Wonders of Life (2013) s01e01 Episode Script
What Is Life
1 This creature is a wonder of life.
A voracious predator, this male has lived underwater for nearly five months, feeding, growing, preparing for this moment.
He's about to undertake one of the most remarkable transformations in the natural world.
From aquatic predator to master of the air.
The brief adult life of a dragonfly is amongst the most energetic in nature.
Dragonflies are the most remarkable animals.
You can see their incredible agility in flight just watching them skim across the surface of this pond.
They can pull two and a half G in a turn, and they can fly at 15 mph, which is fast for something that big.
They've been around on Earth since before the time of the dinosaurs, and in that time they've been fine-tuned by natural selection to do what they do - which is to catch their prey on the wing.
So, dragonflies are beautiful pieces of engineering.
They're intricate, complex machines.
But is that all they are? Because once their brief lives are over, their vitality will be gone.
And this raises deep questions.
What is it that makes something alive? And how did life begin in the first place? So, what is the difference between the living and the dead? What is life? I've come to one of the most isolated regions of the Philippines to visit the remote hilltop town of Sagada.
It's a two-day drive from the capital, Manila, over some of the country's roughest roads that wind their way 1,500 metres up into the hills.
This is a place where the traditional belief is that mountain spirits give us life and that our souls return to the mountain when we die and where the people who live here still imagine that the spirits of the dead walk among the living.
Tonight is November 1st, and here in Sagada - in fact across the Philippines - that means it's the Day of the Dead.
That's the day when people come to this graveyard on a hillside and, well, celebrate the lives of their relatives.
The people light fires to honour and warm the departed, inviting their souls to commune with them.
Now, not matter how unscientific it sounds, this idea that there's some kind of soul or spirit or animating force that makes us what we are and that persists after our death is common.
Virtually every culture, every religion, has that deeply-held belief.
And there's a reason for that - because it feels right.
I mean, just think about it.
It's hard to accept that when you die you will just stop existing and that you are, your life, the essence of you, is just really something that emerges from an inanimate bag of stuff.
Don't get too close.
You can see that these people feel not only do they come to celebrate the lives of their relatives, but they're coming in some sense to communicate with them.
Their relatives, even though their physical bodies have died, are still in some sense here.
When you think about it, that's not so easy to dismiss.
If we are to state that science can explain everything about us, then it's incumbent on science to answer the question, what is it that animates living things? What is the difference between a piece of rock that's carved into a gravestone and me? For millennia, some form of spirituality has been evoked to explain what it means to be alive, and how life began.
It's only recently that science has begun to answer these deepest of questions.
In February 1943, the physicist Erwin Schrodinger gave a series of lectures in Dublin.
Now, Schrodinger is almost certainly most famous for being one of the founders of quantum theory.
But in these lectures, which he wrote up in this little book, he asked a very different question - What Is Life? And right up front, on page one, he says precisely what it isn't.
It isn't something mystical, says Schrodinger.
There isn't some magical spark that animates life.
Life is a process.
It's the interaction between matter and energy described by the laws of physics and chemistry.
The same laws that describe the falling of the rain or the shining of the stars.
So, the question is, how is that this magnificent complexity that we call life could have assembled itself on the surface of a planet which itself formed from nothing more than a collapsing cloud of gas and dust? To Schrodinger, the answer had to lie in the way living things process one of the universe's most elusive properties - energy.
Energy is a concept that's central to physics, but because it's a word we use every day its meaning has got a bit woolly.
I mean, it's easy to say what it is in a sense.
Obviously this river has got energy because over decades and centuries it's cut this valley through solid rock.
But while this description sounds simple, in reality things are a little more complicated.
For me, the best definition is that it's the length of the space time four vector and time direction, but that's not very enlightening, I'll grant you that.
Over the years, the nature of energy has proved notoriously difficult to pin down.
Not least because it has the seemingly magical property that it never runs out.
It only ever changes from one form to another.
Take the water in that waterfall.
At the top of the waterfall, it's got something called gravitational potential energy, which is the energy it possesses due to its height above the Earth's surface.
See, if I scoop some water out of the river into this beaker, then I'd have to do work to carry it up to the top of the waterfall.
I'd have to expend energy to get it up there.
So it would have that energy as gravitational potential.
I can even do the sums for you.
Half a litre of water has a mass of half a kilogram, multiply by the height, that's about five metres, the acceleration due to gravity's about ten metres per second squared.
So that's half times five times ten is 25 joules.
So I'd have to put in 25 joules to carry this water to the top of the waterfall.
Then if I emptied it over the top of the waterfall, then all that gravitational potential energy would be transformed into other types of energy.
Its sound, which is pressure waves in the air.
There's the energy of the waves in the river.
And there's heat.
So it'll be a bit hotter down there because the water's cascading into the pool at the foot of the waterfall.
Buy the key thing is energy is conserved, it's not created or destroyed.
So, because energy is conserved, if I were to add up all the energy in the water waves, all the energy in the sound waves, all the heat energy at the bottom of the pool, then I would find that it would be precisely equal to the gravitational potential energy at the top of the falls.
What's true for the waterfall is true for everything in the universe.
It's a fundamental law of nature, known as the first law of thermodynamics.
And the fact that energy is neither created nor destroyed has a profound implication.
It means energy is eternal.
The energy that's here now has always been here, and the story of the evolution of the universe is just the story of the transformation of that energy from one form to another, from the origin of the first galaxies to the ignition of the first stars and the formation of the first planets.
Every single joule of energy in the universe today was present at the Big Bang, 13.
7 billion years ago.
Potential energy held in primordial clouds of gas and dust was transformed into kinetic energy as they collapsed to form stars and planetary systems, just like our own solar system.
In the Sun, heat from the collapse initiated fusion reactions at its core.
Hydrogen became helium.
Nuclear-binding energy was released, heating the surface of the Sun, producing the light that began to bathe the young Earth.
And at some point in that story, around four billion years ago, that transformation of energy led to the origin of life on Earth.
Around 350 kilometres south of Sagada, this is Lake Taal.
Despite its sleepy, languid appearance, this landscape has been violently transformed by energy.
When I think of a volcano, I usually think of a pointy, fiery mountain with a little crater in the top.
Probably a bit like that one.
But actually this entire lake is the flooded crater of a giant volcano.
It began erupting only about 140,000 years ago, and in that time it's blown 120 billion cubic metres of ash and rock into the Earth's atmosphere.
This crater is 30 kilometres across and in places 150 metres deep.
That's a cube of rock five kilometres by five kilometres by five kilometres just blown away.
It's a big volcano.
Taal Lake is testament to the immense power locked within the Earth at the time of its formation.
Since the lake was created, a series of further eruptions formed the island in the centre.
And at its heart is a place where you can glimpse the turmoil of the inner Earth, where energy from the core still bubbles up to the surface producing conditions similar to those that may have provided the very first spark of life.
The water in this lake is different from drinking water in a very interesting way.
See, if I test this bottle of water with this, which is called universal indicator paper, then you see immediately that it goes green.
And that means that it's completely neutral.
It's called PH7 in the jargon.
But then look what happens when I test the water from the lake.
Now the indicator paper stays orange.
In fact, it might have gone a bit more orange.
So that means that this is acid.
It's about PH3.
At the most basic level, the energy trapped inside the Earth is melting rocks.
And when you melt rock like this you produce gases.
A lot of carbon dioxide, and in this case of this volcano, a lot of sulphur dioxide.
Now, sulphur dioxide dissolves in water and you get H2SO4, sulphuric acid.
Now, what I mean when I say that water is acidic? Well, water is H2O - hydrogen and oxygen bonded together.
But actually when it's liquid it's a bit more complicated than that.
It's actually a sea of ions.
So H-plus ions, that's just single protons.
And OH-minus ions, that's oxygen and hydrogen bonded together, all floating around.
Now, when something's neutral, when the PH is seven, that means that the concentrations of those ions are perfectly balanced.
When you make water acidic, then you change the concentration of those ions and, to be specific, you increase the concentration of the H-plus ions of the protons.
So, this process of acidification has stored the energy of the volcano as chemical potential energy.
The volcano transforms heat from the inner Earth into chemical energy and stores it as a reservoir of protons in the lake.
And this is the same way energy is stored in a simple battery or fuel cell.
These bottles contain a weak acid and are connected by a semi-permeable membrane.
Passing an electric current through them has a similar effect to the volcano's energy bubbling up into the lake.
It causes protons to build up in one of the bottles.
You can think of it, I suppose, like a waterfall, where the protons are up here waiting to flow down.
All you have to do to release that energy and do something useful with it is complete the circuit.
Which I can do by just connecting a motor to it.
There you go.
Look at that.
That's the protons cascading down the waterfall and driving the motor around.
It actually works! Quite remarkable, actually.
Now, the fuel cell produces and exploits its proton gradient artificially.
But there are places on Earth where that gradient occurs completely naturally.
Here, for example.
So we've got the proton reservoir over there, the acidic volcanic lake.
If you look that way, there's another lake, and the reaction of the water with the rocks on the shore make that lake slightly alkaline, which is to say that there's a deficit of protons down there.
So here's the waterfall, a reservoir of protons up there, a deficit down there.
If you could just connect them, then you'd have a naturally occurring geological fuel cell.
And it's thought that the first life on our planet may have exploited the energy released in those natural proton waterfalls.
What do you think? It's good, isn't it? These are pictures from deep below the surface of the Atlantic Ocean, somewhere between Bermuda and the Canaries.
And it's a place known as the Lost City.
You can see why.
Look at these huge towers of rock, some of them 50-60 metres high, reaching up from the floor of the Atlantic and into the ocean.
It's what's known as a hydrothermal vent system.
So these things are formed by hot water and minerals and gases rising up from deep within the Earth.
But the reason it's thought that life on Earth may have begun in such structures is because these are a very unique kind of hydrothermal vent called an alkaline vent.
And, about four billion years ago, when life on Earth began, seawater would have been mildly acidic.
So, here is that proton gradient, that source of energy for life.
You've got a reservoir of protons in the acidic seawater and a deficit of protons around the vents.
And the vents don't just provide an energy source.
They're also rich in the raw materials life needs.
Hydrogen gas, carbon dioxide and minerals containing iron, nickel and sulphur.
But there's more than that.
See, these vents are porous - there are little chambers inside them - and they can act to concentrate organic molecules.
You've got everything inside these vents.
You've got concentrated building blocks of life trapped inside the rock.
And you've got that proton gradient, you've got that waterfall that provides the energy for life.
So this could be where your distant ancestors come from.
And places like these could be the places where life on Earth began.
The first living things might have started out as part of the rock that created them.
Simple organisms that exploited energy from the naturally-occurring proton gradients in the vents.
And we think this because living things still get their energy using proton gradients today.
Deep within ourselves, the chemistry the first life exploited in the vents is wrapped up in structures called mitochondria - microscopic batteries that power the processes of life.
This is a picture of the mitochondria from the little brown bat.
This is a picture of the mitochondria from a plant.
It's actually a member of the mustard family.
This is a picture of the mitochondria in bread mould.
And this of mitochondria inside a malaria parasite.
So, the fascinating thing is that all these animals and plants, and in fact virtually every living thing on the planet, uses proton gradients to produce energy to live.
Why? Well, the answer is probably because all these radically different forms of life share a common ancestor.
And that common ancestor was something that lived in those ancient undersea vents, four billion years ago, where naturally-occurring proton gradients provided the energy for the first life.
So, if you're looking for a universal spark of life, then this is it.
The spark of life is proton gradients.
In those four billion years, that spark has grown into a flame.
And a few simple organisms clustered around a hydrothermal vent have evolved to produce all the magnificent diversity that covers the Earth today.
Today, life on Earth is so diverse, it covers so much of the planet that you can find places like this lake, where it's effectively its own sealed ecosystem.
It's saltwater, it's connected to the sea, but it's only connected through small channels through the rock.
So that means that the marine life in here is effectively isolated.
This is the Golden Jellyfish, a unique sub-species only found in this one lake on this one island, in the tiny Micronesian Republic of Palau.
They used to live like most jellyfish, cruising the open ocean, catching tiny creatures, zooplankton, in their long tentacles.
But today their tentacles have all but disappeared because the Golden Jellyfish have evolved to do something that very few other animals can do.
It really is incredible.
There are, I want to say millions of jellyfish, as far as you can see, all the way down till the light vanishes there are jellyfish.
And you can see they've congregated in the sun.
If you go over there to where the lake's in shade, there are just none.
They're in this pool of light, beneath the sun.
There are millions of them.
Beautifully elegant things just floating around.
I'm not being unduly hyperbolic, it's quite remarkable.
This lake is home to over 20 million jellyfish.
Whose success comes down to a remarkable adaptation.
Their bodies play host to thousands of other organisms - photosynthetic algae that harvest energy directly from sunlight.
The jellyfish engulf the algae as juveniles, and by adulthood algal cells make up around 10% of their biomass.
Grouped into clusters of up to 200 individuals, they live inside the jellyfish's own cells.
The Golden Jellyfish uses algae to get most of its energy from photosynthesis.
They go to the surface and gently Wow, there's one there.
They're gently turning.
The reason they do that is to give all their algae an equal dose of sunlight.
So they're quite democratic creatures, just making sure they get as much food as they can.
They just come up you, jellying around, photosynthesising.
They tell me they don't sting.
But I'm sure I've got a tingling from it.
And it's not just their anatomy that's adapted to harvest solar energy.
Every morning as the sun rises, the jellyfish begin to swim towards the east.
As the sun tracks across the sky, they move back again towards the west, where they spend their night.
So the jellyfish have this beautiful, intimate and complex relationship with the position of the sun in the sky.
As sunlight is captured by their algae, it's converted into chemical energy.
Energy they use to combine simple molecules, water and carbon dioxide, to produce are far more complex one.
Glucose.
Once absorbed by the jellyfish, glucose and other molecules not only power their daily voyage across the lake, they provide the basic building blocks the jellyfish use to grow the elegant and complex structures of their bodies.
So the jellyfish, through their symbiotic algae, absorb the light, the energy from the sun, and they use it to live, to power their processes of life.
And that's true, directly or indirectly, for every form of life on the surface of our planet.
But things are a little bit more interesting than that, because energy is neither created nor destroyed.
So life doesn't eat it somehow, it doesn't use it up, it doesn't remove it from the universe.
So what does it do? To understand how energy sustains life, you have to understand exactly what happens to it as the cosmos evolves.
In the first instance after the Big Bang there was nothing in the universe but energy.
As it changed from one form to another, galaxies, stars and planets were born.
But while the total amount of energy in the universe stays constant, with every single transformation something does change.
The energy itself becomes less and less useful.
It becomes ever more disordered.
And you can see this process in action as energy from the sun hits the surface of the Earth.
So think about think about this sand on the beach, it's been under the glare of the sun all day, it's been absorbing its light which has been heating it up, and now that the sun is dipping below the horizon, then the sand is still hot to the touch because it's re-radiating all the energy that it absorbed as heat back into the universe.
The key word there is "all".
All the energy.
If it didn't do that then it'd just gradually heat up day after day after day, and eventually, I suppose, the whole beach would melt.
So what's changed? Well, it's the quality of the energy, if you like.
Think about it.
If as much energy is coming back off this sand now as it absorbed from the sun, then it should be giving me a suntan.
I should need sun cream if I sit looking at this beach all night.
And obviously I don't.
The difference is that this energy is of a lower quality.
It can do less.
It's heat, which is a very low quality of energy indeed.
So what the sand's done is take highly ordered, high quality energy from the sun and convert it to an equal amount of low quality disordered energy.
This descent into disorder is happening across the entire universe.
As time passes, every single joule of energy is converted into heat.
The universe gradually cools towards absolute zero.
Until with no ordered energy left, the cosmos grinds to a halt and every structure in it decays away.
Yet whilst the universe is dying, everywhere you look life goes on.
It's a deep paradox that Schroedinger was well aware of when he wrote his book in 1943.
"How can it be," writes Schroedinger, "That the living organism avoids decay?" In other words, how can it be that life seems to continue to build increasingly complex structures when the rest of the universe is falling to bits, is decaying away? Now, that's a paradox, because the universe is falling to bits, it is tending towards disorder.
That is enshrined in a law of physics called the Second Law Of Thermodynamics.
And I think most physicists believe that it's the one law of physics that will never be broken.
The key to understanding how life obeys the laws of thermodynamics is to look at both the energy it takes in and the energy it gives out.
This is a thermal camera, so hot things show up as red, and cold things show up as blue.
So what you're seeing here is that the chicken is hotter than its surroundings.
Now, heat is a highly disordered form of energy, so the chicken is radiating disorder out into the wider universe.
By converting chemical energy into heat, life transforms energy from an ordered to a disordered form, in exactly the same way as every other process in the universe.
In fact, every single human being can generate 6,000 times more heat per kilogram than the sun.
And it's by converting so much energy from one form to another that life is able to hang on to a tiny amount of order for itself.
Just enough to resist the inevitable decay of the universe.
So it's no accident that living things are hot and export heat to their surroundings.
Because it's an essential part of being alive.
Living things borrow order from the wider universe, and then they export it again as disorder.
But it's not precisely in balance.
They have to export more disorder than the amount of order they import.
That is the content of the Second Law Of Thermodynamics.
And living things have to obey the Second Law because they're physical structures, they obey the laws of physics.
Just by being alive, we too are part of the process of energy transformation that drives the evolution of the universe.
We take sunlight that has its origins at the very start of time, and transform it into heat that will last for eternity.
So, far from being a paradox, living things can be explained by the laws of physics.
The very same laws that describe the falling of the rain and the shining of the stars.
The dragonfly draws its energy from proton gradients, the fundamental chemistry that powers life.
But the real miracles are the structures they build with that energy.
Borrowing order to generate cells.
Arranging those cells into tissues.
And those tissues into the intricate architecture of their bodies.
So we've developed a quite detailed understanding of the underlying machinery that powers these dragonflies, and indeed all life on Earth.
And whilst we don't have all the answers, it is certainly safe to say that there's no mysticism required.
You don't need some kind of magical flame to animate these little machines.
They operate according to the laws of physics, and I think they're no less magical for that.
Yet the dragonfly will only maintain this delicate balancing act for so long.
Because all living things share the same fate.
Each individual will die.
But life itself endures.
This is because there's something that separates life from every other process in the universe.
This is the Malaysian state of Sabah, on the northern tip of the island of Borneo.
It's one of the most bio-diverse places on the planet.
Home to 15,000 plant species 3,000 species of tree 420 species of bird and 222 species of mammals.
Including those.
Borneo's rainforests contain trees that are thought to live for more than 1,000 years.
But the forest itself has existed for tens of millions of years.
The reason it persists is because each generation of animal and plant passes the information to recreate itself on to the next generation.
And that's possible because of a molecule found in every cell of every living thing.
A molecule called DNA.
Now, all I need to isolate my DNA is some washing up liquid, a bit of salt, and the chemist's best friend, vodka.
Now, to get a sample of DNA I can just use myself.
If I just swill my tongue around on the edge of my cheek, I'll dislodge some cheek cells into my saliva.
I missed the test tube.
There we are.
A physicist doing an experiment.
Then I add a bit of washing up liquid.
Now, what this will do is it will break open those cheek cells and it will also degrade the membrane that surrounds the cell nucleus that contains the DNA.
Salt will encourage the molecules to clump together.
DNA is insoluble in alcohol.
So you should get a layer of alcohol with DNA molecules precipitated out.
Yeah.
There, can you see? Those strands of white.
And so in that cloudy, almost innocuous looking solid are all the instructions needed to build a human being.
So that is what makes life unique.
Only living things have the ability to encode and transmit information in this way.
And the consequences of that profoundly affect our understanding of what it is to be alive.
This rainforest is part of the Sepilok Forest Reserve, and in here somewhere are some of our closest genetic relatives.
Shh-shh.
There, there, can you see? Orangutans are highly specialised for a life lived in the forest canopy.
Their arms are twice as long as their legs.
And all four limbs are incredibly flexible.
Each one ending in a hand whose curved bones are perfectly adapted for gripping branches.
These adaptations are encoded in information passed down in their DNA.
He's got a hat on.
He has actually just put a hat on.
This is the orang-utan's genetic code.
It was published in 2011, and there are over three billion letters in it.
If flip through it look at that.
Now, it's composed of only four letters, A, C, T and G, which are known as bases.
They're chemical compounds.
They're molecules.
And the way it works is beautifully simple.
They're grouped into threes, called codons, and some of them just tell the code reader, if you like, how to start, or where to start and when and when it's going to stop.
He's fast.
So you'd have a start and a stop.
In between, each group of three codes for a particular amino acid.
Now, amino acids are the building blocks of proteins, which are the building blocks of all living things.
So you would just read along, you'd find, start, stop, and then you'd go along in threes, build amino acid, build amino acid, build amino acid, build amino acid, stitch those together into a protein, and if you keep doing that, eventually you'll come out with one of those.
It's not that simple of course.
But the basics are there.
This code, written in there, are the instructions to make him.
To faithfully reproduce those instructions for generation after generation, the orang-utans and, and indeed all life on Earth, rely on a remarkable property of DNA.
Its incredible stability and resistance to change.
Every time a cell divides, its DNA must be copied.
And the genetic code is highly resistant to copying errors.
The little enzymes, the chemical machines that do the copying, on average make only one mistake in a billion letters.
I mean, that's like copying out the Bible about 280 times and making just one mistake.
That fidelity means adaptations are faithfully transmitted from parent to offspring.
And so while we think of evolution as a process of constant change, in fact the vast majority of the code is preserved.
So even though we're separated from the orang-utans by nearly 14 million years of evolution, what's really striking is just how similar we are.
And those similarities are far more than skin deep.
Orang-utans are surely one of the most human of animals.
And they share many behavioural traits that you would define as being uniquely human.
They nurture their young for eight years before they let them go on their own into the forest.
In that time the infants learn which fruits are safe to eat and which are poisonous.
Which branches will hold their weight and which won't.
And they can do all that because they have a memory, they can remember things that happened to them in their life, they can learn from them, and they can pass them on from generation to generation.
And that deep connection extends far beyond our closest relatives.
Because our DNA contains the fingerprint of almost four billion years of evolution.
If I draw a tree of life for the primates, then we share a common ancestor with the chimps, Bonobos.
About four to six million years ago.
And if you compare our genetic sequences you find that our genes are 99% the same.
You go back to the split with gorillas, about six to eight million years ago and again, if you compare our genes you find that they are 98.
4% the same.
Back in time again, common ancestor with our friends over there, the orang-utans, then our genes are 97.
4% the same.
And you could carry on all the way back in time.
You could look for our common ancestor with a chicken, and you'd find that our codes are about 60% the same.
And in fact, if you look for any animal, like him, a little fly, or a bacteria, something that seems superficially completely unrelated to us, then you'll still find sequences in the genetic code which are identical to sequences in my cells.
So this tells us that all life on Earth is related, it's all connected through our genetic code.
DNA is the blueprint for life.
But its extraordinary fidelity means it also contains a story.
And what a story it is.
The entire history of evolution from the present day all the way back to the very first spark of life.
And it tells us that we're connected, not only to every plant and animal alive today, but to every single thing that has ever lived.
The question, what is life, is surely one of the grandest of questions.
And we've learnt that life isn't really a thing at all.
It's a collection of chemical processes that can harness a flow of energy to create local islands of order, like me and this forest, by borrowing order from the wider universe and then transmitting it from generation to generation through the elegant chemistry of DNA.
And the origins of that chemistry can be traced back four billion years, most likely to vents in the primordial ocean.
And, most wonderfully of all, the echoes of that history, stretching back for a third of the age of the universe, can be seen in every cell of every living thing on Earth.
And that leads to what I think is the most exciting idea of all, because far from being some chance event ignited by a mystical spark, the emergence of life on Earth might have been an inevitable consequence of the laws of physics.
And if that's true, then a living cosmos might be the only way our cosmos can be.
Just remember you're a tiny little person on a planet In a universe expanding and immense That life began evolving and dissolving and resolving In the deep primordial oceans by the hydrothermal vents Our Earth which had its birth almost five billion years ago From out a collapsing cloud of gas Grew life which was quite new And eventually led to you In only 3.
5 billion years or less.
A voracious predator, this male has lived underwater for nearly five months, feeding, growing, preparing for this moment.
He's about to undertake one of the most remarkable transformations in the natural world.
From aquatic predator to master of the air.
The brief adult life of a dragonfly is amongst the most energetic in nature.
Dragonflies are the most remarkable animals.
You can see their incredible agility in flight just watching them skim across the surface of this pond.
They can pull two and a half G in a turn, and they can fly at 15 mph, which is fast for something that big.
They've been around on Earth since before the time of the dinosaurs, and in that time they've been fine-tuned by natural selection to do what they do - which is to catch their prey on the wing.
So, dragonflies are beautiful pieces of engineering.
They're intricate, complex machines.
But is that all they are? Because once their brief lives are over, their vitality will be gone.
And this raises deep questions.
What is it that makes something alive? And how did life begin in the first place? So, what is the difference between the living and the dead? What is life? I've come to one of the most isolated regions of the Philippines to visit the remote hilltop town of Sagada.
It's a two-day drive from the capital, Manila, over some of the country's roughest roads that wind their way 1,500 metres up into the hills.
This is a place where the traditional belief is that mountain spirits give us life and that our souls return to the mountain when we die and where the people who live here still imagine that the spirits of the dead walk among the living.
Tonight is November 1st, and here in Sagada - in fact across the Philippines - that means it's the Day of the Dead.
That's the day when people come to this graveyard on a hillside and, well, celebrate the lives of their relatives.
The people light fires to honour and warm the departed, inviting their souls to commune with them.
Now, not matter how unscientific it sounds, this idea that there's some kind of soul or spirit or animating force that makes us what we are and that persists after our death is common.
Virtually every culture, every religion, has that deeply-held belief.
And there's a reason for that - because it feels right.
I mean, just think about it.
It's hard to accept that when you die you will just stop existing and that you are, your life, the essence of you, is just really something that emerges from an inanimate bag of stuff.
Don't get too close.
You can see that these people feel not only do they come to celebrate the lives of their relatives, but they're coming in some sense to communicate with them.
Their relatives, even though their physical bodies have died, are still in some sense here.
When you think about it, that's not so easy to dismiss.
If we are to state that science can explain everything about us, then it's incumbent on science to answer the question, what is it that animates living things? What is the difference between a piece of rock that's carved into a gravestone and me? For millennia, some form of spirituality has been evoked to explain what it means to be alive, and how life began.
It's only recently that science has begun to answer these deepest of questions.
In February 1943, the physicist Erwin Schrodinger gave a series of lectures in Dublin.
Now, Schrodinger is almost certainly most famous for being one of the founders of quantum theory.
But in these lectures, which he wrote up in this little book, he asked a very different question - What Is Life? And right up front, on page one, he says precisely what it isn't.
It isn't something mystical, says Schrodinger.
There isn't some magical spark that animates life.
Life is a process.
It's the interaction between matter and energy described by the laws of physics and chemistry.
The same laws that describe the falling of the rain or the shining of the stars.
So, the question is, how is that this magnificent complexity that we call life could have assembled itself on the surface of a planet which itself formed from nothing more than a collapsing cloud of gas and dust? To Schrodinger, the answer had to lie in the way living things process one of the universe's most elusive properties - energy.
Energy is a concept that's central to physics, but because it's a word we use every day its meaning has got a bit woolly.
I mean, it's easy to say what it is in a sense.
Obviously this river has got energy because over decades and centuries it's cut this valley through solid rock.
But while this description sounds simple, in reality things are a little more complicated.
For me, the best definition is that it's the length of the space time four vector and time direction, but that's not very enlightening, I'll grant you that.
Over the years, the nature of energy has proved notoriously difficult to pin down.
Not least because it has the seemingly magical property that it never runs out.
It only ever changes from one form to another.
Take the water in that waterfall.
At the top of the waterfall, it's got something called gravitational potential energy, which is the energy it possesses due to its height above the Earth's surface.
See, if I scoop some water out of the river into this beaker, then I'd have to do work to carry it up to the top of the waterfall.
I'd have to expend energy to get it up there.
So it would have that energy as gravitational potential.
I can even do the sums for you.
Half a litre of water has a mass of half a kilogram, multiply by the height, that's about five metres, the acceleration due to gravity's about ten metres per second squared.
So that's half times five times ten is 25 joules.
So I'd have to put in 25 joules to carry this water to the top of the waterfall.
Then if I emptied it over the top of the waterfall, then all that gravitational potential energy would be transformed into other types of energy.
Its sound, which is pressure waves in the air.
There's the energy of the waves in the river.
And there's heat.
So it'll be a bit hotter down there because the water's cascading into the pool at the foot of the waterfall.
Buy the key thing is energy is conserved, it's not created or destroyed.
So, because energy is conserved, if I were to add up all the energy in the water waves, all the energy in the sound waves, all the heat energy at the bottom of the pool, then I would find that it would be precisely equal to the gravitational potential energy at the top of the falls.
What's true for the waterfall is true for everything in the universe.
It's a fundamental law of nature, known as the first law of thermodynamics.
And the fact that energy is neither created nor destroyed has a profound implication.
It means energy is eternal.
The energy that's here now has always been here, and the story of the evolution of the universe is just the story of the transformation of that energy from one form to another, from the origin of the first galaxies to the ignition of the first stars and the formation of the first planets.
Every single joule of energy in the universe today was present at the Big Bang, 13.
7 billion years ago.
Potential energy held in primordial clouds of gas and dust was transformed into kinetic energy as they collapsed to form stars and planetary systems, just like our own solar system.
In the Sun, heat from the collapse initiated fusion reactions at its core.
Hydrogen became helium.
Nuclear-binding energy was released, heating the surface of the Sun, producing the light that began to bathe the young Earth.
And at some point in that story, around four billion years ago, that transformation of energy led to the origin of life on Earth.
Around 350 kilometres south of Sagada, this is Lake Taal.
Despite its sleepy, languid appearance, this landscape has been violently transformed by energy.
When I think of a volcano, I usually think of a pointy, fiery mountain with a little crater in the top.
Probably a bit like that one.
But actually this entire lake is the flooded crater of a giant volcano.
It began erupting only about 140,000 years ago, and in that time it's blown 120 billion cubic metres of ash and rock into the Earth's atmosphere.
This crater is 30 kilometres across and in places 150 metres deep.
That's a cube of rock five kilometres by five kilometres by five kilometres just blown away.
It's a big volcano.
Taal Lake is testament to the immense power locked within the Earth at the time of its formation.
Since the lake was created, a series of further eruptions formed the island in the centre.
And at its heart is a place where you can glimpse the turmoil of the inner Earth, where energy from the core still bubbles up to the surface producing conditions similar to those that may have provided the very first spark of life.
The water in this lake is different from drinking water in a very interesting way.
See, if I test this bottle of water with this, which is called universal indicator paper, then you see immediately that it goes green.
And that means that it's completely neutral.
It's called PH7 in the jargon.
But then look what happens when I test the water from the lake.
Now the indicator paper stays orange.
In fact, it might have gone a bit more orange.
So that means that this is acid.
It's about PH3.
At the most basic level, the energy trapped inside the Earth is melting rocks.
And when you melt rock like this you produce gases.
A lot of carbon dioxide, and in this case of this volcano, a lot of sulphur dioxide.
Now, sulphur dioxide dissolves in water and you get H2SO4, sulphuric acid.
Now, what I mean when I say that water is acidic? Well, water is H2O - hydrogen and oxygen bonded together.
But actually when it's liquid it's a bit more complicated than that.
It's actually a sea of ions.
So H-plus ions, that's just single protons.
And OH-minus ions, that's oxygen and hydrogen bonded together, all floating around.
Now, when something's neutral, when the PH is seven, that means that the concentrations of those ions are perfectly balanced.
When you make water acidic, then you change the concentration of those ions and, to be specific, you increase the concentration of the H-plus ions of the protons.
So, this process of acidification has stored the energy of the volcano as chemical potential energy.
The volcano transforms heat from the inner Earth into chemical energy and stores it as a reservoir of protons in the lake.
And this is the same way energy is stored in a simple battery or fuel cell.
These bottles contain a weak acid and are connected by a semi-permeable membrane.
Passing an electric current through them has a similar effect to the volcano's energy bubbling up into the lake.
It causes protons to build up in one of the bottles.
You can think of it, I suppose, like a waterfall, where the protons are up here waiting to flow down.
All you have to do to release that energy and do something useful with it is complete the circuit.
Which I can do by just connecting a motor to it.
There you go.
Look at that.
That's the protons cascading down the waterfall and driving the motor around.
It actually works! Quite remarkable, actually.
Now, the fuel cell produces and exploits its proton gradient artificially.
But there are places on Earth where that gradient occurs completely naturally.
Here, for example.
So we've got the proton reservoir over there, the acidic volcanic lake.
If you look that way, there's another lake, and the reaction of the water with the rocks on the shore make that lake slightly alkaline, which is to say that there's a deficit of protons down there.
So here's the waterfall, a reservoir of protons up there, a deficit down there.
If you could just connect them, then you'd have a naturally occurring geological fuel cell.
And it's thought that the first life on our planet may have exploited the energy released in those natural proton waterfalls.
What do you think? It's good, isn't it? These are pictures from deep below the surface of the Atlantic Ocean, somewhere between Bermuda and the Canaries.
And it's a place known as the Lost City.
You can see why.
Look at these huge towers of rock, some of them 50-60 metres high, reaching up from the floor of the Atlantic and into the ocean.
It's what's known as a hydrothermal vent system.
So these things are formed by hot water and minerals and gases rising up from deep within the Earth.
But the reason it's thought that life on Earth may have begun in such structures is because these are a very unique kind of hydrothermal vent called an alkaline vent.
And, about four billion years ago, when life on Earth began, seawater would have been mildly acidic.
So, here is that proton gradient, that source of energy for life.
You've got a reservoir of protons in the acidic seawater and a deficit of protons around the vents.
And the vents don't just provide an energy source.
They're also rich in the raw materials life needs.
Hydrogen gas, carbon dioxide and minerals containing iron, nickel and sulphur.
But there's more than that.
See, these vents are porous - there are little chambers inside them - and they can act to concentrate organic molecules.
You've got everything inside these vents.
You've got concentrated building blocks of life trapped inside the rock.
And you've got that proton gradient, you've got that waterfall that provides the energy for life.
So this could be where your distant ancestors come from.
And places like these could be the places where life on Earth began.
The first living things might have started out as part of the rock that created them.
Simple organisms that exploited energy from the naturally-occurring proton gradients in the vents.
And we think this because living things still get their energy using proton gradients today.
Deep within ourselves, the chemistry the first life exploited in the vents is wrapped up in structures called mitochondria - microscopic batteries that power the processes of life.
This is a picture of the mitochondria from the little brown bat.
This is a picture of the mitochondria from a plant.
It's actually a member of the mustard family.
This is a picture of the mitochondria in bread mould.
And this of mitochondria inside a malaria parasite.
So, the fascinating thing is that all these animals and plants, and in fact virtually every living thing on the planet, uses proton gradients to produce energy to live.
Why? Well, the answer is probably because all these radically different forms of life share a common ancestor.
And that common ancestor was something that lived in those ancient undersea vents, four billion years ago, where naturally-occurring proton gradients provided the energy for the first life.
So, if you're looking for a universal spark of life, then this is it.
The spark of life is proton gradients.
In those four billion years, that spark has grown into a flame.
And a few simple organisms clustered around a hydrothermal vent have evolved to produce all the magnificent diversity that covers the Earth today.
Today, life on Earth is so diverse, it covers so much of the planet that you can find places like this lake, where it's effectively its own sealed ecosystem.
It's saltwater, it's connected to the sea, but it's only connected through small channels through the rock.
So that means that the marine life in here is effectively isolated.
This is the Golden Jellyfish, a unique sub-species only found in this one lake on this one island, in the tiny Micronesian Republic of Palau.
They used to live like most jellyfish, cruising the open ocean, catching tiny creatures, zooplankton, in their long tentacles.
But today their tentacles have all but disappeared because the Golden Jellyfish have evolved to do something that very few other animals can do.
It really is incredible.
There are, I want to say millions of jellyfish, as far as you can see, all the way down till the light vanishes there are jellyfish.
And you can see they've congregated in the sun.
If you go over there to where the lake's in shade, there are just none.
They're in this pool of light, beneath the sun.
There are millions of them.
Beautifully elegant things just floating around.
I'm not being unduly hyperbolic, it's quite remarkable.
This lake is home to over 20 million jellyfish.
Whose success comes down to a remarkable adaptation.
Their bodies play host to thousands of other organisms - photosynthetic algae that harvest energy directly from sunlight.
The jellyfish engulf the algae as juveniles, and by adulthood algal cells make up around 10% of their biomass.
Grouped into clusters of up to 200 individuals, they live inside the jellyfish's own cells.
The Golden Jellyfish uses algae to get most of its energy from photosynthesis.
They go to the surface and gently Wow, there's one there.
They're gently turning.
The reason they do that is to give all their algae an equal dose of sunlight.
So they're quite democratic creatures, just making sure they get as much food as they can.
They just come up you, jellying around, photosynthesising.
They tell me they don't sting.
But I'm sure I've got a tingling from it.
And it's not just their anatomy that's adapted to harvest solar energy.
Every morning as the sun rises, the jellyfish begin to swim towards the east.
As the sun tracks across the sky, they move back again towards the west, where they spend their night.
So the jellyfish have this beautiful, intimate and complex relationship with the position of the sun in the sky.
As sunlight is captured by their algae, it's converted into chemical energy.
Energy they use to combine simple molecules, water and carbon dioxide, to produce are far more complex one.
Glucose.
Once absorbed by the jellyfish, glucose and other molecules not only power their daily voyage across the lake, they provide the basic building blocks the jellyfish use to grow the elegant and complex structures of their bodies.
So the jellyfish, through their symbiotic algae, absorb the light, the energy from the sun, and they use it to live, to power their processes of life.
And that's true, directly or indirectly, for every form of life on the surface of our planet.
But things are a little bit more interesting than that, because energy is neither created nor destroyed.
So life doesn't eat it somehow, it doesn't use it up, it doesn't remove it from the universe.
So what does it do? To understand how energy sustains life, you have to understand exactly what happens to it as the cosmos evolves.
In the first instance after the Big Bang there was nothing in the universe but energy.
As it changed from one form to another, galaxies, stars and planets were born.
But while the total amount of energy in the universe stays constant, with every single transformation something does change.
The energy itself becomes less and less useful.
It becomes ever more disordered.
And you can see this process in action as energy from the sun hits the surface of the Earth.
So think about think about this sand on the beach, it's been under the glare of the sun all day, it's been absorbing its light which has been heating it up, and now that the sun is dipping below the horizon, then the sand is still hot to the touch because it's re-radiating all the energy that it absorbed as heat back into the universe.
The key word there is "all".
All the energy.
If it didn't do that then it'd just gradually heat up day after day after day, and eventually, I suppose, the whole beach would melt.
So what's changed? Well, it's the quality of the energy, if you like.
Think about it.
If as much energy is coming back off this sand now as it absorbed from the sun, then it should be giving me a suntan.
I should need sun cream if I sit looking at this beach all night.
And obviously I don't.
The difference is that this energy is of a lower quality.
It can do less.
It's heat, which is a very low quality of energy indeed.
So what the sand's done is take highly ordered, high quality energy from the sun and convert it to an equal amount of low quality disordered energy.
This descent into disorder is happening across the entire universe.
As time passes, every single joule of energy is converted into heat.
The universe gradually cools towards absolute zero.
Until with no ordered energy left, the cosmos grinds to a halt and every structure in it decays away.
Yet whilst the universe is dying, everywhere you look life goes on.
It's a deep paradox that Schroedinger was well aware of when he wrote his book in 1943.
"How can it be," writes Schroedinger, "That the living organism avoids decay?" In other words, how can it be that life seems to continue to build increasingly complex structures when the rest of the universe is falling to bits, is decaying away? Now, that's a paradox, because the universe is falling to bits, it is tending towards disorder.
That is enshrined in a law of physics called the Second Law Of Thermodynamics.
And I think most physicists believe that it's the one law of physics that will never be broken.
The key to understanding how life obeys the laws of thermodynamics is to look at both the energy it takes in and the energy it gives out.
This is a thermal camera, so hot things show up as red, and cold things show up as blue.
So what you're seeing here is that the chicken is hotter than its surroundings.
Now, heat is a highly disordered form of energy, so the chicken is radiating disorder out into the wider universe.
By converting chemical energy into heat, life transforms energy from an ordered to a disordered form, in exactly the same way as every other process in the universe.
In fact, every single human being can generate 6,000 times more heat per kilogram than the sun.
And it's by converting so much energy from one form to another that life is able to hang on to a tiny amount of order for itself.
Just enough to resist the inevitable decay of the universe.
So it's no accident that living things are hot and export heat to their surroundings.
Because it's an essential part of being alive.
Living things borrow order from the wider universe, and then they export it again as disorder.
But it's not precisely in balance.
They have to export more disorder than the amount of order they import.
That is the content of the Second Law Of Thermodynamics.
And living things have to obey the Second Law because they're physical structures, they obey the laws of physics.
Just by being alive, we too are part of the process of energy transformation that drives the evolution of the universe.
We take sunlight that has its origins at the very start of time, and transform it into heat that will last for eternity.
So, far from being a paradox, living things can be explained by the laws of physics.
The very same laws that describe the falling of the rain and the shining of the stars.
The dragonfly draws its energy from proton gradients, the fundamental chemistry that powers life.
But the real miracles are the structures they build with that energy.
Borrowing order to generate cells.
Arranging those cells into tissues.
And those tissues into the intricate architecture of their bodies.
So we've developed a quite detailed understanding of the underlying machinery that powers these dragonflies, and indeed all life on Earth.
And whilst we don't have all the answers, it is certainly safe to say that there's no mysticism required.
You don't need some kind of magical flame to animate these little machines.
They operate according to the laws of physics, and I think they're no less magical for that.
Yet the dragonfly will only maintain this delicate balancing act for so long.
Because all living things share the same fate.
Each individual will die.
But life itself endures.
This is because there's something that separates life from every other process in the universe.
This is the Malaysian state of Sabah, on the northern tip of the island of Borneo.
It's one of the most bio-diverse places on the planet.
Home to 15,000 plant species 3,000 species of tree 420 species of bird and 222 species of mammals.
Including those.
Borneo's rainforests contain trees that are thought to live for more than 1,000 years.
But the forest itself has existed for tens of millions of years.
The reason it persists is because each generation of animal and plant passes the information to recreate itself on to the next generation.
And that's possible because of a molecule found in every cell of every living thing.
A molecule called DNA.
Now, all I need to isolate my DNA is some washing up liquid, a bit of salt, and the chemist's best friend, vodka.
Now, to get a sample of DNA I can just use myself.
If I just swill my tongue around on the edge of my cheek, I'll dislodge some cheek cells into my saliva.
I missed the test tube.
There we are.
A physicist doing an experiment.
Then I add a bit of washing up liquid.
Now, what this will do is it will break open those cheek cells and it will also degrade the membrane that surrounds the cell nucleus that contains the DNA.
Salt will encourage the molecules to clump together.
DNA is insoluble in alcohol.
So you should get a layer of alcohol with DNA molecules precipitated out.
Yeah.
There, can you see? Those strands of white.
And so in that cloudy, almost innocuous looking solid are all the instructions needed to build a human being.
So that is what makes life unique.
Only living things have the ability to encode and transmit information in this way.
And the consequences of that profoundly affect our understanding of what it is to be alive.
This rainforest is part of the Sepilok Forest Reserve, and in here somewhere are some of our closest genetic relatives.
Shh-shh.
There, there, can you see? Orangutans are highly specialised for a life lived in the forest canopy.
Their arms are twice as long as their legs.
And all four limbs are incredibly flexible.
Each one ending in a hand whose curved bones are perfectly adapted for gripping branches.
These adaptations are encoded in information passed down in their DNA.
He's got a hat on.
He has actually just put a hat on.
This is the orang-utan's genetic code.
It was published in 2011, and there are over three billion letters in it.
If flip through it look at that.
Now, it's composed of only four letters, A, C, T and G, which are known as bases.
They're chemical compounds.
They're molecules.
And the way it works is beautifully simple.
They're grouped into threes, called codons, and some of them just tell the code reader, if you like, how to start, or where to start and when and when it's going to stop.
He's fast.
So you'd have a start and a stop.
In between, each group of three codes for a particular amino acid.
Now, amino acids are the building blocks of proteins, which are the building blocks of all living things.
So you would just read along, you'd find, start, stop, and then you'd go along in threes, build amino acid, build amino acid, build amino acid, build amino acid, stitch those together into a protein, and if you keep doing that, eventually you'll come out with one of those.
It's not that simple of course.
But the basics are there.
This code, written in there, are the instructions to make him.
To faithfully reproduce those instructions for generation after generation, the orang-utans and, and indeed all life on Earth, rely on a remarkable property of DNA.
Its incredible stability and resistance to change.
Every time a cell divides, its DNA must be copied.
And the genetic code is highly resistant to copying errors.
The little enzymes, the chemical machines that do the copying, on average make only one mistake in a billion letters.
I mean, that's like copying out the Bible about 280 times and making just one mistake.
That fidelity means adaptations are faithfully transmitted from parent to offspring.
And so while we think of evolution as a process of constant change, in fact the vast majority of the code is preserved.
So even though we're separated from the orang-utans by nearly 14 million years of evolution, what's really striking is just how similar we are.
And those similarities are far more than skin deep.
Orang-utans are surely one of the most human of animals.
And they share many behavioural traits that you would define as being uniquely human.
They nurture their young for eight years before they let them go on their own into the forest.
In that time the infants learn which fruits are safe to eat and which are poisonous.
Which branches will hold their weight and which won't.
And they can do all that because they have a memory, they can remember things that happened to them in their life, they can learn from them, and they can pass them on from generation to generation.
And that deep connection extends far beyond our closest relatives.
Because our DNA contains the fingerprint of almost four billion years of evolution.
If I draw a tree of life for the primates, then we share a common ancestor with the chimps, Bonobos.
About four to six million years ago.
And if you compare our genetic sequences you find that our genes are 99% the same.
You go back to the split with gorillas, about six to eight million years ago and again, if you compare our genes you find that they are 98.
4% the same.
Back in time again, common ancestor with our friends over there, the orang-utans, then our genes are 97.
4% the same.
And you could carry on all the way back in time.
You could look for our common ancestor with a chicken, and you'd find that our codes are about 60% the same.
And in fact, if you look for any animal, like him, a little fly, or a bacteria, something that seems superficially completely unrelated to us, then you'll still find sequences in the genetic code which are identical to sequences in my cells.
So this tells us that all life on Earth is related, it's all connected through our genetic code.
DNA is the blueprint for life.
But its extraordinary fidelity means it also contains a story.
And what a story it is.
The entire history of evolution from the present day all the way back to the very first spark of life.
And it tells us that we're connected, not only to every plant and animal alive today, but to every single thing that has ever lived.
The question, what is life, is surely one of the grandest of questions.
And we've learnt that life isn't really a thing at all.
It's a collection of chemical processes that can harness a flow of energy to create local islands of order, like me and this forest, by borrowing order from the wider universe and then transmitting it from generation to generation through the elegant chemistry of DNA.
And the origins of that chemistry can be traced back four billion years, most likely to vents in the primordial ocean.
And, most wonderfully of all, the echoes of that history, stretching back for a third of the age of the universe, can be seen in every cell of every living thing on Earth.
And that leads to what I think is the most exciting idea of all, because far from being some chance event ignited by a mystical spark, the emergence of life on Earth might have been an inevitable consequence of the laws of physics.
And if that's true, then a living cosmos might be the only way our cosmos can be.
Just remember you're a tiny little person on a planet In a universe expanding and immense That life began evolving and dissolving and resolving In the deep primordial oceans by the hydrothermal vents Our Earth which had its birth almost five billion years ago From out a collapsing cloud of gas Grew life which was quite new And eventually led to you In only 3.
5 billion years or less.