Evolution or Creation - Was Darwin Wrong

From the air to the depths of the oceans, our planet Earth is teeming with life. To some, it's a miracle. But can science explain how all this came into existence? Critics have attacked the theory of evolution for 150 years. They claim it's full of holes, and the gaps reveal the hand of a creator. Who's right? Naked Science investigates the most explosive science question of them all. Was Darwin right or wrong? The debate has never been more intense. I think it's a war. It's a real battle between worldviews. We believe that the theory of evolution should be taught alongside the alternative theory of special creation. On this foundation here of creation, God's word is true. Creation and, you know, any supreme being can't be addressed in a science classroom. There are those who believe that life on our planet is so complex that the only explanation is to say that somewhere behind it, there is a creator. On the other side are a group of men and women who believe that nature can create life's countless varieties with no outside help at all. They have a name for it, one of the most hotly debated words in our language, evolution. One single word, one incredible idea, and almost entirely the brainchild of one man, Charles Darwin. The theory of evolution was born out of a remarkable journey. In 1831, the naturalist and explorer Charles Darwin embarked on a five-year voyage around the world. Along the way, he collected fossils, plants, and animals. Back in his home near London, England, he spent the next 22 years piecing together a theory for how the great variety of life came to exist. Even in Darwin's time, scientists already knew that extinct creatures had roamed the planet in the distant past. Some were strange, terrifying beasts, unlike any that walk the Earth today. Others were more familiar, animals so similar to modern creatures that they had to be related. Could today's animals and plants be their descendants? Could one species change into another over time? Darwin thought they could. In 1859, he published his ideas in a book on the origin of species. The book rocked the world. In it, Darwin made three bold claims. First, that life was old and had existed for hundreds of millions of years. Second, that it started out with just one or a few simple organisms, which then evolved into the millions of species that exist today. And third, that this whole process of creating new species was driven by a force of nature he called natural selection. For God-fearing people, the inescapable conclusion was astounding. Life didn't need a creator. But was Darwin right? We're going to examine Darwin's claims one by one to see if they're true or false. If a single one of these claims fails, the whole theory will come crashing to the ground. First, we look at the mystery of when life began. Darwin didn't claim to know how life started, but he did say that it was old. He thought it had existed for hundreds of millions of years. But many of his opponents argue that life is young, that God created all living things within the last 10,000 years. So who's right? When did life begin? In the Western Australian outback, geologist Martin van Cranendonk is on the trail of the world's oldest fossil. Fossils are the preserved remains of creatures that lived long ago. The fossils in this part of Australia are as close as we can get to an amazing moment, the moment when everything began. What's remarkable about this outcrop is that it contains the oldest evidence for life on Earth. These wrinkly forms are very different from what we'd normally see in a geological environment. They can only be formed by living organisms. These are fossilized stromatolites, structures built by colonies of bacteria that lived in the sea. Biologists think that all life on Earth evolved from organisms like these, even us. We're looking at here in front of me our great-great-great-great-great-great-great-grandfathers and grandmothers. Scientists are confident that these structures are the remains of living organisms because their direct descendants still exist today. Over 600 miles away, in Sharp Bay, on the west coast of Australia, are colonies of living stromatolites. But how old is the world's oldest fossil? Will it prove that living things are old, as Darwin said they were, or young, as his opponents argue? To find out, scientists use a surefire method of dating rocks. Radiometry. By measuring the decay over time of certain elements within the rocks, they can determine their age to within 0.1%. When geologists put the fossilized Dramatolites in the Australian outback to the test, they discovered that they were 3.56 billion years old. Scientists have now discovered dozens of fossils that are over a billion years old. On the first test, is life old or young? Darwin was more than right. Life is thousands of millions of years old. But how does he fare on the second test? Darwin said that life started out with one, or at most a few, simple living things. Over millions of years, these simple creatures evolved into new species, which then evolved into other new species. This process created millions of species that became increasingly varied and more complex. The creationists argue that life hasn't changed, that a creator created everything at one time, just as we see it today. So who's right? The best way to find out is to examine the fossil record. The museums around the world contain millions of fossils that reveal what life was like on Earth at different stages in its history. Because each fossil creature can be radioactively dated, we know when and in which order they lived. If Darwin is right, we would expect to find that the earliest fossils are of simple creatures, and that as time passes, fossils get more varied and complex. to visualize what creatures lived on earth and when imagine the whole history of life on our planet as a skyscraper about as tall as the empire state building the first floor represents the moment when the earth formed about four and a half billion years ago and 91 stories higher the roof is the present day each floor of the building represents 50 million years of passing time six thousand years the whole length of recorded history would be just 1 50th of an inch that's the thickness of the coat of paint on the roof the first fossil evidence for life appears three and a half billion years ago on the 22nd floor this is where we first come across stromatolites and nothing else stromatolites are made by bacteria one of the simplest of life forms So life started out simple, just as Darwin said it did. But as we go forward in time, when do living things become more complex and more varied? For the next 1,400 million years, or 28 floors of our skyscraper, little changes. The only life forms are simple, single-celled creatures. 2.1 billion years ago, on the 50th floor, we find the first cells with a nucleus. the type of cell we see in 99% of living things today. From here, we have to travel all the way up to the 80th floor, 600 million years ago, before we find the first animals. Scientists think these inch-wide disks are the remains of cup-shaped creatures that lived on a muddy sea floor. They're similar to modern sea anemones. Finally, two floors later, life has really taken off. these fantastic creatures are from the Cambrian period 500 million years ago they are very different from the simpler life that existed before they have heads and limbs their strange shapes and elaborate bodies reveal that life has become more varied and more complex the dating of fossils confirms Darwin's prediction that life started out simple with no evidence of complex life until much later. Living things weren't all created at once, but over thousands of millions of years, the theory of evolution passes the first two tests. But Darwin's biggest idea, and the one on which his whole reputation rests, is his third claim. His explanation for how life became more complex. Darwin said there was a force of nature that created new species. He called it natural selection but what is natural selection and can it really have transformed a few simple bacteria into the rich complex life forms we see today panama central america as dawn breaks the forest comes alive this is one of the richest environments on earth here more than anywhere you cannot avoid one inescapable fact. Life is varied. Biologist David Rubik of the Smithsonian Tropical Research Institute has spent 30 years studying the wildlife here. Even after all that time, he's still amazed at the diversity of life in this small patch of jungle. Look at all the action here. If we looked around here, we would find almost 500 different kinds butterflies that live just in this one acre of tropical forest even in the tiny area the crane covers at full reach scientists have found 240 species of plants over 4 000 species of insects and nearly 50 species of mammals and they're still counting but what created this dazzling diversity and how did the earth's myriad of species come to be some think they must be the work of a divine creator darwin on the other hand claimed that they evolved naturally through a process he called natural selection it's one of the most breathtaking ideas ever conceived but what is natural selection and how does it work how can a blind undirected force of nature create new species darwin saw the answer in an unlikely place the relentless slaughter of the natural world nature is brutal most creatures that are born on this earth die before they can reproduce and it's not just animals most plants die young too according to darwin out of this ghastly slaughter something beautiful emerges some individuals have characteristics which make them more likely to survive perhaps they have sharper eyes or quicker hooves to help them escape a predator either way these individuals are more likely to live long enough to produce young this is survival of the fittest and it's mainly the fittest who passed their characteristics on to the next generation in natural history there's a future and the future belongs to the fit darwin said that over many generations these small differences can grow into large differences Eyes get sharper. Legs go faster. Eventually the changes become so great they lead to new species. This explains how life gets more complex. But how does it get more diverse? How does one species become two? According to Darwin, the answer lies in the environment. Imagine that a group of brown bears leaves its natural home and heads north to the Arctic. In this new environment, a bear with light-colored fur will find it easier to hunt seals, making it more likely to survive. More light-colored bears reproduce, and eventually the color of the bear population changes. According to the scientists, that's what happened. Step by step, a population of brown bears became polar bears. One species became two. This is Darwin's big idea. evolution by natural selection species can branch off like limbs of a tree and over time evolve into new species it's an extraordinary idea that tiny changes each offering some small advantage can build up into a new species but is it true darwin's opponents say not they argue that many animals have features so complex that they can't possibly have evolved. The aerodynamics of a hummingbird's wings, the pumping action of a beating heart, the firing of neurons in an active brain. But are these the work of a supreme designer, or did they evolve by natural selection? Critics of Darwin's theory focus their attacks on one organ in particular. The eye, they argue, only works when it's fully formed like a camera the eye needs a lens to focus the image an iris to control the amount of light that enters and photoreceptors to detect that light what use they ask is a half-built eye to show that natural selection works scientists have to demonstrate that an eye could evolve in small steps each step offering an advantage over the one before at lund university in sweden dan eric nielsen researches animal vision he's convinced that eyes evolved by natural selection not just once but several times so these are eyes of box jellyfish each animal has four of these structures and each carries one large lens eye a smaller lens one pair of slit eyes and one pair of pit eyes they've got 24 eyes all together they haven't got a brain our eye is very sophisticated but could it have evolved from simple eyes like these nielsen has built models to show how natural selection can turn a simple patch of light sensitive cells like these into a complex eye step by tiny step the first shows the earliest stages of eye evolution. It demonstrates how a flat piece of light-sensitive skin could deepen over thousands of generations to form a depression. And if you hold this model up against the light, see that the flat piece of skin gives you no information about where the lamp is. But if, step by step, the eye socket got deeper and the opening at the front smaller, represented here by the ping-pong balls the direction of the lamp becomes clearer each step offers an advantage over the one before pit eyes like this are used by some flatworms detecting the direction of light helps them avoid predators the biggest improvement came with natural selection found a way to focus light we can focus light gradually by this little device which is a water inflatable lens by injecting water into the lens we can gradually form the lens so the image gradually becomes sharper until we eventually have a pretty nice and crisp image at the bottom of the retina the combination of an iris and a lens created a defined image on the retina in nature the most likely way the lens formed was when part of the transparent liquid that fills the eye became denser little by little this focused the light and vision became sharper once again each step is an improvement on the last the demonstration shows that the eye could have evolved by natural selection just as darwin said it did in the cambrian period of earth history 543 million years ago the competition to hunt food escape predators and find a mate drove the eye's rapid evolution dame is true of other complex organs from beating wings to pumping hearts nielsen's demonstration shows that darwin's big idea natural selection is theoretically possible but is it true in practice what evidence is there that evolution happened in these small step-by-step changes evolutionists claim that all large creatures living on land today including us came from fish that walked out of the water but if some fish did become land animals where is the evidence they're all familiar with the idea that we descended from apes but if we travel further back in time our ancestors according to the fossil evidence were far stranger to illustrate where we could have evolved from imagine this skyscraper represents the history of life on earth the first floor is when the earth formed about four and a half billion years ago each floor we go up represents 50 million years and the roof is the present day if we travel to floor 87 250 million years ago our forerunners would have been reptiles creatures like today's lizards turtles and crocodiles drop down another floor back in time another 50 million years and we were amphibians two floors further down 400 million years ago our ancestors were primitive fish swimming in the sea in the big picture the fossil evidence tells an extraordinary story of our past one in which living things evolved into new species step by step but there's a problem look closely and the fossil record is imperfect it contains gaps missing links that cast doubt on Darwin's theory so do these missing fossils exist and it's just we haven't found them yet or was darwin wrong when darwin wrote his theory in 1859 the gaps in the fossil record were enormous little was known of human evolution there were no fossil remains of hominids fossil birds seemed to appear in the rocks out of nowhere and there was no evidence of how fish could crawl out of the sea to walk on land all crucial missing links. If Darwin's theory is to stand up, scientists need to find the missing links, the transitional animals that show that evolution happens step by step. Fossil hunter Neil Shubin of the Field Museum and University of Chicago is on a mission to fill one of the most crucial of these missing links. The world is full of missing things. That's the joy of science, right? If there weren't missing things, they'd be out of business. He hopes to find the transitional animal between fish and amphibians that shows how life came out of the water. His search has led him to one of the most northerly places in the world, Ellesmere Island, just 600 miles from the North Pole. What's remarkable about the place is there you're standing in an arctic landscape today with muskox and polar bear. But the rocks that you're standing on, if you look inside them, have a tropical world, have tropical plants, have tropical fish. The rocks here once straddled the equator. But the action of plate tectonics over hundreds of millions of years has pushed them toward the North Pole. The rocks are 375 million years old, a time just before the first land animals appeared. If fish came out of the water, Shubin predicts they did it here. For five years, Shubin and his team traipsed across this barren landscape, scouring the rocks for signs of a missing lake. But all they found were sea creatures. Finally, in 2004, they made a breakthrough. We found little bits of pieces of bone on the surface. We dug in. Then we found a layer that contained whole skeletons. Then we dug further, and one of my colleagues, oh, I'll never forget this, My colleague was flipping rocks, and he found a snout sticking out the side of the cliff. We looked at that snout, and it turned out it was a flat-headed creature. Now, this flat-headed creature is unlike any fish that really lives straight in water. It was a very crocodile-like animal. And it's when we discovered that we knew we were finding what we were looking for. It was the highlight of five years of fieldwork. Back in the laboratory, they carefully removed the rock from around the fossil. The result was stunning. a creature that perfectly bridged the gap between fish and land animals. Like a fish, it has scales on its back and fins, and you can see the webbing right here. But like animals that evolved to walk on land, it has a neck where a head can move separately from the body. It has a flat head with eyes on top, much like a crocodile. And most interestingly, when we take the fin apart, what we see inside are bones that correspond to bones of our own arms. Shoulder, elbow and wrist They named the creature Tiktaalik Inuit for large freshwater fish Tiktaalik is a true missing link A creature with scales like a fish And limbs for walking Developing legs helped fish that moved onto land survive It was probably because they offered this crucial advantage That legs and walking on land took off Tiktaalik is a missing link that helps prove that Darwin was right. But we're lucky to have it. A rough estimate says that only one in a thousand of all species that ever lived are preserved as fossils. If you think that it took us six years of dedicated work to find Tiktaalik, that gives you a sense of how difficult it is to find fossil intermediates. Despite that, we have fossil intermediates for almost every major evolutionary transition. Since Darwin's day, science has advanced. Fossil hunters have found many of the so-called missing links. Fossils like Archaeopteryx and bird fossils recently discovered in China bridge the gaps between reptiles and modern birds. And excavations in Africa have uncovered over a dozen species of hominid. Fossils show that starting about 4 million years ago, an ape-like creature's brain grew steadily larger. It began to walk on two legs and learned to use tools. Step by step, it became a modern human. Natural selection can explain how new species evolve, including us. But some species remain a puzzle, because if natural selection works, they should not exist. So far, Darwin's theory has withstood the objections of its critics. But can it withstand the next challenge? Among the thousands of creatures on our planet are some that are so bright, so beautiful, they should not be able to survive. Evolution is all about acquiring features that help you survive. But many birds are so brightly colored that predators can spot them a mile away. so how can natural selection explain this how could creatures evolve that are just begging to be eaten in India their natural home peacocks are on the menu of one of nature's most ferocious hunters the tiger bird to survive in the wild the last thing it needs is a handicap a tail that makes it visible to predators and slows down its escape this is easy to explain God created them this way but for evolutionists it's a puzzle how could natural selection produce features that seem to hinder rather than help an animal survive it's a problem that threatens to undermine Darwin's whole theory behavioral ecologist Marian Petrie has tackled this puzzling phenomenon Darwin once said that the sight of the peacock's train whenever i gazed it makes me sick because he couldn't understand how something that was clearly detrimental to survival could have evolved if survival of the fittest was at work you would think that peacocks would have died out but darwin realized that evolution wasn't just about surviving it involved something else sex darwin proposed that the female brain played a key role in evolution. Female birds, he argued, preferred males with bright feathers and flashy tails. Because these flashy males were more successful with the girls, they had more offspring. Over many generations, their brighter colors spread through the population, and gradually, dull-colored birds died out. For over a century, no one investigated to see if this was true, until Petrie decided to tackle the problem. On a pea fowl farm in Norfolk, England, she decided to find out if pea hens really preferred the peacocks with the flashiest tails. Her research tool? A pair of scissors. To make some of the flashiest males a little less fancy, she cut off 20 outer eye spots on their tails. During the mating season, Petrie and her team watched to see whether the cut down peacocks or their intact rivals were the biggest hit with the girls we recorded mating success of each particular male and we found that peacocks with the fancier tails actually achieved more matings petrie found that a bird with a full tail was more than twice as likely to mate than one with a cut down tail darwin was right female choice drives the evolution of colorful long-tailed birds. But the result opens up another question. Why have generations of females chosen mates with bright colors and flashy tails? The answer could lie in the quality of their genes. Only the males with the best genes are strong enough to grow the longest tails and produce the brightest colors. By mating with the most colorful males, the females help to ensure that their offspring will survive and reproduce female choice explains why male birds are so brightly colored just as Darwin predicted once again Darwin's theory survives intact but one final mystery remains biologists need to show how change happens how on the microscopic level could this evolve into a human from all the evidence we've seen so far it seems that Darwin was right life evolved over millions of years nature transformed simple living things into modern plants and animals back in the 19th century Darwin didn't have the tools to explain how but today at last we can last few decades a revolution has swept through biology. Researchers now have the tools to unravel the greatest riddle of all, how one species turns into another. The first clue came in 1953 with the discovery of the structure of DNA. DNA carries the genetic instructions for building life. It's passed down from one generation to the next. Unravel its coiled double helix structure and you find stretches of code called genes we have around 22 000 genes in our dna they carry the information that determines eye color height and just about everything that makes us us it's the genes that tell an embryo what to become one set of genes will produce a fish another set will make a frog and it's the genes that tell scientists how one living thing transforms over millions of years into another University of California in Berkeley professor Mike Levine and grad student Brad Davidson have discovered that changing just one gene can make a huge leap in body design they study sea squirts well it looks humble doesn't look like much when you compare it to most other animals but in the laboratory it's a star researchers consider the sea squirt larvae a good approximation of what our early human ancestors might have looked like around 550 million years ago if they're right then the human heart evolved from a heart like the sea squirts our heart has four chambers frogs or snakes their hearts have three chambers then you go down the fish, they have two chambers. Well, the sea squirt heart has only one chamber, but it is unquestionably related to our heart. So can this humble creature tell us how our heart evolved? At a harbor near San Francisco, the team collects sea squirts for an experiment. In the laboratory, Davidson extracts and fertilizes their eggs. He then zaps them with an electric current to insert a loop of DNA into the developing embryo. The operation is equivalent to changing the activity of one gene in the squirt's DNA. But it has a remarkable effect. Under the laser microscope, Levine and Davidson watch the cells that will form the one-chambered heart. An extraordinary transformation takes place. If you look at the C-squirt embryo, it has spare parts. It has extra cells. Normally, those cells form tail muscles. and what we did was to convert those tail muscle cells into extra hearts instead of a single chamber the c-squared heart now has two and in this case there's a nicely formed long heart here and then there's this little extra chamber up here so you'll see these individual blood cells making this kind of s-like twisting motion moving first through the long chamber and then up and back through the second chamber we're not just getting a heart that looks like it has two chambers those two chambers are really functioning with one tiny genetic change they have turned a simple heart into a more complex one in just one generation changing genes in the laboratory is one thing but for evolution to happen genes have to change by themselves in nature it turns out that all animals including us have a way of making this happen to pass the instructions for life from one generation to the next, an animal has to copy its DNA. And whenever anything's copied, errors can occur. But the enzymes that are responsible for constantly replicating DNA do not do it with 100% precision. They're a little off. It's almost as if there's a built-in mechanism for change. these random errors are the building blocks of new species when the dna changes genes change and animals change too but research in the last few years has thrown up a mystery when biologists started decoding the dna of plants and animals in the 1970s they assumed that the genes of one animal would be very different from another. They were in for a shock. It turns out that when it comes to genes, we humans aren't that different from other species. Around 96% of our DNA is the same as chimpanzees. Around 75% of our genes are the same as dogs. And we share around a third of our genes with daffodils. So if our DNA is so similar, why do earth's creatures all look so different to find the answer we have to look at one of the most amazing transformations that ever occurred whales and dolphins are not fish they're mammals about 55 million years ago their ancestors gave up the land and began to live in the sea at Stanford University biologist David Kingsley is investigating the mystery of how the whale lost its legs if you look at a whale they're streamlined they're able to swim at high speeds in the ocean the streamline has been achieved by the loss of what would normally be behind limb structure the whales ancestors transformed their front legs into flippers but how did they lose their hind legs completely what change in DNA caused this to happen the answer to this huge problem comes down to one of of the smallest animals on the planet. Sticklebacks come in two forms. Some have a hind limb, and for a good reason. In this rare film, a trout attempts to swallow a stickleback, but the hind limb makes the stickleback too wide to swallow, and it escapes. But in ponds without trout, some sticklebacks have lost their hind limbs, and this provides a clue to how the whale lost its legs. In his laboratory, Kingsley and his team look for the genes responsible for the stickleback's disappearing limbs. They found that the development of the fish's hind limbs is largely controlled by a gene called PIDX1. It's only a single gene itself, but it's a white-collar gene. The way that a hind fin develops requires this manager gene turning on very early in development and coordinating the activity of a whole series of other genes. Fish with hind limbs and fish without them, both contain the PIDX1 gene. What makes them different is not the gene itself, but a nearby piece of DNA. In sticklebacks with hind limbs, a piece of DNA called a regulating switch responds to a chemical stimulus and turns the PIDX gene on. The hind limb grows. But in sticklebacks without hind limbs, a small change of DNA in the switch has inactivated it. The gene doesn't turn on when it should, and the hind limb doesn't develop. Kingsley and his team now think that what happened in the stickleback also occurred in whales. A small change of DNA in the regulating switch in the ancestors of whales could have turned off the PITX1 gene. It would have stopped their hind legs developing. The discovery of switches that turn genes on and off reveals how one species transforms itself into another. It also explains why the genes of animals are so similar. One extreme point of view is that basically all the animals, you know, from the simplest worms right up to humans, have more or less the same complement of genes. What has happened that makes all these animal groups so very different from one another is that the genes are deployed in different ways. A new science of genetics shows that evolution can occur faster and more easily than scientists thought. For over 140 years, people have attacked Darwin's theory. But look at the evidence, and the objections don't stand up. One by one, science has proved them wrong. The evidence is so overwhelming that knowledgeable experts now regard the theory of evolution as fact. Was Darwin wrong? You're serious. Was Darwin wrong? He was one of the first people with the intelligence and imagination to get it right. All of this information, this vast crush of knowledge, has vindicated Darwin in general, in particular, specifically, and every other way. There's always going to be things we don't know about nature. But what we know is so profound and so elegant and shows us so dramatically how evolution happened, including our own evolution, that it's an inescapable fact. Natural selection not only explains the rich variety of the natural world, it's the only rational explanation for it. From the color of flowers to the fins of a whale. From a distance, the variety and richness of life is dazzling. It can seem almost like a miracle But the real miracle is that simple natural laws Can create such an extraordinary and varied world And that one of nature's own creations The human mind Is capable of understanding the simple scientific truth Of how we came to be here