Tell us about your journey into the field of Evolutionary Biology.
As a child I was interested in being out in nature in a general way, and I remember having strong feelings towards trees. But I was never that interested in natural history, of knowing plants and animals by name (although I am now). I was more fascinated by art and history, and by fiction and drama.
This means I came to biology quite late, and I think my route into it was through watching plays and comedy, which made me think a lot about trade-offs in behaviour; especially the point where characters are guided by past experience, or by novel environments, into making bad and irreversible decisions, despite their earnest intentions. I liked the tragedy of that.
And then I read an HG Wells essay where he writes that “all history is human ecology”. And I thought – why study history in one species, when you can study the history of all of them? And where you can think about trade-offs in phenotypes and behaviours in all populations in nature, and how history has shaped their present and will shape their future. And - that’s basically evolutionary biology in a nutshell.
I also remember being really affected by a Rebecca Horn exhibition I went to as a teenager - she had appendages that extended some parts of her body – like on her fingers, or around her face - at the expense of other things, like mobility, or precision. Soon after that I started reading about adaptive radiations of birds on oceanic islands like Hawaii (where I ended up studying as a graduate),and the trade-offs involved the evolution of beaks to specialise on different flowers, insects, or seeds. And that exhibition came back to me in a flash.
Another reason I choose to study biology – and evolutionary biology in particular - was because biologists seemed very interesting people; humane, engaged with the world, and appreciative of different ways of being and living. And they wanted the world to become larger through their study of it. It takes imagination and empathy to start to see the world from the perspective of a plant, or a fungus, or a coral.
What are your main projects as Director of CBER?
As Director of CBER, my role is to advocate for our fundamental research into biodiversity, and why and how it matters for the resilience and stability of ecosystems at all levels of organisation, from genes to cells to individuals and ecosystems. And to continually highlight how all human economies are fundamentally dependent on biodiversity, although most economic theory assumes these services are provided without cost, and can be exploited without limit.
On a practical level, this means raising the profile of the biodiversity crisis, which is discussed far less than the climate crisis, even thought it would remain a planetary emergency even if climate change stopped tomorrow. Also, it’s important to remember that –the rapid biodiversity loss of the past 100 years has not been caused by climate change but largely by land use change (mainly deforestation for animal farming) due to human overconsumption.
The second thing to stress is that the biodiversity and climate crises are closely interlinked - and must be considered together to shape the solutions we need. Climate stability depends on biodiversity, and with less biodiversity, climate impacts on human health, livelihoods and social justice will be much greater – causing more conflict, disease and societal collapse in the decades to come.
In CBER we’re also acutely aware that biodiversity loss us caused by, and causes great social injustice, and the marginalisation of the world’s poor. The fact that in our current economy, the world’s poor, as well as our own children and grandchildren are paying for a small proportion of people to profit from destroying the environment, while being supported by large subsidies to do so. And this loss of nature means the irrevocable loss of the products of billions of years of evolution on this planet..
What area of your work most excites you and why?
I’m really excited by the prospect of using population genomics, combined with laboratory and field experiments to understand how genotypes make phenotypes, and their effects on fitness in natural populations, to predict limits to rates of adaptation to global change. And on a longer time scale, such constraints to adaptation within populations are what lead to the formation of new species, and biodiversity itself.
On a day to day level - it’s the conversations that I get to be part of -when something you thought you understood suddenly becomes more complex and beautiful - that excite me – the level of curiosity and enthusiasm that scientists have, and the desire to continually re-examine the familiar and whether or not we really understand something. I find that thrilling. I also love being at UCL, where people feel they have the potential to make a difference, and that universities - and the nuance, rationality, and complexity that they defend - matter.
Which bit of research are you most proud of and why?
I’m always most proud of the research we’re doing now – for example our research on the slopes of Mount Etna, where we’re transplanting thousands of cuttings of plants of known genotypes within and beyond their familiar habitats, and testing the capacity for their behaviour (as measured by changes in gene expression) and their leaf morphology to evolve to these new conditions, and the consequences of such changes for fitness. One important finding of this work is that populations already harbour genetic variation that could allow the rapid evolution of new forms of plasticity. However – initially at least – this involves making smaller changes in leaf morphology, probably because committing to hasty, irreversible decisions is a bad strategy for genotypes when in environments that they’re not familiar with.
How likely are evolutionary responses because of the biodiversity and climate crisis?
Well – evolutionary responses are more likely to occur when there is more biodiversity within populations; where populations can grow quickly; and when selective pressures are persistent and strong (but not too strong). Much of the theoretical foundations for these predictions were made at UCL in the 1930s. However, testing these predictions demands measurement of difficult and quite transient parameters in natural populations.
That said, we know that rapid evolution will be necessary for many populations and species, given biodiversity loss and climate change is pushing them into environmental regimes and communities beyond what they’ve ever experienced before. These novel climates and interactions with other organisms will demand the evolution of new phenotypes, and forms of behaviour. We need to understand how quickly such evolution can happen, how much it will restore the fitness of genotypes, and whether adaptation will depend on existing rather than novel genetic diversity.
Do you have a favourite species of butterfly?
The Brown Argus butterfly – Aricia agestis – is wonderful, small but beautifully formed, and the mothers have a lovely looping way of flying when looking for places to lay their eggs. This becomes a darting, fast and straight flight as soon as they’re disturbed. Their caterpillars are beautiful too, especially in their early instars.
What’s also amazing is that we know so much about the life history of UK butterflies - how and where they overwinter, on which plants mothers lay their eggs, how the decisions they make as larvae affect their adult behaviour. In fact, we’re doing really interesting research to identify the genes associated with maternal preference for host plants, how these preferences are evolving with climate change, and how this affects caterpillars’ fitness under novel thermal conditions.
That said, every organism I’ve ever studied has shown more and more of its beauty the more you come to know it. That’s the amazing thing about nature – there are no surfaces, and no apparent limits to the complexity and nuance that is revealed with each continued study.
What’s your next big challenge in terms of your research?
We’ve started working a lot recently on how genotypes make different phenotypes across tissues and across life stages – especially in plants and in butterflies. So, my challenge now is to learn more about development, and the constraints acting on genes that need to be expressed across many tissues as well as at different times in a genotype’s lifetime. This seems to me a key constraint in multicellular organisms like us, that are composed of 30 trillion cells at any one time.
Understanding and predicting evolution – and its limits - is difficult. However, our ability to use genomics to explore adaptive responses has advanced hugely in the past decades. It’s something like we’re astronomers in 17th century Florence, and we’ve just discovered the telescope.
Understanding how population genetics intersects with ecology is another key challenge, in order to predict when mutations can spread in populations, to cause evolution by natural selection, and for populations and communities to persist in response to environmental change.
Key questions for me are: what makes the difference between success or failure of a given mutation, and how much of this is chance, and how much can be predicted? Do mutations need to spread based on their own contributions, or in combination with others? What does this tell us about the kinds of populations where evolution will occur most easily and quickly? I find much drama and tragedy in this – just as I do in the fiction and plays that I started to read when I was a teenager.