Interestingly, Charles Darwin was born a very lightly pigmented man, in a moderately-to-darkly pigmented world. Over the course of his life, Darwin had great privilege. He lived in a fairly wealthy home. He was raised by very supportive and interested parents. And when he was in his 20s he embarked upon a remarkable voyage on the ship the Beagle. And during the course of that voyage, he saw remarkable things: tremendous diversity of plants and animals, and humans. And the observations that he made on that epic journey were to be eventually distilled into his wonderful book, "On the Origin of Species," published 150 years ago.
Zanimljivo, Charles Darwin se rodio kao čovjek jako svijetlog pigmenta, u umjereno do tamno pigmentiranom svijetu. Tijekom svog života, Darwin je imao velike privilegije. Živio je u dosta bogatom domu. Odgojili su ga roditelji puni potpore i brige. I kad je bio u svojim 20-ima odvažio se na značajno putovanje brodom Beagle. I tijekom tog putovanja, vidio je znamenite stvari: golemu raznolikost biljki i životinja, i ljudi. I primjedbe koje je stekao na tom epskom putovanju su se s vremenom razvile u njegovu divnu knjigu, "O porijeklu vrsta", objavljenu prije 150 godina.
Now what is so interesting and to some, the extent, what's a bit infamous about "The Origin of Species," is that there is only one line in it about human evolution. "Light will be thrown on the origin of man and his history." It wasn't until much longer, much later, that Darwin actually spoke and wrote about humans.
Sad, ono što je tako zanimljivo i što je, u neku ruku, pomalo ozloglašeno o "Porijeklu vrsta", je da je tamo samo jedan redak o ljudskoj evoluciji. "Svjetlo će biti bačeno na porijeklo čovjeka i njegovu povijest." Tek puno kasnije, puno kasnije je Darwin zapravo progovorio i pisao o ljudima.
Now in his years of traveling on the Beagle, and from listening to the accounts or explorers and naturalists, he knew that skin color was one of the most important ways in which people varied. And he was somewhat interested in the pattern of skin color. He knew that darkly pigmented peoples were found close to the equator; lightly pigmented peoples, like himself, were found closer to the poles.
Za vrijeme putovanja na Beagleu, i slušajući izvještaje istraživača i prirodoslovaca, znao je da je boja kože jedan od najvažnijih načina u kojima se ljudi razlikuju. I bio je donekle zainteresiran za obrazac boje kože. Znao je da se tamno pigmentirani ljudi nalaze blizu ekvatora, svijetlo pigmentirani ljudi, poput njega samoga, su bili bliže polovima.
So what did he make of all this? Well he didn't write anything about it in The Origin of Species. But much later, in 1871, he did have something to say about it. And it was quite curious. He said, "Of all the differences between the races of men, the color of the skin is the most conspicuous and one of the best marked." And he went on to say, "These differences do not coincide with corresponding differences in climate." So he had traveled all around. He had seen people of different colors living in different places. And yet he rejected the idea that human skin pigmentation was related to the climate.
I što je zaključio iz svega ovoga? Pa, nije ništa o tome napisao u Porijeklu vrsta. Ali mnogo kasnije, 1871., imao je nešto za reći o tome. I to je bilo poprilično zanimljivo. Rekao je, "Od svih razlika između rasa čovjeka, boja kože je najizraženija i jedna od najbolje označenih." I nastavio je, "Ove razlike se ne događaju u skladu s odgovarajućim razlikama u klimi." Dakle, putovao je svugdje okolo. Vidio je ljude različitih boja koji žive u različitim mjestima. Pa ipak je odbacio ideju da je pigmentacija ljudske kože povezana s klimom.
If only Darwin lived today. If only Darwin had NASA. Now, one of the wonderful things that NASA does is it puts up a variety of satellites that detect all sort of interesting things about our environment. And for many decades now there have been a series of TOMS satellites that have collected data about the radiation of the Earth's surface. The TOMS 7 satellite data, shown here, show the annual average ultraviolet radiation at the Earth's surface. Now the really hot pink and red areas are those parts of the world that receive the highest amounts of UV during the year. The incrementally cooler colors -- blues, greens, yellows, and finally grays -- indicate areas of much lower ultraviolet radiation.
Da je Darwin barem živio danas. Da je Darwin barem imao NASA-u. Sad, jedna od divnih stvari koje NASA čini je da postavlja razne satelite koji otkrivaju svakakve zanimljive stvari o našem okolišu. I sad već mnogo desetljeća postoji serija satelita TOMS koji su skupljali podatke o radijaciji na površini Zemlje. Podaci satelita TOMS 7, pokazani ovdje, pokazuju godišnji prosjek ultraljubičastog zračenja na površini Zemlje. Sad, stvarno vruće ružičasta i crvena područja su oni dijelovi svijeta koji dobivaju najveći dio UV zračenja tijekom godine. Dodavanjem hladnijih boja -- plave, zelene, žute, i konačno sive -- pokazuju se područja mnogo nižeg ultraljubičastog zračenja.
What's significant to the story of human skin pigmentation is just how much of the Northern Hemisphere is in these cool gray zones. This has tremendous implications for our understanding of the evolution of human skin pigmentation. And what Darwin could not appreciate, or didn't perhaps want to appreciate at the time, is that there was a fundamental relationship between the intensity of ultraviolet radiation and skin pigmentation. And that skin pigmentation itself was a product of evolution. And so when we look at a map of skin color, and predicted skin color, as we know it today, what we see is a beautiful gradient from the darkest skin pigmentations toward the equator, and the lightest ones toward the poles.
Ono što je značajno za priču o pigmentaciji ljudske kože je to koliko se zapravo sjeverne polutke nalazi u ovim sivim zonama. Ovo ima ogroman utjecaj na naše razumijevanje evolucije pigmentacije ljudske kože. I ono što Darwin nije mogao cijeniti, ili možda želio cijeniti u to vrijeme, je da postoji fundamentalna veza između intenziteta UV zračenja i pigmentacije kože. I da je sama pigmentacija kože rezultat evolucije. I tako kad pogledamo kartu boje kože, i predvidimo boju kože, kako je znamo danas, ono što vidimo je predivna gradacija od najtamnije pigmentacije prema ekvatoru, do najsvjetlije prema polovima.
What's very, very important here is that the earliest humans evolved in high-UV environments, in equatorial Africa. The earliest members of our lineage, the genus Homo, were darkly pigmented. And we all share this incredible heritage of having originally been darkly pigmented, two million to one and half million years ago.
Ono što je jako, jako važno u tome je da su najraniji ljudi evoluirali u okolišu visokog UV-a, u ekvatorijalnoj Africi. Najraniji članovi našeg porijekla, rod Homo, su bili tamnog pigmenta. I svi dijelimo ovo nevjerojatno nasljedstvo da smo originalno bili tamnog pigmenta, prije dva milijuna do milijun i pol godina.
Now what happened in our history? Let's first look at the relationship of ultraviolet radiation to the Earth's surface. In those early days of our evolution, looking at the equator, we were bombarded by high levels of ultraviolet radiation. The UVC, the most energetic type, was occluded by the Earth's atmosphere. But UVB and UVA especially, came in unimpeded. UVB turns out to be incredibly important. It's very destructive, but it also catalyzes the production of vitamin D in the skin, vitamin D being a molecule that we very much need for our strong bones, the health of our immune system, and myriad other important functions in our bodies.
Sad, što se dogodilo u našoj povijesti? Pogledajmo najprije vezu između ultraljubičastog zračenja i površine Zemlje. U onim ranim danima evolucije, gledajući na ekvator, bili smo bombardirani visokim razinama UV zračenja. UVC, najenergičniji tip, je odbijala Zemljina atmosfera. Ali UVB i posebno UVA su nesmetano ulazili. Ispostavilo se da je UVB nevjerojatno važan. Veoma je destruktivan, ali također ubrzava proizvodnju vitamina D u koži, s time da je vitamin D molekula koja je jako potrebna za naše snažne kosti, zdravlje imunosustava, i mnoštvo drugih važnih funkcija u našim tijelima.
So, living at the equator, we got lots and lots of ultraviolet radiation and the melanin -- this wonderful, complex, ancient polymer compound in our skin -- served as a superb natural sunscreen. This polymer is amazing because it's present in so many different organisms. Melanin, in various forms, has probably been on the Earth a billion years, and has been recruited over and over again by evolution, as often happens. Why change it if it works?
Tako, živeći na ekvatoru, primili smo mnogo mnogo ultraljubičastog zračenja i melanin -- ovaj divan, kompleksan, prastari polimerni spoj u našoj koži -- je služio kao nadmoćna prirodna zaštita od sunca. Ovaj polimer je sjajan zato što je prisutan u tako mnogo različitih organizama. Melanin, u različitim oblicima, je vjerojatno bio na Zemlji milijardu godina, i iznova i iznova se koristio u evoluciji, kako to često biva. Zašto mijenjati ako radi?
So melanin was recruited, in our lineage, and specifically in our earliest ancestors evolving in Africa, to be a natural sunscreen. Where it protected the body against the degradations of ultraviolet radiation, the destruction, or damage to DNA, and the breakdown of a very important molecule called folate, which helps to fuel cell production, and reproduction in the body. So, it's wonderful. We evolved this very protective, wonderful covering of melanin.
Tako se melanin koristio, u našem porijeklu, i posebno kod naših najranijih predaka koji su evoluirali u Africi, kao prirodna zaštita od sunca. Tamo gdje je štitio tijelo od štete od ultraljubičastog zračenja, raspad, ili šteta na DNK, i slom veoma važnih molekula zvanih folat, koja pomaže u pogonu proizvodnje stanica, i reprodukciji tijela. Tako, to je divno. Razvili smo ovu jaku zaštitu, predivnu pokrivenost melaninom.
But then we moved. And humans dispersed -- not once, but twice. Major moves, outside of our equatorial homeland, from Africa into other parts of the Old World, and most recently, into the New World. When humans dispersed into these latitudes, what did they face? Conditions were significantly colder, but they were also less intense with respect to the ultraviolet regime.
Ali onda smo se preselili. I ljudi su se raspršili -- ne jednom, nego dvaput. Velika kretanja, van naše ekvatorijalne domovine, iz Afrike u druge dijelove Starog svijeta, i najkasnije, u Novi svijet. Kad su se ljudi raspršili u ove zemljopisne širine, sa čim su se suočili? Uvjeti su bili puno hladniji, ali i manje intenzivni po pitanju ultraljubičastog sustava.
So if we're somewhere in the Northern Hemisphere, look at what's happening to the ultraviolet radiation. We're still getting a dose of UVA. But all of the UVB, or nearly all of it, is dissipated through the thickness of the atmosphere. In the winter, when you are skiing in the Alps, you may experience ultraviolet radiation. But it's all UVA, and, significantly, that UVA has no ability to make vitamin D in your skin.
Pa ako smo bili negdje u sjevernoj polutci, pogledajte što se događa s ultraljubičastim zračenjem. Još dobivamo dozu UVA. Ali sav UVB, ili gotovo sav, se rasipa kroz gustoću atmosfere. Zimi, kad skijate u Alpama, možda iskusite ultraljubičasto zračenje. Ali to je sve UVA, i, značajno, taj UVA nema mogućnosti proizvoditi vitamin D u vašoj koži.
So people inhabiting northern hemispheric environments were bereft of the potential to make vitamin D in their skin for most of the year. This had tremendous consequences for the evolution of human skin pigmentation. Because what happened, in order to ensure health and well-being, these lineages of people dispersing into the Northern Hemisphere lost their pigmentation. There was natural selection for the evolution of lightly pigmented skin.
Tako da ljudi koji nastanjivaju područja sjeverne polutke su ostali bez potencijala da proizvode vitamin D u svojoj koži većinu godine. Ovo je imalo goleme posljedice za evoluciju pigmentacije ljudske kože. Zbog tog što se dogodilo, da bi se osigurali zdravlje i dobrobit, one linije ljudi koje su se raspršile u sjevernu polutku, su izgubile pigmentaciju. Na djelu je bila prirodna selekcija za evoluciju svijetlo pigmentirane kože.
Here we begin to see the evolution of the beautiful sepia rainbow that now characterizes all of humanity. Lightly pigmented skin evolved not just once, not just twice, but probably three times. Not just in modern humans, but in one of our distant unrelated ancestors, the Neanderthals. A remarkable, remarkable testament to the power of evolution. Humans have been on the move for a long time. And just in the last 5,000 years, in increasing rates, over increasing distances. Here are just some of the biggest movements of people, voluntary movements, in the last 5,000 years.
Ovdje počinjemo vidjeti evoluciju predivne duge u sepiji koja je sad karakteristična za ljudsku vrstu. Svijetlo pigmentirana koža je evoluirala ne samo jednom, ne samo dvaput, već vjerojatno tri puta. Ne samo kod modernih ljudi, nego i u jednog od predaka s kojima nismo u srodstvu, Neandertalaca. Značajan, značajan prilog moći evolucije. Ljudi su bili u pokretu dugo vremena. I samo u zadnjih 5.000 godina, u povećanoj mjeri, preko sve većih udaljenosti. Ovdje su samo neki od najvećih seoba ljudi, dobrovoljna preseljenja, u posljednjih 5.000 godina.
Look at some of the major latitudinal transgressions: people from high UV areas going to low UV and vice versa. And not all these moves were voluntary. Between 1520 and 1867, 12 million, 500 people were moved from high UV to low UV areas in the transatlantic slave trade. Now this had all sorts of invidious social consequences. But it also had deleterious health consequences to people.
Pogledajte neke od glavnih transgresija u zemljopisnoj širini: ljudi iz područja visokog UV-a idu u područja niskog UV-a i obrnuto. I nisu sva ova kretanja dobrovoljna. Između 1520. i 1867., 12 milijuna, 500 ljudi se preselilo iz visokog UV-a u područja niskog UV-a u prekoatlantskoj trgovini robljem. Ovo je pak imalo svakakve zlokobne društvene posljedice. Isto tako je imalo poguban utjecaj na zdravlje ljudi.
So what? We've been on the move. We're so clever we can overcome all of these seeming biological impediments. Well, often we're unaware of the fact that we're living in environments in which our skin is inherently poorly adapted. Some of us with lightly pigmented skin live in high-UV areas. Some of us with darkly pigmented skin live in low-UV areas. These have tremendous consequences for our health.
Pa što? Selili smo se. Bili smo tako pametni i nadišli sve ove prividne biološke prepreke. Pa, često nismo svjesni činjenice da živimo u okolišu u kojem je naša koža nasljedno slabo prilagođena. Neki od nas sa svjetlije pigmentiranom kožom žive u područjima visokog UV-a. Neki od nas s tamnije pigmentiranom kožom žive u područjima niskog UV-a. Ovo ima goleme posljedice na naše zdravlje.
We have to, if we're lightly pigmented, be careful about the problems of skin cancer, and destruction of folate in our bodies, by lots of sun. Epidemiologists and doctors have been very good about telling us about protecting our skin. What they haven't been so good about instructing people is the problem of darkly pigmented people living in high latitude areas, or working inside all the time.
Moramo, ako smo svijetlije pigmentirani, biti oprezni zbog problema s rakom kože, i uništavanjem folata u našem tijelu, zbog puno sunca. Epidemiolozi i doktori su bili jako dobri i rekli nam da zaštitimo svoju kožu. Ali nisu bili tako dobri pri upućivanju ljudi u problem s tamno pigmentiranim ljudima koji žive u područjima visoke zemljopisne širine, koji rade u zatvorenom cijelo vrijeme.
Because the problem there is just as severe, but it is more sinister, because vitamin D deficiency, from a lack of ultraviolet B radiation, is a major problem. Vitamin D deficiency creeps up on people, and causes all sorts of health problems to their bones, to their gradual decay of their immune systems, or loss of immune function, and probably some problems with their mood and health, their mental health.
Zato što je tu problem jednako ozbiljan, ali je i zlokobniji, zbog nedostatka vitamina D, zbog nedostatka ultraljubičastog B zračenja, što je glavni problem. Nedostatak vitamina D se prikrada ljudima, i uzrokuje razne zdravstvene probleme s kostima, do postupnog raspada imuno sustava, ili gubitka imunološke funkcije, i vjerojatno nekih problema s raspoloženjem i zdravljem, njihovim mentalnim zdravljem.
So we have, in skin pigmentation, one of these wonderful products of evolution that still has consequences for us today. And the social consequences, as we know, are incredibly profound. We live in a world where we have lightly and darkly pigmented people living next to one another, but often brought into proximity initially as a result of very invidious social interactions. So how can we overcome this? How can we begin to understand it? Evolution helps us.
Tako imamo, u pigmentaciji kože, jedan od ovih divnih proizvoda evolucije koji i dan danas ima posljedice za nas. I društvene posljedice su, kako znamo, jako duboke. Živimo u svijetu gdje imamo svijetlo i tamno pigmentirane ljude koji žive jedni do drugih, ali često su dovedeni blizu počevši kao rezultat veoma zlokobnih ljudskih interakcija. Pa kako možemo nadići ovo? Kako možemo početi to razumijevati? Evolucija nam pomaže.
200 years after Darwin's birthday, we have the first moderately pigmented President of the United States. (Applause) How wonderful is that? (Applause) This man is significant for a whole host of reasons. But we need to think about how he compares, in terms of his pigmentation, to other people on Earth. He, as one of many urban admixed populations, is very emblematic of a mixed parentage, of a mixed pigmentation. And he resembles, very closely, people with moderate levels of pigmentation who live in southern Africa, or Southeast Asia.
200 godina nakon Darwinova rođendana, imamo prvog umjereno pigmentiranog predsjednika SAD-a. (Pljesak) Zar to nije divno? (Pljesak) Ovaj čovjek je značajan zbog velikog mnoštva razloga. Ali moramo razmisliti kako on stoji u usporedbi, s obzirom na svoju pigmentaciju, s drugim ljudima na Zemlji. On, kao jedan od mnogih urbanih miješanih populacija, je jako dobar primjer miješanih roditelja, miješane pigmentacije. I jako nalikuje, jako blizu, ljudima s umjerenom razinom pigmentacije koji žive u južnoj Africi, ili jugozapadnoj Aziji.
These people have a tremendous potential to tan, to develop more pigment in their skin, as a result of exposure to sun. They also run the risk of vitamin D deficiency, if they have desk jobs, like that guy. So lets all wish for his great health, and his awareness of his own skin pigmentation.
Ovi ljudi imaju ogroman potencijal da potamne, da razviju više pigmenta u svojoj koži, kao rezultat izlaganja suncu. Također su pod rizikom nedostatka vitamina D, ako imaju uredske poslove, kao taj čovjek. Pa poželimo mu svi odlično zdravlje, i da bude svjestan svoje pigmentacije kože.
Now what is wonderful about the evolution of human skin pigmentation, and the phenomenon of pigmentation, is that it is the demonstration, the evidence, of evolution by natural selection, right on your body. When people ask you, "What is the evidence for evolution?" You don't have to think about some exotic examples, or fossils. You just have to look at your skin.
Ono što je divno u evoluciji pigmentacije ljudske kože, i fenomenu pigmentacije, je da demonstrira, da je dokaz evolucije prirodnim odabirom, upravo na vašem tijelu. Kad vas ljudi pitaju: "Koji je dokaz evolucije?" Ne morate razmišljati o nekom egzotičnom primjeru, ili fosilima. Samo morate pogledati na svoju kožu.
Darwin, I think, would have appreciated this, even though he eschewed the importance of climate on the evolution of pigmentation during his own life. I think, were he able to look at the evidence we have today, he would understand it. He would appreciate it. And most of all, he would teach it.
Darwin bi, mislim, ovo cijenio, iako mu je izmakla važnost klime na evoluciju pigmentacije tijekom njegova života. Mislim, da je mogao pogledati na dokaze koje imamo danas, da bi razumio. Cijenio bi to. I najvažnije, poučavao bi to.
You, you can teach it. You can touch it. You can understand it. Take it out of this room. Take your skin color, and celebrate it. Spread the word. You have the evolution of the history of our species, part of it, written in your skin. Understand it. Appreciate it. Celebrate it. Go out. Isn't it beautiful? Isn't it wonderful? You are the products of evolution. Thank you. (Applause)
Vi, vi to možete poučavati. Možete to dotaknuti. Možete to razumjeti. Odnesite to iz ove sobe. Uzmite svoju boju kože, i slavite je. Raširite vijest. Imate evoluciju povijesti naše vrste, dio toga, ispisan na vašoj koži. Razumite. Cijenite. Slavite. Idite van. Zar nije predivno? Zar nije prekrasno? Vi ste proizvod evolucije. Hvala vam. (Pljesak)