370: The Evolution of Life and the 'Dead Species Walking' with Henry Gee
“One of the reasons, for example, that all the aliens in Star Trek and even Star Wars are kind of humanoid is that it’s actually quite hard to feel empathy with a blob or an intelligent slug.”
The holidays are a time for storytelling, and what better story to re-experience than the greatest one of all: the history of the universe and life on Earth. In today’s episode, Indre is joined by writer and editor Henry Gee to discuss this most epic of all stories and how it’s depicted in Henry’s new book, A (Very) Short History of Life on Earth. Henry is a senior editor at Nature and the author of several books, including Jacob’s Ladder, In Search of Deep Time, and The Accidental Species. He’s appeared on BBC Television and Radio and has written for The Guardian, The Times, and BBC Focus.
Henry kicks things off with a reading from the first chapter of his new book, which describes the very beginnings of life on Earth (which apparently started with some very determined soap bubbles). He then gives a peek into his writing process, including his strategic use of footnotes to provide scientific backup, Tolkien’s influence on the new book, and how anthropomorphizing is key to writing an engaging story. Henry goes on to talk about how the natural tendency of geological periods to end in catastrophe is very useful for structuring a compelling narrative and how knowing the ending sometimes makes a story more fun to read. Moving on, he gives a brief account of how life on Earth evolved, including bacterial communities, the role of giant sea scorpions, and the evolution of ear bones, before explaining how the discovery of fire led to Homo erectus becoming a persistence hunter. Finally, Henry addresses the future of the human species, predicting that while society is making some progress in the campaign against climate change, in the long term, humans will be extinct within a few hundred years due to our domination of the habitat and its resources. Condensing 4.6 billion years into one 50-minute conversation is no easy task, but if anyone can do it, and do it in a way that is both accessible and fun, today’s fascinating guest Henry Gee is that person.
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Indre Viskontas: [00:00:10] Welcome to Inquiring Minds. I'm Indre Viskontas. This is a podcast that explores the space for science and society collide. We want to find out what's true, what's left to discover and why it matters. During the holidays, no matter what your beliefs are, there are lots of opportunities to hear or tell a great story. And there's a certain pleasure we get from listening to a story or watching a movie version of it or reading it in a book. So why not take this holiday time to re-experience the greatest story of all time? The story of the history of the Universe and life on Earth. There's a lot of great information from scientists of all fields telling us what happened from the moment there was a Big Bang to where we are today and maybe even looking out into the far future. But I've never come across all of this information told in a form that is so compelling and interesting that it rivals some of my favorite novels. This telling is by Henry G. He's a senior editor at Nature and the author of several books, including Jacob's Ladder in Search of Deep Time. The Accidental Species he's appeared on BBC Television and Radio has written for The Guardian, The Times and BBC Focus. And now he's just published a new book called A Very Short History of Life on Earth. And I'm telling you this one's a page turner. Henry, G. Welcome to inquiring minds.
Henry Gee: [00:01:52] Thank you very much for having me.
Indre Viskontas: [00:01:54] So this episode is happening around the holiday time. It's a time when we often get immersed in various kinds of stories and fantastical tales, and so I'm really delighted to have you on the show to give us what is probably the most amazing but also seemingly fantastical tale in the entire history of the universe.
Henry Gee: [00:02:16] Yeah, it certainly is. Well, I think so.
Indre Viskontas: [00:02:19] Yeah, and I loved your I don't know if it was a nod to Game of Thrones, but your first chapter is called A Song of Fire and Ice.
Henry Gee: [00:02:26] I very much use. You saw what I did there.
Indre Viskontas: [00:02:30] Obviously I did, and I loved it. So I actually never asked a guest of inquiring minds to do this. But I would really like it if you would read a little bit from that very first chapter starting in the middle of Page four.
Henry Gee: [00:02:46] Yeah, I have that here
Indre Viskontas: [00:02:48] Because I think there is no better introduction to what this is all about than having you read from it. So, so give us a read.
Henry Gee: [00:02:55] Are you sitting comfortably? Yes. Then I'll begin amid all this tumult and disaster. Life began. It was the tumult and disaster that fed it, nurtured it, made it develop and grow. Life evolved in the deepest depth the ocean, where the edges of tectonic plates plunged into the crust and where boiling hot jets of water rich in minerals and under extreme pressure gushed out and cracks in the ocean floor. The earliest living things were no more than scummy membranes across microscopic gaps in rock. They formed when the rising currents became turbulent and diverted into eddies and losing energy dumped their cargo of mineral rich debris into gaps and pores in the rock. These membranes were imperfect. Sieve like and like sieves allowed some substances to cross, but not others. Even though they were porous, the environment inside the membranes became different from the raging maelstrom beyond calmer, more ordered, a log cabin with a roof and wall is still a haven from the Arctic blast outside, even if its door bangs at its windows rattle the membranes made a virtue of their leaky ness, using holes as gateways for energy and nutrients and as exit points waste protected from the chemical clamor of the outside world. These tiny pools were havens of order. Slowly, they refined the generation of energy, using it to bud off small bubbles. Each encased in its own portion of the parent membrane. This was haphazard at first, but gradually became more predictable as a result of the development of an internal chemical template that could be copied and passed down to new generations of membrane bound bubbles. This ensured that new generations of bubbles were more or less faithful copies of their parents. The more efficient bubbles began to thrive at the expense of those less well ordered. These simple bubbles found themselves at the very gates of life in that they found a way to halt if temporarily and with great effort, the otherwise inexorable increase in entropy. The net amount of disorder in the Universe. Such is an essential property of life. These foamy lavas of soap bubble cells stood as tiny, clenched fists defiant against the lifeless world.
Indre Viskontas: [00:05:50] So listeners, that is but two pages of this. Well, it's called a very short history of life on Earth, and it reads, as you can see, like a great, you know, George R.R. Martin novel. It's only 206 pages and we cover 4.6 billion years give or take a billion. And yet you wrote it with such poetry and such information in each sentence. I just want to ask you, first off, if we could like look underneath the hood a little bit at your process. I mean, because it seems to me that you, as an editor of Nature, you know, as someone who is very much, I'm sure, concerned about accuracy to be able to be accurate and yet tell such a good story seems to me remarkable. So how do you do it?
Henry Gee: [00:06:38] Well, thank you very much for those kind words. What I do is cheat because what? I didn't say anything. About in the passage that I read was that a lot of the science is in the footnotes at the end and that part that I read as footnoted that says, Hey readers, this is the closest I get to making stuff up because we can't actually say anything definitive about the very origins of life. So what I do as a as a scientist, because all trained scientists feel undressed unless they can support everything they say with a footnote. In fact, one science fiction writer said that if you read nature obsessively enough, your dreams will start to carry footnotes to other dreams. So there are lots of footnotes. So but the second one is, as you said in the introduction, this is a great story. So I wanted to tell it as a story. And although I am a social scientist and a science journalist, I also love reading science fiction and fantasy fiction. And I grew up reading Tolkien, and I wanted to add some of the resonance and the use of language to make this story into a thrilling, I hope, epic tale that's more than just the usual scientific discourse on how life might have evolved. La Dee da Dee DA. Here are some cells here, some DNA, and this is what scientists think happened. So I wanted to make it a story as when I was writing books. You know, I've been doing this for 30 years.
Henry Gee: [00:08:26] I would write stuff when my discourse and I'd be writing with great fun and absorption, and I was the text was flowing like a very flowy thing, and I'd get it back from my editor with red lines through it all, saying, Henry, just tell the story. And that's actually very difficult to do. You usually find yourself being distracted by lots of little baubles along the highway. But what I wanted to do was just tell the story, and the story of life is the greatest story. It's full of heroes and villains and hair breadth escapes and cliffhangers and fantastic vistas and incredibly strange creatures and immense periods of time. And I thought, Wow, this is a great canvas for writing a story. So I just sat and wrote the story. Well, that's very simple. It took quite a long time to get it into this particular condensed form, but that's essentially what I did. And the great thing about writing a book, even one without pictures, is that was kind of deliberate. I was reminded of what a great science fiction writer Ian Banks wrote, which is the great thing about writing as opposed to say, filmmaking is you can have an infinitely large special effects budget. So with the cost of almost nothing, you can conjure up asteroid impacts and vast earthquakes and huge apocalypses and ice ages that cover the whole Earth and all the great stuff that I've got in this tinyIndre Viskontas: [00:10:01] Book, you know, and I'm sure as a paleontologist, you know, one of the kind of sins to avoid is anthropomorphizing. But in this case, your story has characters that have sort of human like or at least, but you know, it's not just human life like kind of and, you know, a desire to survive, a desire to outcompete, et cetera. But that's at the core of sort of very much what I like about it is even in the beginning, we talk, you talk about how it's not kind of an intentional thing. It's kind of something that happened. And that was the passage that you read is a great example of that of how there are these membranes that provided a bit of shelter and allowed for these other things to happen. But there's still a sense that there's a character there.
Henry Gee: [00:10:44] Yeah, my editor Ravi Mirchandani, who I've known for a very long time, he said. I have to be careful about anthropomorphizing that things here. And it's something that I've caught and people against in earlier books is that you can't tell stories like that, but thinking about it as a story rather than as a scientific exercise. That's exactly what you do. That's exactly what you should do to make it kind of intelligent and interesting. One of the reasons, for example, that all the aliens in Star Trek and even Star Wars are kind of humanoid is that it's actually quite hard to feel empathy with with a blob or an intelligent, intelligent slug or anything like that. So if you want to carry your readers with you, you have to make them feel something for the for the characters. Ok, you don't have to make all your mice into Mickey Mouse, but you have to give a bit of drama to it, even though there is no actual. Purpose to it, so I hope that even if you're reading about bacteria that squirted oxygen into the oxygen free atmosphere, thus killing all their friends 2.5 billion years ago, even though they're mindless bacteria, I'm hoping to make people feel that they were there and this was important.
Indre Viskontas: [00:12:06] Yeah, I mean, it definitely feels that way. It was the first time I have to say where I have been continuously like wanting to know more, what happens next, what happens next, especially, you know, given that like a large portion of the book takes place well before humans are even a glint in any kind of DNA. And yet it's still interesting, not even not just as a from a kind of scientific or intellectual exercise, but just like all the richness, the vivid details that you conjure up. And, you know, I think if you hadn't made it into this story setting, certainly I wouldn't have continued to come back to it, you know, wanting to turn the next page to find out what happened.
Henry Gee: [00:12:46] It's great. It's thank you for saying that. Of course, I'm helped because geological periods that comprise the record of the past on Earth tend to fall into convenient chapters that end with catastrophes or calamities. Because the Victorian letter to gentleman who they were, who defined the geological periods defined them on the basis of the fossils they contained. And they found that the fossils in one period tended to be quite different from the fossils in the next one. So obviously something had happened that replaced one load of fossils with another one. And quite often we find that at the end of geological periods, there was some kind of catastrophe like an asteroid impact or some episode of continental drift or mountain building that changed one thing for another. And of course, so that's a gift for a writer because it gives you wonderful ways of having cliffhangers and getting rid of characters. I mean, it's like. And some of these seem totally random, shocking. It's like the Red Wedding in Game of Thrones or when you know when you watch the first series of Game of Thrones, you think it's all about Sean Bean and you think the whole thing is going to be Sean Bean and then he gets killed at the end of series one. And then you start to wonder if Sean Bean has any contract that he should be bumped off by the end of Series one. I mean, even in The Martian, he gets fired and has to play golf. So what you do is the history of life is is constructed so that you can make a thrilling story made out of episodes. It was a gift. It's a gift to a writer.
Indre Viskontas: [00:14:34] And you know, you have plenty of spoilers about sort of what's going to happen to our pithy human existence. I mean, you're the very first sentence. Once upon a time, a giant star was dying portends the end of our own.
Henry Gee: [00:14:51] I haven't. I hadn't thought of it like that,
Indre Viskontas: [00:14:54] But I do want to talk a little bit about that, about how how you come to grips, knowing that the extinction of life on Earth in your very first timeline is already laid out. It's already there, and it's quite a bit closer to now than everything that came beforehand. So the distance between birth of the universe and now is about 10 times greater than between now and extinction of life on Earth. So I wondered if you could tell us a little bit about how you grapple with that and how that affects your view on, you know, these cataclysmic events that we are faced with, like climate change and what it might do for the extinction of our species.
Henry Gee: [00:15:39] Well, first in constructing a story, I didn't really think of it like that, but only in retrospect. I thought of two or three different things. Sometimes a story is richer if you already know the ending. I mean, one of my favorite books is Emma by Jane Austen, and years ago, when I was a lad, I thought Jane Austen was just for girls. You know, it's only posh people having dances and tea parties. And while at the time the Napoleonic Wars were raging and all the most exciting thing that happens in in in a Jane Austen story is somebody drops a teaspoon. But then one of the scholars of Jane Austen, David Lodge, said, If you read Emma, it's much more fun when you know the ending and you can, you know the consequences of Emma's actions. So if you read it for the first time, it's a great yarn. But when you read it from the second time, even if you know what's going to happen, the story is richer for all that because you feel the kind of impending. Tomb like watching a road crash happen and you can't do anything about it, and the other one was, I suppose, came from my fondness for Tolkien and for the older kinds of Viking type of stories like Beowulf and the Norse myths is in the Viking women Norse religion.
Henry Gee: [00:17:08] They knew that the end of the world Ragnarok, the last battle was going to happen and they would lose actually got the gods lose in Ragnarok, but they still kept fighting nonetheless. It was still worth doing, even though they were going to lose. And of course, you know, back to the when you were a kid, which I'm sure is much more recently than me. You always love the stories that you knew the ending, and if you knew the words in between, it was somehow comforting. My mother tells me that when my sister and I were read Peter Rabbit by Beatrix Potter, and if she would inadvertently miss a page, she'd be told all about it. No, you forgot the page, and even we knew it off by heart. Even down to each sentence. And when you think about it, this is a story supposedly for children, but looked at objectively. This is about a single mother with four children who has to raise money by selling rabbit tobacco on the streets, and she has to leave her children unattended. And one of her children, Peter Rabbit, is a juvenile delinquent who can't help getting into trouble.
Henry Gee: [00:18:28] And the reason she's a single parent is because her husband is a career criminal who got killed during a botched robbery. And what's more, eaten by the householder? But when you're a small child, you you don't think of that. You just enjoy the story and you enjoy the words and the repetition. So this is the beginnings of story. Even before people were literate, people would gather around the campfire and the meat hall and listen to the Bard telling them things they already knew. And it was. The little embellishments may be along the way, the kind of in-jokes. But it's the stories that we already know that are often the most fun. This is why you tend not to keep very many thrillers or murder mysteries hanging around in your house, because unless it's a particularly good one, once you know who done it, it's kind of spoiled. Once you know the spoilers, it spoiled unless it's something that you feel is told very well, and the tale is all in the telling rather than the result. So that's a rather long answer to part one of your question, and I've forgotten the part, too. It was about the fate of human beings and and other small matters like that.
Indre Viskontas: [00:19:45] Yeah, we'll get to that in a minute. But I do want to stick with this notion to you for a minute, because that's actually one of the reasons that I so loved that section that you asked that I asked you to read from on Page four about the membranes, because it's a foreshadowing of essentially what in what equips us with a nervous system, what allows us to have neurons that send messages, right? It's the poorest membranes. And to so like, see, you lay out about how this is because they were scum on rocks like it. Just because I know where the story is going, it's so much richer for me.
Henry Gee: [00:20:20] Oh, well, thank you. That's great. Yeah, I haven't thought of that either. But that's true. I mean, the nervous the neuroscientists now think that the the sign apps actually originated before the nerves. In other words, it's the doughnut actually started as a whole and the actual doughnut grew around the hole, which is a weird thing. But yes, it's that cells are powered by electricity and they're powered by electrical potential across membranes. And one of the influences behind that was a fantastic book I read a few years ago by a man called Nick Lane called the Vital Question, and he talks about life on Earth, and he talks essentially that life started by pumping protons across membranes because unless you have a way of separating electrical charge, you can't have any kind of life, you can't have DNA, you can't know anything. You have to have some way of conserving and channeling and using energy. And the electrical potential across a membrane is quite high as the order of milli volts, which is the kind of potential in the pick up of an electric guitar. So, so it's and that's of course, a microscopic membrane. So once Kroto life got the knack of separating molecules across semi permeable membranes, they were almost all the way there the whole business of information. Dna and genetics came later, and that's why I didn't go over big on that. Besides, I didn't want to do the usual science writing thing of saying the informational molecule is DNA and it's ANC and GNT and yawn. Yawn, yawn. I didn't want to do all that I wanted to to keep it as broad brush as I possibly could. And of course, in the footnotes, you can look up whatever you like, but it's not essential to enjoying the story, I hope.
Indre Viskontas: [00:22:15] No, and I think that's one of the things too that throughout there are things that you highlight that many other histories of the of the universe or the or the world have not focused on. And so it feels very new like new information at every, every turn of the page. Maybe we'll get to the second part of my question about just how do you continue to get through your day knowing everything is going to end just like a question? I ask, you know, physicists and I guess now paleontologists alike, because it's still something that I struggle with. But let's do a couple more steps along the story, so we go from these little membranes and, you know, how do we get from there to the backbone? Maybe that's a good next place to go.
Henry Gee: [00:23:11] I'm going to sort of try and do this in a very telescoped way. Rather like the the opening sequence to the Big Bang Theory from the little membranes evolved. The first bacterial cells and bacterial cells look very boring, but are incredibly effective at chemistry. Their little bacteria that do all kinds of things and they live in communities such that the food of one bacteria is the waste product of another bacterium, and they recycle whole ecological communities together. So they're very gregarious. So the next stage after that was when bacteria got together so effectively. But little colonies became the cell, the eukaryotic cell where there are some bacteria that became the chloroplasts. That's the green bit that does photosynthesis in plants, and some bacteria became the mitochondria. The little pink power packs that almost all cells have, and other bacteria became the nucleus. They became the library and a repository of of heredity. So that was the eukaryotic cell. And what happens is something that I that dawned on me while I was writing the book was that life tends to respond to challenges by becoming more complex and through that more efficient. So it was the Great Oxidation event that in a two and a half billion years ago and the subsequent 300 million year Ice Age that prompted bacteria to become cells. And then during the next epoch, various events prompted the eukaryotic cells to get together themselves, another order of complexity to become multicellular creatures. And so in a phase of life called the boring billion, which is only boring for geologists who don't get out of bed unless there's an apocalypse, eukaryotes evolved so that you can see the first things that look a bit like fungi and seaweeds and little creeping things.
Henry Gee: [00:25:14] But then another phase of apocalypse and ice ages about 700 million years ago that generated the animals that were tough, hardened and looking for trouble. So the animals originated 700 ish million years ago. But then another what would you believe it? Episode of Catastrophe At the beginning of the Cambrian period, when the Earth was so weathered that virtually all the minerals on the Earth were washed into the sea, allowed animals to construct skeletons with hard parts. And that's when the fossil record really begins, because most fossils are hard parts. So they invented teeth so they didn't have to suck their prey to death and those that were being sucked to death developed armor. So in the Cambrian period between about about around 500 million years ago, most kinds of animal we know today and quite a lot of other ones, a first appeared in the fossil record. And among those animals were still very soft bodied creatures. The first fish, they had an internal structure which became the backbone that they could anchor muscles to and flip through the water later on. Not much later on. They became armored on the outside because they kept being attacked by these gigantic, googly eyed, nightmarish sea scorpions, which really the earliest fishes spent most of their time escaping.
Indre Viskontas: [00:26:51] Yeah, I mean, you talk about how it was these, yeah, the giant sea scorpions that the fish were running away from, and you make this really nice introduction to the mammal chapter. You know, once upon a time, back in the Devonian period, there was a pair of bones inside an armored fish, but the fish paid them no mind because it was busy running away from the giant sea scorpion. So tell us about these two bones and their significance.
Henry Gee: [00:27:23] Oh, well, first of all, the giant sea scorpions, I like to think of them as the as these nightmarish animals that we always have just at the edge of our consciousness. You know, the creatures under the bed, the dragons, the things that inhabit misty forests. They're like the mythical adversary, but they're not mythical. I mean, they really were there and they really were terrifying, especially if you only a fish a couple of inches long. But the two bones, when I said that fish. Got to be armored. The backbone was a squishy, cartilaginous structure for a long time. A bit like one of those long, thin balloons that entertainers twist into entertaining shapes at parties that you could twist them around and they'd always spring back. But over the head region, the fish were armored. On the outside. They had armored helmets. And what these little bones did was they were bracing struts. They would brace this helmet on the outside against the braincase, which was just soft cartilage on the inside. So they were just structural beams to start with. But by the chance of evolution, it happened that the inner edge, the inner end on the braincase happened to sit next to the inner ear, which was an organ of balance, really.
Henry Gee: [00:28:43] And on the outer end happened to brace a gill slit. So this was all completely by chance, just by the luck of anatomy. And when animals first came onto the land, the gill slit became roofed over our thin membrane and became the eardrum. And so this strut connected the eardrum on one side, on the outside to the inner ear on the inside. And this strut became a conductor of sound it by its vibration conducted sound. We still have that in our ear today. It's called the staples or stirrup bone. It doesn't look like a strut in human beings. It's got a little hole in the middle for an artery to go through and a little flat plate that sits against the inner ear. So it looks like a stirrup. And for millions of years, that was the way that animals heard sound. Vibrations on the air on the eardrum would vibrate this stampedes, and it would conduct the vibrations into the inner ear. But then, in mammals to other bones were added to use the kind of horny handed blacksmith metaphor. One was called the anvil and one was called the hammer. So there's this blacksmith of evolution, walloping a stirrup with his anvil and his hammer.
Henry Gee: [00:30:07] And in the mammals, these bones, which became very small and thin, amplified the sound and allowed higher frequencies to be heard. Now, birds which still have the one bone, although they make a lot of noise they can't hear, sounds very much above well to use numbers 10000 hertz, 10 kilohertz, whereas small children can hear to 20000. Now, I probably can't hear more than 10000 because I'm nearly 60, and I've listened to Hard Rock all my life, so that's me. But many mammals can hear much higher than that dogs. That's why dog whistles work. We can't hear them, but the dogs can. Dolphins bats, they can hear many times higher than that. But when the mammals evolve to this hearing, it became their own realm. It was as if they'd been to be metaphorical, floundering about in a dark forest, all their lives that had suddenly found this gate in the woods that led onto this huge field with open vistas. And it was all their own. And that's one of the great things that make mammals mammals is this fantastic hearing, and it all started with two bones in the back of the skull when a fish was trying to avoid being eaten by a giant sea scorpion.
Indre Viskontas: [00:31:24] Yeah, I mean, it's such a it's such a fascinating history right there. I mean, that's what enables podcasts. It's kind of like, in some ways, our own history.
Henry Gee: [00:31:33] Well, you could write an entire book and people have about the origin of the mammalian ear. It's just the most amazing story in itself.
Indre Viskontas: [00:31:40] So we're going to run short on time relatively soon, or we still have quite a bit to cover. So let me just jump to another part of the story Homo erectus. And you know, the way that you tell the story of Homo erectus doesn't sound like a particularly compassionate ancestor. Why don't you tell us a little bit about sort of the kind of just the sort of way in which fire played a role in getting some some of our ancestors to live longer than others? And then just how brutal it must have been?
Henry Gee: [00:32:13] Well, we tend to think of when our ancestors were inventing tools and inventing technology, but they were looking up in some fit of heroic ellipses and say, Ah, I've just invented fire this now I'm going to go and invent the wheel and civilization. But of course, they didn't do it like that. And in a marvelous book, Pat Shipman and Alan Walker wrote about Homo erectus, and they said in many ways it looked very human. But if you looked into its eyes, you wouldn't see any humanity. You'd see the the canny wisdom of a savannah. Predator like a hunting dog, because that's what Homo erectus was, it was a it was a savanna predator that hunted impacts. But Homo erectus, like all humans, are very good at sexual display, extreme violence and cookery. Now, somewhere along the line, Homo erectus tamed the use of fire and found that eating meat, which is what they were specialized to do around a fire, was a sociable thing to do, especially if you cooked the meat because the meat became tender and more chewable and easier to digest. And another thing they wouldn't have realized at the time was when you cook meat, it kills any germs or parasites that might have existed in the meat.
Henry Gee: [00:33:43] So what meat does is it gives you a huge amount of concentrated calories that chewing raw vegetation doesn't do. To get the same amount of energy from chewing raw vegetable vegetation, you have to chew it all the time, which is why the contemporary of Homo erectus, which was a creature called Grantham, was a pure vegetarian, spent all its time chewing and it had huge teeth and immense chewing muscles. It was a kind of human version of a cow. But Homo erectus, the teeth were smaller, the muscles were smaller. And another thing that eating food, along with a lot of other things allowed was the enlargement of the brain. The brain of Homo erectus wasn't as large as ours, but actually, it's not really the size, it's how you use it with brains. So just talking about brain size is only one part of the story. Predators tend to have more brains than prey anyway, but brains are very, very expensive to run, and one way to run them is to feed yourself a lot with the high density, energy rich, easy to digest food source such as meat. Another thing that this allowed was herbivores often have very big guts because a lot of the nutrition comes from fermenting the food in a gut like a gigantic compost heap, which is why cows fart a lot and have to chew their food a lot to get the same energy.
Henry Gee: [00:35:11] But Homo erectus could have a slimmer gut because it's easier to absorb a mixed diet based on meat. And because I had a slimmer gut, they had a taller, leaner frame that allowed them to do something that earlier hominins couldn't do, which was run. And now hominins have been bipedal for millions of years by that time. But they had a rather had while the short legs and were rather potbellied so they could walk around perfectly fine. But they wouldn't. They were not very good as as runners. So one thing that Homo erectus invented was long distance running and just like hunting dogs. They pursued game for mile after mile after mile until the game fell down with exhaustion. Because although human beings are not very good sprinters compared with other animals, human beings are excellent long distance runners, one of the best in the animal kingdom. And so they could slowly pursue other animals until they died of heat exhaustion. And that's how hunters work today in traditional societies, and Homo erectus was the first to perfect that art.
Indre Viskontas: [00:36:24] Yeah, it's so fascinating to sort of hear about these facts placed within this context of, you know, what's happening when. And so just as you describe all of the things that you've just said are backed up by solid factual evidence, but it also makes for a great story. So now we get towards the end of the story and one in which doesn't end well for any of the hominins, you know, ancestors going going forward. And also, in terms of this long view perspective, I mean, I think a lot of us and hopefully many more of us as we continue to understand what we can do and the causes are very, very worried about climate change. And in particular, you know what humans are doing. So, you know, tell us a little bit about sort of your long view. And does that give you a bit of a sanguine perspective onHenry Gee: [00:37:15] Oh, well, yes and no. Sometimes I spend the day in complete terror about what's going to happen to the human species. But then really, one just has to get through once day as elegantly as possible, being as nice to people as one can. So I tend to look askance at the kind of hysterical climate change industry Oh, it's all going to die, it's all going to be terrible. However, this isn't to say that climate change caused by human beings isn't an urgent problem because if. Is it's a very, very urgent problem, but it's not about saving the planet, the planet will happily carry on whether we're here or not. It's about saving ourselves to ensure that we can continue to live on the planet that provides us with all our means for living our fresh air and clean water and food. So it's necessary to try and live more sustainably and economically in the world. Now we are already doing things better. It's not true that people and governments and economies and companies are not being are not thinking about this because people have been making economies for a long time. Sustainability started in the 1970s. I mean, nobody drives those huge cars anymore. Your engines at both ends, you only ever see them in Greece now, and the internal are taking the long view. A lot of the threat that humans have created are very, very recent.
Henry Gee: [00:38:54] I mean, the huge expansion in the population is less than a century old. The internal combustion engine is less than 150 years old. And yet within 30 years, it will be as extinct as typewriters. It'll be there as a kind of heritage item, but people will be driving electric cars or not driving at all. I remember when plastics were first used in a in a great way. And this was only when I was a child. It wasn't like in ancient history. And already people have been trying to phase out these things. So people are aware of the things that are happening in our lifestyles and have been doing going some way to correct it. A fact that I discovered which made me really sit up was that the per capita energy use in Britain has declined by a fifth since the year 2000. That's a fifth in 20 years. And it's the same in many other developed economies. I mean, when I went to university, gosh, 30 years ago, I used to, you know how it was. Everyone went with these armfuls of vinyl records and record players, and we had light bulbs that were had tungsten filaments and had mostly heat. Now we don't have light bulbs like that. We have light bulbs that that are much brighter and consume a tiny amount of energy, and all our music is on our iPhone. So in all sorts of little ways, things are getting better, but the major determinant of human welfare.
Henry Gee: [00:40:31] The single most important determinant that has happened in the past hundred years has been the empowerment and emancipation of women, which has led to a doubling of the workforce and longevity, increased longevity and health and welfare for everyone. I mean, there have been significant reverses, and this is a broad brush picture. It goes one way and it goes the other. But one of the reasons that the human population has managed to expand and live much more comfortably than anyone could have predicted in the 60s is because of the emancipation of women. That's it. So that gives me a certain amount of hope for the near future. But in the long term, human beings are mammal species, just like any other mammal species and mammal species come and go. In fact, all species come and go. Now, the late paleontologist Dave Rupe, who is himself extinct, once said that at a first approximation, there is no life on Earth because 99 percent of all species that existed are extinct. And we're all going to go that same way. And my worry? Well, it's not a worry. My fear prediction suggestion is that human beings are going to go very soon. I was very vague about this in the book, but after the book, I started thinking about this some more.
Henry Gee: [00:41:56] And I wrote an article in Scientific American a couple of weeks ago that seems to have got everybody in a fit of conniptions that human beings are going to become extinct within a few hundred years. There are a number of reasons for this. One is that the population, although it was increasing at a rapid rate in the 60s, over two percent, it's now down to just over one percent. The peak was in 1968. But the people are not having as many children, and this is true all over the world, not just in developed economies, but in what we patronizingly call the developing world. This is also true. The rate of replacement of population is far below the death rate in many countries. But there are a number of reasons for this. One is that sperm quality for some reason, for reasons no one knows are declining. Another is that people can't afford to have children and people are putting off having children in many countries where they love children like Italy, for example. You can't afford to have children. So the Italian population is tanking in some countries where they traditionally discourage immigration like Japan. It's already a serious problem. But behind all this is something else I heard, which is that the world economy has basically been static for 20 years. All these various are growths, and recessions are basically against a long, a longer episode of status.
Henry Gee: [00:43:28] And this, I think, is because we're running out of resources. We cannot sustain an economy based on growth. Politicians can no longer sell economies that say they're growing the economy. This no longer works because human beings, just one species out of millions, sequesters more than a quarter of all the energy resources of the world in terms of plant production. More than a quarter, maybe as much as 40 percent. Nobody really knows, but it's an awful lot for one species, and that is gives a clue to why a lot of other species are dying out. Because if one species has all the gets, all the beans, there are fewer beans for anyone else and they die out. But then I thought back to a paper I handled in Nature in the 90s, which put across a new concept called Extinction Debt, and it shows that it's all about animals living in. It was a very short paper, very dry and theoretical. But it talked about animals living in patches of habitat like little patches of woodland or little ponds, or anything divided by gaps which most animals live in. Like if you're a butterfly and you only make your only lay your eggs on a certain kind of plant. Well, the whole world isn't a lawn of this plant. They're little clumps of this plant and you go from one patch to the other.
Henry Gee: [00:44:52] And this paper showed that if you're a species that flits between patches, you're more likely to live longer than a species that dominates in any particular patch. Because what happens if you live? If you're what's called a dominant competitor living in a particular patch, you can show that just a tiny diminution in the quality of that patch will lead to the inevitable extinction of the whole species, even though everything seems to be fine and dandy. So then it occurred to me that as human beings, we only live in one patch the Earth because we farm just about every part of the Earth. That's farmable. We've colonized every continent and there are people everywhere you look. There is no such thing as a pristine habitat anymore. There are no patches of habitat on the Earth. The Earth is one habitat patch and we're staying in it. We are degrading the habitat quite significantly. And that leads me to think that we're a dead species walking. The population growth of human beings will peak in this century and start to go down. It might be lower than it is now in 2100. Although opinions vary, demographers can't agree on exactly when it'll peak and exactly when it'll go down, but all agree that the population will start to decline and go down very quickly. And I think it's going down one way. I think we'll be extinct in a few hundred years.
Indre Viskontas: [00:46:29] Well, on that note, I'd like to remind our listeners that Henry G's book A Very Short History of Life on Earth 4.6 billion years in 12 pithy chapters. And now, you know, the ending is available at booksellers everywhere. It makes a great holiday, read. It's a really wonderful story.
Henry Gee: [00:46:46] It's actually quite cheerful, really. I mean, I wouldn't want to end.
Indre Viskontas: [00:46:50] I'm just kidding. Yeah.
Henry Gee: [00:46:51] No, that that that doom, doom laden note.
Indre Viskontas: [00:46:55] It is. It is very cheerful.
Henry Gee: [00:46:57] Yeah, because even though, like the Vikings, like Ragnarok, we know they'll be the last battle and we know we're going to lose. It's good to keep fighting anyway, even though we know what's going to happen.
Indre Viskontas: [00:47:10] And maybe one more incentive to do whatever you need to do to visit with your loved ones, talk to them on the phone or give them a hug in person.
Henry Gee: [00:47:18] Yeah, it's not going to happen next week, folks. I mean, you know, these things will take a long time to happen. So, so have fun.
Indre Viskontas: [00:47:26] Yeah. Well, after you and I have left this Earth.
Henry Gee: [00:47:30] Indeed, indeed.
Indre Viskontas: [00:47:32] All right. Well, thanks very much for being on inquiring minds.
Henry Gee: [00:47:34] Thank you very much.
Indre Viskontas: [00:47:38] So that's it for another episode. Thanks for listening. And if you want to hear more. Don't forget to subscribe. If you'd like to get an ad free version of this show, consider supporting us at Patreon inquiring minds. I want to especially thank David Noel Herring, Chang, Shawn Johnson, Jordan Miller, Chi Roy, Hala, Michael Googol, Eric Clarke, Yoshi, Lin Clarke, Lindgren, Joel, Stefan Meyer, Awal, Dale LeMaster and Charles Blow. This episode was edited by Daniel Lynch. I'm your host, Indre Viskontas. See you next time.