100 Greatest Discoveries (2004) s01e05 Episode Script
Evolution
A killer asteroid streaking to our earth at sixty seven miles an hour.
Giant chimney like tower scorching hot, rising from the bottom of the ocean floor.
A young man at the sea voyage shook the foundation of the world.
An expedition back through time into the heart of human ancestry Of all the discoveries in the histories of science, few have the power to compare Or the potential for controversy.
And those concerning how life on earth begin How species evolved Why some species survive And others become extinct These are the greatest discoveries in the origin and evolution of life.
Life is a game of chance.
The odds of surviving or facing extinction are always changing.
Some changes are gradual, result of slow process of nature Others happened in a blink.
Like one that caused the extinction of the ancient dinosaurs.
In 1980, a geologist named Walter Alvarez was studying rock stratum in mountains north of Rome.
When he came cross something curious, a thin ancient layer of clay.
So, this clay layer right here marks the boundary between two different geological periods.
The clay of layer marks what is known geology as KT boundary.
A dramatic turning point in history of earth about sixty five million years ago.
When the ancient dinosaur mysteriously vanished.
For Alvarez, here was the moment of discovery, Analyzing samples of KT boundary, he found the clay contain extremely high levels of iridium And element rare of them on earth, but abundant in space.
When similar levels of iridium was found around the world.
Alvarez began to wonder what could have cause it to blank the earth The answer he concluded was the impact form an asteroid of gigantic proportions.
Over six miles across, taller than Mount Everest Moving at a speed of sixty seven thousand miles an hour.
Doctor Elisabeth Pierazzo is a research scientist in the planetary science institute in Tucson Arizona.
So how much energy is this thing has An energy that's about a hundred million megatons of TN and this is about ten times the world wide nuclear arsenal at the peak of the cold war.
Ten times world's nuclear arsenal Well it was really big.
Yes.
All in one place, All in one point, released in a second So that was humongous amount of energy that was delivered to the earth.
The devastation was colossal The cloud of vaporized rock bring mushroom into the air, blocking the sun.
Scorching fire balls blasts across the face of the earth The air became choke with poisonous gases and soot Nearly half of all life forms on earth perished in the including the ancient dinosaurs The only piece of puzzle missing from Alvarez's story was proof of the asteroid.
If it was as big as he said it was, then it must have left a large crater.
Finally geologist found one that just happened to be about sixty five million years old The Chicxulub crater And a main's hole 112 miles wide, buried under the thick layer of settlement at the bottom of the Gulf of Mexico Of the coast of the Yucatan Peninsula concentric rings.
Yes, so the complexity increases with the magnitude of the impact event because the Chicxulub crater is underwater, this is a good place to get the sense of what happened when the asteroid hit.
This is a meteor crater in Arizona.
Fifty thousand years ago, a meteorite about the size of a house Streak out of the sky and slammed into the earth.
Its triggers and explosion greater than twenty million tons of TNT.
And created this, a crater five hundred and fifty feet deep and three quarters of a mile cross.
Room enough for twenty football fields and more than two million spectators.
Impressive, isn't But remember, the asteroid that caused the KT event was a size of Mount Everest So to visualize the crater that it made we need something a lot bigger.
Like the grant canyon.
This is the south ramp; from here to the other side is 16 miles But even that is not big enough.
The asteroid that caused the KT extinction blasted a crater 8 times as large.
125 miles across, from here the gaming tables in Las Vegas And when the asteroid hit, it went deep as well It's a long climb here to the bottom of the canyon, about a mile and a quarter But according to Walter Alvarez, the asteroid made a crater that was staggering twenty miles deep upon impact Then quickly filled in.
How do scientists know all this The evidence is come from a variety of sources Seismic studies revealed that enormous ring-like shape of the crater.
Thousands of course samples uncover rocks with traces of having been altered by high impact collision.
And computer modeling calculated explosion what would take the crater of The Chicxulub crater But Walter Alvarez's discovery would caused the extinction of ancient dinosaurs is not without controversy.
His asteroid scenario at the center of now going to debate.
With the opposing scientists offering their own theories One theory argued that intense volcanic eruptions poisoned the earth's atmosphere And killed the ancient dinosaurs before the KT event ever occurred.
But Alvarez's theory has with stood the challenge.
So this has been almost twenty five years.
It's about.
Yeah The theory is still got, oh, the theory is stronger and stronger Because scientist form many disciplines have investigated the evidence Form paleontologists to oceanographers, and their research overwhelmingly support what Alvarez said the discovery That the KT asteroid was responsible for the extinctions of the dinosaurs Today, the extinction of the ancient dinosaurs is taken for granted But for centuries, the world had no inkling that the fable creature ever existed Dinosaurs fossils have been turning up since ancient times A jaw here, a claw there.
But no one has the clue who are what the enormous bones belong to But all that began to change in the early part of the ninetieth century, The discovery of the dinosaurs unfolded in a series of small but significant fossil fines The first brought the ancient reptiles to the attention of scientific world In 1828, a naturalist gave the name iguanodon to the creature Whose large chisel shaped teeth were found protruding from piece of sandstone in the south of England Around the same time, megalosaurus was named By a professor of geology after some of its bones were unearthed in a London quarry Because so little evidence existed to prove that these reptiles had ever roomed in the earth.
Scientist relied heavily on their imagination to interpret the anonymous of the giant creatures Often they described them as oversized version of living lizard But with each new fossils discovered came greater new understanding.
By 1849, the fossils of nine completely different reptiles had been discovered.
And British anatomist named Richard Owen created a new scientific category for their identification Readopt them dinosaurs, meaning terrible lizard To the world of the eighteenths hundreds, the discovery was revolutionary It helped give birth to the science of paleontology And because this creature are obvious extinct, the discovery stirred the debate about the history of life on earth For hundred fifty million years, dinosaurs dominated life on earth But when they were showed the access doorit made rooms for other species to evolve and dominate 65 million years later, here we are See, the ancient dinosaurs hadn't die out.
You have to figure we wouldn't be here.
So, how do we get here in the first place Where on earth did life emerge Our next great discovery offered a compelling possibility for the kitchen of creation.
Think of the volcano and the image that comes to mind is a mountain miles high with steam rising out of its crater, But the volcano here in yellow stone is a little bit different.
We are standing on it.
Nearly all of yellow stone's two million acres sit on top of an enormous underground super volcano, forty miles wild Its crater is here, just below the surface.
And down there is molten rock, the source of intense heat, the power of old faithful And the simmering volcano fuels the hot spring here as well A crater that some of the primitive microbes on the planet.
Bain in the primitivesoup, incubated by volcanic steam The organism flourished.
This led some scientists to speculate that the setting with condition like this here in yellow stone Could have been where life first started.
And our next great discovery demonstrated how it might have happened In 1953, a doctoral student named Stanley Miller conducted a series of experiments To reproduce his lab the same conditions that probably existed on primeval earth.
Water but no oxygen in the air An atmosphere teaming with mixed of gases.
Sulfur and methane, hydrogen and ammonia Miller started by filling in an enclosed container with water, then he added the mix of gases.
To replicate the effect of the sun, he heated the mixture with Bunsen burner To simulate lightning bolts, he jolted the concoction with bursts of electricity He waited several days before analyzing the liquid in the container.
The result was astonishing.
The liquid contained organic compounds, a central building block for creating proteins.
Which play a vital role in the biochemical spark that starts life.
So what did Stanley Miller discover While he didn't create life in the lab, He created the potential for life.
And that's significant.
It meant with the right materials and right conditions, life could happen anywhere.
However there's no shortage of the theories.
Some scientists have even speculated that the life building protein that Stanley miller created in his lab Could have arrived aboard a comet or asteroid form deep space, seeding the earth Or perhaps the answer lies in the bottom of the ocean.
With our next great discovery In 1977, a deep sea submarine descended over 8000 feet Its mission To investigate hydrothermal activity on the ocean floor.
Marine explorer Robert Ballard was on board He detected a dramatic change of the ocean's temperature.
We were not expecting what we found.
We are expecting to find water And we had a camera inside vehicle but it was, just taking pictures We didn't know we have it came back We brought it up to the surface And we processed the film And we got, we knew the spot that the temperature was and it was like going to Disneyland Probably one of the biggest biological discovery ever make on earth was made that day Ballard and his team were the first to see it, face to face Hydrothermal vents.
And mass chimney like structures, several stories high.
Spewing hot water Geyserblack with mineral and nutrients.
And then the astonishing sight.
Life thriving without sunlight, a biological community never seen before.
An exotic garden of marine life.
Species without eyes What we totally were blind away by were these giant tube worms, among eight, nine, ten feet tall And when you cut them, they bled human like blood I mean when the submarine landed, there was a squash and red blood came up around all portholes And that's how, how eerie it was And then to find this extremely unusual creatures living in this oasis It had no relationship to the normal life in the deep sea And here they were living in this toxic water But yet this creature was thriving on it And then when we dissected, I remember, when we took on a clams We opened up it first and, oh, since we open it up, it 's stonk It's full of hydrogen and sulfur.
It's horrible smell, raw eggs Yes, and when we look, it did, it looked like beef.
Was red, bright red, and it didn't have anatomy clam, those like What happened to the clam, someone is taken over its body And something was bacteria A tiny bacteria that had figured out over years of time How to duplicate photosynthesize in the dark chemically Through processes we know chemosynthesis.
That was the discovery That there was another life system on earth that did not go by the book that you and I read There was not living on energy like sun, but was living on energy of the earth itself.
And that really opened up the board gain, I'll see It's bacteria we now think are the largest mass of living things on earth.
And there are in the rocks, everywhere, under the ocean If you add all the people and all the living things on land And bought the creation in the ocean and through few things in the sky and you got number somebody tons There's more tons of biomass It you think that the insects rule the world Wrong, it's bacteria So where are these vents All over the earth.
Imagine a baseball that was seam on it That seem began beneath the polar icecaps, goes down through the Atlantic.
Into the Indian ocean, across the Pacific Ocean As a largest feature on earth, the mid ocean ridge And it's underlying by literally ten thousands of Magma Chambers Is that where life began Well that's what people are now thinking The biology books that we were reading have now been thrown away.
And when I grown I have learned everything on surface.
Yes you have this soup in the lightning heated and new formed amino acid and things like that But now, we think that the hydrothermal vents may have been the site of life on earth It also given us a new prospecting to, for searching for Elsewhere with our solar system.
We now are looking at the moon of Jupiter called Europe Which we think has an ocean, we think it has underwater volcanoes and should be life on there.
The question is how smart the clams Did hydrothermal vents give birth to the first primitive microbe on earth Perhaps But one thing is certain, Their discovery challenged the long beliefs about the conditions necessary for creating life.
And once life happened, there was no stopping Was doing some field work in British Columbia He and his wife were riding along a mountain trail The story goes; one of their mules lost a shoe.
And when Walcott bent down and retrieved it, he came across a piece of shale A rock, and it was ordinary looking at first when the sunlight heated it, it shimmered like silver And he looked closely and it was a pattern, a fossil So it needs more exploration to find this one piece of rock come from They came across something that no one has ever seen before Wolcott called his discovery the burgess shale.
Douglas Erwin is curator of the Smithsonian national museum of natural history.
Like the dinosaurs you find the bones, you find the bones.
You can't find the intestine, stomach and eyes or whatever The burgess shale we find all of these in pieces For under I take you into the secret room.
Yes, this is a secret room.
How action seen And this is a general keep a lot of important fossils traveled by Trilobite, ammonite and burgess shale.
That's what I want to show you We have the cart part here So, originally these would have been one piece like this.
Somebody hit this of the hammer.
And split one middle from fossil So this is the Aysheaia, aysheaia is a form of worm When they moved from the ocean to land, We have no idea, but you can see the legs, like, or something like the antenna And if you move that back and forth, you can see shinny beats at the end of the legs And those the toenails Of course they are The fossils that Wolcott discovered were remarkably preserved A vivid snapshot of the time when ancient life on earth was dominated by curious underwater creatures This is a bigger predator of the Cambrian, In china, some probably to three feet long to six feet long It's probably a cousin of the anthropoid, insects and crabs and something like these The mouth actually opened up, and as those rotated and close, it crunched the carapace Like the beak of an octopus Yeah, this is an Opabinia Opabinia It's one of my favorites, probably cause it's a such weird animal It's just like someone had made it up Yean, I mean, it's sort like the Chinese menu You take one part from column A, one part from column B, and you end up something like this But it's something we can't compare with today Five eyes, claws, claws The site of the burgess shale was created by a sudden and violent active nature Underwater mudflow stroke fast A landslide of settlement crashed down, burring everything as it passed They were remained in tomb for hundreds of millions of years Nothing to help to complicated Only began to have first animal diversifying of this whole wide arrange of things So far, the discovery of the burgess shale An astonishing explosion of multicell body types Astonishing because for billions of years, the earth had been dominated by one celled creatures For many scientist, The diversity of the burgess shale fossils is evidence of dramatic shift in the evolution of life on earth the evolution equivalent the big bang The burgess shale is a wonderful window into this big bang of animal life.
Where very rapidly we get plates of the always different architectures always different ways of making a living in this whole ecosystem Better than play with the dinosaurs, Why do you think it's better than play with dinosaur Well, these are much more fascinating And dinosaurs are not very long until that they turned into birds Yes, they're soft Opabinia is a much cooler animal when into crunch and shrug But the five year old kids don't know it yet Even Steven Spielberg and Lucas wouldn't come up with Opabinia That's why it's so cool.
We never know the exist without the burgess shale.
Not all the great discovery started with uncovering a piece of physical evidence It wasn't always a place to explore or fossil to find.
Our next great discovery started with an idea.
Early in the 18th century, scientists were just coming to grip the idea that species could become extinct.
It could disappear And that sort of was a slight show.
The main attraction was the classification of the naming of all these newly discovered types of plants and animals Now, back then, they didn't really have a good system to the classification and naming of living things So, scientists might find a new type of living thing, and then just named whatever they wished.
Making someone weird Latin word A botanist named Carl Linneus straight things out when he came up with his system for classify every living thing Scientists at the time thought it was genius But Linneus had the self-called greatest achievement in science.
Well we still use a lot of Linneus's tradition today Including naming things by their genus and species the binomial system.
You and I are still called Homo sapiens for example Now that Linneus's system was based on the sex organs of plants So one of the contemporary guy named ++ thought it was immoral and offensive So, then he's named a particular plant sigas bekia cause it was a stinky weed Today, the science of classify species has expanded beyond the Linneus's system With information from deep DNA sequencing and analysis of miraculous data Scientist had new understanding of relationships among species As a result, modern classification systems advocate categorizing species based on how they evolved How they fit in the tree of life A concept that Linneus will never consider because the theory of evolution by natural selection had yet to be developed.
But when it was, many would consider it was the greatest discovery in the history of the world.
There was no anesthetic And young medical students were forced to watch and learn, The young man who worked out that day was Charles Darwin.
He audeal of the operating room was too much for him.
Over his father's subjection, he quit medical school To pursue his dream of becoming a naturalist.
Darwin was hired as a naturalist to board the British amoulty HMS Beagle Which embarked on expedition to survey and map coast water around the world He shared a small cabin with the captain, with whom he has several disagreements, including the story of creation.
Darwin While the captain held the bible's account of creation.
Darwin believed that the earth had changed slowly over millions of years.
It was a debate that followed Darwin for the rest of his life The British government paid for this.
No actually Darwin's father paid for his voyage.
And also paid for his assistant to come with Darwin and helped him Skin the specimen and prepare the crates for shipment He worked at little poor deck where he had all his specimens.
Just about something like this.
The beagles made stop over ports of Australia to south America And Darwin made the most of it.
He recorded the extensive observation about the indigenous plants and wild lives He collected preserved thousands of specimens for study For years after the voyage, Darwin recorded the observations he made while aboard the beagle He opened his first species notebook and asked himself a question.
What are the laws of life Is this Darwin's whole point It was Darwin's whole point To try to find laws operating in the natural worlds and laws and physicists and chemists had found in inorganic nature.
Darwin searched to understand the laws of nature took shape as he studied the animals on the Galapagos Islands Of special interests to him, the physical differences was within a certain species.
For example, the finches on the Galapagos Islands had different shape of beaks They varied according to the environments where the finches live Some had beaks that were hard and blunt, idea for hammering open crab shells Others had beaks that were more taper and suited for hunting and packing among rocks The difference was puzzling As Darwin analyzed it, He began thinking about how the struggle to survive was the driving force behind the all life As the species is thriving at its environment, it has to evolve or perish, With this simple yet powerful insight, history was made.
Darwin discovered the mechanism that made evolution work.
The process of natural selection.
Darwin isn't the first guy really come up with this right What was his special or particular insight He was the first to come up with the specific mechanism, that's natural selection He was the first to popularize the idea deep time millions of years that this process involved He was the first to popularize the idea of the tree of life.
Which were related to all the living things The great geneticist Dobzhansky once said Nothing in biology makes sense without evolution.
How we got here, what kind of creature we are .
How we were related to everything in the nature.
It has been established we are all part of wonderful great tree of life.
Plug into a blood line to a DNA that links us to every living thing on earth.
That's not a matter of foragle.
That's literal.
He knew there may be a religious storm protest His own wife was not happy that he was going to write things that were incompatible with the bible She wrote him a letter when they first marriage, saying, I hope that your science will not lead us to spend the eternity to very different places And she was seriously concerned about this Plus he was trying to build up amount of evidence that would be incontrovertible Finally in 1859, Darwin published his theory of natural selection.
His book, origins of species is considered one of the greatest books ever written.
People are talking about the theory of evolution, right But Darwin was the guy that said that there isn't any absolute truth there.
Darwin being one of the first thinkers try to tell us that science is provisional.
It changes What do you mean by provisional.
That the best truth you have in that moment And when you get more data, it can't been explained that way, And you have to get a new theory.
So, that is not an eternal truth.
It's a provisional truth.
It changes.
And he didn't want evolution to be accepted an the dogma or a creed He would be the first to say throw out if you got something better But we didn't find anything better.
Yes, we didn't find anything better.
In fact, what we found was that an entire new sciences that were undreamed up in Darwin's day have come up with the study of molecular genetics and DNA which enforces the idea of evolution so, now, everywhere we look today, we see something from Darwin's insights Darwin's theory of evolution changed everything.
His assertions that Humans evolved from ancient ancestors in Africa challenged traditional religious beliefs And motivated scientist of many disciplines to begin exploring the theory His one thing to claim that the human evolved from the Africa apes, it would be another thing to prove it In 1974, anthropologist Donald Johannsen and his team were working in Ethiopia When they came upon partial remains of an ancient hominoid A species considered to be part of family that includes human kind He named her Lucy.
After the beetle's song Lucy in the sky with diamonds.
Despite of her fragment remains, Lucy has remarkable secrets to share about her life.
As the time of her discovery, the most complete hominoid skeleton ever found was last a hundred thousand years old.
Doctor ken Mowbray is an anthropologist within the America museum of natural history.
Well, Lucy really shook up the family of tree sort of speak Why was she such a big deal She was a big deal for many reasons.
First of all, her skeleton was 40 percent complete.
40 percent complete to you guys You know in fossil terms that's a lot for a fossil bones for individual Something even more important that makes it really significant Is that we believe that she was bipedal Have a of the cast here of the pelvis of the Lucy, the left side.
The pelvis is like this in the human body, it's short and it's broad If you look at chimpanzee, gorilla or orangutan their blades are really narrow and really tall.
The blade of Lucy and like ours is stand out really This allows the transference of weight if you were going to walk onto limbs So, from this pelvis lonely, think that, Lucy move on the landscape as a bipedal or biped Or he or me Exactly, he was walk around, he centrally like us.
Lucy's discovery sparked the debate of whether she would be the long sought after missing link Connecting apes with the first humans But some anthropologist like doctor Mombray believed that the missing link is a myth Now, for long time, people thought there was a link between chimpanzees and humans And when I look at chimpanzees and humans, I can see where it get that idea.
But is not that simple right Absolutely To have a better understanding that there wasn't a linear progression of evolution, especially with human That was much more diversified.
With Lucy and subsequent fossil fines, we really know that this tree of life is much more like a bush There's a lot experimentations going on and a lot of dead ends.
Regardless of whose ancient footstep we may be walking in.
There is one remarkable set of footprints without dispute When they made one of the greatest discoveries in the study of human origins A paired of fossilized footprints, old enough and small enough To have been made by two hominids, much like Lucy.
Those are the oldest human ancestors footprints that we have we know of today More importantly I think, it records behavior Their footprints let us know they were walking bipedally They were no fingerprints, there were no knuckle marks around, the imprints of their feet And on top of that, we know that they were in groups, they were social.
They weren't just walking by themselves.
A volcano erupted, covering the landscape with the thin layer of ash As rain fell, the ash became thick like wet cement And soon was covered by animal tracks Birds A rabbit And then the footprints of two hominids.
Eventually another volcanic eruption blanketed the spot with more ash, A protective layer that preserved the prints they hard and remained hidden Until Mary Leakey revealed them to the world.
Toumai A research team led by Michelle Bruyne unearthed six skull fragments of an ancient hominids They nicknamed toumai, meaning hope of life.
The skull revealed features never seen before.
An ape like cranium But with teeth far more humanlike More than twice as old as Lucy, raising significant new questions about the diversity of life among ancient hominids so, what's the significance of the skull for Chad, toumai.
Its tell us couple of different things.
What its telling is lot of diversity in the human fossil records There are lots of branches on this supposed tree.
And ended up just as evolution experiments at best We luckily are upon as a little twig of a really diverse family tree The last significance of the toumai skull is that it telling us to step back wave a huge of yellow caution flag And we evaluate the fossils we already have in the human family tree And reassess what it means to be a hominid What is it mean to you be a hominid Well, I look it being a hominid in two different ways Hominid's lack the ability to remain bored There were a group of primate out there that they had no ability just sit there and doing nothing And this coupled with operate perpetual bypetalism.
This is what a hominid means to me.
Bipedal and unable to remain bored Yes.
I'm a hominid doga.
Oh absolutely, we are hominids It's a fact of life on earth.
Extinction happens Eventually every species goes away of ancient dinosaurs So, why are we still here So, we are smart in the competition.
We are very well suited the earth's environment right now.
We've our shared damn luck So far, species that face catastrophe of a speeding asteroid Life, like a roulette is a game of chance.
But since the greatest discoveries we just explored The odds for our survival may be proved, because the more we understand about origin and nature of life, the more we may be able to keep our streek alive
Giant chimney like tower scorching hot, rising from the bottom of the ocean floor.
A young man at the sea voyage shook the foundation of the world.
An expedition back through time into the heart of human ancestry Of all the discoveries in the histories of science, few have the power to compare Or the potential for controversy.
And those concerning how life on earth begin How species evolved Why some species survive And others become extinct These are the greatest discoveries in the origin and evolution of life.
Life is a game of chance.
The odds of surviving or facing extinction are always changing.
Some changes are gradual, result of slow process of nature Others happened in a blink.
Like one that caused the extinction of the ancient dinosaurs.
In 1980, a geologist named Walter Alvarez was studying rock stratum in mountains north of Rome.
When he came cross something curious, a thin ancient layer of clay.
So, this clay layer right here marks the boundary between two different geological periods.
The clay of layer marks what is known geology as KT boundary.
A dramatic turning point in history of earth about sixty five million years ago.
When the ancient dinosaur mysteriously vanished.
For Alvarez, here was the moment of discovery, Analyzing samples of KT boundary, he found the clay contain extremely high levels of iridium And element rare of them on earth, but abundant in space.
When similar levels of iridium was found around the world.
Alvarez began to wonder what could have cause it to blank the earth The answer he concluded was the impact form an asteroid of gigantic proportions.
Over six miles across, taller than Mount Everest Moving at a speed of sixty seven thousand miles an hour.
Doctor Elisabeth Pierazzo is a research scientist in the planetary science institute in Tucson Arizona.
So how much energy is this thing has An energy that's about a hundred million megatons of TN and this is about ten times the world wide nuclear arsenal at the peak of the cold war.
Ten times world's nuclear arsenal Well it was really big.
Yes.
All in one place, All in one point, released in a second So that was humongous amount of energy that was delivered to the earth.
The devastation was colossal The cloud of vaporized rock bring mushroom into the air, blocking the sun.
Scorching fire balls blasts across the face of the earth The air became choke with poisonous gases and soot Nearly half of all life forms on earth perished in the including the ancient dinosaurs The only piece of puzzle missing from Alvarez's story was proof of the asteroid.
If it was as big as he said it was, then it must have left a large crater.
Finally geologist found one that just happened to be about sixty five million years old The Chicxulub crater And a main's hole 112 miles wide, buried under the thick layer of settlement at the bottom of the Gulf of Mexico Of the coast of the Yucatan Peninsula concentric rings.
Yes, so the complexity increases with the magnitude of the impact event because the Chicxulub crater is underwater, this is a good place to get the sense of what happened when the asteroid hit.
This is a meteor crater in Arizona.
Fifty thousand years ago, a meteorite about the size of a house Streak out of the sky and slammed into the earth.
Its triggers and explosion greater than twenty million tons of TNT.
And created this, a crater five hundred and fifty feet deep and three quarters of a mile cross.
Room enough for twenty football fields and more than two million spectators.
Impressive, isn't But remember, the asteroid that caused the KT event was a size of Mount Everest So to visualize the crater that it made we need something a lot bigger.
Like the grant canyon.
This is the south ramp; from here to the other side is 16 miles But even that is not big enough.
The asteroid that caused the KT extinction blasted a crater 8 times as large.
125 miles across, from here the gaming tables in Las Vegas And when the asteroid hit, it went deep as well It's a long climb here to the bottom of the canyon, about a mile and a quarter But according to Walter Alvarez, the asteroid made a crater that was staggering twenty miles deep upon impact Then quickly filled in.
How do scientists know all this The evidence is come from a variety of sources Seismic studies revealed that enormous ring-like shape of the crater.
Thousands of course samples uncover rocks with traces of having been altered by high impact collision.
And computer modeling calculated explosion what would take the crater of The Chicxulub crater But Walter Alvarez's discovery would caused the extinction of ancient dinosaurs is not without controversy.
His asteroid scenario at the center of now going to debate.
With the opposing scientists offering their own theories One theory argued that intense volcanic eruptions poisoned the earth's atmosphere And killed the ancient dinosaurs before the KT event ever occurred.
But Alvarez's theory has with stood the challenge.
So this has been almost twenty five years.
It's about.
Yeah The theory is still got, oh, the theory is stronger and stronger Because scientist form many disciplines have investigated the evidence Form paleontologists to oceanographers, and their research overwhelmingly support what Alvarez said the discovery That the KT asteroid was responsible for the extinctions of the dinosaurs Today, the extinction of the ancient dinosaurs is taken for granted But for centuries, the world had no inkling that the fable creature ever existed Dinosaurs fossils have been turning up since ancient times A jaw here, a claw there.
But no one has the clue who are what the enormous bones belong to But all that began to change in the early part of the ninetieth century, The discovery of the dinosaurs unfolded in a series of small but significant fossil fines The first brought the ancient reptiles to the attention of scientific world In 1828, a naturalist gave the name iguanodon to the creature Whose large chisel shaped teeth were found protruding from piece of sandstone in the south of England Around the same time, megalosaurus was named By a professor of geology after some of its bones were unearthed in a London quarry Because so little evidence existed to prove that these reptiles had ever roomed in the earth.
Scientist relied heavily on their imagination to interpret the anonymous of the giant creatures Often they described them as oversized version of living lizard But with each new fossils discovered came greater new understanding.
By 1849, the fossils of nine completely different reptiles had been discovered.
And British anatomist named Richard Owen created a new scientific category for their identification Readopt them dinosaurs, meaning terrible lizard To the world of the eighteenths hundreds, the discovery was revolutionary It helped give birth to the science of paleontology And because this creature are obvious extinct, the discovery stirred the debate about the history of life on earth For hundred fifty million years, dinosaurs dominated life on earth But when they were showed the access doorit made rooms for other species to evolve and dominate 65 million years later, here we are See, the ancient dinosaurs hadn't die out.
You have to figure we wouldn't be here.
So, how do we get here in the first place Where on earth did life emerge Our next great discovery offered a compelling possibility for the kitchen of creation.
Think of the volcano and the image that comes to mind is a mountain miles high with steam rising out of its crater, But the volcano here in yellow stone is a little bit different.
We are standing on it.
Nearly all of yellow stone's two million acres sit on top of an enormous underground super volcano, forty miles wild Its crater is here, just below the surface.
And down there is molten rock, the source of intense heat, the power of old faithful And the simmering volcano fuels the hot spring here as well A crater that some of the primitive microbes on the planet.
Bain in the primitivesoup, incubated by volcanic steam The organism flourished.
This led some scientists to speculate that the setting with condition like this here in yellow stone Could have been where life first started.
And our next great discovery demonstrated how it might have happened In 1953, a doctoral student named Stanley Miller conducted a series of experiments To reproduce his lab the same conditions that probably existed on primeval earth.
Water but no oxygen in the air An atmosphere teaming with mixed of gases.
Sulfur and methane, hydrogen and ammonia Miller started by filling in an enclosed container with water, then he added the mix of gases.
To replicate the effect of the sun, he heated the mixture with Bunsen burner To simulate lightning bolts, he jolted the concoction with bursts of electricity He waited several days before analyzing the liquid in the container.
The result was astonishing.
The liquid contained organic compounds, a central building block for creating proteins.
Which play a vital role in the biochemical spark that starts life.
So what did Stanley Miller discover While he didn't create life in the lab, He created the potential for life.
And that's significant.
It meant with the right materials and right conditions, life could happen anywhere.
However there's no shortage of the theories.
Some scientists have even speculated that the life building protein that Stanley miller created in his lab Could have arrived aboard a comet or asteroid form deep space, seeding the earth Or perhaps the answer lies in the bottom of the ocean.
With our next great discovery In 1977, a deep sea submarine descended over 8000 feet Its mission To investigate hydrothermal activity on the ocean floor.
Marine explorer Robert Ballard was on board He detected a dramatic change of the ocean's temperature.
We were not expecting what we found.
We are expecting to find water And we had a camera inside vehicle but it was, just taking pictures We didn't know we have it came back We brought it up to the surface And we processed the film And we got, we knew the spot that the temperature was and it was like going to Disneyland Probably one of the biggest biological discovery ever make on earth was made that day Ballard and his team were the first to see it, face to face Hydrothermal vents.
And mass chimney like structures, several stories high.
Spewing hot water Geyserblack with mineral and nutrients.
And then the astonishing sight.
Life thriving without sunlight, a biological community never seen before.
An exotic garden of marine life.
Species without eyes What we totally were blind away by were these giant tube worms, among eight, nine, ten feet tall And when you cut them, they bled human like blood I mean when the submarine landed, there was a squash and red blood came up around all portholes And that's how, how eerie it was And then to find this extremely unusual creatures living in this oasis It had no relationship to the normal life in the deep sea And here they were living in this toxic water But yet this creature was thriving on it And then when we dissected, I remember, when we took on a clams We opened up it first and, oh, since we open it up, it 's stonk It's full of hydrogen and sulfur.
It's horrible smell, raw eggs Yes, and when we look, it did, it looked like beef.
Was red, bright red, and it didn't have anatomy clam, those like What happened to the clam, someone is taken over its body And something was bacteria A tiny bacteria that had figured out over years of time How to duplicate photosynthesize in the dark chemically Through processes we know chemosynthesis.
That was the discovery That there was another life system on earth that did not go by the book that you and I read There was not living on energy like sun, but was living on energy of the earth itself.
And that really opened up the board gain, I'll see It's bacteria we now think are the largest mass of living things on earth.
And there are in the rocks, everywhere, under the ocean If you add all the people and all the living things on land And bought the creation in the ocean and through few things in the sky and you got number somebody tons There's more tons of biomass It you think that the insects rule the world Wrong, it's bacteria So where are these vents All over the earth.
Imagine a baseball that was seam on it That seem began beneath the polar icecaps, goes down through the Atlantic.
Into the Indian ocean, across the Pacific Ocean As a largest feature on earth, the mid ocean ridge And it's underlying by literally ten thousands of Magma Chambers Is that where life began Well that's what people are now thinking The biology books that we were reading have now been thrown away.
And when I grown I have learned everything on surface.
Yes you have this soup in the lightning heated and new formed amino acid and things like that But now, we think that the hydrothermal vents may have been the site of life on earth It also given us a new prospecting to, for searching for Elsewhere with our solar system.
We now are looking at the moon of Jupiter called Europe Which we think has an ocean, we think it has underwater volcanoes and should be life on there.
The question is how smart the clams Did hydrothermal vents give birth to the first primitive microbe on earth Perhaps But one thing is certain, Their discovery challenged the long beliefs about the conditions necessary for creating life.
And once life happened, there was no stopping Was doing some field work in British Columbia He and his wife were riding along a mountain trail The story goes; one of their mules lost a shoe.
And when Walcott bent down and retrieved it, he came across a piece of shale A rock, and it was ordinary looking at first when the sunlight heated it, it shimmered like silver And he looked closely and it was a pattern, a fossil So it needs more exploration to find this one piece of rock come from They came across something that no one has ever seen before Wolcott called his discovery the burgess shale.
Douglas Erwin is curator of the Smithsonian national museum of natural history.
Like the dinosaurs you find the bones, you find the bones.
You can't find the intestine, stomach and eyes or whatever The burgess shale we find all of these in pieces For under I take you into the secret room.
Yes, this is a secret room.
How action seen And this is a general keep a lot of important fossils traveled by Trilobite, ammonite and burgess shale.
That's what I want to show you We have the cart part here So, originally these would have been one piece like this.
Somebody hit this of the hammer.
And split one middle from fossil So this is the Aysheaia, aysheaia is a form of worm When they moved from the ocean to land, We have no idea, but you can see the legs, like, or something like the antenna And if you move that back and forth, you can see shinny beats at the end of the legs And those the toenails Of course they are The fossils that Wolcott discovered were remarkably preserved A vivid snapshot of the time when ancient life on earth was dominated by curious underwater creatures This is a bigger predator of the Cambrian, In china, some probably to three feet long to six feet long It's probably a cousin of the anthropoid, insects and crabs and something like these The mouth actually opened up, and as those rotated and close, it crunched the carapace Like the beak of an octopus Yeah, this is an Opabinia Opabinia It's one of my favorites, probably cause it's a such weird animal It's just like someone had made it up Yean, I mean, it's sort like the Chinese menu You take one part from column A, one part from column B, and you end up something like this But it's something we can't compare with today Five eyes, claws, claws The site of the burgess shale was created by a sudden and violent active nature Underwater mudflow stroke fast A landslide of settlement crashed down, burring everything as it passed They were remained in tomb for hundreds of millions of years Nothing to help to complicated Only began to have first animal diversifying of this whole wide arrange of things So far, the discovery of the burgess shale An astonishing explosion of multicell body types Astonishing because for billions of years, the earth had been dominated by one celled creatures For many scientist, The diversity of the burgess shale fossils is evidence of dramatic shift in the evolution of life on earth the evolution equivalent the big bang The burgess shale is a wonderful window into this big bang of animal life.
Where very rapidly we get plates of the always different architectures always different ways of making a living in this whole ecosystem Better than play with the dinosaurs, Why do you think it's better than play with dinosaur Well, these are much more fascinating And dinosaurs are not very long until that they turned into birds Yes, they're soft Opabinia is a much cooler animal when into crunch and shrug But the five year old kids don't know it yet Even Steven Spielberg and Lucas wouldn't come up with Opabinia That's why it's so cool.
We never know the exist without the burgess shale.
Not all the great discovery started with uncovering a piece of physical evidence It wasn't always a place to explore or fossil to find.
Our next great discovery started with an idea.
Early in the 18th century, scientists were just coming to grip the idea that species could become extinct.
It could disappear And that sort of was a slight show.
The main attraction was the classification of the naming of all these newly discovered types of plants and animals Now, back then, they didn't really have a good system to the classification and naming of living things So, scientists might find a new type of living thing, and then just named whatever they wished.
Making someone weird Latin word A botanist named Carl Linneus straight things out when he came up with his system for classify every living thing Scientists at the time thought it was genius But Linneus had the self-called greatest achievement in science.
Well we still use a lot of Linneus's tradition today Including naming things by their genus and species the binomial system.
You and I are still called Homo sapiens for example Now that Linneus's system was based on the sex organs of plants So one of the contemporary guy named ++ thought it was immoral and offensive So, then he's named a particular plant sigas bekia cause it was a stinky weed Today, the science of classify species has expanded beyond the Linneus's system With information from deep DNA sequencing and analysis of miraculous data Scientist had new understanding of relationships among species As a result, modern classification systems advocate categorizing species based on how they evolved How they fit in the tree of life A concept that Linneus will never consider because the theory of evolution by natural selection had yet to be developed.
But when it was, many would consider it was the greatest discovery in the history of the world.
There was no anesthetic And young medical students were forced to watch and learn, The young man who worked out that day was Charles Darwin.
He audeal of the operating room was too much for him.
Over his father's subjection, he quit medical school To pursue his dream of becoming a naturalist.
Darwin was hired as a naturalist to board the British amoulty HMS Beagle Which embarked on expedition to survey and map coast water around the world He shared a small cabin with the captain, with whom he has several disagreements, including the story of creation.
Darwin While the captain held the bible's account of creation.
Darwin believed that the earth had changed slowly over millions of years.
It was a debate that followed Darwin for the rest of his life The British government paid for this.
No actually Darwin's father paid for his voyage.
And also paid for his assistant to come with Darwin and helped him Skin the specimen and prepare the crates for shipment He worked at little poor deck where he had all his specimens.
Just about something like this.
The beagles made stop over ports of Australia to south America And Darwin made the most of it.
He recorded the extensive observation about the indigenous plants and wild lives He collected preserved thousands of specimens for study For years after the voyage, Darwin recorded the observations he made while aboard the beagle He opened his first species notebook and asked himself a question.
What are the laws of life Is this Darwin's whole point It was Darwin's whole point To try to find laws operating in the natural worlds and laws and physicists and chemists had found in inorganic nature.
Darwin searched to understand the laws of nature took shape as he studied the animals on the Galapagos Islands Of special interests to him, the physical differences was within a certain species.
For example, the finches on the Galapagos Islands had different shape of beaks They varied according to the environments where the finches live Some had beaks that were hard and blunt, idea for hammering open crab shells Others had beaks that were more taper and suited for hunting and packing among rocks The difference was puzzling As Darwin analyzed it, He began thinking about how the struggle to survive was the driving force behind the all life As the species is thriving at its environment, it has to evolve or perish, With this simple yet powerful insight, history was made.
Darwin discovered the mechanism that made evolution work.
The process of natural selection.
Darwin isn't the first guy really come up with this right What was his special or particular insight He was the first to come up with the specific mechanism, that's natural selection He was the first to popularize the idea deep time millions of years that this process involved He was the first to popularize the idea of the tree of life.
Which were related to all the living things The great geneticist Dobzhansky once said Nothing in biology makes sense without evolution.
How we got here, what kind of creature we are .
How we were related to everything in the nature.
It has been established we are all part of wonderful great tree of life.
Plug into a blood line to a DNA that links us to every living thing on earth.
That's not a matter of foragle.
That's literal.
He knew there may be a religious storm protest His own wife was not happy that he was going to write things that were incompatible with the bible She wrote him a letter when they first marriage, saying, I hope that your science will not lead us to spend the eternity to very different places And she was seriously concerned about this Plus he was trying to build up amount of evidence that would be incontrovertible Finally in 1859, Darwin published his theory of natural selection.
His book, origins of species is considered one of the greatest books ever written.
People are talking about the theory of evolution, right But Darwin was the guy that said that there isn't any absolute truth there.
Darwin being one of the first thinkers try to tell us that science is provisional.
It changes What do you mean by provisional.
That the best truth you have in that moment And when you get more data, it can't been explained that way, And you have to get a new theory.
So, that is not an eternal truth.
It's a provisional truth.
It changes.
And he didn't want evolution to be accepted an the dogma or a creed He would be the first to say throw out if you got something better But we didn't find anything better.
Yes, we didn't find anything better.
In fact, what we found was that an entire new sciences that were undreamed up in Darwin's day have come up with the study of molecular genetics and DNA which enforces the idea of evolution so, now, everywhere we look today, we see something from Darwin's insights Darwin's theory of evolution changed everything.
His assertions that Humans evolved from ancient ancestors in Africa challenged traditional religious beliefs And motivated scientist of many disciplines to begin exploring the theory His one thing to claim that the human evolved from the Africa apes, it would be another thing to prove it In 1974, anthropologist Donald Johannsen and his team were working in Ethiopia When they came upon partial remains of an ancient hominoid A species considered to be part of family that includes human kind He named her Lucy.
After the beetle's song Lucy in the sky with diamonds.
Despite of her fragment remains, Lucy has remarkable secrets to share about her life.
As the time of her discovery, the most complete hominoid skeleton ever found was last a hundred thousand years old.
Doctor ken Mowbray is an anthropologist within the America museum of natural history.
Well, Lucy really shook up the family of tree sort of speak Why was she such a big deal She was a big deal for many reasons.
First of all, her skeleton was 40 percent complete.
40 percent complete to you guys You know in fossil terms that's a lot for a fossil bones for individual Something even more important that makes it really significant Is that we believe that she was bipedal Have a of the cast here of the pelvis of the Lucy, the left side.
The pelvis is like this in the human body, it's short and it's broad If you look at chimpanzee, gorilla or orangutan their blades are really narrow and really tall.
The blade of Lucy and like ours is stand out really This allows the transference of weight if you were going to walk onto limbs So, from this pelvis lonely, think that, Lucy move on the landscape as a bipedal or biped Or he or me Exactly, he was walk around, he centrally like us.
Lucy's discovery sparked the debate of whether she would be the long sought after missing link Connecting apes with the first humans But some anthropologist like doctor Mombray believed that the missing link is a myth Now, for long time, people thought there was a link between chimpanzees and humans And when I look at chimpanzees and humans, I can see where it get that idea.
But is not that simple right Absolutely To have a better understanding that there wasn't a linear progression of evolution, especially with human That was much more diversified.
With Lucy and subsequent fossil fines, we really know that this tree of life is much more like a bush There's a lot experimentations going on and a lot of dead ends.
Regardless of whose ancient footstep we may be walking in.
There is one remarkable set of footprints without dispute When they made one of the greatest discoveries in the study of human origins A paired of fossilized footprints, old enough and small enough To have been made by two hominids, much like Lucy.
Those are the oldest human ancestors footprints that we have we know of today More importantly I think, it records behavior Their footprints let us know they were walking bipedally They were no fingerprints, there were no knuckle marks around, the imprints of their feet And on top of that, we know that they were in groups, they were social.
They weren't just walking by themselves.
A volcano erupted, covering the landscape with the thin layer of ash As rain fell, the ash became thick like wet cement And soon was covered by animal tracks Birds A rabbit And then the footprints of two hominids.
Eventually another volcanic eruption blanketed the spot with more ash, A protective layer that preserved the prints they hard and remained hidden Until Mary Leakey revealed them to the world.
Toumai A research team led by Michelle Bruyne unearthed six skull fragments of an ancient hominids They nicknamed toumai, meaning hope of life.
The skull revealed features never seen before.
An ape like cranium But with teeth far more humanlike More than twice as old as Lucy, raising significant new questions about the diversity of life among ancient hominids so, what's the significance of the skull for Chad, toumai.
Its tell us couple of different things.
What its telling is lot of diversity in the human fossil records There are lots of branches on this supposed tree.
And ended up just as evolution experiments at best We luckily are upon as a little twig of a really diverse family tree The last significance of the toumai skull is that it telling us to step back wave a huge of yellow caution flag And we evaluate the fossils we already have in the human family tree And reassess what it means to be a hominid What is it mean to you be a hominid Well, I look it being a hominid in two different ways Hominid's lack the ability to remain bored There were a group of primate out there that they had no ability just sit there and doing nothing And this coupled with operate perpetual bypetalism.
This is what a hominid means to me.
Bipedal and unable to remain bored Yes.
I'm a hominid doga.
Oh absolutely, we are hominids It's a fact of life on earth.
Extinction happens Eventually every species goes away of ancient dinosaurs So, why are we still here So, we are smart in the competition.
We are very well suited the earth's environment right now.
We've our shared damn luck So far, species that face catastrophe of a speeding asteroid Life, like a roulette is a game of chance.
But since the greatest discoveries we just explored The odds for our survival may be proved, because the more we understand about origin and nature of life, the more we may be able to keep our streek alive