Adam Rutherford | Humanimal: How Homo sapiens Became Nature’s Most Paradoxical Creature

my fellow primates welcome to the Free Library of Philadelphia my name is Jason Freeman I'm a producer and editor here in the author events office and I'm very excited to be here tonight to introduce Adam Rutherford mr. Rutherford's books included 2017 a brief history of everyone who ever lived a daunting title if ever there was one the ages spanning story of our species told through the study of genomics winner of the 2018 Thomas Bonner book prize a finalist for the National Book Critics Circle Award and a National Geographic best book of 2017 it tracks the recently unlocked secrets of the migration disease war birth and sex experienced by our ancient ancestors in addition to the wonderful New York Times Book Review blurb you can see write in your program it was also referred to you by the Guardian as quote an effervescent work brimming with tales and confounding ideas carried in the epic poem in ourselves a University College PhD mr. Rutherford is also written and hosted several programs for the BBC including the cell and playing God and is the presenter of the BBC of BBC Radio 4's premiere science show inside science he is a frequent contributor to The Guardian he's appeared in BBC Radio's the Infinite Monkey cage and a self-proclaimed movie geek he has served as the science advisor for several films and television shows including World War Z ex machina and the Cat in the Hat knows a lot about that I'll be asking about two of those after tonight's talk his new book is called humanimal how Homo sapiens became nature's most paradoxical creature a new evolutionary history it asks the question what does it mean to be human our genome is 98% identical to a chumps so are we as remarkable as we think we are our chimps even more extraordinary than we think they are and King Lear Shakespeare ways in saying thou art the thing itself an accommodated man is no more than such a poor bear forked animal as thou art and he ought to know he was a very smart primate himself here to shed some light on just what it is that makes us human animal and truly exceptional way these gentlemen and humana moles of all ages join me in welcoming Adam Rutherford to the free library Thank You Jason that's a very generous introduction and thank you for inviting me to Philadelphia's my first time here it's a real honor to be in such a prestigious space as Jason said this is a book about about what it means to be human in my last book a brief history of everyone who ever lived I covered about about a million years worth of human evolution in this one I'm limiting my scope to just well pretty much the last hundred thousand years of human evolution so you know I'm really focusing and narrowing it down that subtitle there how Homo sapiens became nature's most paradoxical creature that is really crucial the central thesis to the book that we are both animals we are evolved we have the same DNA the same proteins that same cell structures as every organism that has ever existed and yet at the same time we are capable of such wonders so this question of human uniqueness is central but in all of my work I try to embrace the complexity and the reality of science and evolution and I try to steer myself away from singular narratives from uniqueness theories this is the thing that is triggered our modern human behavior there are many things which we have historically thought of as being unique to humans which turn out to be maybe different by degree or by kind or not different at all and those are the sorts of areas I want to explore a lot of people have made entire careers suggesting that there are individual things that are unique to us like speech or control of fire or tool use recently a paper suggesting that are taking hallucinogenic drugs was equivalent pivotal moments in our development from an earlier less sophisticated open to the one that we recognize today the truth of the matter is that the thing that makes us human is having two human parents and having a human genome but that is a terribly dull answer and it doesn't really help us at all in answering questions about the human condition how he got to be where we are so this this paradoxes paradox that is inherent to the human condition in a scientific sense it was my intellectual hero Charles Darwin who first pointed this out in his second best book The Descent of Man in 1871 at this beautiful quote so Don was a outstanding writer beautiful writer of the most wonderful prose and also of course the founder of the best idea that anyone ever had in the descent of man he talks about this paradox he says that we have godlike intellect we can understand the solar system the mechanisms of the solar system we have these exalted powers and yet man in 18th century language still bears in our bodily frame the indelible stamp of our lowly origin so there is the paradox we are superior intellectual beings and yet at the same time we carry this this stamp of our evolution a better writer than Darwin and thank you Jason for quoting Shakespeare up top said this 250 years earlier in the very famous the wonderful soliloquy by Hamlet where he says what a piece of work is a man how noble in reason how infinite in faculty in action how like an angel in apprehension how like a god this line the net the line that comes next the paragon of animals so this is a is such a wonderful evocative phrase so much so that I wanted to call the book the paragon of animals but my editor told me that was really pretentious just after this line Hamlet goes on to say but what is this quintessence of dust expressing exactly the same idea as Darwin that we are wonderful we are the paragon of animals and yet at the same time we are merely made of of matter now as adjacent an introduction and very kindly alluded to I do work in films and I'm a film obsessive and there was a third line that I actually wrote in the final parrot or the final chapter in the last book a brief history of everyone who ever lived because I was expressing a slightly different idea but it was so perfect it was it was in fact a trigger for writing this book and the line was everyone is special which is another way of saying that no one is and I wrote this and realized well I didn't realize in fact it was my editor who thanked me for putting another movie quote in and I didn't realise what it was does anybody know what this film from its from The Incredibles yes so in the first three pages of this book I quote Darwin Hamlet's and - from The Incredibles so I'm proud of that now human evolution the study of how we got to be here has radically transformed in the last 10 years even more so in the last five years and the primary reason for that is the introduction of a new source material a new piece of evidence in studying old bones and that is DNA so in the last few years since about 2008 or 9 we began to invent the technology to actually get DNA out of bones that have been in the ground for tens of thousands or even hundreds of thousands of years and with our increased understanding of how the code of DNA relates to the phenotype the way we are the physical presence of our of our lives we began to extract tons more information about our evolutionary cousins and antecedents and so that entire picture of human evolution has radically transformed it's been a revolution it's an ongoing revolution in it it's quite hard to keep up but I just let me give you a quick recap of the last million years so this is a tree of life a standard tree of life as we draw in evolutionary biology on the side nearest to me it's a million years ago so a root to the tree of the branch that is the humans and on the far side is the present at the bottom we've got Homo sapiens that's us divided into three groups Asians Europeans and Africans now there was an earlier type of Homo sapiens so the same species as us that migrated Out of Africa more than a hundred thousand years ago and made it all the way into Eurasia but doesn't leave any living descendants today so that was a terminal branch now you all know about the Neanderthals so the Neanderthals primarily a European species but actually Eurasian so the more we look the more we find Neanderthals into Asia and we divide the Neanderthals into Western and Eastern now we sequenced the Neanderthal genome in 2009 so I've got a full genome from a species of human been extinct for about 40,000 years and then you might recall in about 2010 there was the discovery of a single finger bone the distal tip of the little finger of a teenage girls and just this bone at the end of your pinky and a single tooth in it in a cave in Siberia the cave called Denisova named after a 18th century Russian era might call Denis and those physical remains are not enough to characterise an entire species so there's just not enough physical material to say this is a this what species this this girl was but researchers managed to get the entire genome out of the finger bone and we could tell by comparing it to the Neanderthal genome and the Homo sapiens our extant living genome that it was significantly different enough that it costs it could be classified as a human but different in the avatars and different to us and we call those people that Denis Evans now this is an evolutionary tree and these are the types of trees that we were brought up thinking about standard issue in evolutionary biology the first one drawn by Charles Darwin in 1837 so this is one of the sort of hallmarks of evolutionary theory however genetics has shown that this metaphor the tree well it doesn't really work that well in many cases and it doesn't really work that well for humans and the reason we know it doesn't work very well for humans is because of genetics so genetics is effectively the study of inheritance and families and sex and we talked about as a euphemistic term which is called a gene flow event right a gene flow event is the flow of genes from one creature to another yeah it means sex and because of genomes because of because of being able to get DNA out of these three types of humans the Denisovans Neanderthals and Homo sapiens we actually began to discover and in 2009/2010 that there are gene flow events between all of these and so what the map actually looks like it has dotted lines these trees have dotted lines between the branches that we used to think were distinct so for example we know that the Western Neanderthals had gene flow events with the people who emerged from Africa who would become Asians and Europeans we also know that the Western Neanderthals had gene flow events they interbred with Europeans and just glancing around the room most of you are from in this light look like you have recent European ancestry the evidence for that is that you carry something like 1 to 1.5 percent Neanderthal DNA the further east you go the more you find that that Neanderthal DNA is replaced by Denis urban DNA so East Asians have a percentage of of Denis of and DNA where Europeans tend to have a Neanderthal DNA so that's another gene flow event between the Neanderthals and the archaic modern humans both archaic modern Homo sapiens in the east and the anti tolls they're both now extinct but we can tell that from the bones from the DNA taken out of the bones and I just mentioned that the Denis Evans interacted they had gene flow events between the East and the and atolls so I don't know what the right metaphor for this is but it's not a tree it's a sort of tangled thicket a tangle bank maybe which is a very Darwinian phrase but it's definitely not a tree because all of these branches of species that we walked thought were distinct and separate actually interbred successfully with almost all other types of humans and I guarantee you this picture is going to get more complicated within the next year and definitely more complicated in the next few years now you might have noticed that I haven't mentioned the top branch on this tree because it's a piece of science which is why it's it's so awesome I think it's close to it's indistinguishable from magic almost which is that when you compare when we compare the genomes of Homo sapiens with Neanderthals with the Denisovans the Denis Tobin's appear to have a bit of DNA which doesn't correspond to either of the other two and so from that we can legitimately infer that there was another species that we don't have any physical remains for we call this a mystery human or a phantom species and we know that this mystery human interacted had gene flow events with the Denis ponds because the Denisovans carry that that genetic information we may know what species that is we may have that those bones but we've never got DNA out of them so until we find until we get DNA out of those bones it remains a phantom species so there is the picture of the last million years of human evolution as we now know it a result of genetics this picture will change it will get more complicated as we continue to look now one aspect of this paradox the conundrum of human evolution is exemplified by what is now the oldest Homo sapiens specimen that we're aware of which doesn't come from the Rift Valley in East Africa which is where we typically think of as the cradle of Homo sapiens but actually from Morocco place called jebel yurt and this this image here is the skull from jeboa roads that was dated a couple of years ago as being three hundred thousand years old a minimum of three hundred thousand years old so that puts the location of the earliest Homo sapiens away from East Africa into North Africa and it pushes back the date by another hundred thousand years now the point about this is that if you were to take one of the Jedi Lords specimens and we met them for real and they were alive and we tidied them up and shaved them or put them in some nice clothes put them in a sudra or a dress then you wouldn't be able to tell the difference between them and us if they were sitting next to you in this room or on the subway physically we haven't significantly changed in more than a quarter of a million years that also applies genetically as well there are there are plenty of genetic changes that we can track and then we can measure as we adapted to local environments as we spread around the world but the truth is they're not so significant that we wouldn't be able to win to breed with any human or any Homo sapiens for the last quarter of a million years so anatomically physiologically genetically we haven't significantly changed in a quarter of a million years we have spread all over the world but we remain the same species and yet something really significant did change within the last hundred thousand years but more specifically the last forty thousand years and that's exemplified by the presence and the discovery of artifacts from our cultural history such as this amazing specimen which is was discovered in the 1930s in a cave in Germany and it's referred to as the low end mensch of Holland Stein stardoll it's a lion mane it is a 12 inch stature you carved out of a tusk and it is a man it has seven stripes down the left arm which maybe maybe representative tattoos we know that tattooing was a thing at that time in homo sapiens and in the Ansel's but it has a lion's head cave lions head so it's an imagined being it's a it's a creation of a mind which is not dissimilar to our own it requires a great deal of skill a great deal of foresight it wouldn't have existed in isolation it would be a part of a series which we will probably never find but the amount of planning the amount of skill the amount of imagination the amount of abstract thought that has gone into this indicates that whoever the artist who created this amazing statue had a mind that was no different from ours today we don't see evidence of this type of abstraction of thoughts earlier than 40,000 years ago which is the date of the lion man within a few thousand years of that we see a series of other little statuettes figurines they're called Venus figurines they all tend to be they're all females they're smaller this this one I'm showing here is the oldest it's called the venus of hohle fels about thirty eight thousand years old also found in southern germany and they are often thought of written about as being fertility amulets or reproductive charms they often have exaggerated sexual characteristics the truth of the matter is we have no idea what they were for that is speculation it's difficult enough to know the mind of someone sitting opposite you today let alone the mind of someone who died 40,000 years ago we don't know what their motivation was they may have been toys they might have been dolls they might have been fertility amulets they might have been pornography that is not my suggestion that is in the academic literature but again the point is that the minds behind these creations these figurative depictions of human beings were no different from our own today again they take foresight abstraction artistic skill all sorts of aspects of behavioral modernity as we sometimes call it which are no different from us today within a few thousand years of that we have cave paintings that you all be aware of things like this beautiful image of the mega Saurus in Alaska in the southwest of France and cave paintings all around Europe Europe is the place that we've studied the most but that Eurocentrism is fading as we keep looking all over the rest of the world a couple of years ago these cave paintings from Sulawesi in Indonesia were dated as being 35 to 38 thousand years old they're actually hand stencils so they're they're hollow tubes probably bones with red okra blown through them to create stencils and we see this type of art all over the world within a few thousand years of Sulawesi in Indonesia so we've moved away from Europe but I said that the lion man was the oldest piece of figurative art that we were aware of well that was true until last year when this cave painting in a cave in Borneo a huge Cathedral like space not dissimilar to the room that we're in this is a painting of a band Tang which is an indigenous cow it's huge it's like you know several feet across on the ceiling and this was read ated in a paper published just in autumn last year this is an indication of how quickly this field is moving much to the chagrin of my editors when I constantly change things after deadlines have passed but the date of this ban Tang in Borneo is about is a minimum of 40,000 years so it's the same sort of age range as the lion man of Hohenstein startled but it's a minimum so it's probably a bit older than that and what this shows is that these ideas of behavioural modernity these ideas of abstract thought processes mind similar to our own is not just happening in Europe it doesn't have a single focal point it actually is occurring all around the world at approximately the same time everything I've shown you so far has been Homo sapiens now that changed in 2018 when some cave paintings in Cantabria which is on the northern coast of Spain discovered in the 60s but were read ated in February R and they're a depiction a very abstract depiction paintings on a wall again red ochre of that was the back end of a bovid some sort of cow we can't really tell the front end of a cow and and an abstract sort of a figure this is an enhanced image because it's quite faded on on the stone itself but this was data's being a minimum of 60 years oh now the only people in Spain sixty thousand years ago were not us they were Homo neanderthalensis and the and atolls and this is part of a revision of what Neanderthals were because we tend to historically think of Neanderthals as being Wow cave people you know thuggish grunting oaths and it's just not true part of that legend is because one specimen found in the 1920s actually had osteoporosis but we didn't discover it had osteoporosis until the 1980s and so it was hunched over but that's because it was a very old diseased man and that we thought that that was typical from the Anna tolls when in fact it was incredibly atypical but Neanderthals were cultured humans they had complex culture complex art abstract thought if this dating is correct they probably revered their dead and they did look a bit different from us they had heavier brows than us barrel chests much more muscley than homo sapiens but not so different that your ancestors didn't have sex with them now when we're thinking about art and the creation of these types of cultural artifacts these indications of mind similar to our own we have to think about one of the things one of the two or three things that Charles Darwin identified as possibly being unique to Homo sapiens unique to us and I go through all of these in the book in great detail but I'll just focus on on a couple here now Darwin thought that we were possibly unique in our use of tools we are obligate tool users meaning that we cannot exist without extending our physical capabilities by manipulating the environment in front of us in the 1960s the Leakey family working out in older Vicodin in the Rift Valley discovered an early the earliest known examples of tools associated with homo sapiens and they're known as the older one chopper or the older one tool set the first ones found were made from obsidian which is a volcanic igneous glass chipped away to create sharp edges and they were discovered these these tools these napped stones were discovered alongside human remains other species which is the earliest known member of the genus Homo therefore the humans and it was named Homo habilis and Homo habilis literally translates from the Latin as handyman so the fact that we were finding tools associated with this new species of human and we defined this new species of human the earliest species of human known as tool users is indicative of how long we have been obligate tool users how long we've been associated with extending our range with tools with technology we are a technological species that was the 1960s as ever science progresses the more we look and in fact in the 1990s and earlier species not in the genus Homo but in a in a new category called Kenya anthropos pati ops was discovered in the same place in all of I Gorge but dates to more than three million years old and was also found with the older one tool set in the same lithic layers meaning that we have been obligate tool users for at least three million years a million years longer than we've been in the family human and you know more than two 2.7 million years longer than we've been on the sapiens so we've been tool users for a very long time the Alduin tool set is stable through time for more than one and a half million years and then we see it all over the world we see it from from Europe Africa all over East Asia right down into Australia as humans spread we don't see it on the American continents because humans didn't really reach there until about 20,000 years ago but the older one chopper is replaced by a slightly more sophisticated set of tools which are referred to as the eschew lien toolset and they tend to be bigger and more versatile sharper edges different types of tools now what these don't these are lithic so they're stones they're the things that remains what these don't show these tools is what these tools we use to create other tools made out of biodegradable materials like wood and animal products but these are the ones that remain and indeed we name our geological eras after stone Neolithic new stone Mesolithic middle aged stone Paleolithic old stone so the question is right we are obligate tool users we've been able to get two years to users for three million years what's Darwin right are we the only organism to use tools in this manner well you know the answer to this because for years people like Jane Goodall and Fran's Duval have been studying tool use in primates and we see amazing films with by David Attenborough and others in which we see things like orangutan spearfishing and all the primates use wooden tools to some degree in in many forms you probably are aware that more and more we're studying poor vets particularly the Caledonian crows there are also obligate tool users and very skilful not only do they use tools for particular tasks they create tools by bending them so they have hooked looks rather than straight spikes a hook is better than a spike if you're catching a fat grub we also know that the corvids use one tool to get another tool if you put an experiment a good-looking tool out of reach through a bars they will use a less good tool to actually pull the good one through and then they'll go and use it so primates use it we use it lots of lots of mammals use tools or obligate tool users what's really interesting is l1 percent of animals turn out to be able to get tool users and that ranges across all classes of animals nine classes of of animals including mammals primates but also mollusks so the octopus uses tools my own personal favorite is the crustacean this is a boxer crowd used to be called a boxer crab there's several species of these and what they do is they pick up stinging and enemies in their pincers and they use them to fight with other crabs and ward off enemies they they get they don't get caught boxer crabs anymore because the action itself is much more reminiscent of being a cheerleader so they actually get called pom pom crabs instead which I'm sure is not their intention but do have a look at those videos on YouTube because they head so we see tool use across tons and tons of different animals that range that are very distantly related and it indicates that being a tool user is not it hasn't had a central origin from which all other subsequent tool users have been descended it's clearly a useful trick which is something that Daniel Dennett describes that a good trick so you know being extending your range through the physical manipulation of your environment it's a good thing to do what is different about humans is that we tend to craft our our tools and the extension of our physical forms through cultural accumulation as the technical term but basically we're not reliant on passing down information from one generation to the next or to people that we are very directly related to we are effectively this is the way I'm characterizing in the book we are a species of teacher many animals learn but only humans teach further most part biology is a science of exceptions and there are a couple of exceptions but this idea of cultural transmission is really central to the book and I'll come on to why towards the end but before that I just want to talk about a couple of examples of cultural transmissions the very very few examples of cultural transmission of tool use in other animals and the first is the Dolphins of shark Bay so these are bottlenose dolphins they've been studied since the 1970s 1980s and a few years ago in the 1980s it was observed that some of these dolphins in Shark Bay it's a big pod it's a big big family extended family in a large area of ocean were doing they're observing something slightly odd which is they were swimming down to the bottom finding conical shaped sponges and working the sponges on to their rostra which is that they're beaked or they knows if you like and holding them on their nose and then swimming off and further study so divers found out that the reason they were doing this is because they're using the sponges to protect their noses when they're foraging at the bottom of the of the ocean they're protecting from getting scratched up by rocks when they're actually trying to eat things like boxer crabs or pom pom crabs and that is really I mean that is a fascinating legal thing in terms of a behavior that is just magnificent it became more interesting in the 1990s and into the 2000s when they were studied more closely because something very unusual about the sponging dolphins is was discovered which is that the only members of the bottlenose dolphin species in Shark Bay that do this behavior are female so no male has ever been observed doing this behavior we don't know why that is there doesn't appear to be any reproductive differential success between the males and the females but there's never been a male dolphin observed doing this highly sensible behavior so you can draw your own conclusions about that but then further into in 2015/16 researchers down in Shark Bay start to take genetic samples from the sponging dolphins and from that we can get two really interesting pieces of information the first is that the females doing the sponging behavior are not particularly closely related so we think this is an example of cultural transmission these are dolphins learning this behavior off they're not just sisters but female cousins female relatives never from the male relatives so it's one of the few examples of cultural transmission outside of humans in another mammal in this case but the other thing which is really I just love this is that by looking at the spread of the genetic the genetics of the individuals doing sponging behavior we can also track back through evolutionary time we know the generational time of bottlenose dolphins is about 25 years and the pattern of who was doing this behavior meant that we could isolate it turned out an individual a female dolphin originated this behavior in the middle of the 19th century so one morning a female dolphin got up we get up to half Birds woke up found thought found a conical sponge thought I got a good idea work this sponge onto her rostro and then from that point onwards female dolphins in this one particular pod continue to do this to that day so it's a great it's an amazing example of one animal using another animal to hunt for a third animal but only 50% of the animals are actually doing this and they have here to be passing this on in a teaching learn based way rather than a genetically encoded way passed down now talking about dolphins introduces an another concept in the book that I like talking about because it is it's not something that we we we talk about that much in the sort of public discourse on evolution and I'm not written for a second allowing the idea that evolution by natural selection is not the accurate description of the way life on earth radiated it is our it's the only game in town as far as understanding biology but natural selection and sexual selection which is a subset of natural selection is the main driving engine behind evolutionary change but there's also a less talked-about aspect to evolution which is sometimes referred to as drift genetic drift but just the notion that some stuff just happens it happens because of the situation you're in the environment you're in but it's not actually driven by selection itself so many of our human characteristics are not things that we can demonstrate are adaptations that just stuff that happened in the genomic age we are very good at identifying bits of our genome which have definitely undergone selection and there's there's quite a lot of it regional adaptation is how we became so global but so many things that we think of as being while we speculate particularly in branches of evolutionary psychology we speculate as being part of natural selection and thus can explain contemporary behavior actually turn out to be just stuff that happened to us there's a line from one of your presidents Teddy Roosevelt which I love which is this do what you can with what you have where you are now he wasn't talking about evolution but it really does encapsulate this key idea about the sort of cosmic happenstance of where a creature revolves and the reason I bring this up in reference to dolphins is because what we know dolphins are smart and they do smart behaviors they also do plenty of real noxious behaviour particularly sexually but I'm not going to talk about that you'll have to buy the book to discover that stuff but we teach in high school we teach how the paddles of the front fins of a dolphin the four limbs have exactly equivalent bones to our own hands right but they're fused in dolphins because they need those four limbs to paddle through the sea so they can't do this they can't type they can't play the piano they can't carve lion men out of tusks because they need their paddles to swim really well they're not very good at holding things at all whereas we can hold things very incredibly sophisticated ways enough to be able to you know play the violin like in white children and so this is a really important point that we sometimes underestimate in terms of trying to understand the evolutionary trajectory of all sorts of organisms it sounds like a cruel point but dolphins are never gonna evolve the ability to create fire because they live in the sea I was waiting for you to get that right that's just never gonna happen and Darwin argued that controlled use of fire was absolutely essential to our own evolution but it changes it changes us and it's changed lots of organisms but sea creatures are never gonna get to the stage where they could Forge steel which is another significant development in our own evolutionary timeline that's never going to happen for the Dolphins because they live in the sea so let's talk about fire because Darwin thought that we were obligate fire users which we absolutely are the benefits of fire are well there's tons of them not just for warmth it allowed us to migrate to northern Cline's whereas colder it also allowed us to cook food now cooking food is absolutely essential to our own development there's lots of theories that it particularly cooked meat allowed us to spend less time chewing which reduced the musculature in our heads if you look at gorillas skulls they have a huge sagittal crest which is we take them take if you look at a gorilla skull it has an enormous like a crown and it's because the muscles their jaw muscles their masters connect right up to the top because they spend most of their time chewing chewy leaves now you feel your own temples and clench your jaw is the same muscles but they stop at your temples because we don't spend nearly as much time chewing one of the reasons for that is because we began to cook our food and so what what is what is Cook's food it's an external stomach we begin the digestion process before we put food in our mouth and that is we get all sorts of nutrition out of that out of that cooking process but also we get protection because if you spend a lot of time with your head in an animal carcass then you're spending a lot of time eating which is time that you could be being eaten right so if we can minimize the time eating then that is a that is something which can be selected so cooking food absolutely essential and then there's all the cultural aspects about being around a half being around a fire and that comes later lots of organisms are also too fully dependent on fire we know the chimpanzees in faun goalie in Senegal who have very sophisticated understanding of the annual Savannah fires that come in that area and they will stand very close dangerously close to a fire which is of course you know mercurial in its behavior and they will wait until it's gone out and soon it's gone out seconds later they will go into a burnt area and they will fish out burnt toasted semi-cooked mammals or lizards that they that they can eat vervet monkeys spend and marmots as well in Africa in South Africa spend less time looking standing on their back legs and looking into the long distance for fear of predators when the grass is burnt down and herbivores do that as well so lots of animals are also dependent on fire and have a complex understanding of fire but some sapiens really has a incredibly obligate pyro philic relationship with fire and has done for well several hundred thousand years at a minimum it wasn't just us though and I mentioned earlier that only the stone tools remain well there are very few examples of wooden tools that remain but one was discovered a couple of years ago discovered in a site in Tuscany in Italy and it's a it's a set of boxwood clubs boxwood is very hard and due to the nature of the soil that leaves were discovered in they were preserved and they have been preserved for more than 120,000 years now the club itself is interesting as a tool but also it shows very clearly that the small twigs on the outside this branch have been deliberately burnt off in order to shape the club now a hundred and twenty thousand years ago in what is now Italy the only people present were done the and adults so again Neanderthals were they had a complex culture and a relationship with fire which appears to be similar maybe indistinguishable from our own but of course in young cells are extinct and so we are the only organism that is capable of starting new fires also we thought until 2017 when the scientific publication of a piece of indigenous experts knowledge from Aboriginal Australians was published in the scientific literature but known about by indigenous people of Australia for maybe thousands of years and it was three species of Raptor three species of birds of prey who had a very specific behavior that they have annual savannah fires in Western Australia as well and these birds were observed hanging around the edges of these fires going down and picking up burning or smoldering sticks in their beaks or their talons and then flying away over natural or man-made fire barriers dropping them into dry brush and then they go and sit up on a tree and they go and sit up on a tree and as the fire rages they see the little mammals and the little lizards running away from their fiery death into the mouths of the hungry kites now what an amazing behavior that is there is a suggestion I don't know how true it is but it's an interesting suggestion that this may be a behavior which humans learn from the birds and that management of forest fires of savanna fires in Australia which the Aboriginal Australians have been doing for thousands of years may have been learned we see references to fire Hawks in some Aboriginal Australian ceremonies which certainly predates the arrival of Western colonizers in the 17th and 18th century so we're not the only animal that can start fires we are the only animal that can start fires from scratch but I don't know maybe the birds are working on that too okay so I've touched on a couple of things I've touched some tools I've touched on fire as a tool there's much more content in the book particularly about things like speech and language there's a long section on sexual behavior but it's this is it just doesn't feel appropriate talking about it in such an August library because a lot of its just absolute filth but I want to get to the core idea so cultural transmission is the is the thing that we do with doing it now teachers do it every day in fact humans do it every time we open our mouths and communicate a unit of information every time we speak to another human we are transmitting a piece of information to someone or a group of people to whom you might not be related and we share we radiate out information in every direction with every breath we have done that for tens of thousands of years now the new bit of this is it's an idea which is really only emerged in the last well last five or six years last decade tops but it's it's it's underrepresented in evolutionary and paleontology PI anthropology for reasons that I think are quite interesting but it's it's a very specific area which I think and I argue in the book under writes all of the uniqueness theories that you will no doubt be thinking of things like fire use things like sexual behaviors things like emotional traits things like mourning the dead all of those things that people suggest and think about as being these are things that we do and other animals don't or they do differ by degree or by kind or you know any of those sort of qualifications but I think that there is an underlying behavior which which under writes all of the development of those sorts of aspects of cultural transmission it's referred to as demographic transition which is not a very sexy way of describing it but what it is is this idea that where we see these sudden explosions in technology and culture and abstraction of thought musical instruments and art and things like that we they coincide with massive expansions in populations and we see this all over the world we see it in Africa we see it in Europe we see it in Indonesia in those spots where we see those examples of behavioral modernity we also see populations expanding in in size and maybe those populations are expanding in size due to climate climate changes we don't you know that's that's part of the theory which is being worked on but it's also been mathematically modelled so there's two key areas of research about this one is Joseph Heinrichs and it's harvard's and the other group is Mark Thomas's group of colleagues of mine at UCL and they put together mathematical models we do a lot of mathematical modeling and evolutionary biology we plug in tons and tons of data available archaeological and other data into a model and then you try to work out what the best mode of transmission of these types of units of information a key a key part of this as well is the correct assumption that humans unlike every other species we are a species of experts so there isn't another species where talents are so unevenly distributed and of course you know that's true because if you want to learn how to do something what do you do you ask someone who knows how to do it that's why we have mechanics and teachers and librarians we don't do every job we tend not to be generalists but I think that's crucial in the understanding of this idea of how populations expanded that once one person has an area of expertise maybe they were super good at some carving lion-men or carving flutes out of bones or making tattoos or cooking aspects of hunting once one person is capable of doing that then it benefits the rest of the group by spreading that information as far and as wide as possible and what the mathematical models say very clearly is that this transmission of information occurs in an optimized rate when a population reaches a certain threshold when it gets to a particular size you get just a much better more efficient way of communicating these units of information in and amongst the groups than you do when the size is reduced and so that's the working theory that's that's that's the idea that is currently being developed it's the one that I pinned my colors to there's there's a good piece of physical evidence which shows that the opposite but is part of reinforcing this this similar idea and it relates to in technology so we've been obligate Fisher's for Fisher people for tens of thousands of years the earliest known fishing hook is the bottom of a flat shell one of those conical shells that you see on the beach and this this one I'm showing in the picture here is from Java it's about 24,000 years old the actual specimen is still sharp enough to cut your skin so that's twenty four thousand years ago by ten thousand years ago we have this incredibly sophisticated fishing technology fine toothed harpoons that allow us to go out into the ocean and cartilaginous fish in a much more sophisticated fishing technological way now this is a slightly culturally sensitive thing to discuss but I'll just give you the facts part of our evidence for this idea of demographic transition is to do with the relationship between indigenous people of Tasmania and indigenous people of Australia before the end of the last ice age the last glacial maximum meant the oceans were significantly lower than they are today and Tasmania is attached to Australia 11,000 years ago because all the water is sucked up into the glaciers as the earth warms the glaciers melt and the sea levels rise and about 10 to 11,000 years ago Tasmania is separated by what we now refer to as the bass straits from Australia now the people the indigenous people of Australia and Tasmania at that time are separated and we've got no evidence that there was any communication between the island that the two islands after that separation but the population size on Tasmania remained very small and isolated compared to the population of the indigenous people of mainland Australia which continued to flourish now what we know from the archaeological record is that the number of tools on both Tasmania and Australia when they were connected was a few dozen but by the time European colonizers arrived in the 17th and 18th century the number of tools on mainland Australia had gone up into the hundreds as you would expect and the number of tools in tasmania had dropped to below 20 and concomitant with that they had lost a bunch of technologies such as fishing hooks and have returned to being foragers at the seashore and didn't hunt cartilaginous fish we see the disappearance of cartilaginous fish bones in the archaeological record as you go from 10,000 years ago into the present and to the extent that some of James Cook's men observed the indigenous people of Tasmania freaking out when they saw them fishing for cartilaginous fish out beyond the reef and so the idea is its reinforced by this piece of evidence that's in fact we think that that small isolated population meant that technological development did not occur in the same way that it did in mainland Australia where the transfer of ideas was maximized so this is the key idea this is the new idea I think it's right so think it's an area of that we will continue to research over the next few years as people get more interested and as we keep digging as we keep looking and we keep finding more genetic evidence I say it's a new idea because it was first described in 2010 11:12 and more recently a couple years ago in the most detailed form but the truth of the matter is all the best ideas in biology actually do start with Charles Darwin and in the descent of man just in a passing paragraph he mentions pretty much exactly this idea and I'll just read you out this quote but I'm gonna modernize it because he uses Victorian language and manages to well ignore 50% of humans and doing so and the quote from the descent of man is this as humans advanced in civilization and small tribes are united into larger communities the simplest reason would tell each individual that he or she ought to extend their social instincts and sympathies to all members of the same nation though personally unknown to him it's an amazingly prescient phrase and it says a lot about human behavior today but also 40,000 years ago and that is why Darwin is the great genius that he is I argue our greatest thinker of all time but fundamentally it says that thing which I think is really important something to really latch on to that humankind's if you want a definition if you want a single thing which I don't but if you do than humans are a species of teachers thank you very much so the first Tasmanians were from where and the population once it was isolated were inbred and had no incentive to push out into that sea the way we've seen the migration out of what is that I'm sorry New Guinea Papua New Guinea across the Pacific all the way into Hawaii well we see no evidence of a seafaring culture in Tasmania after it's been isolated the evidence is not particularly robust we do know there's plenty of archaeological evidence but it is all you know this is ten thousand years old so it's quite scanned but what we we don't see very large population sizes it's reasonable to assume that there is therefore isolation and genetic isolation so a bottleneck which means an increase in inbreeding as you suggest but fundamentally we just don't we don't see evidence of extensive communication with any other humans beyond Tasmania after the last glacial maximum it's not I don't wanna be judgmental about that it's not it's not it's not indicative of them devolving or in any way it's just that they didn't continue to develop technology as indigenous Tasmanians than the people from which they were separated within a very within the last ten thousand years which is mainland of Australia so it's a different evolutionary pathway but it does exemplify this central idea which is that when we share ideas widely and spread them that technology progresses and cultural technology progresses as a result I'd like to take you back to your mention of phantom species all right I don't think this planet is a closed system and there might be other drivers like beachside time and chance as far as the evolution process you may know where I'm going with this Carl say and said it's most probable that we have been visited before by higher intelligences this has been discussed by a variety of what might might be caught Ashville archaeologists from Zacharias and Erich von Daniken the and the the assumption is that the genetic code might have been possible possibly let us say altered and that this might have called this rapid evolution from ape-like species to Homo sapiens on earth and a quick arrival of the Sumerians in the early civilizations and what do they all have in common they all have in common the mentions of God so they're not talking about walking trees common is invited I didn't hear a question never that's a great statement well look I am a huge science-fiction fan I'm a huge fan of Carl Sagan he is you know close to Darwin as being one of my great inspirations ideas about extraterrestrial input to biology on earth where it starts much earlier than that there's an earlier theory that some Fred Hoyle proposed which was which is called panspermia which is that life on Earth was actually seeded from space I'm not aware of the one you're talking about but I follow you like a panther on it the problem with it as an idea is that there's no evidence to support it that's the second the follow-up problem to it is that it's not the parsimonious explanation we do have really good evidence to support all of the steps that I've talked about it doesn't it doesn't mean that there are tons of gaps that still need to be filled and when I say that there's a mystery human there is a human that we haven't identified we have evidence that it did exist and that evidence is that it was a human and not extraterrestrial when we talk about the great leap forward or the cognitive revolution it's it is sudden and evolutionary timescales but it's ten thousand years or twenty thousand years so it's not like you know the click of a the flip of a switch or the click of a finger there is no Thanos involved but so these these very quick switches occur over huge amounts of time but I think the key thing is that it's not parsimonious it's no we don't actually require that explanation because we have really really solid scientific evidence that does include gaps but it doesn't include gaps so large that we have to invoke extraterrestrials as for the existence of religion through cultural history we also have parsimonious explanations for this which I do talk about briefly in the book and and it's to do with the psychological behavior which is known as agency detection something which does appear to be you know very hyper developed in us but may exist in other organisms as well which is just the the notion that we need to be able to if we see observe something rather than just assuming it's dumb nature or the laws of thermodynamics enacting it it's useful if we can attribute the fact that your cousin has been ripped to pieces understand it's dead next to you that a cave lion did that rather than I just observing that he doesn't look that good right now so that's agency detection and but in us it has become so hyper develops that we have agency detection all the time for things which are massively don't require agency that's why haunted houses exist when tonight when your house is shrinking as a result of it getting colder you'll hear a creaky floorboard and think holy crap that was a ghost well it wasn't it was just a bit of thermodynamics now when we see enough agency detection it's a useful cultural attribute to say well why you know why what is a better explanation from stuff that we don't understand because we don't have thermodynamics in our lexicon 40,000 years ago oh this there's something supernatural going on there one of the things I argue in the book I'm not a religious person but I come from a Catholic family one of the things I say in the book is that if these psychological aspects during our development of behavioral modernity are responsible for the creation of gods we have also gone down a pathway she's allowed us to tuck them back away again going back to something which is more obvious while there were populations and civilizations of of Indians in North and South America they did not have much technology before the Europeans arrived and my own thought I have no idea if it's based in anything is that they had no load bearing animals other than the mammoths that they killed off and the Yama's that were used in South America so therefore they didn't have any need for a wheel no one invented a wheel and there all these other things they didn't invent either so that's just something to throw out to you if there's any or any ideas on why the cultures in this in North and South America did not develop as much well I think well the first thing is that I think the that's you may have misrepresented the technology of the indigenous people of the Americas there who for 20,000 years have been incredibly sophisticated tool users equivalent to what we see all over the rest of the world so the we now the current working theories is that in the last book is that the indigenous people of the Americas migrated from Siberia about 24,000 years ago across what is now the Bering Straits but then again during the last glacial maximum was just land we call those people that bur Indians but there's tons and tons of evidence of very sophisticated tool use that starts I think the earliest is something like 13,000 years but that is changing rapidly and next Friday I'm going to the American Physical Anthropology meeting in Cleveland where we'll be discussing these things but I think part of our problem with assessing the differential development of technology sort of relates to that Teddy Roosevelt quote do what you will do what you can with what you've got where you are the Native Americans indigenous people of the Americas were doing they were doing fine until the Europeans came and some and we did a really good job of murdering most of them so the Mexican population people who refer to as the Incas in the Aztec had incredibly sophisticated and a population of tens of millions I forget the exact number something like 75 million within two years of Europeans arriving their population had dwindled down to about 1.5 million now the story of European colonization is the story of decimation of indigenous peoples and so we hold these ideas about what we as people with European ancestry brought to the rest of the world and make comparisons which which are well they are there their comparisons of superiority they're saying that we have this technology and you didn't and it's part of the subjugation of people it all starts during colonization European expansion the age of exploitation and plunder which coincidentally is the beginning of the first descriptions of scientific racism and when I say coincidentally I don't mean coincidentally I mean because of this is this is all content from my next book but this is again what we'll be discussing next next week in in Ohio in Cleveland so I think it's good to think about these things but it's it's something we have to think about very carefully because everyone whether you're a scientist or not whether you're liberal or a conservative or you know whatever political or professional aspect you take we are not immune none of us is immune to hundreds of years of ingrained prejudices which many of which we're just not even aware of I'm not laying that at you madam but because these are questions that we need to ask but the best way to answer them is to look harder at the data and to talk to the people that the indigenous people whose whose cultures we plundered at what at what point did the chromosomal number of pairs diverge from other species and is that important okay so this this is this is it's a great question and it is one we have a good answer to and genetics my is my subject so I feel very comfortable talking about this the what you're alluding to just for the benefit of the rest the rest of the audience is that we have 23 pairs humans have 23 pairs of chromosomes and the other great apes have 24 now okay so okay so so we have one fewer chromosome than gorillas or one to two as a pair 48 compared to 46 this is this is a we can track for evolutionary time by looking at genetic differences especially macro differences such as chromosome number which is a huge difference and we know very well that our chromosome two number two which is the biggest chromosome is a fusion of two chromosomes that we see in gorillas today so we can see this very very specifically this you know when you remember you might remember we draw chromosomes as they look like sort of pinched socks well we can see the pinch of two different chromosomes it's now gone but we can see the remnants of it like a fossil in the chromosome which indicates very clearly that at some point in the last eight million years the two chromosomes in in an ancestor of the great apes and us fused and that became our line and it didn't fuse and that became the gorillas bonobos chimps and bonobos chimps and orangutangs thank you okay so that's that's one aspect to it now it becomes an interesting question for two reasons this is in the book because well we interbred with Neanderthals we interbred with the Denisovans we don't know how many chromosomes they had because chromosome number is not preserved in the DNA that we get out of the ancient bones when I say we get the full genome sequence it's actually just bits of it that we then staple together very very carefully so it's not like taking a cheek swab from a living person getting the full 3 billion letters of genetic code but chromosome number and chromosome breakages are not preserved in that so we don't we cannot categorically state that Neanderthals had 23 pairs of chromosomes how whether basic biology high school biology meiosis and mitosis indicates that you have to have the same number of chromosomes in order for sperm and egg to fertilize and to become the next generation for conception to happen so it's not an unreasonable supposition to say that Neanderthals annelids and Eastman's had 23 pairs of chromosomes this is quite a technical answer but it's quite fun too so I think it is reasonable to say Denisovans and the Ansel's have the same number of chromosomes that same ploidy as as us however and this is why biology is always fun and frustrating because it is a science of exceptions paper was published 18 months ago which indicated that equites so animals like horses zebras donkeys and things like that they have a range of chromosome number between 16 and 31 depending on the species and those numbers have no bearing on whether they produce fertile offspring or not and we do not know how that works when that paper arrived on my desk I looked at it and I had two simultaneous reactions the first one is wow that's super cool and the other one is God no really you know because this is one of the basic fundamentals of biology that I learned for the first time when I was 10 and it turns out well it's a bit more complicated than that and we don't really understand it but that's why we study this stuff that's why it's called research [Applause] you

Channel: Author Events

Views: 6,957

Keywords: Adam Rutherford, Humanimal, BBC, Inside Science, evolution, natural selection, neanderthals, history of humanity, homo sapiens, The Guardian

Id: LScfRoudcC4

Length: 64min 0sec (3840 seconds)

Published: Mon Mar 25 2019