The Origins of Life

Hello, I'm Brian Cox, and my aim is to raise the level of scientific discourse on the BBC.

And I'm Robin Ince, and my aim is to reduce the level of human anxiety and the volume of complaints when levels of scientific discourse are raised on the BBC.

Today, we're going to be looking at how life began.

That's right, yes, the charade that is life.

Life is the name of the game.

Life to see you, to see you life.

Saturday prime time, here comes science.

You see, that wouldn't have happened if around four billion years ago chemistry hadn't got interesting, turned into biology, and embarked on a journey towards ever-increasing self-replicating complexity that appears, only appears, mind you, Robin, to violate the second law of thermodynamics.

Now, you will, of course, have been surprised there to hear Brian say the words chemistry and interesting so closely together because for any regular listeners, they will know that Brian considers biology to be one of the arts, like contemporary dance,

or juggling, another one one of the arts.

But since that, you've actually had a Damasian moment, haven't you?

And you have now become a lover of photosynthesis to a point with legal ramifications.

Leave the water lilies alone, Brian Cox, and step away from the pond.

Today, we ask the question: what is life, as posed by the great physicist Owen Schrödinger in his iconic 1943 lectures.

In the introduction, he asked whether science will ever be able to fully explain the events taking place within living organisms, and immediately answered that the obvious inability of present-day physics and chemistry to account for such events is no reason at all for doubting that they can be accounted for by those sciences.

Yet, almost 70 years later, many prefer still to believe in the idea that it was a bored deity who wanted to make a garden, and others believe in the wonderfully worded idea of panspermia, that life on Earth came from outer space.

But that, in the end, provides very few answers and a lot of terrible books about was Pythagoras an astronaut.

Did life then begin with the primordial soup that over geological time evolved into a main course of brains, thumbs, and self-consciousness?

Or did it emerge from the high-energy environment of deep-sea geothermal vents?

Are we going to find out?

Today we may well find out how life truly started, though.

To be fair, that is probably quite unlikely.

If we do finally, after hundreds of years of scientific research, go, Yeah, we've come up with the exact answer.

That's uh that's where all the exact answers happen on Radio 4 panel shows.

I'm sure many of you heard, I'm sorry I haven't a clue the other day, where Barry Cryer invented that perpetual motion machine.

It was

just just a week after Nicholas Parsons was abducted by aliens on Just a Minute and came back pregnant.

To take us through the many questions of the origin of life, we have two self-conscious organisms whose ancestors were fortunately victorious in the struggle for existence and one who was clearly significantly luckier than that.

You decide.

Nick Lane is a reader of biochemistry.

It's not you, Nick.

Necessarily.

Nick Lane is a reader in biochemistry at University College London, advisor on the upcoming BBC TV TV Meister work Wonders of Life to be broadcast in autumn 2012 in high definition

and author of the book Life Ascending which looks at the ten great inventions of life including DNA, photosynthesis, movement and sight.

It's very exciting by the way Wonders of Life because that is a show which Brian is not allowed to look up at anything.

He has to look down at stuff.

You bring your neck down.

I can't look that far down, but that's when life is.

It's down there.

Ow.

Dr.

Adam Rutherford is one of the country's leading experts on whether it might snow this winter after

presenting the documentary, Will It Snow, with Kate Humble.

We're not wondering if it might snow, he has written and presented documentaries on the cell and the gene code.

But his next project with Kate Humble is Do you think it might be parky in April?

This will be followed by the incisive three-part series, Should I Take My Umbrella?

Since our next guest was last on the show, he's written a critically acclaimed musical based on Royal Dials Matilda, toured with the full orchestra and made waves in America.

He's also found out that however beautifully written your songs are, for some reason, barefooted, unruly, hairy-mouthed atheist in heavy eyeliner might find it hard to hire a piano in Dallas.

Tim Minchin, and this is our panel.

Well, I'm going to start off with you, Tim, as the non-expert.

Well, we're both non-experts, obviously, which is the hardest thing when we talk about how life began is actually defining what is a living thing.

So I want to find out from you, first of all, what do you think would define a living thing?

I should have an answer.

This is the sort of thing you get taught in year nine and should remember, isn't it?

Like something crossing a semi-permeable membrane, one of those phrases that you should remember.

But I don't have it.

I guess it needs to reproduce, doesn't it, to be life?

Otherwise, everyone's just spontaneously bouncing into life.

So it would have to reproduce and it would have to have the metabolism stuff going in and it has to have a chemical working system, something.

Can I just say this begins to feel like an episode of Family Fortunes made by Open University?

We asked 100 people what made a living thing and the top answer was

homeostasis.

So homeostasis, well done.

That do you get a point for homeostasis?

That's one I remember.

Metabolism and homeostasis.

So reproduction, metabolism, yeah.

Is that all right?

Is that good?

Well let's find out.

That's better than

so Nick, what is better write a song about it?

Pinky, pinky, pinky, clonkey.

There is that classic definition, isn't there, that you learn at school along those lines.

There must be a mnemonic.

What is it?

Mrs.

Gren.

And it stands for, I can't remember any of them now.

Reproduction.

Metabolism, reproduction.

Metabolism.

Gren.

I think Gren is one of them.

But there's like seven of them, but I think the question is wrong.

Yes.

You're just describing what life does.

You're not actually defining what life is.

And I don't think there is a definition of what life is.

Well, that saved us a lot of time.

Thank you very much for listening.

But

that's like a philosophical distinction that has no real-world interests.

I mean, what life does is surely the definition to the point where it's interesting.

We can talk like stone teenagers on the roof about what life is,

but that's not going to move us forward.

But it does inform what experiment you have to do to answer that question.

So if you're not sure.

So imagine what would you, yeah, yeah, yeah, describe the exception.

If you look at a description of what life does, all of those things like metabolism and reproduction and sentience and movement and all those things that make up Mrs.

Grimm, right?

Those are the types of things that you can use to test what a life form does during its normal behaviour.

But it's not a very good way of approaching the question of how life began in the first place, unless you can come up with a sort of really neat way of saying this is exclusively what life does to the exclusion of everything else.

Well, Nick, let's go back then to the origins of life.

So we're talking about what, four billion, three and a half billion years ago on the Earth.

I suppose the first question is, did it begin as soon as it could?

And if so, what did it need to begin?

Well, we don't know to within about a billion years or so, because the earliest traces are extremely difficult to interpret.

But the earliest traces are around about 3.8 billion years ago, and they're persuasive to most people.

I mean, we're talking about changes in the mineral composition of tiny little minerals that you can barely see under a microscope.

So it's basing a lot on something very small.

But it's the best we've got.

And yes, if it if it did start 3.94 billion years ago, that's very soon after the early bombardment.

And probably life did get going pretty much as soon as it could.

So the Earth was formed, what about 4.8 billion years ago, let's say, 4.5 billion?

4.5.5 billion was the number I thought, yeah.

So just a few

billions.

So as soon as, and by late bombardment, you mean the thing that probably brought most of the water back to the Earth again at some point?

So that's the bombardment of asteroids, meteorites, and so on, yes.

So as soon as you've got liquid water on Earth, then life may have appeared round.

Well, within a few hundred million years, which sounds like a long time, but in terms of the planet, it's no time at all, really.

Yes, and there's a lot of evidence to suggest that we had liquid water and land on Earth within a few tens of millions of years after the formation of the Earth.

So, in this period, which is called the Hadean, which is from the Greek word Hades, meaning hell.

And for ages, we thought that during the Hadean, it was just molten and tumultuous and hellish.

But in in fact, it now looks like we had liquid water and we had land, but much of it was destroyed by this hundred million years worth of meteorites bombarding the earth and just absolutely destroying it all.

So we don't have any geology, we don't have any rocks older than 3.9 billion years because it was destroyed by space.

So the surface of the earth was made molten and then re-solidified at this point?

Yeah, around about 4.2 billion years ago, and possibly on other occasions since then.

But I mean, all of this is fairly conjectural, really.

I mean, we know that the Earth was hit by large objects, one of which probably knocked off the moon, and it quietened down around about 3.9 billion years ago, and almost straight afterwards, you see signs of life in the rocks.

And it's possible that it could have gone right back through this bombardment.

It depends where it started.

If you start life in some kind of primordial soup that people talk about,

then if you vaporize the oceans periodically, that's not good.

But if you start it at some kind of vent or down in the rocks underneath the oceans, then you know you're probably not that bothered by the odd meteorite.

There we go.

That's our message, by the way, to the audience: is please stop vaporising the oceans.

Tim, do you like one of the things that I love in these kind of when it is, as you say, Nick, conjectural, is the fact you're allowed to be out by quite a lot in science when you get to, not when it gets to very small things, but once you get to very, very big things, like you're allowed to go, well, there's somewhere around between 100 billion and 400 billion stars in our galaxy.

You go, so we could be 300 billion out.

Yeah, but it's just 300 billion, isn't it?

Yeah, I mean, it's all bollocks.

These people don't know what they're talking about.

So, Tim, how did life begin?

Well, what I want to know is that your question that, you know, it got cranking pretty quickly implies that it's a necessary result of these conditions, but that's not the case.

We've only got one data point for this stupid experiment.

So the idea that we know that the Earth got, you know, watery and nice and stable 4.2 billion years ago and life started about 3.8 billion years ago implies oh well it's probably you know if it happened that quickly it's probably inevitable but it could have happened the next day and still never happen again in the rest of the universe.

Is there a reason to suggest there's an inevitability to it if you've got the right junk?

Yeah, I think there is.

I mean yes you're right with a statistical sample size of one you can't read anything into that.

But if you also consider the kind of environments where life might have arisen, like for example a particular kind of deep ocean vent, everything, I mean I think this description of life is much better than a definition of life.

You know, all living cells have all of these things going on in them, and pretty much they all seem to be necessary.

So, if you can find some environment where all those things just happen naturally, then you're at least pointing in the right direction.

And that's what's true of these vents.

It's thermodynamically, all the driving forces are forcing cells into existence almost.

And there's one other point as well, which is that we very strongly believe, based on the evidence, that there was a single origin of life.

Everything that's ever existed on this planet for the last four billion years comes from a single origin.

So every living thing on Earth at the moment is based on DNA.

So we all share the same basic genetic code.

How it works as a code is also totally conservative, an incredibly conservative system.

There are only twenty amino acids which make every single protein which have ever existed, as far as we know, on Earth.

And then you combine all of that with the fact that cells all reproduce from each other and the theory of evolution, and we can draw back from now via everything that's ever existed to a point four billion years ago approximately, which says everything came from this one point.

Well, couldn't make we go back to that point.

I mean, you mentioned these deep sea vents before.

So, could you outline what they would have looked like at that time and why you think that that might be the key to the origin of life?

Well, they look pretty much like they actually look today because we found some about ten years ago.

Now, everybody's familiar with black smoke events, which look fantastic.

They belch out this kind of black smoke, but these vents look quite different.

They're almost gothic.

They're all kinds of little doodles made of limestone.

Now, what's happening in the vents is you have alkaline fluids rich in hydrogen coming into what would have been an acidic ocean, and so you have proton gradients, and you have hydrogen, and you have carbon dioxide, and you have a compartmentalized system.

So, more or less, everything which you require for cells today is there in that environment from the very beginning.

Now, you mentioned proton gradients there, which I know are important in biology.

So, could you just describe in a bit more detail what they are,

Tim.

So

we had a bet on whether in the first 10 minutes you'd say proton gradient.

I didn't say it.

And whether you could say it without jiggling in excitement.

Oh, protein gradients.

So Tim, can you allow me to

tell Tim what a proton gradient is?

A proton is a hydrogen ion and a gradient of protons is just more protons in one place and less protons in another place.

It's really that simple.

Why is that important?

What's about it?

It's ATP.

Is it ATP?

Yeah, they make ATP.

That's right.

This is something that really came as a shock.

Actually, 50 years ago, this year, Peter Mitchell, who won the Nobel Prize in 1978, came up with this idea called chemiosmosis, which is a horrible word and which is why nobody knows about it.

But every time you breathe, what's happening is you're stripping electrons from food and you're passing them down a kind of a little wire to oxygen.

And the energy that that's releasing is pumping protons across a membrane.

And so you end up with an electric charge across this membrane, which is equivalent to a bolt of lightning.

It's thirty million volts per meter is that is the strength of this.

It's incredibly it's just over such a tiny distance, five nanometers, but and all life works that way.

And it it's just shocking actually that bacteria work that way, you know, photosynthesis works in the same way, we work in the same way, you know, you've got a hundred trillion mitochondria in your body, and all of them are producing these little proton gradients over their membranes.

So you mean it's a rather odd way of extracting energy out of it.

A bizarre way of going about things, But they're there naturally in these vents, and that's at least suggestive.

I was just going to say that sounds incredibly like the more detailed version of what you were saying, as why we think there's a universal common ancestor.

I mean, if two dudes came up with that at the same time, that'd be pretty

weird, but they all do.

Work on gradients.

That was my idea.

No, I didn't at first.

But see, the thing is, this really gets to the nub, but we started by trying to get a definition of what life is.

And I think, and I've already said that, I don't think that you can do one, but if you forced me, I'd say that life is about energy capture.

It's about taking energy from the local environment and hanging onto it and manipulating it as much as you can.

And that is a basic physics property.

So, what's the big blurred area then between if we're talking about living things and non-living things?

So, there must then be this huge kind of foggy area of uncertainty.

And what kind of things would that contain?

Nick, if you it would depends, because

now I've found out that that under threat, you will answer anything, Adam.

If I was forced to,

will it snow?

Tell us, will it snow?

Yes, it will.

Science says so.

White Christmas.

All it needs to do now is snow in the next three months, and you become a shaman.

It's very impressive.

What I think Nick Robin was trying to get to was that

there must have been some point when

this rock, these vents with just chemistry, made the transition to something that we might call living.

Do we have any idea of when that or how that was, what that transition was?

I think the point at which something becomes really living is when it becomes cellular, because then it can be free-living.

So, all these things which are somewhere between living and not, like a virus, for example, viruses depend on cells.

There's all kinds of dubiously alive kind of genetic parasites of one sort or another.

You know, the mitochondria, they're not really free-living, they're not really alive in a sense, but they were once.

And so, you have all these continua.

But the one point where you can place a cut-off is something that can live by itself, and then it has to be cellular.

So the moment these vents produced cells that could exist outside that environment, that's really when life started.

Now, Adam, we should just clear up mitochondria.

Give us a 30-second introduction to mitochondria.

30 seconds, right?

About

a couple of billion years ago, there's two free-living types of organisms, small cells, one called archaea, one called bacteria.

At one point, one went inside another.

At that point, that cell became complex and enabled itself to to generate more energy.

All things, apart from archaea and bacteria, nowadays, have mitochondria in them, and that is what enabled complex life because it could generate much more energy.

Now, I wish the audience at home could have seen your hand gestures, which were far more Freudian than they might imagine.

Therefore, some of the audience there did notice that, so that was what the reaction was about.

It was as the mitochondria went in there, there was a swanny whistle sound really going on in a lot of our heads.

Tim, do you think biology's got more jargon than physics?

Because I do, after the first 15 minutes of this show.

I seem to be able to get my head around biology more easily than physics, only because big stuff freaks me out.

The things that freak you out are really big things and really tiny things.

That's physics.

I think cells are big, though.

Yeah, quarks.

Enormous.

Quarks are just annoying.

You have got to stop using quarks as your comparison now.

It's leading to a lot of disappointment.

Yeah, and making me feel obese.

Yeah, does physics make you feel fat?

I measured my waist in plank lengths, and now I feel awful.

This is quite an interesting calculation, actually.

How many plank lengths is your belt?

Yeah, lots.

I'm leaving it to you.

If you want to finish it,

this is, I will, actually, Tim, on the side, I suppose on the more kind of elaborate mythic thing, is we haven't really talked about this, but before ideas, you know, the scientific ideas of what may well define life and what life is, there are fabulous myths about how life began.

Do you feel that, you know, will they be destroyed once we get to the point of actually going here's the answer, let's just forget about these.

You know, it's like the Milky Way, you know, that wonderful idea that the milk is which which goddess is it?

I can't remember.

Nut.

Nut.

Yeah.

You should.

Nuts the goddess of the Egyptian goddess of um milk, isn't it?

Let's take it all these.

Yes.

Doesn't she have loads of breasts, isn't she?

So her picture has been a whole array of breasts reaching across the sky?

So this is it.

So for those of you who've just tuned in, we're debating whether the sky is a male or female, whether it's.

We have got to the point the sky is definitely mammalian, we're certain of that.

Gender non-specific.

Cumulonimbus, I hear, is a more male cloud.

But is it snowier than some of the other ones?

Yes, it will be snowy from cumulonimbus.

I don't think there's any reason to suggest that mythology is in any way affected by knowledge.

or the acquisition of knowledge.

I mean, the only reason we can, I mean, you know, the theory of evolution is the only reason we're even asking this question.

And actually, it's sort of as soon as you realized if you can get your head around evolution, which is not easy, it's easier than quarks, but it's not, it takes a bit of work,

and you can get your head around the idea that there's a universal common ancestor and that sort of stuff, it's actually

not a logically difficult thing to do to get your head around the idea of chemistry going into what we call life.

It's actually once you've got your head around humanity and every other living thing on the planet, starting with a little dude in a rock,

there should be no problem left.

I mean, God recedes into the distance as you get more knowledge, but he never goes away, or God or Noot or whatever, multi-breasted star woman.

But it's not about knowledge.

The myth just has to stay existing, regardless of what you know.

You touched on it earlier, Adam.

There's an interesting point here.

We've talked about how life may have begun, simple life, but that transition to complex life, which ultimately leads to us, I mean, are we as clear about that progression and do we have any idea of the chance of that happening?

Well, we're never 100% clear about any of these things in science because that would be a belief system.

But what we do do is experiment, right?

And when it comes to experimentation, the origin of life is an area of science which really has had a huge lack of experiments in it.

There have been some iconic ones in the 1950s when Stanley Miller put a set of kit together and bubbled various gases around and came up with some amino acids.

And everyone said, Oh, look, he's created life, which he absolutely categorically hadn't done.

And so, we've got this really sort of like there's a big ideological grasp on this whole subject, and it desperately lacks experimentation, which is where this man comes into it.

Well, that's what Nick, I would say that the Yuri Miller.

He wasn't pointing at Robin Ins when he said this man.

That would have been weird on the radio.

Robin started talking.

talking that Robin's not doing experiments on the origin of life

if he was it would be more like weird science trying to make a multi-breasted star woman

still coming out really wonky at the moment

and I like the way you pointed it because Nick's also got a big beard as well people went is he God the

but Nick when we're talking about you know discoveries and the change in ideas of life is the fact that another thing we've seen is places where we didn't think life could exist.

Are we seeing again different definitions of the possibility of living things?

No, I don't think so.

I mean, what we see is actually a very, very similar process.

So, things that live off hydrogen sulfide, for example, what they're doing is they're treating it like food.

They're stripping electrons from it and they're passing it down to an electron acceptor, like oxygen, for example.

That's what happens in all the black smoke events down at the bottom of the ocean.

Hydrogen sulfide gas is bubbling out.

They're using exactly the same respiration with electron acceptors and they're producing proton gradients.

It's astonishing how similar they are.

And we've got this thing about hydrogen sulphide being sewer gas and so on and it being really awful.

But the actual principles underlying how it's used are essentially universal.

So it seems what we are drifting towards is a sense in which life may be inevitable given the right conditions.

Now I was going to say there is this strange gap though, because I think that the origin of life and the way in which bacteria took over the planet was practically inevitable.

I think it happened very early because it was thermodynamically probable.

But then this chimeric cell of the two cells, one getting inside another, all complex life.

He did the action again.

That happened once.

That's quite shocking, actually.

How do we know that?

Well, we are very closely related to mushrooms, for example.

If you look at it.

That's a pretty surreal answer.

How do we know that?

Well, we're pretty closely related to mushrooms.

I'm closely related to a mushroom.

You could use that.

Sitting in a pizza restaurant, a man runs in and goes, cannibal!

Thought I'm having a Hawaiian.

Sorry, my mistake.

You could use that to answer any question, couldn't you?

Well, we're pretty closely related to mushrooms.

I should let you finish your sentence.

No, I don't think we should finish that sentence.

I think that's the perfect place to end the show.

So the question was each year.

Just to reiterate, the question was: how do we know that that chimeric cell, as it were, that that only happened once, this merger of two cells happened once?

What you might guess is that plants would derive from one kind of bacteria and animals from a different one and fungi from a different one, but that's not actually the case.

And if you look at a fungal cell, a mushroom cell down a microscope, and you look at a plant cell and an animal cell or an alga or something, they all have an awful lot of things in common.

They've all got a nucleus, they're full of things inside, and they're basically the same things.

I challenge people in the audience: you know, look at a mushroom cell down a microscope and compare it with your kidney cell and see if you can tell the difference.

It's really not that easy.

So, it may be that we are here because in one ocean somewhere at one point, a cell got inside another cell and this thing lived.

This thing continued to live, it survived that fusion process.

We don't know whether it's happened dozens or millions of times, but what we do know is that it only survived once.

So there is that single origin point.

And that goes for the origin of life itself as well.

All the evidence firmly points towards there being a single origin, but what we do not know is whether life emerged because it might be energetically inevitable.

We don't know whether it happened dozens of times, but what we do know is it only survived once.

So, just like the sort of misunderstanding of evolution that this adaptation happened, it was the only one that happened, and you're like, oh,

flippers got a bit fingery or whatever.

Wow, what are the odds on that?

In fact, there were billions of parallel adaptations that didn't work or whatever, or weren't going to work because it doesn't have intent.

They're just things that happened, and they didn't.

So, similarly, the sexy cell that got in the other cell could have happened loads of times, but it's what happened to those combined cells from that moment forward that matters.

And only one dude got further than that, or this far, anyway.

So that's Grandad.

So that's all I can actually do.

I'm sorry, Tim.

This to me is like the big Lebowski does science.

Have we got to any answers yet?

Have we got to any conclusions?

Let's begin to bring this to some kind of conclusion.

And

so if we do find out, then I mean, it seems to me what you're saying is that the origin of life, we're probably closer to understanding the origin of basic life than we are to understanding how that basic, simple life became as complex.

Yeah, I think that's exactly right.

Yeah.

Good.

Well,

you know, you're winding up, bit going.

Let's bring this to some.

Oh, we came to a conclusion last quick of the reason.

We've still got three minutes spare.

This is a disaster.

Tim, get the piano out.

Mushroom, mushroom, mushroom, mushroom, mushroom.

Given that, I think that it may be time to go to

the audience.

We asked the audience a question: which is: what is your theory of how it all began?

So, what is the theory of how it all began?

I like this this one from Claudia.

Wait, I thought I was here so you could tell me.

Quite right.

What have you got there?

A mummy universe and a daddy universe loved each other very much.

Is that all the ones you got?

This pretty much brings us to the end.

So, just a few things.

First of all, if any of the issues we've discussed have affected you,

good, that's what we were trying to do.

There's not a helpline, just go to a library, look stuff up, find out things.

I love that

So lovely how he thinks people still go to libraries.

Now we are recording this on the f on the day of the first show of the series being broadcast, so we can't answer any complaints unfortunately, and I think we're going to get a few.

So we've decided to invent some and answer them that we're sure we're going to get over the course of the series.

No, it would not kill a cat, but it may damage it psychologically.

6.6 Six times 10 to the minus 34 is a very small number, and that's why you're wrong, Deepak.

Well, it's your own fault for reading the Telegraph Review section.

It's infinite.

Goodbye.