uh [Music] [Music] uh it was perfect but the boys knocked out some of the teeth throwing stones at it how much quantico i wonder why these creatures no longer exist perhaps the ark was too small to allow them entry and they perished in the flood [Laughter] what is there to laugh oh nothing nothing do you mock me or the bible oh neither [Music] what sort of clergyman will you be mr darwin dreadful dreadful and god said let the waters bring forth abundantly the moving creature that hath life and foul that may fly above the earth in the open firmament of heaven and god created great whales and every living creature that moveth hello what are you doing here [Music] god [Music] if i were to give a prize for the single best idea anybody ever had i'd give it to darwin for the idea of natural selection ahead of newton ahead of einstein because his idea unites the two most disparate features of our universe the world of purposeless meaningless matter in motion on the one side and the world of meaning and purpose design on the other [Music] he understood that what he was proposing was a truly revolutionary idea [Music] the darwinian revolution is about who we are it's what we're made of it's what our life means insofar as science can answer that question so it in many ways was the singularly deepest and most discombobulating of all discoveries that science has ever made in darwin's day the idea of evolution was regarded as highly unorthodox because it went against all of natural history in great britain it jeopardized the standing of science it did jeopardize the standing of a stable society the bible and the church as well darwin kept his thoughts to himself for many years and agonized over the problem if it ever got out that he was doing something that ran slap counter to establish science would ruin his career ruin his reputation he was a respectable man with a dangerous theory [Music] [Music] did you never get your sea legs it's not once in five years whenever the sea was up so is the contents of my stomach what a delightful thought we should be able to squeeze 400 a year out of the governor why what's he said he hasn't said anything but i've seen it in his eyes the way he poured over your letters a very proud father i told him you were going to publish a journal of your travels there was a definite flicker of interest published yes of course no country parsonage for you my boy you're under my wing now i'll take charge of your affairs introduce you to all my clever witty friends betrayed on your your celebrity celebrity certainly everyone wants to meet you hear stories of naked tahitian women and giant slobs or whatever captain fitzroy this is my brother erasmus mr darwin captain good god a man can collect a lot of rubbish in five years it's a wonder you didn't sink the ship charles named i take it after your grandfather yes and an uncle who drowned himself in the river derwent and are you a free thinker like him i'm more of a free drinker really [Music] and how was the voyage for you captain that's not for me to say no 40 views of the coast as seen from the sea 80 plans of harbors and 82 coastal maps all for the hydrographic department of the admiralty bravo dinner at sea must have been a jolly affair yeah from the galapagos islands humor roasted over an open fire rather like veal armadillo roasted in its shell a lot like duck tortoise of course some of them weigh as much as 500 pounds one i measured was uh 96 inches around the waist if one of them ever needs a suit of clothes we must send it to fathers taylor what else uh llama ostrich people wonder how it is some animals come to be extinct now we have the answer eaten by charlie darwin you look as though you're going to the scaffold dignity toys smile remember all eyes are on you the judging has begun mr president my lords ladies and gentlemen no no no start with a bang of athens what friends romans countrymen that sort of thing right i can't do this yes you can you mustn't let the fact that every leading geologist in the land will be there puts you off oh god now let me hear an interesting bit there aren't any the earthquakes oh stand still and don't wave your arms around like that leave your tyre alone don't squint and speak up the earthquake ran for 400 miles along the coast accompanied by the simultaneous eruption of a line of volcanoes we found fresh mussel beds lying above high tide the shellfish all dead the land had risen eight feet mountains must be the product of thousands and thousands of such rises occurring again and again throughout history even at the very crest of the andes we found marine remains the fossilized shells of creatures that once crawled about at the bottom of the sea elevated nearly 14 000 feet above its level time unimaginable tracks of time is the key [Music] [Applause] splendid thank you thank you very much congratulations interesting paper thank you where have you placed your fossil specimens i was thinking of the british museum ah you're happy to have them languish in some dusty bloomsbury cellar no not at all you'd better let me look over them for you then we'll let you know thank you tom soph who does he think he is he thinks he's richard owen the most brilliant anatomist and you're erasmus darwin's little brother darwin of the beagle darwin lord it while you can i don't want to lord it liar what a brilliant red brighter than the actual plumage i try to allow for the loss of color that comes with death and can you do this with my galapagos birds i haven't finished identifying them yet mr darwin i do know that you're wren is a finch your gross beak is a finch even your black bird is a finch and they're unique all new never described before there's even evidence that there are separate species for each galapagos arnold but i didn't label mine by ireland you didn't label them by ireland why do you want them well i told you i failed to label mine by island no no i uh i mean why are the birds i collected some such interest to you well the vice governor of the galapagos told me he could identify which island a tortoise came from by its markings yes yes small variations impossible from island to island adaptations to climate and so on yes but the islands all have the same climate my expert john gould tells me he's found different species of finches what if these finches were blown to the galapagos from south america and then began to change adapt if you will become more and more different from their ancestors generation after generation first into varieties then into new species each new species marooned on its own island what are you talking about what if the finches were blown to the galapagos god put those creatures there that makes no sense why would god put different birds on almost identical i have no idea it's not a question that requires an answer species were commanded into existence by god they're perfect forms and they've been perfect since the day of creation it's divine law god's will i'll see to it that your expert receives my birds thank you it's god you should give thanks to [Music] so come on tonight and for one night only ladies and gentlemen a guided tour of charles darwin's boneyard for goodness sake hurry up yes this is a large extinct llama-like creature and this is a giant ground sloth discovered by mr darwin at the remains of mr darwin's breakfast this skull belongs to a huge rodent a relative of the south american capybara if that's the size of a rat imagine how big the cats must have been i have named it toxidon thank you thank you professor owen for identifying and describing the extraordinary array of fossils discovered by mr darwin on his voyage to south america we allow the planets and the sun to be governed by natural laws but the smallest insect we wish to be created by a special act of god surely the creation of life has to be explained in the same way as geology using natural ordinary everyday causes well in theory yes but in practice there can be no question about the prime cause divine will shouldn't men of science be free to investigate each and every means by which new species come into being if by that you mean wild accusations about man's ancestry the answer is no to destroy man's unique status is to open the floodgates to anarchy you might just as well throw muskets to the rabble people like owen think that if there was no church of england cucumbers wouldn't grow if the globe has undergone such profound changes in its history geologically and surely all living creatures must have changed with it to adapt to their new conditions otherwise they would have perished some did perish it seems yes but the continued existence of life on earth can only be explained by the assumption that a creature like this was replaced by the modern day armadillo [Music] there must be a law which causes new species to appear in place of the extinct ones that my boy is the mystery of mysteries the person who can solve that riddle will take all of the scientific prizes it's the variety of their beaks that's so amazing they graduate perfectly in size from this large parrot-like beak similar to a half inch perfectly designed for cracking nuts to this tiny warbler finch fine as a chaffinch to feed on insects and they're all descended from this one the common ground finch i've started to prepare some color plates now put my words to shame rise razz razz [Music] wake up what time is it lunchtime oh well then go away and come back a teaser the galapagos islands are almost identical the same geology the same climate i'm glad to hear it now go away so why should different finches inhabit identical islands brazil changes over ages and ages can throw up mountain ranges and sink continents if mountains can move and rivers can move then why can't animals finches tortoises iguanas if you trace animals across the surface of the earth or dig down and trace them back through time you come face to face with the same truth which is new beings can appear on the earth [Music] [Music] perhaps everything is part of one ancestral chain [Music] man mouse [Music] armadillo [Music] it's nonsense to think of animals or mans climbing some ladder to talk of one animal being higher than another no no [Music] i think [Music] it's more like a tree a tree of life each new species springs from the parent tree like a chute these shoots branch and divide in their turn and so on and so on some branches die out others keep developing the trunk the ancient common ancestor the stock the stock from which all animals and plants sprang nursed by warm sunbeams in primeval caves organic life began beneath the waves hence without parent by spontaneous birth rise the first steps of animated earth grandfather zoonomia would it be too bold to imagine that all warm-blooded animals have arisen from one living filament it's in our blood charles my grandfather was vilified for it it's in our blood what charles darwin glimpsed over 150 years ago is now the bedrock of biology all forms of life on earth have evolved on a single branching tree of life [Music] one of the most important ideas that darwin had was that all living things on earth were related how can you realize that you are part of this single tree of life and not be fundamentally moved by that uh it's it's a it's something that that stirs the soul following in darwin's path biologist chris schneider and his colleagues have come to south america to a remote region of ecuador near the base of the andes mountains the rainforest may be home to more species of animals than anywhere else on earth darwin had been awestruck by its endless variety of life he wrote that he felt like a blind man being given sight and that the sounds of the rain forest were like a great cathedral that even saw for biologists today the lowland rainforest and the nearby andes mountains are laboratories for exploring darwin's ideas over the next several days schneider's team will track down rats and frogs bats birds and lizards through day and night both here in the rainforest and high up in the mountains by comparing the two groups of animals they hope to better understand how changing environments might trigger the evolution of new species you just can't help but be awestruck by the fact that there are so many different kinds of things here there are 12 species of primates there are 550 species of birds that have been identified here there are a hundred species of frogs right here in this little area wow that's great the spiciness why is there such diversity here we've got plenty of stuff oh we got some good stuff i got a mind blower or two yeah did you yeah i'll show you this one ornithologist tom smith wants to compare the size of bird's beaks from the rain forest with those he hopes to find in the mountains even subtle differences may offer clues about how and why new species arise just as it was the beaks of finches from the nearby galapagos islands that spurred darwin's thinking in the 1830s [Music] darwin saw that the finches he brought back had uniquely shaped beaks adapted to the different foods on the islands he envisioned that these different species of finch had all descended with modifications from a common ancestral population that had flown over from the mainland [Music] darwin's bold insight was to apply this vision to all of life to see that the great variety of life on earth leopards and lichens minnows and whales [Music] flowering plants and flatworms apes and human beings all descended from one root one common ancestor it was indeed another one of his radical proposals not only to say that evolution happened but that there was a root of common advanced ancestry to everything that lived on this planet including us you could construe it in other ways that as i like to say more user-friendly you could have thought well god had several independent lineages and they were all moving in certain pre-ordained directions which pleased his sense of how a uniform and harmonious world ought to be put together and darwin says no it's just history all coming with dissents with modification from a single common ancestry the key to darwin's thought in every realm is that given enough time and innumerable small events anything can take place by the laws of nature so whether it's the raising of mountains or the evolution of new species all of these things happen through time and change [Music] the rainforest holds striking examples [Music] take a look at this mantis here this thing is almost perfectly disguised as a leaf i mean but you can see if you look at the underside that it's a praying mantis just like you'd find in a garden in north america but this one is highly modified it's it's thorax is flattened out to look like a leaf and its wings are modified to look like leaves you can even see the veins if you imagined a population of mantises and some looked more like leaves than others uh those ones that look like leaves may tend to survive and reproduce more than others and so a series of modifications could build up over time to result in an almost perfectly leaf like mantis but if you put it on a background you know in which it doesn't belong i mean it just sticks out like a sore thumb and it would almost certainly go in there and almost certainly get eaten by something before heading into the mountains smith collects more birds to add to what he's learned in the rainforest how different will the highland birds prove to be 9.2 coleman is 10 different enough to be considered new species branching off in a new direction on the tree of life [Music] when the andes were uplifted it created a whole variety of new habitats the animals that were in the lowland rainforest had an enormous opportunity to colonize these new habitats and they did so [Music] the real question is whether adaptation to these new environments can lead to the formation of new species flying less than one hour schneider and smith moved from the steamy lowlands to the windswept andean peaks animal populations made the same journey but gradually over many generations [Music] and as the environment changed from rainforest to the high cool grasslands animal populations were forced to adapt these grasslands lie nearly two miles above sea level seasons never change here so close to the equator but it is said that winter visits every night temperatures often drop below freezing animals not well adapted will not survive [Music] hummingbirds are amazing it turns out that they can drop their body temperature 50 degrees and go into a state of hibernation to withstand the frigid nights here you can imagine a small build hummingbird living in cloud forest some thousand meters downslope from us and if those individuals were to expand their range up into this habitat where perhaps flowers are much longer you could expect that individuals with slightly longer bills might survive better and in fact there are many examples in hummingbirds where we know that small changes in bill length can make important differences in how that bird extracts nectar and how well it survives we're seeing that changes in the environment can be very important in changing the characteristics of those animals as they move between environments and we believe very strongly that in many cases anyway that this can be very important in the progression to new species from one species of bird the common ancestor hummingbirds with peaks of different lengths evolve over many generations and if these populations change so much that they can no longer reproduce with one another they are considered separate species on the tree of life [Music] smith and snyder want to see how closely related the highland birds are to the birds they examined in the lowland rainforest they compare color beak length wingspan just as darwin would have done but they have another tool that darwin never even dreamed of dna darwin was convinced that traits were passed on from generation to generation but he didn't understand how [Music] we now know that the sequence of the four chemical building blocks of dna determines the traits of all living things each generation passes on this text of a's t's c's and g's to its offspring but occasional mistakes in copying mutations can result in new traits by comparing dna we can determine who's most closely related to whom we can determine when they had a common ancestor when they diverge from that common ancestor laboratory analysis reveals that dna from the rain forest hummingbirds differs only very slightly from that of the highland hummingbirds they must have diverged from a common ancestor relatively recently in the history of life on earth about three million years ago we're examining the genetic material that makes organisms what they are and written in that dna is the history of their evolution [Music] the fact that the blueprints for all living things are in the same language the genetic code of dna is powerful evidence that they all evolved in a single tree of life how is it that organisms that are so different can be related that we are related to a flat worm or a bacteria darwin emphasized that small changes would accrue every generation and these changes could build up to amount to enormous changes [Music] it's not really hard to understand how major transitions could come about given that life has been around for three and a half billion years darwin really had it right there we a are good shot hello parker miss wedgwood you've met my cousin mr darwin before sir he's fast eh fastest in the county you breed him yourself i mated him with a who was pretty swift and how would you breed a fellow like squib here from the runts i suppose how dare you squib is quite as nice as any of your rotten dogs it's true it's from the rants and monsters that breeders can produce tailless cats or pygmies like squid i'm not listening to any more of this take me back to the house at once and stop saying horrid things from walls to greyhounds from bulldogs to fellas like squib in what a matter of a few hundred years i take it you don't find talk of dogs all that interesting i can think of more interesting topics of conversation such as the novels of miss austin and what does she have to say about selective breeding nothing as i recall that's a great pity why shouldn't nature produce such differences these different breeds of dog why should it what would be the point survival in nature a little poppet like squib who was the smallest in her litter would die you nearly did die didn't you yes that's true but what about the one with a little more vigor or a head start because of some peculiarity such as a puppy born with an extra thick coat in a hot climate would be a monstrosity but in a cold climate that would be a good adaptation that puppy would have an advantage got you charles emma let me go not until you've paid the top which is a kiss for me rather than the dog you can make a big dog or a small dog but you can't produce feathers on a dog nor can you create organs as miraculous as the heart and the eyes that can only be the work of god [Music] hurry up these blasted ties marry not marry marry children if it please god give me that it's private nonsense i'm your brother you've no secrets from me yes i do i have secrets from everybody give it to me thank you garmin constant companion and friend in old age to be loved and played with better than a dog anyhow you old romantic well it's intolerable to think of oneself spending one's life like a new to be working working working and all this is a response to your trip to cousin emma's not necessarily well you don't know anyone else no it's true your collection won't be complete without that most interesting specimen in the whole series of vertebrate mammals and why haven't you married if it's such an enviable state oh i'm too lazy to take on anything requiring as much effort as a wife and family but you're the marrying kind good they probably think we're poor law commissioners why would they think that it's enough that we have top added tops in a smart carriage and they're scavenging on rubbishy starving to them too many people not enough food thank god we'll always have food on our plates speaking of which i think i'll have the turbid in the white sauce cabbage sprout cauliflower all bread from the same ancestor cabbage the leaves sprouts and side buds cauliflower the flower head all monstrously enlarged sitting opposite me is that strange creature homo thesis half man half theory a word of advice in my entire life i have known only three women who were skeptics and two of them were not permitted in polite society keep your theory from emma it's too late i told her i'm sort of not a theory i don't have a theory i just thought how did she take it she asked me to read her favorite part of the new testament our savior's farewell to his disciples you see what i mean i am the vine and year the branches if man abide not in me will the force's ears have pricked up if man abide not in me he is cast forth as a branch and is withered and men shall gather them and they shall be cast into the fire and they are burned and how is your soul what your fish delicious i understand your carriage was stoned on the way here tonight well we're making a threat on the streets head on we're drilling with the honorable artillery company gentlemen volunteers in the event of riots we will back the police every man as long as he obeys the law of the land should be free to pursue his own interest in his own way yes of course charge what he likes for bread or anything else for that matter lazy fair let individuals compete and struggle for their advantages good night good night all right [Music] uh whenever i can't sleep i reach for malthus or as i prefer to think of him the reverend t r morpheus still warm two brandis hmm yes sir the natural tendency of mankind is to reproduce humans can double their numbers every 25 years [Music] but they don't a struggle for resources slows growth and death and disease war and famine check the population i know the argument yes but don't you see exactly the same struggle takes place throughout nature i don't know why i didn't make the connection before why are we not overrun with insects and frogs well given the rate at which they reproduce the number of eggs produced by each and every female nature's broom sweeps away the ugly ducklings the runts yes it's not that simple it's not that simple sometimes it's the ugly ducklings that are better adapted to the situations of life they have longer legs and can run faster they have bigger beaks that can crack harder nuts and seeds in harsh winters they survive have more offspring nature selects them to pass on their traits to future generations and where do we fit in [Music] well the sun does not revolve around the earth nature does not revolve around man man must fall into nature's cauldron he's no deity no exception once you accept that species can pass into one another the whole fabric totters and falls they'll burn you at the stake for this yes but now you have a theory so i said don't come down the ladder mother i've taken it away good evening darwin's work began with the observation that individuals differ from each other and these minor differences darwin believed might be advantageous it might give each individual an edge when it came to getting food or finding a place to survive in nature darwin realized that in nature individual organisms compete for limited resources those with some kind of advantage in coloration for example or in speed or envision [Music] are more likely to survive and reproduce and pass on these advantages to their offspring those who are less fit will not succeed darwin called it natural selection because the forces of nature select which organisms will survive the survivors will be those whose variation fortuitously adapts them better to changing local environments and then because they pass on those trades to their offspring the population changes that's natural selection that's all it is it's not a principle of progress it's just a principle of local adaptation you don't make better creatures in any cosmic sense you make creatures that are better suited to the changing climates of their local habit that's that's it darwin couldn't actually see natural selection acting in real time but today scientists can by observing the evolution of hiv the virus that causes aids [Music] jeff gustafsson has been infected with hiv for over a decade he takes a host of medications but too little avail the virus keeps adapting evolving into new strains that evade the drugs there's a pervasive feeling that all you have to do is take your medicine and you'll be okay and that really isn't the case you know hiv has the capacity to evolve no matter what you give it there are 19 hiv drugs on the market today and of those 19 i've already been through 14 of them clarence johnson too is locked in a daily struggle against the rapidly evolving virus sometimes i feel like i'm fighting a losing battle i haven't given up yet but there have been times and i just want to just lie down and give up but um i can't leave my family behind clarence johnson's doctor michael sack has seen hiv evolve into new varieties over the last dozen years the virus is constantly changing subject to the forces of natural selection in the environment of a patient's body imagine we didn't have the concept of evolution and we started giving drugs to patients that in the test tube looked great and all of a sudden the virus starts coming back and it's not susceptible to the drugs anymore what a mystery how in the world did that happen there's only one way that it happened through evolution once inside a patient's white blood cells hiv replicates at an alarming rate billions of new viruses are spawned every day and each time it reproduces random genetic copying mistakes mutations result in slightly different varieties of the virus bursting forth into the bloodstream some of these new varieties just by chance will have traits that make them resistant to certain drugs so when drugs enter the bloodstream natural selection favors the drug resistant forms they survive and reproduce before long drug resistant viruses dominate in the patient's body evolution seems pretty easy to understand when we look at big animals we can kind of see it in a sense but that's evolution that took centuries to develop when you're talking about something like a virus that you can't see in everyday life it's hard to imagine how it changes in the case of hiv we're talking about minutes to hours to move from one species to another it's mind-boggling in terms of the speed with which hiv can replicate [Music] parents how are you feeling overall i'm doing okay great okay every time i see a patient in the back of my mind i'm thinking what is the virus doing in the environment of that patient the virus is producing itself on the order of billions of copies a day those few that happen to be able to work in the presence of drug say hey this is my chance and they emerge so it creates the appearance that the virus has thought this through but in fact it's just a matter of chance it's a matter of a virus being there that's not susceptible to the drugs it emerges and the virus begins to win the war that's just what happened to jeff gustafsson each time he tried a new drug the virus evolved to resist it even a cocktail of multiple drugs made little difference this puny little virus that doesn't have a brain and yet it can dealt with some of the top scientists in the world all the the virus has gone for it is it it can't copy itself too well i mean that's pretty awe inspiring and scary all that happens in evolution at least under darwinian natural selection is that organisms are struggling in some metaphorical and unconscious sense for reproductive success however it happens the process of natural selection feeds on randomness it feeds on accident and contingency and it gradually improves the fit between whatever organisms there are and the environment in which they're being selected but there's no predictability about what particular accidents are going to be exploited in this process for millions of hiv patients evolution is the enemy if only there were a way to take advantage of natural selection to make it work in a patient's favor in 1997 at goethe university in frankfurt germany a researcher may have discovered such a way [Music] quite accidentally we had a patient and even though he was being treated with five drugs his virus replication could not be controlled and at the same time he was suffering from a lot of side effects of the medications um so at that point he asked his physician if it wouldn't make sense to just stop taking the drugs for a while since he was really having nothing much from them other than the toxicities he was experiencing after three months off drugs the patient's virus population was tested for drug resistance dr miller could not believe the results at first i thought a mistake had happened because the lab that that did the resistance test was not able to detect any resistance whatsoever in this virus population we sent a second sample and this result was confirmed within a matter of three months his virus population had changed completely from being resistant to every single drug to appearing to be susceptible to every single drug that we currently have here's what had happened with drugs present in the patient's bloodstream only the drug resistance strains of the virus could replicate but some of the non-resistant virus the wild type still lingered in the white blood cells when the patient stopped taking drugs the environment changed and the wild type came back it replicated extremely rapidly and soon outnumbered the drug resistance strains in darwinian terms the wild-type virus was more fit in this drug-free environment dr miller's findings have led to a new experimental treatment strategy take a patient off drugs for a time and if the virus reverts to the non-resistant wild type hit it hard with a combination of drugs clarence how are you doing how are you doing good to see you so the concept of a treatment interruption is a new strategy that we might be able to apply in clarence's case but we just got to make sure that we aren't putting him at too much risk if we choose that route so one of the options is to take all the drugs away for a while let the virus spring back into its natural state of not having any mutations and then pounce on it again with the regimen and it might even be the same regimen that we used before okay how's that sound on first blush the evolution back to wild type would seem to be a great thing the drugs all of a sudden can work again but it's a double-edged sword as the virus goes back to wild type it becomes more dangerous for the host it's a much more effective killer of cells and so we have to find a way to balance those two things out jeff gustafsson is also beginning a treatment interruption despite the risks i feel like i've played all the cards that i have in my hand with the medicines that are available i feel like it's worth the risk to try and take another card or our different strategy and and just stop taking medicine all together and hope that the next time that i do go on medicine that will actually work after five weeks off drugs clarence johnson is enjoying being free at least temporarily from their debilitating effects if the wild-type virus is staging a comeback it doesn't yet appear to be affecting his immune system we took a bit of a gamble i think so far you know it's paid off and uh the virus has gone from being resistant to certain drugs and now that population has shifted so that now they're susceptible again now what i hope for clarence is that we can find the right course find a way to stretch his survival out even further so that he's healthy and happy until the next new approach to treatment is able to get him to a point where he can live to 80. my greatest hope is that when i do go back on medications those drugs will bring my viral load down to undetectable amount because i don't know what it feels like to be undetectable so that would be a great experience six weeks into his treatment interruption jeff gustafsson's virus also has changed to the drug-susceptible wild-type he's now on a new course of medication and responding well from day one of this epidemic we were put into a race with hiv over the last decade or so we've been catching up we've learned a lot about it we've scouted out the enemy we've learned how it replicates we learned how it tries to survive we learned how it evolves and we're now taking those principles that we've learned and applying them to putting the brakes on the virus in this race [Music] towards me to me personally that the ant needs to be more acute more cute well let's see if it works and open good god brad what a horrible shot it's all i'd surprise you welcome to down house when is the motor to be done when the drawbridge is in place are you trying to keep out charlie everyone especially you franz what a wonderful surprise my dear what a journey it's not far the nature a journey of 16 miles almost as much as a vacuum hello annie one and a two and a three and off you go i thought of a new name for the village oh yes down in the mouth if you speak i can find you really easily shh how's your work progressing oh i sent the manuscript off to be copied no idea what i'm going to do with it when it comes back everyone be quiet are we glad we're not blind if you're blind you can't see the sky or the flowers or anything else for that matter i can get anywhere anytime i want well go on then yes we feel sorry for moles don't we moles don't need to be able to see because they live underground that's why their eyes have got smaller and smaller and smaller and owls they've got bigger and bigger i can't okay everyone's talking about eyes all the time you're going to talk to william hmm come on go on brody willian she'll soon talk him round she has the knack you look pale my stomach rejects food i'm not strong anymore i'll never achieve anything in science now what's rot you're coming back to london with me oh no i'm not yes you are i'm not letting you stagnate down here while your rivals make all the progress you must visit your publisher you don't understand raz even when i talk about my theory with you i feel like i'm confessing a murder i can't publish well you're coming back to london with me charlie whether you like it or not if only to remind the opposition you're still alive and kicking take care and make sure you get plenty of rest erasmus he's not to spend all night at the club with you no mother i mean it or he'll be utterly done for the next day yes mother don't worry it'll do him good come on your slos awaits you sir what a magnificent piece hey raz my word owen's done a remarkable job he really is a splendid specimen yes i thought you'd be pleased come through see what i've been working on the chimpanzee being the highest organized four-handed ape every difference between its anatomy and humans is instructive i've been for example the irrational ape has dog-like canines used as weapons of destruction quite unlike the masters of the animal kingdom yes though and the human footers of decisive taxonomic value our feet are made for walking upon our hands for grasping this brute has its hands and feet made to answer nearly the same purpose there's a striking similarity i'm writing a book on the subject my brother is working on a new book too come here let me show you what i mean [Applause] all the same pattern the bone structure in the hands and feet are all nearly identical the blueprint if you will that existed first in the creator's mind of that there can be no doubt the similarity of structure indicates one thing of one thing an ancient common ancestor real flesh and blood parents why didn't you say so then you must publish your ideas if only to establish your priority what's holding you back [Music] do what is it i've completed a sketch of my species theory i believe it's a considerable step in science if anything should happen to me what do you mean if i should die die charles for goodness sake please my love it's important if anything should happen to me i'd like you to see to it that it gets published 400 pounds should be enough to see it printed and promoted nothing's going to happen to you you say here that the human eye may possibly have been acquired by gradual selection of slight but in each case useful deviations yes that's a very great assumption charles well if i'm wrong about that i'm wrong about everything my entire theory's in ruins can your theory account for the way my eyes and ears and hands and heart combine to reproduce the sounds that chopin heard in his head isn't that a god-given gift what's given but not i think by god you're a man of science you don't want to believe anything until it's proved but some things are beyond proof it would be a nightmare to me if i thought we didn't belong to each other forever in heaven emma was a sincere believer in the christian plan of salvation and that those who trusted in jesus and his resurrection from the dead would spend eternity in heaven she saw that her husband's speculations about the origins of species and of humanity would jeopardize the christian plan of salvation god was being made remote in her husband's universe now if nature by itself unaided by god could make an eye then what else couldn't nature do nature could do anything it could make everything in darwin's day the very existence of an organ of extreme perfection like the eye was taken by many as proof of god as proof of a designer how else could all of the intricate organs and substructures of the eye have come together in just the right way to make vision so possible and so perfect but it turns out the eye isn't exactly perfect after all in fact the eye contains profound optical imperfections and those imperfections are proof in a sense of the evolutionary ancestry of the eye [Music] eyes are imperfect because evolution does not create things the way a designer or an artist does natural selection simply favors random changes that make an organism more fit to survive and imperfections in design often result from evolution's constant tinkering one such imperfection proved traumatic for artist valerie young we just come home from a party and i saw a lot of lights flashing inside my eye especially on the outside edge of the of the right eye and i thought we may be in trouble here and it took me a while to really see that it was my this was coming from inside my eye luckily my husband was with me because i wouldn't have been able to drive to the hospital so my vision was pretty obscured the only way i can describe it is like a jellyfish with lots of little bubbles in it and it just kept turning and floating in front of my eyes [Music] valerie had a retinal tear not an uncommon problem due to the way human eyes evolved from light sensing patches of brain tissue in our ancient ancestors in the human embryo eyes develop from bulges in the brain's neural tube that pinch in to form cavities this top layer the retina which tore in valerie young's eye contains cells that collect light it rests against a second darker layer that lines the back of the eye but the two layers are not attached to one another and when the jelly that fills the eye liquefies as we age it can cause the retina to tear the jelly can then seep into the space underneath leading to a retinal detachment and in some cases blindness when valerie young came in her floaters were an immediate clue that she could have a retinal tear we were able to successfully apply laser treatment in the office that day to seal it off like applying sandbags around something to wall it off so that the vitreous jelly would not get in the break and detach her retina valerie young's retinal tear is just one example of imperfections in the design of human eyes another occurs because nerve cells and blood vessels evolve to lie in front of the retina where they interfere with its ability to form sharp images it's like trying to take a picture through a foggy piece of glass [Music] and the optic nerve itself evolved to connect to the brain through a hole in the retina so the eyes of all vertebrates have a small blind spot right near the middle of the visual field evolution starts with what's already there tinkers with it and modifies it but can never do a grand redesign so even the eye with all of its optical perfection has clues to the fact that its origin is of the blind process of natural selection darwin believed that what he called an organ of extreme complexity like the eye could evolve by small steps given enough time any trait that improved a vision would aid in the search for food or a mate or in the avoidance of predators so natural selection would most certainly favor those traits and what darm was able to do was to point out that you might think in logic that it's difficult to imagine a set of intermediary stages between the simplest little spot of nerve cells that can perceive light to a lens forming eye that makes complex images but in fact these intermediary forms do exist in nature at the university of lund in sweden zoologist dan eric nielsen has developed models to show how a primitive eye spot could evolve through intermediate stages to become a complex human-like eye in less than half a million years yeah i've been interested in my evolution for a long time i mean in particular i've been interested in the question of how long time it would take for an eye to evolve nielsen envisioned a sequence of stages by which a flat patch of light-sensitive cells on an animal's skin could evolve into a camera-type eye as a first step nature would favor any changes that made the flat patch more cup-like as soon as you've created even the slightest depression in the center means that the the edges of the cup will actually shade light from parts of the environment and of course all the light sensitive cells in this little cup they won't measure light in exactly the same direction so already this cup has some pictorial information another model demonstrates what a primitive cup eye can do the brightly lighted skulls cast an image onto a translucent screen nielsen installs at the back of the cup to act like a retina but the image is not at all well defined the cup eye can do little more than detect movement this kind of eye can be found in nature today in flat worms their eyes evolved no further in their environment that's all they needed but if the animals need to move faster or evolve to become fast predators or to see other fast predators then the construction needs to be improved and one way of doing that is to constrict the opening to make it smaller that's just what happened to creatures like the chambered nautilus over thousands of generations natural selection favored those with slightly more constricted eye openings which focus light more sharply this worked well up to a point [Music] since this strategy of making a sharp image also has the drawback of creating a very dim image it's not very popular in the animal kingdom and there is an alternative solution which is has become very popular in the animal kingdom the solution that we use in our own eyes that is to put in a lens nielsen's model lens uses two thin layers of clear plastic he can inject water in between them to make the plastic windows bulge out like a convex lens this mimics what natural selection might have done over a few hundred thousand generations favoring animals with a rounded transparent layer in their eyes that cause light to be focused more sharply on the retina so we can make it gradually from no lens at all and just continue to inject more water making the lenses bulge more and more and the image becomes gradually sharper and sharper so we can go all the way gradually in very small steps from a simple pigment cup eye which has barely got the ability to determine the direction of a light source all the way to a complete camera type eye of the same type as we have ourselves and that is really exactly the way ievolution must proceed [Music] the extreme complexity of the eye left darwin in a cold sweat he wrote to a friend but still he was convinced that an eye could be formed by natural selection he later wrote that eyes must have evolved by numerous gradations from an imperfect and simple eye to one perfect and complex with each grade being useful to its possessor nature unaided by a designer could produce an organ of seemingly miraculous complexity [Music] oh it's smell annie come and look when i first started looking i thought lots of the barnacles had tiny parasites that's an animal or plant that lives on another animal or plant gets its food from it like mistletoe on an apple tree but they're not do you know what they are no they're little tiny husbands the females carry little tiny males around with them clinging to their skirt tails just like you and me just like me and my mom i think it's the most interesting barnacle in the whole white world what do you think we should call it barnabas for short barney the tiny parasitic males are rudimentary in a way that i believe can hardly be equaled in the whole of the animal kingdom they have no mouth or stomach they are really little more than a tiny head atop an enormous coiled penis a bit like me really apart from the bit about the mug from the stomach what's funny nothing nothing are you all right erasmus take him home why must you work so hard at your horrid little mollusks oh they're not horrid little mollusks they're hard little crustaceans and i have horrid pigeons and horrid worms too they're providing the evidence i need for my theory i don't have the right to publish the idea unless i have the evidence we must do something about you [Music] your stomach condition is nervous origin brought on as a result of excessive mental exertion cold water is used to stimulate the circulation and draw the blood supply away from the inflamed nerves of the stomach no sugar no salt no bacon no alcohol no tobacco in fact anything at all that's good i don't know how or why but i feel so much better i look around me and i don't care two hoots how any of this came to be created children last one back to the house is a rice pudding come on william you're laughed come on run quick quick quick come on [Music] edie [Music] [Applause] [Laughter] oh eddie my dear and good child come on come on [Music] is [Music] [Applause] [Music] is [Music] oh papa and he's woken me up and he's woken me up mom wake up wake up annie's crying what's the matter my darling what's wrong does your head hurt ah there's no fever does it hurt here [Music] oh it's all right my darling you'll be all right the doctor's coming you go get dressed i'll stay with her what if she's inherited my wretched digestion she'll be fine dear what did he say it is her stomach but he has no idea what's wrong perhaps i should take her to go see dr gully he cured me you'll be back soon and papa will look after you soon there's going to be a new baby and i shall need your help say goodbye to eti now [Music] [Music] is [Music] she seems so weak isn't that anything you can do all you can do is pray it's my fault first cousin marriages always produce weak children it's my fault hi [Music] i give the cause of death as bilius fever with a typhoid character [Music] the lord gives and the lord takes away [Music] god grant us strength [Music] so [Music] [Music] now please charles please [Music] [Music] oh creatures what annie's death did to darwin's faith was mainly to destroy christianity he could no longer see that a good god ordered and superintended all of the events of human life and of the universe and he believed that she did not deserve punishment by god or by nature either she had simply fallen victim to the struggle for existence the amoral purposeless struggle that ran according to laws of nature darwin certainly didn't think that evolution spoke either for or against the unprovable existence of god or a form of god he didn't desire to cast asparagement on anyone's religious convictions he regarded as a private matter which he was never able to hold with conventional zeal following the tragedy of his life all creatures [Music] today scientists hold all conceivable views on religion from atheism to agnosticism to a general spirituality and many like biologist ken miller adhere to very traditional beliefs i'm an orthodox catholic and i'm an orthodox darwinist my idea of god is supreme being who acts in concert with the principles and the ideas that darwin explained to us about the origin of species my students often ask me you say you believe in god well what kind of god is it a fashionable new age god a pyramid power kind of god do you think like some scientists do that god is the sum total of the laws of physics and i shake those off and say that my religious belief is entirely conventional our father hallelujah it surprises students very often that anyone could say that that kind of very traditional conventional religious belief could be compatible with evolution but it is the peace i find this absolutely wonderful consistency with what i understand about the universe from science and what i understand about the universe from faith tennessee's premiere morning radio talk show the halloran hilton hill morning show on news talk 99 wnox am fm loudoun knoxvilus 12 past the hour of six o'clock it's my pleasure to welcome to the broadcast this morning dr kenneth miller he's a professor of biology at brown university his book is entitled finding darwin's god a scientist search for common ground between god and evolution he's in town tonight let me ask you this as a cellular biologist when in your experience are you studying something or reading something or doing some research when do you come to the point where you go that's god as an experimental scientist i don't find god in the insufficiency of science to explain things in other words i don't find god in ignorance i don't find god because we say well we can't explain that that must be something that god's doing but what did god do did he just create some kind of primordial soup and say go well a long time ago people were sufficiently unknowing of how things worked in the natural world to see when the sun moved across the sky they imagined that god had to push that sun across the sky and gradually we began to realize that the world works according to physical laws science investigated those laws um so what room is there for god in in present-day life well i think if you ask people uh who are believers how does god act they would say he acts in a variety of ways he answers our prayers he inspires us no doubt there are events that take place that are part of what some people might call god's plan and what i would suggest is if you look back in earth's history if god is working today in concert with the laws of nature with physical laws and so forth he probably worked in concert with him in the past in a sense in a sense he's the guy who made up the rules of the game and he manages to act within those rules [Music] for miller and millions of followers of all major religions notions of god and evolution are fully compatible [Music] but not everyone agrees when we replace the traditional idea of god the creator with the idea of the process of natural selection doing the creating the creation is as wonderful as it ever was all that great design work had to be done it just doesn't wasn't done by an individual it was done by this huge process distributed over billions of years god created man in his image in the image of god he created him male and female he created them whereas people used to think of meaning coming from on high and being ordained from the top down now we have darwin saying no all of this design can happen all of this purpose can emerge from the bottom up without any direction at all and that's a very unsettling thought for many people in darwin's day science and politics and religion were all of the peace when you talked about the origins of life and of species astronomy could go along pretty well because it testified to the wisdom and power of god in holding the planets in place but the idea of evolution or transmutation people said with a snarl put in jeopardy the whole established social order [Music] what is in this big book of his do you think transmutation another darwin blotting god out of creation we want to support your scheme for a museum of natural history some people see it as rash extravagant grandiose if it's grand it's because it should house as wide a display as possible but we need your help in return it is up to you as the country's leading anatomist and paleontologist to prove man's superiority we won't have street ruffians tout man's monkey origin in her majesty's museums you can rely on me bishop will before the human brain differs markedly from that of all other mammals in man not only do the cerebral hemispheres overlap the olfactory lobes and the cerebellum but they extend in advance of the one and farther back than the other their posterior development is so marked that i've assigned to that part the character of a third low peculiar to homo sapiens the hippocampus minor peculiar mental faculties are associated with this highest form of brain and i am led therefore to regard man not merely as representative of a distinct subclass but as the inhabitant of one reserved for him alone the human brain is in itself proof of man's moral and religious faculties such are the powers with which we and we alone are gifted i wonder what a chimpanzee would have to say about that mr huxley i think it's priceless his theory is a house built on sand a corinthian portico on cowdung yes damn all the sanctimonious meddlers who try and stifle troublesome research the ultimate court of appeal of science is observation and experiment not authority wealth and rank your disagreements with owen should not be perfect i can't help it he's so pompous the prospect of his slipping on one of his pickled brains is just too good to be true bad feeling will only cloud the issue and lead to bad science tell that to owen [Music] huxley's saying in public what you think in private charles you've stalled long enough you've collected enough barnacles to think a ship of the lie meanwhile you're being upstaged that's not important my book is the thing once my work is done will it deal with man it's too surrounded by prejudices well whether it does or it doesn't you must publish [Music] hmm [Music] oh my god brass what is it [Music] who is alfred wallace my dear huxley it's like a tracy of my theory all my originality whatever it's worth has been smashed had wallace a copy of the essay i'd written in 44 in front of him he couldn't have written a better short abstract variations being pushed further and further from parent species by a struggle for existence overpopulation it's all there is your book ready for publication publish how can i publish honorably i've soon have burned the blasted thing and have here more anyone else think that i behaved in a paltry spirit then publish a joint paper excerpts from your work along with wallace's essay and then you must prepare a manuscript for publication who knows it may all be for the best at last we'll finally get to learn your views in full [Music] this book will be the death of me what a miserable wretch i'd be without you near me when on board hms beagle as naturalist i was much struck with certain facts in the distribution of the organic beings inhabiting south america and in the geological relations of the present to the past inhabitants of that continent [Music] these facts seem to throw some light on the origin of species [Music] that mystery of mysteries [Music] [Laughter] [Music] the times is very positive i should think so it's huxley the ethernet wants me tried in the divinity hall to college the lecture room and museum my book is no more unorthodox and the subject demands i don't discuss the origins of man i don't discuss genesis charles don't be so naive it's clear you think man is no exception whether you're right or wrong you must finish what you started know it darwin how dare you how dare you paint me as a reactionary i didn't paint you with three my name with the defenders of immutability is my concept of the ordained continuous becoming of living things to be ignored what does it mean i don't know what it means it means animals appearing out of thin air not at all oh you believe that selection is the only possible creative law pure chance the roll of the dice in fact new species are created by natural birth according to god's law well i don't believe you up to this huxley well i will have absolutely no truck with the huxleys of this world and nor should you it is an abuser science you should be ashamed of yourself your book is a snub to the clergy and an insult to humanity it's nihilism only a man devoid of a soul could find solace in a beastial ancestry it's as respectable to be modified monkey as modified dirt huxley please no i think it's splendid old ladies are both sexist it's a dangerous book splendid don't worry i'll deal with him i'm sharpening my beak and claws in [Applause] readiness any contribution to our natural history from the pain of mr charles darwin is certain to command attention his latest publication the origin of species is manifestly regarded by him as the opus upon which his future fame is to rest mr darwin claims that every living thing every fish plant fungus fly elephant map are all equally the lineal descendants of the same common ancestor such a notion is absolutely incompatible with the word of god [Applause] man was made in the image of god and redeemed by the eternal son natural selection is an ingenious theory for denying the working and therefore the existence of the creator in fact the human brain differs markedly from that of all other mammals unfortunately my lord bishop you have been misinformed [Applause] if we are unprejudiced judges we have to admit that there is as little interval as animals between the gorilla and the man as there is between the gorilla and the baboon it is speech alone and not some spiritual gift that makes man a reasonable being that is the source of our unlimited intellectual progress but that does not disguise the fact that to the very root and foundation of his nature man is one with the rest of the organic world [Applause] no one who has ever dissected the brain of a name agrees with professor owen his findings are wrong i can only assume that professor owen's brain must have shrunk in the pickling jar i meant of course the chimpanzee's brains he had examined oh lord it was then that god delivered wilberforce into my hands [Applause] i wonder mr huxley is it through your grandfather or your grandmother that you claim descent from an egg i stood up very quiet very grave and said my say with perfect good temperature the question is put to me would i rather have a miserable ape for a grandfather or a man highly intelligent possessed of great means of influence and yet who employ these faculties and that influence for the mere purpose of introducing ridicule into a grave scientific discussion i unhesitatingly affirm my preference for the you didn't i said that or something very like that how dare you attack a live bishop in public have you no respect for the purple waistcoat lady brewster fainted had to be carried from the room and then admiral fitzroy got to his feet that's right oh my we'll probably never know the truth well the truth charles is in your book it's the most interesting thing i've ever read the reasoning is so entirely satisfactory to me if that facts don't fit then well so much the worse for the facts the shakes time i was naturally selected for more than a century people have often thought that the conclusion to draw from darwin's vision is that homo sapiens our species that we're just animals too we're just mammals that there is nothing morally special about us i myself don't think this follows at all from darwin's vision but it is certainly the received few in many quarters ever since the origin of species was published strict believers in biblical creation have attacked darwin's vision their concerns aren't only about the science of evolution at stake many believe is nothing less than the human soul [Music] to suggest that animals and plants and us humans came into being in a natural law-like way in the way the planets move was to put in jeopardy the human soul and the human soul is the crux of the matter because if we are not different from animals if we don't live forever in heaven or in hell then why should we behave other than like animals in this life in the 19th century in darwin's time it was audacious to claim that humans and ships were closely related there wasn't that much scientific evidence but since that time the evidence has become strong first we saw the fossil record appear evidence of human ancestors that had ape-like features established the plausibility of the idea that humans and chimps had common ancestors and then in the last 20 years we've seen the emergence of a whole new type of data that's established the close relationship between chimps and humans and that comes from the analysis of dna this is dna we've got dna chimps have got dna bacteria have got dna petunias have got dna crabs have got dna every living animal plant fish frog has got dna and if we compare the dnas of any two species we can establish how closely related they are one to another [Music] in the early days of dna research a double strand of dna was extracted from each species to be compared when heated the strands split apart when the single strands from each creature were put together and allowed to cool the two always combined to form the familiar double helix the degree to which the strands made it successfully was a measure of their similarity [Music] it turned out that human dna and chimp dna combined almost perfectly today this similarity can be seen even more precisely dna sequences can now be read letter by letter here we're looking at the dna sequences of one particular gene as found in human and chimp and what's immediately evident is that humans and chimps have dnas that are 98 identical they're basically the same they're just a couple of spelling changes why are there only a couple of spelling changes because we and chimps had a common ancestor only a few million years ago and these few spelling differences have accumulated during the propagation of this dna during those few million years if more time had passed since we had our last common ancestor more spelling changes would have accumulated if the same gene from a rat is compared many more spelling differences are seen [Music] that's because our common ancestor with the rat lived about 80 or 100 million years ago and there's been much more time for spelling differences to accumulate [Music] chimpanzees and humans are made from blueprints that are 98 the same but what about the ways humans and chimps think and act in the world are there similarities there as well why doing some pull-ups oh be careful psychologist sally boyzen explores the commonalities between the minds of chimps and humans a quest that may help explain how the human mind evolved the developmental milestones really throughout the life of a chimp are almost exactly the same as humans everything is so similar they respond to new things and new toys and they have the same kinds of rough and tumble play harper's rough and rowdy and runs all over the place and climbs and emma really can almost entertain herself one of the things that our work allows us to see is that chimpanzees can acquire very sophisticated complex cognitive skills like learning to count which they normally wouldn't learn in the wild one two three four five ooh yet they have the requisite neural capacity to do that where did that come from okay she we're gonna do another turn now here we go one of those ooh and a malted milk ball can you tell me the answer to this with the blue and the brown show me yeah go ahead excellent there's almost nothing that the chimps haven't been able to learn that we've tried to teach them we've seen their ability to grasp extremely complex notions like the concept of zero for example okay sheep look what if i didn't put any candy here at all what would you say zero that's right there's no candy here oh that's too bad there's no way the chimps would be able to do this if they didn't have a great deal of commonality in literally the neurological structure that supports their ability to learn just like we do those things are absolutely comparable and had to come from a common ancestor [Music] the similarities that we have with our primate relatives are extraordinary we share so much of our dna we share so much of our morphology we even share our blood types but for all of those similarities there are striking differences i think the reason for this is really very simple and that is the line of evolution that led to us led for reasons which we're only beginning to understand to an explosive development of mental capacity [Music] and what clearly happened is that natural selection favored the evolution of organisms that could communicate that could manipulate symbols and could construct language [Music] darwin's great idea is a grand and marvelous explanation that shows us that we are united with every other form of life on this planet and i find that an exciting and maybe even an enabling way to look at things [Music] darwin died in april 1882 at the age of 73. the family thought he would be buried in the parish church yard darwin had said months before he died that he would have to look forward to it as the sweetest place on earth it was not to be in london darwin's friends determined to make his death and burial a state occasion they went to the royal society and they got signatures they went to the house of commons and got up a petition they telegraphed the dean of westminster who was abroad and got his approval a special anthem was even written for the occasion and on the 26th of april a week after the death darwin's body was born mightily in procession down the aisle of westminster abbey to be interred in the shadow of the grave of sir isaac newton darwin's internment celebrated the vast social transformation that england was undergoing there were new colonies new industries and new men to run them darwin's body was enshrined to the greater glory of these new professionals for he had naturalized creation and delivered human nature and human destiny into their hands society would never be the same darwin's vision of nature was i believe fundamentally a religious vision one with which he ended his most famous work on the origin of species there is grandeur in this view of life with its several powers having been originally breathed into a few forms or into one and that whilst this planet has gone cycling on according to the fixed law of gravity from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved [Music] continue the journey into where we're from and where we're going at the evolution website visit www.pbs.org [Music] hmm