talk, we have to breathe through our mouths as well. [28:10.60] [28:11.10]So we use the same opening for talking, eating, drinking and breathing. [28:15.36] [28:16.80]Children sing Happy Birthday [28:29.27] [28:29.48]Usually this works out fine. [28:31.18] [28:31.75]But sometimes, things go down the wrong way. [28:34.31] [28:35.69]Sometimes with tragic results. [28:37.75] [28:41.03]Normally when we swallow, a flap of cartilage covers the windpipe - [28:44.86] [28:45.13]so the food goes straight down to the stomach. [28:47.19] [28:50.54]But with our larynx now in its lower position, [28:52.77] [28:52.97]just occasionally food falls in and down the windpipe - [28:56.60] [28:56.98]where it blocks the airway to the lungs, making us choke. [29:00.17] [29:08.02]Every year in Britain alone, around 200 people choke to death. [29:12.25] [29:14.26]Talking has been so critical to our evolution that it's even worth risking death for. [29:19.56] [29:30.61]At this point in our journey, [29:31.97] [29:32.18]it had been four million years since we'd split from the apes. [29:35.41] [29:36.55]What happened to us during that time? [29:38.02] [29:39.32]Biological evolution - [29:40.62] [29:40.89]that is, the physical changes to our bodies had worked some slow [29:44.55] [29:44.76]but crucial changes in us. [29:46.45] [29:47.46]First, around four to five million years ago, we stood up on two legs and walked. [29:52.19] [29:59.04]Then it was another three million years before we started getting clever with our hands. [30:03.30] [30:07.08]It wasn't until over a million years later that our brains got as big as they are today. [30:11.71] [30:13.52]And for all this time, [30:14.38] [30:14.59]our only form of conversation was probably just grunting! [30:18.25] [30:23.00]It wasn't until very recently along life's journey - [30:25.59] [30:25.80]around 200,000 years ago that our larynx began to drop. [30:30.03] [30:30.24]Which gave us the power of real language. [30:33.00] [30:33.87]Melee sync comments rugby players [30:36.93] [30:40.31]Now that we could talk - our cultural evolution could take off too. [30:44.54] [30:46.45]Cultural evolution was a brand new trend. [30:48.89] [30:49.25]It isn't based on genes like biological evolution - [30:52.16] [30:52.39]it's about the sharing of ideas. [30:54.48] [30:58.63]Talking allowed knowledge to be passed around quickly, [31:01.83] [31:02.20]it was one of the greatest revolutions in the Journey of Life [31:05.23] [31:05.50]that set us on the path to world dominance. [31:08.27] [31:11.48]But perhaps the greatest drama in the story of the human race was yet to come. [31:15.38] [31:16.98]75,000 years ago, [31:18.95] [31:19.15]when modern, talking humans were thriving here in Africa disaster struck. [31:24.21] [31:29.29]On the other side of the world in Sumatra a volcano called Toba erupted. [31:34.23] [31:57.99]It blasted vast clouds of ash and sulphur dioxide right across the planet blocking out the sun. [32:04.09] [32:08.40]It triggered a six-year global winter which blighted the entire world. [32:13.36] [32:30.42]In Africa, over 6,000 kilometers away, drought and famine followed. [32:35.42] [32:38.33]Millions of animals died - the animals we humans depended on for meat. [32:43.06] [32:47.47]Those early homo sapiens must have been decimated too. [32:50.57] [32:53.78]Because of one freak act of nature, our ancestors nearly became extinct. [32:58.61] [32:59.62]DNA evidence suggests that perhaps as few as a thousand people were left. [33:04.06] [33:04.42]Which could mean that all six billion of us alive on earth today [33:08.45] [33:08.69]are descended from those one thousand survivors in Africa. [33:12.36] [33:20.07]How did we survive? [33:21.63] [33:22.74]Scientists now believe what really may have saved us [33:25.37] [33:25.58]from extinction was working together - [33:27.67] [33:28.21]sharing information. [33:29.48] [33:34.62]To get some idea of what life must have been like after Toba blew its top, [33:38.78] [33:38.99]you can go to the Kalahari desert today. [33:41.22] [33:41.69]It's one of the harshest places anywhere in the world. [33:44.18] [33:45.86]But even here there is water and food if you know where to look. [33:48.99] [33:55.04]The Zhuang people of northern Namibia are mainly hunter gatherers. [33:59.17] [34:01.68]How do they cope with living in such heat and drought? [34:04.08] [34:18.70]Most importantly, they never remain isolated as a single band for long. [34:22.79] [34:23.30]They regularly walk for two to three days across the desert [34:26.36] [34:26.57]to visit different family groups. [34:28.33] [34:42.22]It may have been months since they last saw each other. [34:44.95] [35:20.33]Once here, the highlight of the visit is swapping gifts. [35:23.56] [35:27.47]They do it not only to cement the bonds of friendship, [35:30.13] [35:30.34]but also to secure cooperation and the sharing of ideas. [35:33.93] [35:37.21]And out here, [35:38.20] [35:38.41]what your neighbors tell you could well save your life. [35:41.31] [35:45.35]They may know where the best water sources are or good fruiting trees [35:49.55] [35:49.75]or new hunting grounds, and of course they can tell you the gossip. [35:53.49] [35:57.03]Without this regular exchange of knowledge, [35:58.96] [35:59.16]different villages would become isolated and without outside help, [36:03.26] [36:03.47]even die out. [36:04.66] [36:06.54]It's now thought it was our ability to talk and help each other in a hostile world [36:10.67] [36:10.91]that saved us from extinction after Toba erupted. [36:14.11] [36:18.42]It's encouraging to think that the very existence of the human race [36:21.87] [36:22.09]owes more to cooperation, than to conflict. [36:25.61] [36:34.10]Gradually the world recovered and small bands of pioneering humans [36:38.26] [36:38.47]started to leave Africa and travel to the far corners of the earth. [36:42.30] [36:54.29]By now, we humans weren't just talking and sharing ideas, [36:58.02] [36:58.26]we were working together as never before [37:00.72] [37:01.09]and cultural evolution was going on all around the globe. [37:04.39] [37:13.64]Although telling other people what you know through speech is still vital to man today. [37:18.23] [37:18.61]There's only so much knowledge any individual can store in the memory. [37:22.48] [37:23.48]Yeah I don't know whether there's one up there. [37:25.81] [37:26.08]Muller Road. [37:26.91] [37:27.12]So it's not by the lecky up by that way is it? [37:29.42] [37:29.82]No sorry. [37:30.95] [37:31.19]Oh yeah down there yeah. [37:32.09] [37:32.29]See that red building. [37:33.26] [37:33.46]And no one person can know everything. [37:35.45] [37:44.17]Excuse me mate can you tell me the way to library please. [37:46.57] [37:46.77]Yeah go round here, [37:47.70] [37:47.91]up the top of Park Street, round the triangle up... [37:50.20] [37:50.41]If someone dies without passing on their ideas and culture, [37:54.28] [37:54.58]those ideas are lost - forever. [37:56.74] [38:01.65]Unless of course they've been written down. [38:04.25] [38:07.16]The answer was for us to start preserving our ideas and knowledge - [38:10.79] [38:11.00]in books. [38:12.49] [38:18.07]Cultural evolution could now accelerate further. [38:20.97] [38:30.95]Writing meant successive generations could build on what had gone before. [38:35.41] [38:47.17]No one could remember how to make a space rocket, [38:50.16] [38:50.44]but once it's written down that information is accessible to many others. [38:54.96] [38:58.44]For 2,500 years, we saved our precious culture in our books. [39:03.40] [39:06.62]But the amount of knowledge accessible through a computer [39:09.38] [39:09.59]adds up to all the books, [39:10.85] [39:11.06]in all the libraries, in all the world. [39:13.72] [39:17.36]In the age of the internet anyone, anywhere can tap into this vast central fund. [39:22.60] [39:27.64]Back in the forest reserve in Cameroon, [39:29.66] [39:29.87]Dieudonne can search the web and get hold of the same information [39:33.44] [39:33.65]as anyone at a computer anywhere else on earth. [39:37.24] [39:45.66]And it's fast! [39:47.09] [39:48.76]A picture can be sent halfway round the world in seconds. [39:51.42] [39:52.33]Never before have ideas spread so widely so quickly, [39:55.82] [39:56.13]whether for business, education or purely for pleasure. [39:59.54] [40:01.44]Computers are now the core of modern culture. [40:04.20] [40:06.38]But without writing and without this power to store knowledge - [40:09.64] [40:09.91]where would we be? [40:11.28] [40:12.85]The answer is here - still in the Stone Age. [40:15.88] [40:20.66]If you could use a time machine to bring a Stone Age baby [40:23.86] [40:24.06]forward from 35,000 years ago and educate it here in our modern world, [40:29.52] [40:29.77]it could do anything - [40:31.10] [40:31.37]become an airline pilot, doctor - even president! [40:34.50] [40:35.97]By the Stone Age, people were just as intelligent as us. [40:39.43] [40:43.01]And if a 21st century baby was sent back 35,000 years. [40:47.75] [40:48.09]It would be no more advanced than the people who lived then. [40:50.95] [40:51.56]Strip away our technology, and underneath we're all still cave men! [40:56.26] [40:57.60]That's because our genes haven't changed since the Stone Age - [41:01.05] [41:01.70]both babies would have the same genetic make-up. [41:04.17] [41:06.47]But, just suppose both babies were unlucky, [41:09.80] [41:10.07]and were born with a serious genetic disease. [41:12.74] [41:13.38]In the past, this baby would have died, [41:15.97] [41:16.45]his defective gene would not have been passed on. [41:19.11] [41:19.52]It was, after all, survival of the fittest. [41:22.15] [41:26.06]Today, though, modern medicine is so advanced that [41:28.92] [41:29.13]many of us can live on despite our problem genes. [41:32.26] [41:41.27]Whereas in the past we wouldn't have survived. [41:43.57] [41:47.31]And that's affecting human evolution as a whole. [41:49.97] [41:50.92]Now, without the force of natural selection, [41:53.08] [41:53.28]those problem genes will become more and more widespread. [41:56.85] [42:06.33]Fortunately though our most important evolutionary strong point, [42:10.06] [42:10.27]our big brain, may have come up with a solution. [42:12.96] [42:14.21]Genetic engineering. [42:15.64] [42:16.47]In as little as 10 years from now, [42:18.34] [42:18.54]we may be able to alter our children's genes before they're born. [42:23.24] [42:25.72]We now know which genes are involved in some five thousand illnesses. [42:29.74] [42:32.36]Scientists believe they'll soon be able to manipulate these genes [42:35.79] [42:35.99]in a fertilized embryo. [42:37.66] [42:45.04]So for the first time in our evolutionary history our children, [42:48.20] [42:48.41]and their children could be free of genetic illness and disease. [42:52.60] [42:57.75]And remember, cultural evolution works faster and faster. [43:03.55] [43:04.62]And faster. [43:05.99] [43:13.16]Once scientists have the power to cure these illnesses, [43:16.10] [43:16.30]what else may they do with that knowledge in years to come? [43:19.10] [43:22.14]Imagine a world where the same technology could enhance our children's looks. [43:26.44] [43:26.88]Could we soon be ordering up designer babies? [43:29.35] [43:29.55]So the first thing to think about, [43:30.57] [43:30.78]have you thought about what kind of skin color you'd like? [43:32.27] [43:32.48]Could we choose the perfect features for our child? [43:35.08] [43:37.09]Every detail - from skin tone [43:40.52] [43:40.73]Have you thought about the color of the eyes? [43:42.42] [43:42.89]Yes my husband and I... [43:43.86] [43:44.06]to eye color. [43:45.15] [43:45.60]Can we have blue? [43:46.93] [43:47.17]And have you thought about the features of the face? [43:49.83] [43:50.03]No more nose jobs [43:51.06] [43:51.27]Have you thought about the mouth, the shape of the mouth? [43:52.57] [43:52.77]And no more plastic surgery. [43:54.26] [43:54.47]Yes quite full lips I think. [43:55.84] [43:56.04]Full. [43:56.90] [43:58.98]That's great. [44:00.20] [44:00.41]Yep happy with that. [44:01.17] [44:01.38]Yeah that's fantastic. [44:02.24] [44:02.45]And what about their brain power? [44:03.97] [44:04.18]And there she is, [44:04.88] [44:05.08]she looks like she's going to be a beautiful girl. [44:06.14] [44:06.35]Our offspring could turn out much more intelligent than us, [44:10.01] [44:10.29]much younger. [44:11.38] [44:20.03]Child geniuses could soon become the norm. [44:22.66] [44:22.93]...shape... [44:23.80] [44:24.74]The only other thing is intelligence. [44:27.14] [44:28.11]Our children would be academically successful at a much earlier age. [44:32.04] [44:37.45]And make complex modern technology look like child's play. [44:41.11] [44:46.52]Some scientists even predict that by 2020 [44:49.58] [44:49.89]we'll be able to manipulate the genes that control ageing. [44:53.09] [44:54.37]While we age normally over our 3 score and 10 years. [44:57.73] [44:58.00]Our children could reach 200 years and still keep their youthful good looks. [45:02.94] [45:12.88]We've come a long way from the chimps. [45:14.91] [45:15.49]Amazing considering there's only that crucial one per cent difference in our genes. [45:20.45] [45:26.70]Our journey of life has certainly been a rocky ride! [45:29.79] [45:30.37]Until now our evolution was a Game of chance - [45:33.13] [45:33.47]that we survived at all is something of a miracle. [45:36.07] [45:41.28]No one can really know for sure how much further away from chimps we'll go. [45:45.91] [45:46.52]The difference is that now the choice is ours. [45:49.95] [46:09.17]So what might that space age biologist find if he came back to Earth in the future? [46:14.44] [46:18.95]If he examined apes again, he might get quite a surprise. [46:22.91] [46:29.66]Before, he was comparing us humans with chimps. [46:33.12] [46:40.87]But if he now looked at the chimps. [46:43.14] [46:45.28]And at the average un-modified person of today. [46:48.25] [46:48.91]Then at the new super homo sapiens of the future. [46:52.47] [46:52.85]He might well see a greater difference between me present day human and the superhuman [46:58.72] [46:58.92]than he previously saw between the present day human and the chimps. [47:02.95] [47:05.16]For the first time in the history of life we can control our own evolution. [47:10.33] [47:11.20]Whether we choose to or not, [47:12.67] [47:13.07]we now have the knowledge and power to determine our biological future. [47:17.77] [47:18.21]Our own Journey of Life. [47:21.18] [47:23.18]The End [47:54.18]

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