Lord Robert McCredie May was interviewed in 2011 for the Interviews with Australian scientists series. By viewing the interviews in this series or reading the transcripts and extracts, your students can begin to appreciate Australia's contribution to the growth of scientific knowledge and view science as a human endeavour. These interviews specifically tie into the Australian Curriculum strand ‘Science as a human endeavour’ and its two sub-strands ‘Nature and development of science’ and ‘Use and influence of science’.
The following summary of Lord May’s career sets the context for the extract chosen for these teachers’ notes. The extract discusses his ‘accidental’ transition from physicist to ecologist, and how mathematics allowed him to devise one of the most important theoretical milestones in ecology. Use the focus questions that accompany the extract to promote discussion among your students.
Lord Robert McCredie May of Oxford, OM AC Kt FRS was born on 8 January 1936, in Sydney, Australia. He attended Sydney Boys High School and studied chemical engineering and science at Sydney University. After receiving a PhD in physics from Sydney University in 1959 his academic career included a personal chair in physics at Sydney University aged 33, Class of 1877 Professor of Zoology and chairman of the research board at Princeton, USA, and Royal Society Research Professor in Oxford University, UK.
Lord May was Chief Scientific Adviser to the UK Government and Head of the UK Office of Science and Technology (1995-2000) and President of The Royal Society (2000-2005). He is a member of the UK Government’s Climate Change Committee, a Non-Executive Director of the UK Defence Science & Technology Laboratories and Chaired the Trustees of the Natural History Museum. His research interests include how populations are structured and respond to change, particularly with respect to infectious diseases and biodiversity, and the structure and dynamics of ecosystems.
May was awarded a knighthood in 1996, and appointed a Companion of the Order of Australia in 1998, both for ‘Services to science’. In 2002 he was the seventh Australian in 100 years to be appointed to the Order of Merit by the Queen. His many honours include: the Royal Swedish Academy’s Crafoord Prize (bioscience and ecology’s equivalent of a Nobel Prize); the Swiss-Italian Balzan Prize (for ‘seminal contributions to biodiversity’); and the Japanese Blue Planet Prize (‘for developing fundamental tools for ecological conservation planning’). He is a Foreign Member of the US National Academy of Sciences, an Overseas Fellow of the Australian Academy of Science, and an Honorary Fellow of the Royal Academy of Engineering and several other Academies and Learned Societies in the UK, USA and Australia. In 2007 he received the Royal Society’s Copley Medal its oldest (1731) and most prestigious award, given annually for ‘outstanding achievements in research in any branch of science’.
Lord May is presently Professor at Oxford University and Fellow of Merton College, Oxford.
You have written so many seminal papers. Which was the very first that made the mark?
It wasn’t any of the things that I did in physics, although I did do one or two cute things. My favourite is the first thing I ever did in physics, which was in my first year as a graduate student. This thing is really rather startling although it was completely uninteresting until very recently. At morning coffee at Sydney, somebody mentioned, ‘You know, there can’t be two-dimensional superconductors, because the two-dimensional Bose gas doesn’t condense, and that is a critical phenomenon for getting superconductivity’. I thought, ‘That’s amusing. I’ll have a look at that’. I went home and I discovered that, indeed, it didn’t condense. But it only just didn’t and you couldn’t tell the difference. I came back and told my supervisor Robbie Schafroth this, and he was interested. I also told Pauli.
Then I thought more generally about two-dimensional ideal gases and I proved an amazing and wonderful theorem. It is not very interesting but really cute. In two dimensions, the specific heat of a two-dimensional Fermi gas is identical as a function of temperature with the ideal Bose gas. This is crazy, because the specific heat is determined by just the surface electrons in a Fermi gas and by everything in a Bose gas. But it is true and it is now an exercise in books. Now that we have two-dimensional grapheme, maybe you can actually do an elegant experimental check. I have talked to the people at Manchester about this. But I would never have got elected to the Royal Society for what I did in physics.
A few years after I returned from Harvard to Sydney, I accidentally got interested in problems in ecology. This was very much encouraged by Harry Messel. He said, ‘If you want to do that, by all means stay in the physics department. If you want to go somewhere else, you should do it’. But Harry had been telling me for quite a few years when I came back that I ought to get into bringing physics into biology. So he was very pleased when I did. The first thing I did in ecology is one of the most important things I have done.
Charles Birch was head of biology at Sydney and a wonderful man. He was one of the founders of Social Responsibility in Science in Australia, and involved in all these “1998 things”. Also, in the Vietnam War, he was a willing source of counselling for people who wanted to not be caught up in it – in a very un-ego-gratifying way. In discovering what I was being conscience stricken and socially responsible about, I read a book by Ken Watt on “Ecology and Resource Management”. In it, was a clear articulation of an emerging theoretical notion in ecology. You have got to understand that ecology is a very young discipline. The word is only 100 years old. The oldest professional society, the British Ecological Society, is just about to celebrate its centenary. Its first half century was largely descriptive but with a little bit of theory.
At that time there was a belief articulated by one of the founding fathers of theoretical ecology, Evelyn Hutchinson at Yale. He was building on ideas by Elton and later work by Robert MacArthur at Princeton. The idea was that complicated ecosystems – ecosystems with more species and more interactions among them – would, by virtue of that complexity, be more stable. Hutchinson had formally asserted this as one of the fundamental principles. Ken Watt set that out. Then, very commonsensically, he said, ‘It’s pretty contrary to common experience’. As I read that that evening, I said, ‘Actually that’s right’. Elton gave a series of arguments. One was that mathematical models for two-species systems are characteristically unstable. I thought, ‘That’s not an argument. That’s only half an argument. Let me look at not “one predator one prey”. Let me look at “N predator N prey” ’. I immediately could see that the corresponding system would be less stable.
To cut a long story short, I proved a rather nice theorem. That is, a generalisation of a physics theorem due to Wigner. I am delighted that my name is now coupled – it is the May-Wigner theorem. He proved it for special kinds of symmetrical matrices. But I said, ‘Let’s imagine an ecosystem in which each species by itself would be stable. So, I’ll put minus one down the diagonal to say that in unit time, left alone, each species would recover from a disturbance. Now I’ll start connecting them at random and putting other elements in the matrix. I’ll put plus or minus to give predator-prey, competitors or mutualists. I’ll let them be of different strengths but, on average, some strength – let’s call it alpha’. I proved an interesting generalisation of Wigner’s theorem that said: ‘Such a system will remain stable, stabilised by the intraspecific effects, provided that the average number of species a species is connected to, times the square on the strength, is less than one. One is the normalising time to recover. Otherwise the system will collapse, if “N” is big’. That turns the whole thing on its head and resets the agenda for ecology. I was connecting at random, and ecosystems are the winnowed product of evolution and are not random. So it says: ‘In the real world we see a lot of complicated systems. What are the special, non-random structures that they have, to reconcile exploiting more niches, having more species and being more complicated, with robustness against disturbance?’ We are still working on that, although we have made a lot of progress, particularly with the experimentalists. That was the first thing I did, which was one of the most important, the centrepiece of the monograph on “Stability and complexity in model ecosystems”.
The implication of your theorem is that, if you have a very big, complex population and you reduce it, even if it’s the loss of little creatures you can’t see or elements that you don’t take any notice of, if you reduce it too much, the whole system can break down.
According to what I’m saying, you don’t know what’s going to happen! There has been a lot of subsequent work by some very able younger people too. There are interesting things going on as we speak. But yes, that is a good one sentence summary.
What was Charles Birch’s reaction to that?
When I had this insight about stability and complexity, I immediately went to Charles Birch because he was the co-author of what was then the world-leading text on ecology – Andrewartha and Birch. But he identified with the view that there is no place for mathematics in ecology – it is all about looking at nature. The wonderful thing about Charles was that I told him what I had done and he said, ‘You know that I think mathematics doesn’t have much to say about ecology, but who knows who’s right? My friend Ken Watt, whose book you’ve just read, would really love that. You write it up and send it to him and come and give a seminar in biology’. So I did all that and I had a nice letter from Ken Watt, who wrote ‘this is a milestone in ecology’.
An edited transcript of the full interview can be found here.
Lord May’s full interview is also available on the Australian Academy of Science’s YouTube channel.
The following questions involve ecology, which was Lord May’s second career focus. Some references to activities in physics are provided further below.
Students may need access to a science reference book, dictionary or the internet to answer some of these questions. In his interview Lord May speaks about his proposal for a new theorem that investigated stability and complexity in ecosystems. Professor Robyn Williams summarised it as: if we take a very big, complex population and substantially reduce it, the whole system can break down. After reading this section of his interview and/or watching it on the Academy’s YouTube Channel,
Select activities that are most appropriate for your lesson plan or add your own. These activities align with the Australian Curriculum strands ‘Science Understanding’, ‘Science as a Human Endeavour’ and ‘Science Inquiry Skills’, as well as the New South Wales syllabus stage 6 aenior science outcome 9.3.1 and stage 6 biology outcome 9.5.6. You can also encourage students to identify key issues in the preceding extract and devise their own questions or topics for discussion.
• Related interviews from the Australian Academy of Science
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