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  • They're dazzling, priceless...

  • at times, even glowing.

  • How can one not fall in love with rocks and minerals?

  • I mean, the colors, the shapes...

  • ...and they're the building blocks of modern civilization.

  • We wouldn't have televisions, we wouldn't have automobiles, we wouldn't have

  • buildings without the mineral riches that we have.

  • But could rocks and minerals also solve

  • the greatest mystery of all time?

  • The origin of life.

  • The rocks we pick up tell a story

  • that life couldn't have occurred without rocks.

  • Could cold, lifeless stone hold the key

  • to every living thing on Earth?

  • From Australia, to Morocco,

  • Nova goes around the world and back in time

  • to investigate the origin and evolution of life.

  • Look at a rock and you think ah, well, nothing.

  • but this holds the signature of life.

  • From its first spark...

  • People were saying they've made Frankenstein in a test tube...

  • ...To the survival of the fittest.

  • These were immense creatures. Sharks that may have been 50 or 60 feet.

  • Was it the secret link between rocks and life

  • that made the difference?

  • Life's rocky start. Right now, on Nova.

  • The ancient market of Marrakech,

  • a chaotic, colorful gathering place teeming with life for thousands of years,

  • the perfect place to ask how did this exotic, beautiful and sometimes bizarre

  • thing called life, begin?

  • How did Earth go from a lifeless, molten rock...

  • to a living planet?

  • Full of diverse and spectacular creatures.

  • it's a question that has long perplexed scientists.

  • Now, Robert Hazen, a geologist, is trying to show we are missing an essential

  • ingredient in the recipe for life.

  • -look at that vein of calcite...

  • Rocks.

  • Nothing seems more lifeless than a rock.

  • it's inanimate, it's the antithesis of a living thing, but we're beginning to

  • realize that rocks played an absolutely fundamental role in the origin of life.

  • Hazen is out to expose a secret relationship between rocks and life that

  • helped drive both the origin of life and its evolution into complex creatures.

  • This is a very new set of understandings and the more we look, the more we see

  • that life depends on rocks, rocks depend on life.

  • This has been going on for four billion years.

  • As a geologist, it's no surprise

  • that Hazen is searching for answers written in stone.

  • But is he right?

  • Are rocks the missing spark of life?

  • The history of Earth is unimaginably long.

  • If it were sped up to the equivalent of a single day, all of humankind from the

  • earliest skeletons to the invention of the iphone would have occurred in only

  • the last four seconds.

  • Dinosaurs were still roaming earth about 20 minutes before that,

  • but the creation of our planet occurred more than 23 hours earlier, two cycles on

  • this clock

  • or 4.5 billion years ago.

  • Comprehending Earth's vast history is a formidable task.

  • It is four and a half billion years of change, but you can divide it into half a dozen ways of

  • describing Earth through time.

  • Bob Hazen has come up with another way to visualize Earth's long history that

  • reveals this special relationship between rocks and life.

  • He has divided it into six stages, each represented by a different color

  • to understand how we ended up with green earth, the planet we now know, requires us

  • to turn the clock back to before there was any life at all.

  • Stage one was the creation of black Earth.

  • Back in Morocco, Hazen and Adam Aaronson, a meteorite expert, seek out a small rock

  • from the beginning of our cosmos.

  • -Wow look at this pile here. -yeah.

  • These are meteorites. Rocks that have fallen from space.

  • -This is Tamta. This is the one that fell 20 kilometers up the road from here.

  • People saw it fall.

  • A recent meteorite fall in Siberia was captured in videos that have shown up on Youtube.

  • Other space rocks have ended up for sale here in Morocco.

  • -Say you'd buy this without doing tests...

  • -I'll drop the cash right now here and give me a good price.

  • Meteorites here can sell

  • for tens of thousands of dollars. That may seem a steep price for a lump of

  • rock, but these are some of the very oldest objects in our solar system.

  • This is the oldest object you could ever hold in your hand. It's 4.6 billion years

  • old and is formed before Earth formed. This is the very first solid material,

  • the very first rock in our solar system and these came together to build all the planets.

  • Our Earth was created out of the rocks and dust present at the start of our solar system.

  • Over time, small fragments of orbiting rock collided, coming together into the

  • planet circling the Sun.

  • At first, Earth was molten with temperatures in the thousands of degrees,

  • but in the cold vacuum of space this hot rock began to cool and change.

  • Nothing.

  • Not a speck of dust is believed to have survived from the period of black Earth.

  • It was a hellishly unpleasant time.

  • Volcanoes spewed hot lava from deep inside the planet.

  • When it cooled, it covered Earth with its first rock called basalt

  • and it was black.

  • It seems like a desolate landscape, but some ingredients that life will need are

  • already here in these rocks.

  • Look inside and you begin to understand how intriguing

  • even an ordinary rock is.

  • Every rock, you slice it open

  • you look inside, there's something special. Rocks are made up mostly of

  • minerals, which are crystals like quartz or diamonds. Looking through a microscope

  • at super thin slices of a rock lets you see its mineral composition.

  • This is the rock Peridotite, made up of small crystals, including olivine and pyroxene.

  • Even a simple black basalt rock, spewed from a volcano, becomes a

  • patchwork of colorful minerals.

  • It's sort of like a fruitcake, you know I slice it open, there's nuts and there's

  • dried fruit and maybe some lemon peel.

  • It's made of lots of little things and it is not until you slice into that fruitcake

  • that you see all the stuff inside that makes it special.

  • What makes them special is not only their beauty. Minerals have remarkable

  • chemical and physical properties and are a source of many of the elements -

  • nature's building blocks.

  • That is why they are essential in our modern world to make everything from

  • skyscrapers taller

  • - mobile phones smaller.

  • Extract the element molybdenum from the mineral molybdenite to make steel stronger.

  • Or add a pinch of cobalt and your iphone battery will last longer.

  • Minerals are the fundamental building block of societies. We wouldn't have

  • televisions, we wouldn't have automobiles, we wouldn't have buildings without the

  • mineral riches that we have.

  • So, were the remarkable chemical properties of minerals also key in

  • creating life?

  • If so, Earth would mean more than it started with

  • It's estimated that the meteorites that formed Earth had only about 250 minerals,

  • sort of a chemical starter kit, containing many of the elements.

  • Then, in the intense heat and pressures in the creation of our planet, new

  • minerals began to form. This changed the appearance of our Earth from black to

  • gray.

  • Yosemite national park is a relatively new piece of Earth,

  • but the kind of rock that makes up these dramatic cliffs goes back much further.

  • These huge walls are granite containing minerals like quartz and feldspar.

  • Granite became the foundation of our continents, leading Earth into the gray period.

  • At this point, earth is still a long way from the glorious diversity of plants

  • and animals that makes Yosemite so picturesque.

  • But the stage is set for the next character in our planet story:

  • Water, which will turn Earth blue. Water plays a central role in every model for

  • the origin of life.

  • That's because water is such a great solvent. All these different kinds of

  • molecules can be floating around the water and then they have the potential to

  • interact together. The starting point is the water.

  • So when did Earth cool enough to have liquid water,

  • this element key to life?

  • One of the biggest unknowns in this whole idea of going from black to gray

  • to a blue water-covered earth, is how quickly it happened.

  • The timing is a big mystery.

  • The Pilbara in Western Australia is one of the oldest places on Earth

  • and so, one of the best places to solve the mystery of the planet's first oceans.

  • Hazen joins an all-star team of geologists, including Martin Van Kranendonk

  • from the University of New South Wales and John Valley of the University

  • of Wisconsin.

  • Valley is collecting rocks that could hold clues to when water first appeared.

  • We could get zircons and other minerals that date all the way back to

  • 4.4 billion years old.

  • Hopefully.

  • Some rocks here contain sand-sized grains that wheathered from even older rocks.

  • one in a million, literally, is a crystal called zircon, one of the longest lasting

  • materials in nature.

  • Zircon is a popular gemstone, but the microscopic zircon found here is even

  • more precious.

  • Zircon crystals are especially amazing. Gemstone zircons of course are valued, but

  • these tiny ones the geologists value are microscopic that make a lousy ring, but

  • they tell an incredible story.

  • To tell that story, John Valley must first find the tiny crystals,

  • the ultimate needle in a haystack.

  • If you want to find a needle in a haystack, the first thing you do is you

  • burn down the haystack.

  • Then you sip through the ash to look for the needle. Rocks are pulverized into

  • sand sized grains and sorted by weight in a machine developed to pan for gold.

  • The gold that Valley is looking for are heavy zircon crystals which get

  • channeled into different tracks.

  • Then, grain by grain, with a very steady hand,

  • thousands of small crystals are sorted and analyzed.

  • The chemical structure of a zircon crystal holds evidence of both the environment

  • and the age when it formed.

  • Some of these tiny crystals go very far back,

  • just over a hundred million years after Earth formed.

  • They are the oldest pieces of Earth ever discovered.

  • So they could shed light on what our young planet looked like.

  • It's totally amazing. To hold this grain of sand in the palm of your hand

  • is literally to see back through time.

  • It is a time machine.

  • Valley expected these crystal time machines would confirm the long-held

  • view that the young Earth was covered in molten lava, still cooling after its

  • violent formation.

  • I think the zircon on the left looks very promising.

  • So what he discovered was shocking, because this type of zircon created 4.3

  • billion years ago could only have formed in the presence of liquid water.

  • But how could there be water if Earth was still hot and hell-like?

  • The implications were that the early Earth had water,

  • it was cooler and it was wet.

  • It's starting to look very much more familiar.

  • And if water is a key starting point for life

  • could there be life that early too?

  • The science of the zircon is telling us that the Earth for a very, very long time

  • was a habitable environment, not necessarily that there was life then.

  • We don't know that yet, but there's no reason why there couldn't have been life

  • as early as 4.3 billion years ago.

  • So, if life were possible that early, it begs the question: how did life begin?

  • In 1871, Charles Darwin speculated in a letter to a friend that a warm little

  • pond might be life's birthplace.

  • A warm soup of chemicals bathed by energy from the Sun would have been, well,

  • comfortable for molecules to come together in new ways and create life.

  • Darwin was way, way ahead of his time.

  • A nice little warm soup is gonna get you a long way.

  • Jeff Boda of the Scripps Institution of Oceanography in San Diego has spent his

  • career working to understand the early Earth's soup of chemicals.

  • He began under the direction of perhaps the most famous scientist in origin of

  • life research,

  • Stanley Miller.

  • There are in the history of science turning points where we suddenly see the

  • history of Earth and life differently. In the early nineteen fifties, Stanley

  • Miller, the eager graduate student, and Harold Urey, the Nobel Prize winning

  • mentor at the University of Chicago conducted this astonishing experiment

  • where they made an early Earth environment.

  • It looks like this sort of a Frankenstein type apparatus, but actually

  • it's a very carefully thought out design. Boda sets up a modern-day test of the

  • nineteen fifties experiment on Miller's original lab equipment.

  • One flask contains water. That's to simulate the ocean.

  • The other flask has just got the gases in it, so this is the atmosphere.

  • Just as it does in nature, water from the ocean evaporates and rises into the

  • atmosphere, where it condenses and returns to the ocean.

  • Miller simulated what he believed to be the atmosphere of early Earth with

  • different gases like ammonia and methane.

  • Then he added a spark of genius.

  • Miller and Urey decided to use a spark to simulate lightning, because that's

  • such a ubiquitous process in the atmosphere of the Earth.

  • That was the real inspiration. These little electric sparks that acted like

  • simulated lightning. The energy from the spark of lightning breaks down the gas

  • and water molecules so they can undergo further chemical reactions.

  • To their astonishment, when they turn this apparatus on, after only a couple of days,

  • you started seeing this pink color developing.

  • In a few more days, black

  • oily goo is forming around the electrodes.

  • The electrodes get covered with new substances.

  • Organic compounds, usually associated with life.

  • And it wasn't just any organic compound. It was amino acids that make proteins,

  • the ingredients for life.

  • Amino acids are the building blocks of life.

  • They form proteins, which are the key component of muscles and other tissues.

  • People thought "aha!". This is a key step in the origin of life.

  • And you really believe that you can bring life to the dead?

  • That body is not dead, it has never lived.

  • I created it.

  • The experiment raised a fear that a Frankenstein creation, like in this

  • classic film, was just around the corner.

  • People were saying they had made Frankenstein in a test tube.

  • Had Miller and Urey cooked up life in a test tube?

  • many of the news headlines were saying "life created in the laboratory",

  • "life created in a test tube". Of course, that was wrong.

  • The real news was, he made these compounds that are part of life.

  • By creating amino acids, the Miller-Urey experiment seemed to confirm that Darwin

  • was right.

  • Life must have begun in a shallow pond.

  • But then, 24 years later, a shocking

  • discovery radically challenged that idea.

  • On a dark ocean floor, more than a mile below the surface,

  • explorers found hot, mineral rich hydrothermal vents, like underwater

  • volcanoes.

  • Temperatures reached more than 600 degrees and yet here,

  • life was thriving. Not off the Sun's energy, but through chemical energy from the vents.

  • No one realized that life could thrive without sunlight.

  • Here you have this extreme temperature and extreme pressure and so you have to shift your

  • perceptions and realize that just because it's extreme to us doesn't mean

  • it's extreme to those microbes.

  • Instead of the warm shallow pond,

  • could this dark and unlikely environment be where life began?

  • To answer that,

  • Hazen decided to try creating life's building blocks in the conditions of a

  • deep-sea vent.

  • My first thought was "why don't we do a Miller-Urey experiment but do it

  • at high temperature, high pressures?"

  • Hazen's laboratory is at the Carnegie

  • Institution for Science, which is famous for experiments that simulate the

  • intense pressures deep inside Earth with powerful tools called pressure bombs.

  • They're called bombs for a reason, because things can explode.

  • Hazen and his colleagues adapted these pressure bombs to model the environment

  • of the deep sea vents in a small gold tube.

  • What they discovered came as a surprise.

  • Nothing happened.

  • You can take basic gases.

  • Nitrogen, CO2, maybe some sulfur compounds,

  • you can mix those, you can put them in a gold tube, you can heat them up, you don't get much

  • much that is very interesting.

  • Simply squeezing and heating the ingredients had little effect.

  • Hazen was missing the spark like in the Miller-Urey experiment.

  • The thing that kick-starts the chemistry.

  • So he said, what's going on? What's different?

  • Well, look at the natural environment. There is all these rocks and minerals.

  • Let's try putting some rocks and minerals in.

  • They recreate the early Earth cocktail, but this time grind in powder from rocks and minerals.

  • But will Hazen's beloved rocks do the trick?

  • They run the experiment again.

  • And this time, the atoms reform into new organic molecules, including amino acids.

  • As soon as you put powdered rocks and minerals into the gold capsules then all

  • sorts of really amazing things started happening.

  • You made organic molecules, they became more stable, they lasted longer, and it

  • really pointed us in the direction of "aha", this has got to be part of the story.

  • While scientists still argue if life began in shallow ponds or deep sea vents,

  • both sides wonder what part of the story

  • did rocks and minerals play?

  • One possible answer may be found in London in the powerful properties of mud.

  • Most people will be familiar with the material.

  • It's very gungy. That's a British word that refers to something which is

  • soft and unpleasant generally. Peter Coveney of University College, London is busy

  • playing in mud at a very sophisticated level.

  • He has created powerful computer simulations that can track the precise

  • movement of up to 10 million atoms.

  • Mud can contain clay, which is made up of some of Earth's most common minerals.

  • What makes it so gungy, and perhaps essential in the origin of life, can be seen

  • deep in its atomic makeup. You can see here the basic structure of any play is

  • comprised of a large number of stacked sheets like a deck of cards.

  • Sheets of clay have spaces between them that fill up with water and other molecules.

  • These extensive surface areas can help create more complex molecules,

  • potentially even RNA, an essential part of life's genetic code

  • One of the most challenging questions in the origin of life is how we get from

  • the simple building blocks to the complicated structures we know are

  • fundamental to living systems.

  • Clays provide a clear mechanism for achieving that.

  • These simulations show that the secret to clay lies in its surfaces.

  • The surfaces of these minerals are incredible. They do all sorts of chemical tricks.

  • Hazen says minerals like clays illustrate a fascinating aspect of

  • chemistry, because the surface where reactions take place can be as important

  • as the ingredients themselves.

  • The most exquisite chemistry occurs at surfaces

  • Your body, your cells are almost entirely surfaces on which chemistry takes place

  • So when we think about the origin of life, the minerals is where we place surfaces

  • you have in your body that do that chemical work.

  • We are finally beginning to understand the secret role minerals could have

  • played in life's origin.

  • They provided some of the ingredients. And surfaces, where important chemical

  • reactions take place.

  • So, when in Hazen's color phases did all this happen?

  • One of the best places to figure that out is back in Australia where Hazen and

  • team are now searching for signs of Earth's earliest life.

  • I can't believe these rocks are three and a half billion years old. They would maybe

  • form last week.

  • Martin Van Kranendonk leads the team to a very unusual rock formation.

  • You get your eye casting up. You see them all wrinkly, laminated, black and then if

  • you look a bit further back, you see a very large domical structure.

  • There is no obvious way that a chemical or physical process would form that.

  • Exactly.

  • These strange shapes are fossilized remnants of life, called stromatolites,

  • beautifully preserved in these ancient rocks.

  • This is an amazing spot.

  • We're actually looking down on the surface of the ancient Earth here.

  • This was the seafloor 3.4 billion years ago.

  • I can see it in action, it is like a snap frozen in an instant of time.

  • But billions of years have taken their toll.

  • To really understand stromatolites, we have to go nearly 800 miles away.

  • David Flannery, a geologist, has come to Shark Bay in search of their very

  • distant descendants.

  • Just below the surface,

  • he finds a series of round, black mounts - living stromatolites.

  • Modern environments like these

  • they're very rare, but they are really the key to interpreting what we see in the

  • very early fossil record.

  • Without environments like these, we wouldn't know how stromatolites were built.

  • Stromatolites are something like coral, a hard mineral

  • structure that has been built, layer by layer.

  • A closer look reveals the builders:

  • Microbes - single-celled life.

  • The living part of a stromatolite is only the surface.

  • With a living microbial mat that is building up the structure layer by layer,

  • less than a millimeter per year.

  • The top layer of these stromatolites is alive with microbes that perform a remarkable trick.

  • They capture minerals and sand in the water and biologically

  • cement them, layer by layer, into the solid mounds.

  • The results can be seen in Shark Bay today and in the ancient fossils.

  • Let me introduce you to this outcrop. It's just spectacular

  • to be able to see this.

  • And this outcrop is unique.

  • Van Kranendonk has dated this stromatolite to 3.5

  • billion years ago.

  • This is the very oldest fossil of life on Earth.

  • We all want to know where we come from, where life originated, how long ago in

  • what form and this is the oldest direct evidence we have for life on Earth.

  • But while stromatolites are the earliest fossil of life we've found that does not

  • make them the very first living thing.

  • In fact, Van Kranendonk thinks that by the

  • time stromatolite appeared, life's party was already in full swing.

  • There are whole communities and colonies that are building fantastically complex structures.

  • So, we've actually come in pretty late to the game, there's a lot that's gone on

  • before us to get to this stage. And it's this complexity that tells us that life

  • probably originated on Earth very early.

  • So if these very early fossils are too complex to be the oldest form of life,

  • is it possible to find something earlier?

  • That is what Ruth Blake, a geologist at Yale University, is trying to figure out.

  • By turning to the geological equivalent of a crime scene investigation.

  • The crime has been committed, the criminals gone, but they've left behind

  • some indicators, because they've changed their environment.

  • Blake is analyzing some of the oldest rocks on Earth, like this ground up one

  • from Greenland that formed at the bottom of an ocean

  • She's looking for a chemical signature of life, left by microbes, including bacteria.

  • What we start with is our ocean, trapped in a rock, and our file signature is

  • somewhere in here. We have to get it out.

  • In the lab, Blake and her team dissolve

  • these rocks and extract molecules that are the chemical signature left behind

  • by ancient microbes.

  • Old life, like these microbes, consumes nutrients to produce energy.

  • The leftovers carry the chemical footprint of life.

  • Even today, we humans leave behind chemical footprints.

  • When we breathe, for example, we're taking in oxygen and we are exhaling CO2 and water vapor

  • And water vapor interacts with your environment.

  • Amazingly, rocks from 3.5 billion years ago, at the time of the stromatolites in Australia,

  • also carry a strong chemical footprint of life.

  • But when Blake analyzes the Greenland rocks from 300 million years earlier,

  • she makes a tantalizing discovery.

  • As far back as 3.5 billion years, we see a strong biological signature and the

  • older rocks are approaching that, but not quite there,

  • but we do believe that we see something there.

  • Blake believes she has detected the faint signal of life at 3.8 billion years ago,

  • only 700 million years after Earth was created,

  • early in the blue phase.

  • There is still much that we don't know about our early planet,

  • but some things are becoming clearer.

  • If you could transport yourself back in time,

  • about 4 billion years, parts of our earth might not look too different than this

  • Southern California beach minus the surfers and Google.

  • You could stand on cliffs, probably of granite, overlooking oceans that were increasingly rich with

  • minerals and early microbial life.

  • But you would quickly die in a great deal of pain,

  • suffocating in the heavy atmosphere, rich in nitrogen and carbon dioxide, but

  • lacking in life-giving free oxygen.

  • Then, something truly astonishing happened.

  • Those harmless-looking microbes, floating in the water or on stromatolites,

  • started to change everything, turning Earth red.

  • Wow! Oh my god, this is amazing!

  • There aren't many places on Earth you can see something like this.

  • A remnant of red Earth can be seen in Australia at the Hammersley Basin in Karijini national park.

  • In these rocks, Hazen finds a startling consequence of early life as

  • it began to thrive and evolve.

  • What we're seeing here is one of the greatest tricks that life ever figured out.

  • And that was how to take sunlight and convert it to energy.

  • Microbes, like those in the stromatolites at Shark Bay, eventually began to live off the Sun's energy

  • through photosynthesis.

  • That led to a dramatic rise in a gas that Earth was not accustomed to.

  • Oxygen.

  • While to us, oxygen is a life-giving benign gas, to a world not accustomed to it,

  • oxygen created a dangerously corrosive cocktail.

  • The early oceans were filled with dissolved iron. The new oxygen reacted with that iron and it began to

  • rust and sank to the bottom of the sea.

  • These little microbes they're microscopic things and you wouldn't think

  • they could do all that much, but when they produce that oxygen, the oxygen

  • reacts with the iron in the oceans. You get the world's largest deposits of iron,

  • thousands of feet, covering hundreds of square miles.

  • these formations cover a vast area with trillions of tons of iron ore.

  • That is an unimaginable consequence of trillions upon trillions of microbes breathing.

  • it's a fundamental change in the chemistry of Earth.

  • It's the consequence of the rise of oxygen.

  • The rise in oxygen that rusted iron and sent Earth into the red phase also created many new minerals

  • As a mineralogist, when I look at Earth's history, I see big transitions.

  • I see the moon-forming impact, I see the formation of oceans and so forth. Then nothing,

  • nothing matches what life and oxygen did to create new minerals.

  • Some estimate that the meteorites that formed Earth began with only about 250 minerals.

  • Today,

  • there are more than 5,000.

  • Hazen believes that two-thirds of all the minerals that now make up our planet,

  • were created by the introduction of oxygen and most of that was in turn

  • created by life.

  • It's mind-boggling. Rocks create life, life creates rocks, they're intertwined

  • in ways that are just now coming into focus.

  • But the road ahead for life and for rocks would not be easy

  • As we head into the next phase of Earth, new continents formed and broke apart

  • which may have created dramatic extremes in the climate.

  • Earth plunged into an icy freeze, turning it white.

  • In these frozen conditions, life was nearly wiped out.

  • Fortunately, active volcanoes still poke through the icy veneer, billowing out

  • carbon dioxide, or CO2.

  • Like a thermal blanket around our Earth, this kept heat in and rescued life.

  • Life all but shut down and then the CO2 rises and rises and the greenhouse effect

  • gets hotter and hotter and suddenly the planet melts.

  • Cycles of these snowball hothouse conditions had profound consequences for life

  • One result was more oxygen, which eventually allowed for bigger animals

  • The dramatic changes during white Earth would bring us to the present phase,

  • starting about 540 million years ago.

  • A living planet.

  • Filled with diverse plants and spectacular creatures.

  • But those life forms are pitted against each other in a survival of the fittest.

  • And rocks can make the difference between life and death.

  • That struggle can be seen back in Morocco at the edge of the anti Atlas Mountains.

  • Here, Bob Hazen and Adam Aaronsen are looking for evidence of an evolutionary

  • trick that shows, once again, how life and rocks took a big leap forward together.

  • 520 million years ago, this valley was a shallow ocean,

  • filled with new forms of life.

  • This is when the diversity of life on Earth exploded, all thriving in a living sea.

  • So, if you were a scuba diver, and you dove down to this reef, you'd see all kinds of

  • life swimming around.

  • It would be really amazing, probably very colorful too.

  • There is one creature that dominates this ancient reef that Hazen wants to find.

  • Nothing there, nothing there, and nothing there.

  • Fossil hunting is a game of luck and persistence but it doesn't take long for

  • Hazen to strike geologic gold.

  • Whoa! Geez, look at that!

  • That is amazing.

  • The trilobite.

  • Hey look, there's another head there, and a head there. Two more.

  • Boy, this is rich rock.

  • The trilobites here are amazing because these

  • are the oldest animals that you can find.

  • They're preserved as what you think of as a fossil

  • that you can hold in your hand.

  • Some trilobites were like horseshoe crabs, scurrying about the ocean floor.

  • The reason they are found as fossils today, is because they developed an

  • astonishing evolutionary trick: Shells.

  • Trilobite shells were made of calcium carbonate, the same mineral found in

  • limestone, the rock that built the pyramids.

  • In effect, life itself began to make rocks for its own advantage.

  • And the idea went viral.

  • If you had a shell, you're gonna survive a lot longer than that soft body animal

  • that doesn't have a shell.

  • The trilobite had an advantage. It's survival of the fittest.

  • The trilobites' mineral shell heralded a new phase in the evolution of animals,

  • catapulting our planet into the present stage: Green Earth.

  • One that is rich in diverse life.

  • From humans back to trilobites,

  • we owe our evolution and survival to the world of minerals.

  • With shells, then eventually with bones and teeth that paved the way for life to grow taller

  • and stronger.

  • All are evidence of life

  • co-opting minerals for its own evolutionary advantage.

  • We've thought for centuries animals, minerals, they're separate kingdoms, right?

  • But it turns out they overlap, they're intertwined, they co-evolved,

  • that life makes minerals and minerals has led to new life forms.

  • You can't separate the two.

  • Life and rocks are totally intertwined through billions of years of Earth history.

  • One of Hazen's favorite places to see this intertwined history of life and

  • minerals is at the Calvert cliffs along the Chesapeake Bay

  • He and his wife Margy pick up shells and sharp teeth from a time 18 million

  • years ago, when massive sea creatures swam here.

  • That's nice. You find teeth along the beach that are five, six,

  • sometimes seven inches long with serrated edges, razor-sharp teeth.

  • These were immense creatures. Sharks that may have been 50 or 60 feet long.

  • These giants of the sea would have dwarfed today's great whites and it was

  • the bones and teeth, created with minerals, that enabled them to grow so large and powerful.

  • They were feeding on whales. Dolphins would have been a snack.

  • They are just one small part of a story of coevolution, stretching back to Earth's beginning.

  • The life, the rocks. It's all part of the same story.

  • Step by step throughout Earth's evolution, minerals and life have sparked

  • chemical reactions that sculpted the planet into what we see today.

  • And helped create the life we know.

  • At this place you get a sense of the immensity of time and the constancy of change.

  • Life is creating and sculpting our surroundings in ways that are quite wonderful,

  • and just to recognize the power of life to transform a planet.

  • Of course, humans transform the planet too. We build cities, we build roads, we change

  • the composition of the atmosphere and change the composition of the oceans.

  • There are going to be global changes.

  • These changes, whose consequences are now beginning to unfold,

  • are the latest chapter in Earth's epic story. A story that began four and a half billion years ago

  • with a rock.

They're dazzling, priceless...

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B1 中級 英國腔

生命的起源--生命如何在地球上開始 (Origin of Life - How Life Started on Earth)

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    岑文勁 發佈於 2021 年 01 月 14 日
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