Anyone interested in sustainability and ecology is in for a real treat tonight. We’re delighted to welcome to the Science Gallery distinguished zoologist and broadcaster, Professor Aubrey Manning, who’ll begin his lecture shortly. First, let me introduce you to our Master of Ceremonies for tonight, Duncan Stewart. Duncan is a TV presenter and award‑winning architect and a specialist in ecological design and energy. Duncan has presented many environmental series and in addition he is well known for his popular TV series, About the House. So, over to Duncan.
Thanks, Donna, and it’s great to have such a wide ranging audience here tonight. I know that we’ve got not just scientists here, even though this is Science Week and this is organised by Discover Science & Engineering, which part of Forfás. And, as you know, this is a very important week for science, and science is a very, very important subject for us as we go into the issues of climate change and the big challenges facing us.
And we’re very lucky tonight to have Professor Aubrey Manning, who’s talking about learning to live with our planet. And Professor Manning is one of Britain’s leading authorities on sustainability and ecology. He features on BBC television and natural radio and his main research and teaching interests are on animal behaviour, development and evolution. And he’s been involved in environmental issues since 1966, at the Centre of Human Ecology since its inception in the University of Edinburgh in 1970. He was Professor of Natural History at the University from 1973 until 1997. Professor Manning was elected Fellow of the Royal Society in Edinburgh in 1973 and received an OBE in 1998. He’s also President of the Royal Society of Wildlife Trust. So, we’re going to have a wonderful talk from Professor Aubrey Manning on learning to live with our planet. Thank you.
Well, ladies and gentlemen, thank you very much for having me. It’s a great privilege to kick off Science Week. I wanted to begin with Jacob Bronowski, because I think this, for me, is the moral of Science Week, that actually we want to see science as a part of culture. And I understand that you’re a bit worried in Ireland, as we certainly are in Britain, about what’s been called ‘the flight from science’, that young people think that science is unhuman in some way, not creative. It’s too hard, too rigid, full of facts and no feeling. Nothing could be further from the truth. Of course, the findings of science are hard facts, and if they’re good facts, they’ll hold up and they will explain how our world works. But during the process – the doing of science – scientists are involved in all the emotions as well as the intellect. Science, in practice, involves joy and sorrow, despair, and it’s truly creative. And when you’ve got some result that's come out really well and you understand something, it finally clicks, that must be the same feeling ‑ it is the same feeling ‑ as a poet who finally gets the last stanza of a poem into place. They’re not different.
OK. I have the pleasure to be involved in this International Year of Planet Earth, a United Nations venture with the International Union of Geological Sciences, and I’m happy and proud to be wearing the official tie, which was a present from the Chinese delegation when we launched IYPE in Paris at UNESCO. The logo is worth examining because this is the fiery mantle and core of the Earth. Here is the hydrosphere, the oceans. Here is the lithosphere on which we live and here is the atmosphere that also supports us. Now, the whole point of the IYPE is to bring out to the public ‑ there are a lot of research programmes going, and more of them later – but it is to bring out to the public some of the wonderful, brilliant, fascinating science which earth science has produced recently and in this way help us, I think, to see how science can help us towards a really sustainable mode of living. Through understanding the planet, we should be able to live with it better, learning to live with the Earth.
Now, I am absolutely delighted to be able to quote from the Archbishop of Dublin speaking yesterday, reported in today’s [Irish] Times. He said, ‘We need to start understanding the nature of the society we live in, the way it works and what’s wrong with it, and then we need to find the answer.’ Now, he’s using the word ‘society’ there, but I would substitute ‘world’. We need to understand the nature of the world we live in, the way it works and what’s wrong with it, and that’s what I hope to be talking a bit about today. Let me hasten to say I’m a zoologist; I’m not a geologist. There may be people here – in fact, I dearly suspect there are who know far more geology than I do – but I’m speaking as a generalist. I’m trying to look at the whole picture, because I believe that earth sciences and the biological sciences must go together, because life and the Earth have gone together.
And so, let’s go back to basics, as the Prime Minister of Britain once said. The Sun, our mother star. It’s a medium‑sized star about half‑way through its life, which is about 4.56 billion years. So, it’s going to burn for something over 4 billion years more and I suppose if we’re conservative we can say that it’s got about three billion years more useful life for us, looking at it from a purely selfish point of view. Beyond, the Sun will be dying and changing its nature and it will expand first to envelop the orbit of Mercury, by which time it will have burnt us up. But, still, if a week’s a long time in politics, surely 3 billion years is a reasonable time to aspire to? And one of the things I’m concerned about is that, actually, the human race, which I think is rather nice in moderation, should be able to continue – let’s say for the next 1,000 years, shall we? We’ll be quite modest. But, as you know, things are going wrong with it, as things are going wrong with society, as the Archbishop of Dublin said.
I love giving these statistics to students, because it does cut us down to size, I suppose you might say. The Sun compared to us is really enormously large. We are a small planet, but we’re very fortunately situated. Here is some artistic imagination of the four rocky planets. Here’s Mercury –I think the Sun should be much bigger than that because it’s much closer to the Sun than we are – burnt up on one side, frozen on the other. Here is Venus. We used to think it was a cold, wet planet, or at least a wet planet because its surface is always covered in clouds, but the clouds are of sulphuric acid vapour and the surface has gone runaway greenhouse effect, the surface temperature is about 450 degrees. Lead would be molten on the surface of Venus. Here is Mars. We’ll know a good deal more about this soon, I hope. It’s frozen out. It’s about ‑30. And no prizes for guessing where this is. It looks like the cover of a chocolate box, but what it shows – and this is the important thing – is that Earth has liquid water on the surface, and has had that for almost 4 billion years. It’s just the right size, Earth, just the right distance from the Sun. It is the Goldilocks planet – you remember Goldilocks trespassed into the three bears’ house and the first bowl of porridge she found was too hot – that’s Venus. The second was too cold – that’s Mars. But the third, the baby bear’s porridge, was just right.
So, [that's] the Earth forming, when the sun formed about 4.56 billion years ago, give or take a million here or there, and life began on Earth. There are traces, chemical traces of life on Earth very early in its history, maybe back as far as 4 billion, certainly 3.8, 3.9. Now, when the Earth was young, it was a violent place. I hope you’ve all looked at the Moon through a telescope or binoculars – a fabulous sight. We see the Earth and the Moon about the same age – I don’t have time to go into the ideas of how they formed, but the Earth must have been bombarded, just as the Moon has been bombarded incessantly by meteorites – the stuff in the solar system circulating around.
And if we look in detail at the surface of the Moon, we can see craters, and craters within craters, and craters within craters within craters – continuous bombardment. And, of course, on the Moon, there’s no atmosphere, there’s no wind, so they stay pristine. Only the light gravity of the Moon might cause some of these slopes to collapse occasionally.
Now, on Earth, we know there are traces of early meteor strikes, but most of them have been washed away or blown away over the millennia – not just millennia, I mean millions of billions of years. So, the early history of the Earth must have been very violent and, in fact, the oceans must have frequently been very hot and burnt – more of that in a minute.
Now, we know that the nature of the Earth is very dynamic. It’s the one of the planets in the solar system which is still actively shifting and moving its surfaces. If some space visitor from Andromeda came cruising through the solar system and took some photographs, or whatever way they record data on Andromeda, and then went off into other galaxies and 100 million years later came cruising back home and passed through the solar system again, taking more pictures, Saturn, Jupiter, Mars, Venus would look exactly the same. But the Earth wouldn’t look the same. And maybe the people from Andromeda would say, ‘Aha. Something’s going on down there’. Because the Earth is unique. It’s at the point of its life where it is still shifting and changing. And we know, of course, that the surface that we live on and think is of as so stable and permanent is, in fact, a series of plates and that these plates are moving around on the surface, sometimes sliding alongside one another, sometimes colliding, and mountains are thrown up and so on.
a. Alfred Wegener
All of this is terribly familiar to us now. It’s certainly taught in the early years of secondary school – maybe in primary school – but do remember, ladies and gentlemen, how recent all this knowledge is. When I was a student, which is not far back into the 17th century or so, I was taught that Alfred Wegener, this crazy Austrian had come up with this theory of continental drift, that the continents shifted around on the surface and that once upon a time South America and Africa had been joined. But, I was told, there’s no mechanism for this and we can’t explain the anomalies of the distribution of animals and plants on this theory. It’s crazy.
I wish Alfred Wegener ‑ whose body has never been found, he lies somewhere in the Greenland ice sheet – I wish he could have lived longer to see that yesterday’s heretics become tomorrow’s establishment. We should be looking for today’s heretics because maybe they have something to tell us – and perhaps I can think about some of the ideas they might have.
b. Marie Tharp
OK. All of that is so recent. Fifty, 60 years is all the time that we’ve known actually how the planet works. And this has meant that some of the people who made these pioneering observations are still alive – or certainly I can think of two or three who are still alive. And this was one whom I had the pleasure and the honour of interviewing for some television programmes. This is Marie Tharp. And at the time that this photograph was taken, she was about 84. She’s dead now. But talking to her was as if I, as a biologist, could have spoken to Darwin and said, ‘Tell me, Mr Darwin, what was it first gave you the idea that perhaps species were not constant?’ I could ask Marie Tharp about how she first discovered and measured that there is a mid‑ocean ridge running round the planet. And in the middle of this ridge, most crucially, there is a cleft, at which there is volcanic activity.
Now, she and her collaborator, Bruce Heezen, were taking these measurements from ships with simple asdic in 1960, about. They were employees of a big laboratory in the eastern states, the Lamont‑Doherty, whose director, Ewing, didn’t believe in continental drift. And, in fact, he tried to forbid his workers, his staff, from working on ideas of continental drift. But Marie Tharp made these measurements, and it takes a great deal of skill and immense labour. And she went to her collaborator, Bruce Heezen, and said, ‘Look. Down the middle of this ridge there is a cleft, and I think this may be active. There are faults coming out from it.’ And she told me that he said, ‘Oh no. That means continental drift, and we don’t believe in that.’ And her ideas were greeted with scorn and contempt – a heretic. But I was greatly privileged to meet this person.
So, it is all very recent and that’s why earth science – modern earth science – is such an exciting thing. We biologists have had our general theory for 150 years, but geologists for much less than that.
Now, back to craters again. The early Earth must have been a violent place, but that didn’t stop life getting going. We know now that there are three basic domains of living organisms. Two of them are familiar to us. Ourselves, up here, the complicated organisms – big ones, plants, fungi, animals and some protozoans and others. Then, the bacteria, which we have to live with, which live around us everywhere and in us. They are both bad and they’re good. We couldn’t live without them and we have trouble living with them sometimes.
But there is a third domain, much more recently studied. These are archaeans. Now, these are bacteria, archaebacteria they’re sometimes called, minute microscopic organisms. But they live in very different places. They live in the interstices of rocks, going down two, three kilometres. They live in the cracks in granite, the cracks in basalts. They live in oil wells and they live, for instance, in boiling pools in Iceland and also in the black smokers at Marie Tharp’s cleft on the mid‑ocean ridges. They can do that because their names suggest things. Thermoplasma, thermoproteus – both of those organisms can’t grow at temperatures below 60 degrees and can reproduce at 100 degrees. If the water boils, they’re still growing and reproducing. So in the early Earth, bacteria of this sort could keep going, even if the oceans boiled during this early time of Earth’s history.
Don’t bother about the text [in the slide: "Can deep bacteria live on nothing but rocks and water?"], answer the question. And the answer has to be ‘yes’, because when life first got going on the planet, there was no alternative. If you were an archaebacterium, you couldn’t go and have a nice comfortable life living in the gut of a mammal, because the mammals weren’t existing for another 3.5 billion years. All there was was chemicals – rock and water and the interactions, the hydrogen that was emitted by acid water acting on certain rocks.And these bacteria can build up complicated molecules from simple chemicals – a bit similar to the way that plants do.
Now, they’re still everywhere today. Don’t think that these as being the first form of life have now gone. They’re everywhere. And I am an arch‑conservationist. I’m really worried about the extinction and the threats to other living organisms. But I am consoled to know that there’s no need to have a Society for the Preservation of Archaeans. Nothing we do is going to affect them. They’re going to go on inhabiting the oil wells, the interstices of rocks, the rock pools until the Sun burns us up.
a. The planet affects life
Now, James Lovelock’s hypothesis links life and the Earth, as I want to do, and links it with this Gaia metaphor, hypothesis, model – whatever you like to call it. And you see that he makes it a dynamic duo. Earth supports life, life supports Earth. I would rather say ‘affects’ the Earth. And the way that life supports Earth – I beg your pardon, the way that the planet supports life is, of course, through providing all those – we call them ‘life resources’ – clean air, clean water, fertile soil, the life support systems which have been there for 4 billion years or more.
Now, these plate tectonics movements will illustrate to us a number of features of the way in which the activity of the planet, the life of the – I don’t want to call it ‘the life of the planet’ – the dynamism of the planet has affected the course of evolution. And in particular we can see one here, because notice how the planets [sic] are all together at certain times way back - 225 million years ago, Pangaea, a huge conglomerate of the continents, very much all together. Then they began to split apart and a rather critical splitting apart started occurring here. Here we are back 85 million years ago and here about 35 million years ago, and we can see Australia and South America are splitting off separately from the rest here. That had a big effect on the animal life, particularly the mammal life, that we see today. Because most, if we look around the whole of the main part of the world – OK? – Eurasia and the Americas - most of the mammals are… we call them eutherians. We would call them eutherians – perfect animals, that means – because we’re one of them and we couldn’t be less than perfect, could we? So these are the mammals which have long gestation periods and the young are born relatively advanced.
The alternative – or the others – are marsupials, who give birth to young – at a very, very early stage of development and they spend much more time in the pouch of the mother being, really growing up. They gestate, if you like, externally, in the mother’s pouch.
Now, for reasons which are not altogether clear, where eutherians and marsupials live together, for the most part the marsupials have lost out. They can’t compete so well. That’s what’s happened in all the rest of the world, and the marsupials have disappeared. They were there originally – we’ve got their fossils. But Australia was isolated early on and the marsupials have flourished there because no eutherian mammals had developed. And so the whole fascinating aspect of the zoology, the biology of Australia is dependent, is caused by the movements of the planet, grossly affecting evolution.
Here’s the present day. I hope all of you can see it. But I want to go back – I wish I had the picture – just 8 million years. There’s no Isthmus of Panama. That only formed about 3 million years ago, it became complete. That also affected evolution in a big way because animals which had evolved in isolation in South America were suddenly exposed to a whole lot of immigrants of a more vigorous type ‑ I don’t have deep time to go into details – and a lot of South American animals, unique to South America at that time became extinct. Again, the Earth, as it were, taking a big hand in evolution. I may say that the closing of that isthmus made a big difference to the world’s climate. It stopped warm water from circulating around easily between the Atlantic and the Pacific and that actually began to change the climate system and really set up the climate system that we have in the world today.
b. Life affects the planet
OK, that’s one direction. The planet supports life. But I also mentioned the other half of Lovelock’s metaphor – life affects the planet. I don’t know whether there’s any chalk in Ireland – some of you geologists may be able to tell me. There is masses of chalk in Britain, and we’re very fond of it. I mean, the White Cliffs of Dover of course swing across and there’s the huge chalk of the Pas de Calais in France, which runs through and comes out actually, it’s covered, it comes out in the Crimea. There is a vast amount of chalk. All of it is formed from the skeletons of minute plants and animals living in warm seas, which build calcium carbonate skeletons. These, when they die, these go down to the bottom, become compressed, modified chemically and form chalk. They also form limestone as well. Huge amounts of the Earth’s crust is chalk and limestone. It wouldn’t be there if it weren’t for life. So this is a really big effect that life has had on the structure of our Earth.
One other statistic I can’t resist giving you. If we look at this chalk – this is Dorset and that’s Swanage over there, I don’t know if any of you know the south of England – the giant, the absolute giant amongst the tiny organisms whose skeletons make up this chalk is 2 mm in diameter. How many of them in the chalk? Quite a lot. Life has affected the Earth very greatly.
Here’s another way that life affects the Earth. The huge Boreal forest of Canada here. This is a map drawn by the Natural Resources Canada and it doesn’t, of course, include the Boreal forest which goes right across the north of Europe and Siberia and comes round the other side, and it certainly doesn’t stop at the Alaskan border here. That forest is made up of unbelievable numbers of coniferous trees – there’s some deciduous towards the south, you can see it indicated here. And here is tundra, beyond the treeline. Now, the nature of that forest – this is what it looks like – and there are vast deposits of peat here. This is a gigantic carbon sink. It’s fixing carbon and - because it’s a wet, cold climate - storing it as peat. It’s the best kind of thing that we could possibly have at the moment when we are worried about rising carbon dioxide. Needless to say, in some parts of its range, particularly in Russia, the chainsaws are out in a big way. Well, there’s an awful lot of trees to cut down, but we would be wise to recognise what the forest does for us and how it affects the planet. It’s affecting us as well.
a. The extinction of the dinosaurs
OK, now back to life and the evolution of life. The planet has supported life, but not always easily. Here is modern life ‑ 600 million years ago, a mere snap of the fingers. This is when the big organisms, the big plants, the big animals got going. It’s where we’ve got really good fossils. It goes back a little further than this, but never mind. 600 million when we’re starting records here and we’re going up to the present. And this is a measure of the diversity. We often talk about biodiversity – this is a measure of how diverse life is, and we see that it grows. And there are checks and there are checks – not a good period here. A huge check here. In fact, it’s believed that maybe as much as 95% of all living things became extinct at this point here, about 280 million years ago, the Permo‑Trias. But life recovered. And then there was a further extinction a mere 65 million years ago at the boundary between the Cretaceous and the Tertiary. And every primary school child knows about that extinction, because of course then we lost the glorious dinosaurs. We lost a whole lot of other things as well, but it’s the dinosaurs we really lost. And life, though, recovered. Once the big reptiles had gone, the mammals could get going, and the mammals have really gone and taken off.
Now, what went wrong? If the planet is supporting life, what went wrong at these times? What could have gone wrong to produce this colossal extinction here? What could have gone wrong to extinguish the dinosaurs? Fire. Volcanic activity, we know, on a colossal scale. I mean, the kind of volcanic activity that Mount St Helens would be just an indoor firework. That has gone on in the past and we can see its result. We can see gigantic fields of volcanic ash covering vast areas in Siberia, covering huge areas in south‑western India. Putting enormous amounts of ash and carbon dioxide, sulphur dioxide into the atmosphere, making the oceans acid, all of that would have been hard for life.
Ice. We know it’s affected us in the Northern Hemisphere very greatly over the past 30 million years or so. That might have been involved. And, of course, meteorite strikes, beloved of science-fiction writers. Well, we know that there was a big meteor strike about 65 million years ago when the big mass extinction that I’ve referred to occurred. But there are real biological and geological problems in exactly interpreting this. I mean, what went on?
You may have seen the BBC programme Walking with Dinosaurs. I mean, computer graphics really coming into its own. And there, in the last programme – I think it was the last programme – is the mother tyrannosaurus rex, you know, who is looking after her babies, who are running around. I must say, it was not a picture that really convinced me as a zoologist, but never mind, it was very attractive. And then, of course, there’s a light in the sky and the light gets bigger and bigger, the screen grows white – pfsst, they’re gone.
But, you see, it wasn’t quite like that. We know that there are fossils of some dinosaurs for at least 1 million years after – 1 million years. So flash extinctions we don’t have. I mean, you must recognise that the scale of that mass extinction diagram is enormous. I mean, a minute amount is 1 million years. It’s extremely difficult for geologists to pin this down and also for biologists to understand why some animals survived and others didn’t. All the ammonites in the ocean, all the ichthyosaurs in the ocean went out. But a lot of fish survived. All the big reptiles went out, but the relatives of the crocodile survived. What was going on?
Now, good science – this is one thing that I’m sure will come out in this week – good science comes not from knowing things, but from not knowing things. The stimulus for good science is problems and long may these problems continue in some ways. I mean, there are some problems we want to solve, but there are other problems we want to worry away at till we really reach what we think is a really good theory. And that’s going on hard at the moment, when biologists and geologists, working together in a kind of partnership, are trying to understand what happened at these mass extinctions.
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