Instant Genius - The story of human evolution, from the Big Bang to the advent of consciousness and beyond

Episode Date: June 13, 2024

Why are we here? Where did we come from? What are we even made from? These must be some of deepest questions humans can ever ask. But that has never stopped scientists throughout the ages asking them. In this episode we catch up with Professor Tim Coulson, a zoologist based at the University of Oxford to talk about his new book, The Universal History of Us: The science of why we exist. He helps us trace the origins of human beings right back to the Big Bang and the beginning of the Universe itself and goes on to investigate whether our existence was inevitable thanks to the underpinning laws of nature or whether we were just extremely lucky. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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and high-end materials, delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. Hello and welcome to Instant Genius, a bite-sized master class in podcast form. Each week you'll hear world-leading scientists and experts

talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor at BBC Science Focus. Why are we here? Where did we come from? What are we even made from? These must be some of the deepest questions humans can ever ask. But that's never stopped scientists throughout the ages asking them. In this episode, we catch up with Professor Tim Coulson, a zoologist based at the University of Oxford, to talk about his new book, The Universal History of Us, the Science of Why We Exist.

He helps us trace the origins of human beings right back to the Big Bang and the beginning of the universe itself and goes on to investigate whether our existence was inevitable, thanks to the underpinning laws of nature, or whether we were just extremely lucky. So welcome to the podcast and thanks very much for joining us. Thank you very much for having me. So first of all, can you just briefly introduce yourself to the listeners, please? Yeah, so my name's Tim Colson. I'm Professor of Zoology and the Head of the Biology Department at all.

Oxford University. So today we're talking about your book, The Universal History of Us. I say it really does do what it says on the tin and traces the story of the emergence of human beings, beginning at the Big Bang and the creation of the universe itself and then goes onwards. So as you just mentioned, you're a professor of zoology. So why did you want to take this on? It's a very good question. And I did question myself along those lines a couple of times during writing it. But it's quite a long story. And it all started when I was about 20 or 21. And I'd been over in Africa working on my undergraduate project of all things. And during that trip, I managed to catch malaria. Through my own stupidity, I should add, I muddled up my anti-malaria

tablets with my water purification tablets. So that meant that not only every time I ate my malaria tablets, my stomach burnt because I was swallowing chlorine tablets, but it also meant I got sick from drinking infected water. And when I was sick, I got bitten by a mosquito that carried malaria. The malaria drugs weren't working because I was sick, and I developed malaria, and I nearly died. When I recovered, the doctors told me that the next attack would probably have killed me. Well, I'm pleased to say they completely treated me.

And I guess it was a time of my life when I was trying to work out what I wanted to do. And shortly after that, I thought, well, I kind of guess by the time I eventually lie on my actual deathbed, which I hope it's very many years away, I've had a good, stab at trying to understand what science can tell us about why we exist. And so I started reading widely and I had to get a job. Biology is the hardest bit of science in my opinion. So I thought, well, let's try and study biology and understand biology. And about when I was in my 30s, I started telling my friends, I'm planning on writing a book. But it took me until I was in my early 50s to actually get around and to write the book. And it covers physics, chemistry,

astronomy, Earth sciences, biology, the emergence of life, biology, consciousness, and the factors nature versus nurture versus chance that mold our personalities. And I wrote it all down.

I didn't really know what to do with the book once I'd wrote it all down, but I was very lucky that I got a wonderful agent, and she managed to persuade Penguin that it will be something they'd like to publish, and I hope the listeners read it. Great, I do too. So having said all of that,

we've got an awful lot of ground to cover. We're talking about humans. So let's start with a scientific definition of a human. If an alien came to Earth and wanted to study us as a species, what would they find? That's a very good question. So as a zoologist, one of the things that I do is study animals and study other forms of life to try and understand why they behave and do what they do. And if an alien civilization is able to get to Earth, they have presumably discovered how science works at a scientific method. So they've been able to find out fundamental facts about the universe and they've been able to use those fundamental facts to travel from their planet to hours. And because they know how science works, they would probably study us

in a scientific manner. So I imagine that they would start by observing us and then they might start to do some experiments about what would happen if we did this to them. They might start dissecting us. I imagine the first thing they wouldn't do, which many people who are abducted by aliens claim, is to stick a finger or finger equivalent into any orifice they see. I mean, that strikes me as a very peculiar thing to do if I was to discover a new life form. So what is a human? You wanted a definition of a human? Well, we're unusual amongst the species in terms of our level of intelligence

and the way that we are able to use tools and develop technologies and to use science. And part of that's because we've got, for our body size, we've got a relatively large brain. And in particular, the frontal cortices where intelligence resides is particularly large. humans. So I imagine an alien, if they've got here, would be interested in what evolution on Earth, on the Earth environment had managed to produce. So let's have a look at that then. So one of the reasons we're even having this conversation is, as humans, or most of them anyway, have the ability to think. So where did that come from? So, I mean, one of the questions, and we have a chapter on the book on the evolution of consciousness or sentience. And so why is it? So we're pretty certain

that plants, for example, and fungi or bacteria, very simple organisms, don't have sentience. They don't experience the world around us and respond to those experiences in quite the way that we do. But animals across the tree of animal life, they have a range of brain sizes and a range of structures in their brains that allow them to sense the world around them, both in terms of vision, so seeing things, and hearing things and smelling things, in terms of, in terms of, touch, and they're able to process that to build a sort of simulation or an experience of the world around them. And then they use that experience to behave. And certainly in us, and certainly in other animals, too, there is a role of decision-making and how we respond to the environmental

cues that we get. And what consciousness researchers, I think, have realized over the last few years is that, you know, consciousness is on a continuum. So we're definitely at one end of the continuum. We're more sentient. We think more deeply, and we make rational and some of the continuum. And sometimes irrational decisions based on the experience we have with the natural world. But it's also clear that very simple organisms, like even flies and things, can experience the world and perhaps have a wisp of consciousness. And one of the challenges is working out sort of where on that continuum from a very, very simple wisp of consciousness to us, you know, sort of animals can feel pain and know their suffering pain. And that's important

because that determines how we should treat other organisms on the planet. So far sording a little bit, humans are social animals who live in complex societies. So what do we know about how that arose? So many organisms live in societies or in groups, many organisms are social, not just extant ones like us and dolphins that live in groups and lions live in groups and lions live in groups. But there's quite good evidence that even several species of dinosaurs lived in groups. And animals live in groups, both because we can help them in terms of gaining food and gaining resources. It can provide them with protection from animals that might wish to eat them. It can help with the dissemination of information. So certainly in humans and some birds, when they come back to roost, information about where food has been found is transferred between individuals. And I think that humans probably started living in groups, probably for protection,

are ancestors. So, and actually, you know, ancestral species, so some of the first primates that lived in groups, the Australopithecines and what have you, they probably lived in groups to provide protection from predators. But when you live in a group, you then have lots of interactions with individuals from your own species. And those interactions probably help drive the evolution of brain size and decision-making and consciousness. And so we probably started living in groups for relatively simple reasons. But as those group sizes got larger and we interacted with individuals a little bit more, then trying to work out what the other individuals in a group are thinking, or how how they're behaving was probably one of the drivers of our high level of consciousness.

So where does the sort of concept of technology come into all of this? So certainly the first of our ancestral species that used tools that we know of was Homo Habilis, and Homo Habilis was the first species in the genus, so that's the group of species that include us, and they're ancestors of ours. And the tools that they used were simple-hand, It's made from sort of napped bits of rock and stone. And they would have used those, we know from looking at remains of where they lived, they used those to hack into bones and get at bone marrow. The next species along the line was a species called homo erectus.

That was incredibly successful, and it revolved in Africa, and it spread out of Africa throughout Asia and into Europe. And that started to use more complicated tools. It used wooden tools, bone tools, stone tools, including spears. And there's some debate amongst researchers as to they may have even made boats because they certainly managed to make it to Java. Now, we don't know whether they made boats explicitly or whether they got lucky and a few of them washed over on vegetation that happens to some animals these days. But Homo erectus certainly used tools and there's some evidence in some populations that they also used fire. And then we continue to develop tools as Homo erectus evolved into Neanderthals, a group of our ancestors called Democethoes.

Sovans that lived in Asia, but also homo sapiens that evolved in Africa. And we've continued along that line of producing ever more complicated tools. And those tools these days include rockets that take us into space, that take us to other planets, but also the ability to really study the world in great detail. For example, the world's most complicated machine, something I talk about in one of the earlier chapters when I discuss physics and chemistry, is known as the Large Hadron Collider, and that's based at CERN in Switzerland. And that allows scientists, you know, it's amazing bit of technology that we've developed, it allows scientists to accelerate tiny particles to a fraction, a hair's breadth of the speed of light,

collide them with one another. And sometimes when they collide, they disintegrate and they split off into short-lived particles that we then detect with detectors. And that really has helped us understand some of the fundamentals of the universe. Great. So we'll get into sort of particles and physics in a little bit. But you mentioned the ancestors there. So obviously we've evolved over years and years and years and years via the process of evolution by natural selection. So how can we trace the ancestry of a species

back through time? So what you can do is all life on earth, whether it's the simplest bacteria right the way through to you and me, we have a genome. In each of our cells or in a bacteria, single cell, there are DNA molecules, and those DNA molecules code instructions to self-assemble an organism. So you and I have a genome to self-assemble a human, a human body, you and me. A bacteria like E. coli has a manual to assemble an E. coli and to run an E. coli. And we're very, very distantly related to E. coli. Yet, we share some genes with E. coli. By comparing genomes between organisms, we can build a tree of life. And biologists have done this with over a million species now.

There's a tree of life that it's like a branching pattern, so like the branches of a tree, where we are at one tip and on the other side of the tree, a long way away, are E. coli. The way that tree is assembled is by the similarity in our genomes. So on a twig right next to us, are chimpanzees and bonobos, and then a little bit further away are gorillas. And then you move further away still and you get to cats and dogs and you move further away and you get to fish and further away you get to cockroaches and then further away you get to bacteria.

And so by looking at the DNA and the sequence of DNA and the structure of genomes, we're able to work out how all species alive on Earth are related to one another. And we can actually even date back. We can kind of recreate from that when an all-weigh-weigh-weigh-weigh-weigh-weigh-weigh-weigh- organism called the last universal common ancestor called Luca lived. And that was probably somewhere between 3.8 and 4 billion years ago, Luca existed. And that was the first organism that used the genetic code that's used by all organisms alive on Earth today. This podcast is sponsored by name, audio and focal. With over 100 years of combined expertise, name and focal have been bringing

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Try it for yourself at a focal powered by name boutique. Visit focal powered by name.com for more information. So let's go way back then. What do we know about how life on earth started itself? It's a very good question. because it's a very difficult topic to study. And the reason for that is the only planet that we have so far discovered that has life on is Earth. And life evolved on Earth a long time ago and it looked very, very different to it now.

And life, including us, has really modified Earth over that time. So working out exactly how and where life started is a challenge. Nonetheless, biologists know that life has kind of several key components, and three of those key components are an ability to make copies. So DNA is a chemical that uses you and me and every organism on earth to make copies of itself. I have children from a biological perspective in order to make copies of my DNA, and they have a mix of my DNA and my wife's DNA. And so we know that life needed, when it started, needed to come up with a way of making copies of itself. A chemical that makes a copy of itself using other chemicals is known as autocatalytic. So we know that an autocatalytic reaction

needed to start. And they're not too difficult to get going autocatalytic reactions. You also need the fuel to run life. So all life uses energy. We get our energy from food and what have you. Plants get their energy from light in photosynthesis. And what they do with that energy is they run something called metabolism, and that metabolism allows animals and plants to live and to make copies of themselves through their DNA. And the third thing that all life relies on are cells, so the building blocks of life, and cells have a membrane around them. And that membrane is made from a sort of type of fat known as lipids. And each of those three things, autocatalytic reactions, chemicals that can make copies of themselves, metabolism, so where energy is used to run a

reaction and lipids, each of those things is relatively straightforward to make on its own. But the trick that we don't yet know the answer to is how life brought those three things together to make the first cell, made copies of itself. We know a little bit, and we're learning more with every day about what the early Earth looked like when the first life emerged. But we're not yet able to recreate in the laboratory what early life looked like and exactly where it came from. but I'm hopeful in the coming decades we'll be able to do that. So science doesn't have all the answers, but it knows what life needed to achieve in order to get going.

So of course, stuff, for one of a better word, is just assemblies of molecules. And people like to say poetically that we're all made of stardust. So what do they mean by that? Well, they're absolutely right. We are all made of stardust. All meta, so all stuff in the universe is creating. from atoms. And atoms themselves can be broken down into bits in the middle of the atom,

in the nucleus of the atom called protons and neutrons. And then orbitals around that, so zooming around these atomic nuclei, are electrons. And an electron is a fundamental particle. You can't break it down any further. And the protons and the neutrons that are in the heart of the atom are made from things called quarks, or quarks, as some people call them. And these are up and down quarks. So every neutron and every proton is made from a combination of quarks. Every atom is made from protons and neutrons and electrons. And then every molecule is made from atoms.

But different types of atoms, so different elements, have different numbers of protons and different numbers of electrons. So hydrogen, for example, always has one electron, and it always has one proton, and it may or may not have zero, one or two neutrons. Helium has two protons and two electrons. The way these atoms can interact with one another, it can exchange or they can share electrons.

And they do that through something called electromagnetism, which is one of the four fundamental forces to make molecules. And some of those molecules are very simple and some are really quite complicated. But the simplest element, hydrogen and helium and a little bit of lithium, they form relatively early in the universe's history, after it was about 380,000 years old. It's 13.77 billion years old now.

Then those got collapsed under gravity and other fundamental force to form stars. And when those stars died, they created heavier elements, so things like oxygen, carbon, nitrogen and iron. And then once you've got those more complicated atoms, they're able to interact with one another and with hydrogen within helium

to make complicated molecules like phosphates and like the nuclear basis, so the building blocks of DNA, but also simpler compounds like water. And we know that a lot of the building blocks that life used, because we've studied meteors, were made in space. So they were made in big clouds of dust around the time when new stars formed and old stars died. So when people say we're space dust, it's because a lot of everything on Earth, in fact, all of the building blocks of Earth and us on it, and molecules that have been made from atoms, and many of those atoms were made in the death of previous stars. So we're talking about living things there, and of course, living things need somewhere to live.

We happen to live on planet Earth. So what sort of planet is Earth, and what do we know about how it formed? Well, so what we know is, when the very first stars were made, they were made of hydrogen, predominantly a little bit of helium, and a little bit of lithium. And there weren't any planets around the first generation of stars. But when those stars died and created some of the heavier elements I was talking about earlier, the second generation of stars, the second generation of stars was able to form under the collapse of clouds of hydrogen in these heavier elements, and planets were able to form around the second, third, and fourth generation of stars.

And there's something called the frost line. And the frost line is inside the frost line, when planets form from these kind of clouds of dust and ice, and whatever. They're rocky. They become rocky planets. So those rocky planets are like Earth and like Mars. Further out, you end up with gas giants like Jupiter and Saturn. And so Earth is a rocky planet. We haven't been able to study a huge number of planets around other stars yet, but we do know that other stars do have rocky planets, and some have rocky planets that are orbiting their star about the same distance as Earth. And one of the things that astronomers are trying to do

is to study the atmosphere of these planets to see how typical or atypical Earth is. We know that it's not unusual in the term of the fact that it's a rocky planet. We know there are other stars with rocky planets in about the same location as Earth is, but we don't yet know whether they support life or even have the atmosphere to do that. So you mentioned the atmosphere there. So that's essential for our existence. So how did that arise? That's a very good question.

So when the Earth formed originally, it was formed from accretion of lots of smaller sort of rocky objects orbiting the sun, and the Earth grew out of those things coming together. And initially it didn't have an atmosphere or not very much of one anyway. At some point, a planet which astronomers and space scientists called Thea collided with Earth when it was very, very young. And as it collided, it was quite a large planet, it ended up throwing a huge amount of gas and dust. you know, back out towards space. And that was the cause of the first atmosphere. And that planet, or a fragment of that planet that hit us, went on to form the moon. And so this is very early in Earth's history. And the collision with Thea would have any early life that might have got going, I suspect life hadn't started, but even the building blocks of life would have been wiped out because

the surface of the Earth became molten. But after a Theod hit, we had the first atmosphere, but it was very, very different from the atmosphere that we've got now. If it had any oxygen in it at all, it would have been tiny amounts. It had a lot of water vapor. It would have had a lot of carbon dioxide, some carbon monoxide. It would have had some of the sulfurous gases and what have you. So we would have died instantly if we got there. But it was, or it certainly contributed to the conditions under which the first life formed.

And the atmosphere has changed as life has evolved and life has changed. So oxygen built up in our atmosphere, and oxygen's fundamental for us. We couldn't live without it. That built up because the first forms of life, oxygen was actually a waste product from then. So much as we breathe out carbon dioxide, the early life was sort of breathing out or as a consequence of living was pushing out tiny little puffs of oxygen. And that oxygen reacted with lots of elements on the earth's surface and in the atmosphere until they were used up.

And then it started to build up slowly in the atmosphere. And as it built up, it actually killed. a lot of early life, a lot of bacteria that found oxygen poisonous. But life, and evolution is amazing. Life found a way to use that oxygen. And I'm very glad it did, because that's why we're talking now. Absolutely. So another key feature of the Earth is it's oceans. So what role do they play? Yeah. So water's quite a common element in the cosmos. It forms relatively easily. Hydrogens, very, very, it's the most common element out there. And oxygen's fairly common. And most of the water Earth. There's still some debate about it, but most scientists accept that water arrived

on Earth from meteors that then collided with Earth or on small bits of dust and ice. And so that water built up. Life as we know it requires liquid water and earth has plenty of liquid water in the form of oceans and lakes and clouds, water vapor in the clouds and in the atmosphere. Most of that water appears to have arrived from space and arrived relatively early. And in fact, it appears that the best theory is for where life arose suggested either arose around thermal springs, so volcanic springs in the oceans, or it arrived on volcanic plains, a bit like Yellowstone and in freshwater lakes there. So water appears to have been essential for the formation of life. We don't know whether it was salt water or freshwater yet, and it has

been essential for life ever since. And life up to quite complicated, multicellular organisms needed. It all evolved within the sea in the ocean and within fresh water before it began to spread onto land. So life had already got quite complicated before it started to spread onto land and it was plant life that got there first. So let's go way back now then. What do we know about the origins of the universe itself? That's a really good question. So what we do know is, and there's strong evidence for this, that the universe is currently expanding, and it's expanding, so it's getting bigger. And it's getting bigger at quite a rate. In fact, that rate's getting faster and faster. But if you were to do an experiment and you were to run the

clock backwards, the universe would get smaller and smaller as you run it backwards until eventually you come to the conclusion that it must have started at a single point, or a singularity, as physicists call it. And that singularity would have been just a point of energy, a pinprick of energy, smaller than the smallest fundamental particle that we knew now. And we understand, and that's what the book is largely about, is how we go from that incredibly intense pinprick of energy to develop, at least in our neck of the cosmic woods, to you and me. Now, why that pinprick of intense energy appeared, so in other words, why is there something rather than nothing? Scientists have not been able to approve and not been able to answer that question. They have

some theories, but currently those theories are untestable. We're unable to create conditions in which we can create universes ourselves. So at the moment, we don't know why they arose. We have some ideas, but we're not able to test them. So science, although it's taken us on a long way, does not have all the answers. And one of the things I'm very clear about on the book is there are still things to find out and still things to research. So one final question, which I think is a really deep one, is are we simply here by chance. Was this inevitable just because of the way that the universe works? So there's actually some disagreement among scientists on that question. So there are some physicists, perhaps not

particularly a large number, but there are some physicists who champion a set of theories actually, so metateterminism and the many worlds theory, which essentially say in their various forms that the universe is what scientists call deterministic. And what that means, is that if we were to run the universe again, if we were to do the same experiment, we were to create it as the identical singularity that led to our universe. And we ran the clock forward every time, as long as we had the same starting conditions, you and I would be sat here having this conversation. Now, there's some consequences of that, because if that's true and the universe actually is deterministic, what that means is there's no such thing as free will, and free will is an illusion. And that seems very, very strange thing to think about. Other scientists sort of say, well, no, we think that the universe has random elements to it, or is stochastic as the sort of word they use, which means there are random elements to it. And then, so the question is, where does that randomness come from? Because there are some things we can predict really well. We know the sun's going to come up in the morning. We know that with 100% confidence. We understand the orbits of the planets and the comets that go around, and we can predict those, you know, at least for quite a long time into the future. And so because we can do that, some people argue, that's why they argue that eventually we'll learn that the universe is deterministic, and it's just a matter of us discovering those questions.

But other scientists say, well, where does the randomness come from? And at the moment, the one source of randomness that appears to be true randomness is at the level of the very, very small fundamental particle, and that's known as sort of quantum dynamics or quantum mechanics. And that means that actually when you go down to very small particles like electrons, like protons, like neutrons, or even individual atoms, we can't know everything about those atoms. We only know where they're likely to be. We can't pin them down exactly. And if we can pin their location down exactly, it means we don't know other attributes about them, like how fast they're moving. And so that's what's known as the quantum mechanics. And physicists have spent a long time discussing. what quantum mechanics means, because it's very alien compared to the world that we're in now, to sort of say, well, an electron may be here around the atom, or it may be over here, and we only know in terms of probabilities, we only have an idea of where it is.

That seems a little bit odd, but it does appear at the moment that the quantum mechanics, so things that go on at very small scales, is random, is stochastic. And so the question then comes, how are you able to take that randomness at the level of the very, very tiny particle and multiply it up to generate things like free will or unpredictable things that are truly random, perhaps like genetic mutations that are fuel of evolution and how those arose. And so one of the things I do in the book is I do touch on this discussion about whether the universe is deterministic or the universe is stochastic, how we might solve that answer. And if you want to know my view, you'll have to buy the book, I'm afraid.

Thank you for listening to this episode of Instant Genius, brought to you from the team behind BBC Science Focus. That was Professor Tim Coulson, a zoologist based at the University of Oxford. To discover more about the topics we've just discussed, check out his latest book, The Universal History of Us, the Science of Why We Exist. If you liked what you just heard, then please do consider subscribing to Instant Genius on your app store of choice. The current issue of BBC Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines or downloaders on your preferred app store. You can also find us online at sciencefocus.com.

This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision with analogue warmth. Alongside French acoustic specialist Focal, name creates high-end audio systems, combining innovation, with craftsmanship so you can listen to music, just as the artist intended. Discover more at name audio.com. Ambition comes in all shapes and sizes.

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