The Evolution and Meanings of Human Skin Color | Nina Jablonski

what a terrific Museum you have here this is my first visit to this museum my first visit to Houston I'm enjoying it very much and I'm extremely grateful for the wonderful welcome I've received so far the artist Angelica das several years ago started making photographs of people in her native country of Brazil because she was fascinated by the fact that human coloration grades there is no discontinuity she said look at this wonderful chromatic spectrum that we see in human skin there are no barriers there is just shades of different likenesses and darkness 'as she put them next to various Pantone colors and her work has become world-famous because she has shown that in fact human skin color has no discrete boundaries within it I share her fascination with skin color but mine comes from a different origin not so much the artistic one but why do we have skin that comes in colors this is a fairly unusual situation for primates as we'll see and I wanted to know why most of our relatives don't look like us you didn't have to come to a Leakey lecture to figure that out but we are the only one of the primates that has mostly naked skin all of our close relatives shown here there are the rest of the African Apes and the other apes and old world monkeys are all pretty hairy guys and when we look at their skin they have mostly lightly colored skin under their fur so the question arises how did we come to mostly naked skin that comes in a range of colors we began working on this problem close to 25 years ago and we realized that in order for us to study the evolution of skin color we had to first figure out what was going on in the early ancestors of modern humans so going back into the genus Homo and then beyond that even deeper in time to the genus Australopithecus and earlier hominins to try to figure out hey what was going on there what was going on with their skin paleontologists love fossils okay beautiful lovely you can you have gorgeous halls full of them here but rarely do we have skin preserved in the fossil record and so we don't know what the physical interface between that wonderful individual and the outside world looked like so we have to rise to the challenge of summoning all sorts of available evidence paleontological paleo ecological anatomical physiological now genetic and biochemical also to try to figure out what the skin of our ancestors looked like to make a long story short we spend a long time working on this this issue and we realize that probably the common ancestor of humans and chimpanzees and subsequent forms like the famous Lucy fossil Australopithecus afarensis looked quite chimp like in their skin and the reason that we we made that deduction was on the basis of the limb proportions and the likely activity levels of this of this incredible fossil form because we can actually see from the relatively short lower limbs and the relatively long upper limbs that Lucy and her kind although she was an adept bipedal list she probably wasn't a big runner she still had abilities to climb in the trees and may have even died of a fall from a tree and so what we reasoned was that she probably did not undertake a lot of energetic bipedal locomotion either running or walking and would not have had to dissipate a lot of body heat from the surface of her body through evaporative heat transfer and so that's why we reconstructed her to look much like chimpanzees in her skin having light hair light skin covered by dark hair our ancestors as far as we know from all of the readings of the fossil record evolved first in Africa and all of the major events in human evolution occurred in Africa and most specifically under intense solar radiation close to the equator in Africa my favorite of all graphic descriptions that I use in my lecture is what I call the hairy timeline of human evolution and on the hairy timeline we can go back to that estimated time of the divergence of humans and chimpanzees are closest come our closest living relatives about seven and a half million years ago and from the principles of anatomy physiology and these other fields that I talked about what we can reason is that their skin probably was lightly pigmented covered by dark hair and that that persisted through the time of Lucy and to about two million years when we begin to see a rather dramatic change and the skin becomes more lightly haired and much dark let's see what's going on here this beautiful specimen from the West Turkana site in western Kenya looks very different from the Lucy fossil that you just saw a few moments ago here we have an individual a young male individual from what we can tell who had much longer lower limbs than upper limbs really very modern-looking in his skeleton and when we look carefully at the configuration of the hip knee and ankle joints and at the internal architecture of the bones what we see is an individual who was doing something much different than Lucy he probably could still climb trees but not was not an adept tree climber rather he was a runner and a fast Walker and he probably did a whole lot of it we tend to think that humans are very clever and that they always evaded predation most of the time humans in our history were running away from predators we weren't the Predators ourselves so why the excellent running abilities probably for chasing down some animals but mostly for running away from predators who also were sharing our open environment in Equatorial Africa so when we reconstructed the skin of early members of the genus Homo like the Turkana boy we reconstructed it to look quite different from that of Australopithecus afarensis mostly naked and capable of great sweating abilities for reasons that I won't go into in great detail the ability to sweat liberally was an important innovation in the genus Homo and an early human evolution sweating made it possible for us to lose a lot of internal heat that we build up through muscular activity while we're exercising it in the hot environment so it was a real winner humans can't lose heat through Pantene and other means that other animals use we lose heat from the surface of our skin primarily and so having naked and sweaty skin was really important important also is the fact that through most of human evolution through most of certainly the genus Homo and Homo sapiens evolution naked sweaty skin has been our primary interface with the physical and the social environment it's salutary to reflect on the fact that yes we we're closed today and we live in all these wonderful these wonderful dwellings and work indoors and so forth humans did not have needles to create sewn clothing until 20,000 years ago mostly we were running around with some things perhaps strewn over us or loosely tied around us but mostly we were naked and the skin was our primary interface with the environment that is why we see it undergoing so many dramatic changes that is why it is such a superb object lesson for human evolution and natural selection working in human evolution in the work that we have done and here I referenced the we my husband George Chaplin and I who have worked together on this project for many years George is a GIS professional geographic information system professional and he works in spatial statistics and he was able to really undertake the extensive mapping and statistical work that forms the foundation the empirical foundation for our studies one of the remarkable bodies of evidence that we were able to draw upon in our research was provided by NASA their total ozone mapping spectrometer which still orbits the earth provides wonderful precise data on levels of ultraviolet radiation at the Earth's surface and we specifically George was able to were able to map this in lots of different ways what I've shown here is one map that we created out of literally hundreds that shows annual average ultraviolet radiation at the Earth's surface what you see and these these hot pink and red areas near the equator are the highest areas the cooler tones going into gray are the less intense shades what we can see is a few things firstly that near the equator UV is very very high and in the drier areas near the equator here the Horn of Africa here the in Pat in the atacama desert of Peru as well as some areas in islands Southeast Asia in the middle of the Pacific and here in the Tibetan Plateau weather the pack of atmosphere is very thin over the very high mountains and Plateau we have extremely high levels of ultraviolet radiation but those levels taper off quickly as we get outside of the tropics so that by the time here were around the Mediterranean we have sort of moderate levels of ultraviolet radiation and here in the far northern part of the old world where some humans end up dispersing about 50,000 years ago there's very little this map is the key to understanding the evolution of human skin color ultraviolet radiation is not created equal there are very high intensity rays that are mostly absorbed by the atmosphere and then UVA and UVB that do penetrate the atmosphere to varying extents if we look at the situation at the equator let's say at the autumnal equinox which we just passed the UV is going to be falling or the sun's rays are going to be falling directly on the equator most of the UVC will be absorbed by the atmosphere but some of the UVB is going to pass through the atmosphere to the surface of the earth as is all the UVA along with visible light so at the equator we get this terrifically high load of ultraviolet radiation which is mostly extremely harmful to life on Earth but ultraviolet radiation although we talk about it in mostly negative terms these days was one of the most creative forces in all of biological evolution because all organisms had to adapt to its presence and early organisms on earth had to adapt to extremely intense ultraviolet radiation before the atmosphere was built up so what we have in early members of the genus Homo is naked skin sweaty skin able to lose a lot of body heat through evaporative cooling and mostly dark skin very dark skin imbued with natural sunscreen the pigment you melanin or more simply melanin melanin is nature's sunscreen and it's used lavishly in nature not just by primates but by all sorts of vertebrate creatures including lots of birds and many invertebrates it's one of these molecules and evolution that just gets continually repurposed because it does its job so well it absorbs visible light it also absorbs harmful ultraviolet radiation and so it's recruited over and over and over again humans like their non-human primate relatives can make melanin in abundance in their skin under particular conditions and under conditions under particular genetic conditions and under conditions of high UV our ancestors made lots of protective eumelanin in their skin you melanin is a complex polymer and it's it's incredible it's it actually doesn't really have an end it's sort of like a big long piece of rope and you basically just have to sort of chop it in order to make a piece of eumelanin and it's just fantastic because it not only absorbs ultraviolet radiation and visible light it can also chemically neutralize reactive oxygen species that are formed by solar radiation so it does many kinds of beneficial jobs as a sunscreen in the skin now when the ultraviolet radiation is impinging on the skin this is a this is a diagram that I made with this is the atmosphere here oxygen ozone here's the epidermis of your skin this is darkly pigmented skin where the UVB is actually being attenuated slowed down there is still some passing through but much less UVA is still passing through and is causing quite a bit of damage but what we see here is that the UVB will be slowed down a lot greatly attenuated by the dark pigmentation thus sparing the underlying tissues in the course of our work we collected huge amounts of data on skin color amongst all the world's indigenous peoples we found comparable bodies of data and we did lots of statistics and what we were able to show is basically there is an extremely high correlation between skin colour of indigenous peoples and ultraviolet radiation to the extent that 86% of the total amount of variation in skin color in humans can be accounted for by variations of ultraviolet radiation intensity for those of you are biologists or statisticians you know this is pretty good it pretty good you know we don't get this this kind of statistic very often and it indicates very strongly a cause and effect relationship between intensity of ultraviolet radiation and darkness or lightness of pigmentation now when people first started thinking about reasons for the evolution of skin color they they said oh listen it's got to be down to DNA damage caused by ultraviolet radiation that leads to skin cancer that's got to be it in the 1940s and 50s and early 60s this was the prevalent explanation when any explanations were put forth even before a DNA structure was known it was thought okay the dark pigmentation in human skin protects against skin cancer and then a very clever biologist harold bloom in 1964 wrote a sort of an inconvenient paper because he pointed out listen people get skin cancer when they're passed reproductive age how can this be an evolutionary explanation malignant melanoma the most serious of the skin cancers is extremely rare how can this have a statistical effect and so from the mid 60s onward the explanatory framework for the evolution of skin color more or less unraveled some people ventured parts of hypotheses but a lot remained unexplained and so when I picked up on this years ago I couldn't believe how little was known and I was actually disconcerted by this when I was trying to teach a class about the evolution of skin and skin color I thought how can something that is so important to our lives as physical and social beings not be well known and it's this at this time when I began to realize as a result of reading and some wonderful serendipitous events including listening to a seminar given by a very bright colleague when I realized that the key might be in a place where we never expected that ultraviolet radiation may have an effect on an important vitamin that in turn affects reproductive success what we recognized was that ultraviolet radiation can actually break down various forms of folate the B vitamin that is necessary for DNA production and cell division and the important lecture that I went to that keyed me into this was one on the relationship between folate deficiency and birth defects called neural tube defects and I realized oh my goodness if we have a molecule that is necessary for life for DNA production that's necessary for normal development and it is it is degraded at least in part by ultraviolet radiation this could be a mechanism folate is an amazing important vitamin since the 1980s there has been a lot of fortification of foods especially foods that are going to be eaten by young women and men of reproductive age because it's recognized that folate is incredibly important we get it from whole grains and green leafy vegetables and citrus fruits as well as from fortification and it's required for all of these important processes for actually making DNA for repairing it and for regulating it through the process of methylation now this is you right now you didn't think you looked like this when you were twenty three or twenty six days old as an embryo but this is what you looked like and that precise cell division and choreography of cell movement in the early mammalian including early human embryo is thanks to plentiful cell division fueled by ample amounts of folate being provided from the mothers circulation in if folate stores are inadequate or if folate supplies are inadequate this important neural tube which is the primordial of the nervous system the brain in the spinal cord doesn't fuse properly and so any number of different kinds of birth defects called neural tube defects can be formed the most common of which being spina bifida now almost unheard of but 20 50 years ago especially still very very common almost 70 percent of neural tube defects in humans can be traceable to folate deficiency so we felt that we had the beginnings of an understanding of why skin had evolved a permanent natural sunscreen because it helped to protect folate metabolism and as we have now worked out in in recent work with my colleagues at Penn State we're working on the effects of folate as it determines the vasodilation of arteries in the skin in other words how folate protects us against overheating as well so the main selective force because evolutionary biologists want to know why did something evolve what did it do for an individual so that that individual could have more healthy offspring the primary selective force is to provide protection against UV induced changes in folate availability and when geneticists started working on this problem a little bit after we started what they recognized was that the were several in fact now many genes that contribute to human skin pigmentation they started working on one particular genetic locus the melanocortin one receptor locus which has often been called the key pigmentation gene but it's one of many and what they found was that this particular locus was probably very important in the in the formulation in the development of permanent dark pigmentation in our ancestors and that loss of any variation in this particular gene was actually key to creating dark skin pigmentation the melanocortin one receptor locus determines the configuration of this particular protein on the surface of melon and producing cells and is responsible for making this marvelous eumelanin molecule pheomelanin the yellow red form of melanin is also beautiful and interesting but doesn't have nearly the protective properties and in fact when it's subjected to ultraviolet radiation it actually gives off reactive oxygen species which can be lead to the precursors or damage leading to the precursor of skin cancer so you bill Annan is really the hero of the piece here and so in early homo evolution we have the fixation of the melon a-courtin one receptor locus in early members of the genus Homo right here and all of subsequent early homo and early Homo sapiens evolution in Africa glides onward and people become increasingly dark in parts of Africa that that have very very high concentrations of ultraviolet radiation remember homo sapiens we now know evolved first in Africa about three hundred thousand years ago and all of the salient aspects of our evolutionary history occurred the development of art symbolic language multiple tool types it all happened there when we were undergoing this incredibly dramatic movement around Africa adaptation and increasing dark pigmentation in most of the sunniest latitudes so this is how the hairy timeline ends for modern African people and this is where a few populations begin who subsequently leave Africa because we know that within Africa there are many darkly pigmented as well as moderately and lightly pigmented people and outside of Africa there are lots of people who are lightly pigmented or what I would say is the more accurate term deep pigmented they have lost most of their protective sunscreen UV is mostly harmful your doctors are telling you this all the time slap on the sunscreen wear a hat all the stuff it is mostly harmful but it does one important positive thing which is to begin the process of catalyzing vitamin D formation in the skin specific UVB wavelengths begin the process of converting a cholesterol like precursor in your dermis into pre vitamin d3 and then on to vitamin d3 itself this is all happening very very easily and quickly when your skin is exposed to Sun that has UVB in it now we were talking about this geography let's look back ok and let's let's look at some human dispersals here so humans are are doing all this great stuff for a very very long time for 230,000 years of evolution and after and then we have the beginnings of some dispersal outside of Africa by a few small populations it's really important to remember when we talk about human evolution and Homo sapiens evolution that we're not talking about marauding you know thousands of people going you know over land bridges we're probably talking about dozens or hundreds who were dispersing as they pursued animals that they were hunting what happens when you have a small group of people is that you have a great loss of genetic variability so at all of these major sort of continent hopping events or continent bridging events we have small numbers of people we have founder effect genetic drift happening genes gene pools are greatly lessened and lessened in variation so here humans crossing through the afro Arabian Peninsula some populations going into Southeast Asia fifty to sixty thousand years ago some going into northwestern Europe forty to fifty thousand years ago into northeastern Europe thirty to forty thousand years ago clearly these populations here going into areas of moderate or very low UV and particularly low UVB you can see where we're going here right and where we're going is into the northern hemisphere in winter we're headed in that direction right now now me living in State College I have it much worse than you guys in Houston but still in the middle of the winter UVC completely absorbed just like it was earlier UVB also completely absorbed at the winter solstice in the northern hemisphere although UVA still passes down to the Earth's surface with visible light if there's no UVB in the atmosphere during much of the year there's a problem and that problem has to be solved or else humans can't live there because the UVB is essential for making vitamin D in the skin vitamin D production in the skin by UVB is by far the the most successful way for us to make vitamin D quickly in our bodies and to make large amounts of it vitamin D is essential to human life it's actually a hormone not a vitamin in the strict sense it is a hormone that that has activities on virtually every organ in your body probably some of you have gone to your doctor in the last five years or so in the end the doctor said your vitamin D deficient you've got to do something about it here take some supplements have some very cautious sun exposure but vitamin D deficiency and sufficiency are great effectors of health so when we have very little UVB coming down here we have very little vitamin D formed and this is this is a bleak situation these two guys out in the same level of sunshine the man on the left is going to on a sunny day in the middle of summer be able to make vitamin D in his skin at a rate five to six times faster than the guy on the right by the end of the day they'll both make enough vitamin D in their skin to satisfy their physiological needs but it will happen much faster in the man with slightly deep pigmented skin and it's important to remember that humans during most of prehistory didn't travel during their lifetimes think about it once they dispersed into a particular area they didn't go on vacation right I mean vacations are our cultural productions of the last century for the most part humans stayed put or they would migrate with herds of animals over hundreds or tens of kilometers not like the travel that we engage in today and most time was spent out of doors yes there were caves and and later very simple dwellings but most of the time we spent outdoors again referencing my early comments about skin being the primary interface with the environment without sewn clothing without a roof over our heads and we withstood changes in UV intensity from one season to another because we were outside and in the summer it was sunnier and our skin got darker and in the winter it was less sunny and our skin got lighter and this is regardless of your of your baseline skin pigmentation so what's going on at high latitudes why is vitamin D important vitamin D has multi multi functions the classic function is that it helps it makes it possible for you to absorb calcium and phosphorus from your diet something that is absolutely essential in the maintenance or the the production of your skeleton and your teeth in the first place and the maintenance of your skeleton and teeth and your musculoskeletal system in good shape throughout your life in the absence of adequate vitamin D what we see is now the infamous disease called nutritional rickets which pictured here in some late 19th century kids was became common in many cities during the industrial revolution but occurs occasionally actually quite commonly today in populations in Africa the Middle East and still in some parts of the United States when kids don't get a vitamin D in their diet or they're not exposed to enough Sun to make vitamin D in their skin and if they have the misfortune to be chronically vitamin D deficient when they're growing up and they're female their pelvis can become deformed in such a way that it precludes normal childbirth that is natural selection in action when something occurs that curtails or eliminates reproductive success this is a disaster this leads to extinction unless a change is made we also know that apart from the classical functions of vitamin D that there that there's much more known about the effects of vitamin D on the regulation of the immune system many people are starting to come down with autumnal sniffles as a result in part of lowered vitamin D concentrations in our circulation and vitamin D is really important for for controlling cellular of overgrowth and preventing many kinds of cancers so here we are back in me back in our beautiful map so here look at all these these areas in the northern hemisphere and these early or sort of mid mid road Homo sapiens some of them are headed up here headed over there how is this going to work it's not going to work at all with darkly pigmented skin because darkly pigmented skin in the absence of dietary vitamin D is going to mean very very poor bones very poor health outcomes and probably extirpation or extinction of a population within a few generations so what we see in humans that are dispersing into these high latitudes are a combination of biological and cultural adaptations this is the quintessential human evolution story biology and culture working together over the course of a hundreds of thousands of years to create us today so these biological and cultural adaptations are now becoming much clearer as the result of exquisite genetic and genomic work as well as the work done by anatomist and physiologist like myself and what we have described is is something that we call the vitamin D compromise that includes skin deep pigmentation in the populations that led to Northwestern Europeans and East Asians and what's really cool about this if you're an evolutionary biologist when something like this happens you get very excited but you get even more excited when you realize that different groups of genes that affect skin pigmentation were underwent mutations in order to produce the deep pigmentation effect in other words the natural selection was so strong that whatever variation in whatever pigmentation genes that could produce depigmentation were recruited that is really cool I get very you could see I get very excited about this and we also know too that to the best of our knowledge similar changes occurred in the ancestors of some Neanderthals independently again an example of parallel evolution of deep pigmentation in hominins living under reduced UV conditions to be more conducive to vitamin D production in the skin so here we have the just the opposite of our story of of photo protection under high UV we have many genetic loci associated with deep pigmentation under strong positive selection to make vitamin D in the skin so here we are in a promoting vitamin D production under low or highly seasonal UV conditions where do we see some of the most extreme examples of this vitamin D compromise you can't get a more or almost any more low light and cloudy and low UV and environment than Scotland and here in Scotland we see individuals with some of the most highly deep pigmented skin and that wasn't enough to keep them healthy in order to live under such low UV conditions even in the summer they had to supplement their diets with vitamin D rich foods and not just supplement the vitamin D rich foods like cod fish and cod liver had to form the core the staple foods of the diet what we see throughout the northern part of the northern hemisphere is a dependence of people on vitamin D rich foods requiring the technology of course to harvest them in the first place so deep pigmented skin plus harvesting vitamin D rich foods a bio cultural compromise to allow people to live at extremely high latitudes the vitamin D compromise also involved genes that affect vitamin D metabolism and and it's production in the skin which is really interesting vitamin D rich diet and so when we when we look at skin pigmentation we know that it's strongly related to ultraviolet radiation intensity but it really is a compromise between the two conflicting evolutionary forces of photo protection protect against intense UV near the equator and photosynthesis of vitamin D closer to the poles these two lines meeting together in the mid-latitudes what people do we find here in the mid latitudes in the circum Mediterranean and in the Far tip of South Africa and in much of the Neotropics we find people who have moderately pigmented and highly Tana Belen people who can gain a lot of pigmentation and lose a lot of pigmentation according to the intensity of UV in the sunlight and the genetics of skin pigmentation continue to unfold and amaze tanning as an ability has evolved from multiple genetic substrates multiple times similar skin colors both deep pigmented darkly pigmented and highly tenable skin colors have evolved multiple times independently under the same UV conditions very very very beautiful evolutionary biology and importantly is that we see similar skin tones evolving independently of other traits so when we think about oh yeah well how is that skin tone related to hair color and hair texture and eye color well basically from a genetic perspective almost completely unrelated so we have skin pigmentation genes evolving entirely or mostly entirely independently of genes that determine other aspects of our physical appearance so think about this in terms of the classic definition of races this is something I work on all the time how do people think about race they think about these discrete packages of biological and even behave Averill traits these packages don't exist in life these packages these discrete boundaries packages of genes don't exist and I'm happy to say that that our work on the evolution of skin pigmentation has helped to push this whole area of inquiry about the origins of human diversity and how we talk about it forward this is a discussion that we all have to have how we got to look how how we are is a fantastically interesting story any humans now look at in beautiful plenitude in every shade of the sepia rainbow all over the world as they've dispersed undergone deep pigmentation repigmentation tanning untanned just an amazing array you have skin you can teach human evolution and natural selection using your skin when when teachers talk to me about you know how can I teach evolution in my classroom I say listen one of the best ways available now is using it the story of your own body your own skin color this is the teaching tool that you carry with you cheap available perfect use it it's an excellent example of natural selection acting on the human body we are mammals primates just like the rest of them subjected to the forces of evolution and conspiring with culture doing much of our evolution our recent evolution to come up with all of these wild and wacky compromises that allow us to live in the extremities of the environment on the Earth's surface skin color has tremendous numbers of implications tremendous for our health and social well-being we pay attention to color color is important for us we can't help but see color that's one of the beauties of being an old-world higher primate is that we have trichromatic color vision but the fact that we see it doesn't mean that we judge it the bald assessment of color is completely neutral and free of any judgement we only a fix a value to color through behavior through acculturation through exposure to people who have views about color I'd like and this is one of the illustrations from my kids book I like to talk about the conditions that existed for much of the time in in ancient Egypt as people lived along the extent of the Nile from areas right on the Mediterranean here with moderate levels of UV to areas here in the in the tip of the red sea close to the tip of the red sea in northern Sudan with very very high levels of ultraviolet radiation so along the the upper oops sorry the upper and the lower Nile we see this tremendous gradient of UV radiation and this tremendous gradient of skin color among the various peoples and pharaohs of of the of dynastic and pre-dynastic Egypt people living along the Nile traded with one another regularly they saw the difference in skin color they depicted it in art it along in in sarcophaguses and in other murals along the Nile but color did not distinguish one group from another in terms of anything but the bear color there was no value associated with color for us living in the United States right now it's almost unfathomable to think that there was a time in human history and in fact most of human history when we affixed no value to skin color we had no there were no connotations of skin color but in fact that is the case humans are very very good at discriminating according to language and dress and you know perceived barbarity but for most of human history those boundaries were not drawn on the basis of skin color so here I like to quote to look at the Persian Empire and all of these different empires here that were described in 540 BC really really interesting time in human history when humans were lived in cities when they were extremely sophisticated literate well-read and people were of all different colors language groups and backgrounds they distinguished one from another but not on the basis of skin color so that you would have people with very dark or very light skin that were equally considered barbarians for instance by the the Greeks this is I think a fascinating and again very beneficial thing to reflect on that we're very good at making groups out of humans us and them groups but the kinds of groups that we created in the mid 1700s the so called races of humans were created by a few guys on the basis of their own opinions they were not created on the basis of of ancient patterns of color based discrimination caryl Linnaeus the founder of modern systematics first described humans in four different varieties that he didn't call races he called them varieties and he didn't rank them but he said basically you've got white Europeans you have red Americans you have brown Asians and black Africans so 1748 very very simple that's how he describes them and he's got humans and lots of other primates and lots of plants and other mammals and it's it's a you know he's he's doing a lot of basic systematics ten years later after he reads a lot more travelers accounts of human variation including variation in behavior brought back by explorers we have Linnaeus talking about people who have different color okay so here Americans read but they have a choleric disposition Europeans white sanguine Asians Brown Melancholy blacks Africans black and phlegmatic where did he get this this is stuff that he is taking from the old climatic theories of ancient Greek times and unusual for him making a scientific explanation of diversity that includes pejorative terms pejorative references of behavior over time things just get a bit more exaggerated Immanuel Kant one of the foremost philosophers of Western civilization was fascinated with problems of human diversity and in 1775 wrote a series well began a series of essays on the different human races and he continued this through the early part of his career because he was trying to understand the physical appearance of humans was associated with their potential for moral behavior and the development of civilization and he was convinced that color was the key to understanding this it's beneficial to reflect on the fact that can't hardly ever left his sitting room a very very erudite man brilliant absolutely superb philosopher in many of his writings but when it came to understanding human diversity he only heard secondhand third-hand and hearsay reports and he had very strong opinions about who was better than whom he created and Kant was the first one to create four distinct races that he referred to as races that had no mixing in between them no no sort of Gray's of it as it were between these races that they were completely separate entities unmixable and that they had different capacities for civilization and of course his race was on top god and his Scottish counterpart David Hume had very similar thoughts and they had very similar data to go on they received information from travelers tales explorers that was very poor quality compared to the information we have today on human diversity and they made very clear judgments about people who were not Europeans David Hume said there was never a civilized nation of any complexion other than white these were that the hot cue the Hume can't view was tremendously influential they both held that races were physically and culturally distinct from one another and that the white race was supreme now this paradigm as we could say had tremendous effects remember where are we in history we're in the middle of the 1700s what else is going on here unfortunately a lot both of these guys were very highly regarded their books were widely distributed there were printing presses books were precious but they were widely distributed they were widely distributed throughout Europe and into the American colonies their writings were favored by scholars and statesmen including the founding of the so called founding fathers of the United States and all of this happened at a time when the transatlantic slave trade was going great guns and was under fire in England the abolitionist movement was beginning to grow and there were calls for the abolition of the slave trade which had already been going on for 250 years but if you have what I would now call pseudo-scientific accounts of races and racial hierarchies such as those propounded by Contin Hume what is this going to do to the transatlantic slave trade it's going to support it how convenient have pseudoscience supporting a completely completely bankrupt in inhumane trade in human lives and we have the same kind of pseudoscience that bolsters some pseudo religious accounts the biblical defense of slavery among many other written in the early and mid 1800s that takes these these so-called races of humans that have been described puts them in a clear hierarchy and and indicates that some humans especially Africans are destined following the curse of ham to serve other humans very convenient if you want to promote the slave trade and maintain slavery after the slave trade is officially abolished in England the slave trade was a pernicious trade in human beans that resulted in 14 million mostly West coastal Africans moving to Europe the new world in large numbers to South America and the Caribbean smoked much smaller numbers to North America but this was an absolutely absolutely horrible trade that was created on the back of racial hierarchies and maintained so we have race definitions that begin to be formulated by men with incomplete data but lots of attitude in the mid 1700s leading to quickly the formation of racial stereotypes in this country and elsewhere and the formation of what I call color memes that we associate particular skin colors with particular patterns of behavior creating the psychosocial template for racism excuse me we can see this in our history we can see this in world history we can see it just as clear as we can see the evolutionary biology now what can we do about it what we can do is we can work to teach kids about these different facts of evolutionary biology and the origin of human diversity and skin color and the origin of the fallacy of physical races I don't want to be so bold as to say we can tell kids that race doesn't exist race is a social construct a nine-year-old doesn't know what a social construct is but what we can tell them is that the idea of race was created by some guys who had very very inadequate data and lots of attitude and lots of bigotry old-fashioned bigotry and should we listen to them now should our modern history be forged by the fallacies perpetuated 250 years ago no when we teach this book to kids and in our summer camps what we have are kids who learn about the evolution of skin color and the history of racial types created on skin color and they say what's the fuss about this is something this is a product of evolution and these guys were wrong why are we here that's my question for you why can't we get this information in our schools and this is what I spend my days doing now the book that you just saw there is the book that we wrote this is my South African co-author Cindy who am I gonna my my friend and illustrator Lynn Fellman this book was published in South Africa we're trying desperately to find a publisher to bring it out in the States I'm all ears and in our summer camps we have kids who work on their own jeans who look at their own skin and try to figure out what's going on this this finding your roots curriculum I've been working on it for nearly 10 years now with Henry Louis Gates Jr from Harvard and many other wonderful collaborators geneticists sociologists historians bioethicists evolutionary biologists it's a great group now over 40 strong have contributed to this this marvelous curriculum we've had grants support from the Rockefeller and Robert Wood Johnson foundations and we've had an excellent run of summer camps during which kids study their own DNA their own pigmentation genes their own relatedness they explore their own genealogy they look at their deep history they look at life under the microscope in various ways they learn about their own physiology it's absolutely fantastic if you go to this website wlwt's classroom org you can watch a series of eight soon-to-be nine videos that show our kids in action you can do this in your home and in your classroom you can do this in your after-school program or your summer camp we have the curriculum ready for you to download free everything's there for you to do this anywhere you want skin color is a beautiful evolutionary adaptation and needs to be celebrated by all humans as just that it doesn't divide us it unites us it is the most beautiful and effective product of human evolution on the human body a wonderful teaching tool something to be absolutely celebrated I want all of you to do it I want all of you to go out tell your families and friends about this and just spread the word because the world will be a little bit better place with this knowledge about our evolution and our history thank you very much [Applause] you

Channel: TheLeakeyFoundation

Views: 6,352

Rating: 4.7419353 out of 5

Keywords: skin color, science, Nina Jablonski, The Leakey Foundation, Leakey Foundation, lecture, anti-racism education, Houston Museum of Natural Science

Id: sc4OFcT5m1Y

Length: 64min 24sec (3864 seconds)

Published: Wed Aug 05 2020