 I'm John Bridle, and I'm a biologist in the School of Biological Sciences at the University of Bristol. My research is mostly about understanding how organisms evolve in response to environmental change and how quickly they can do that. Climate change is having big effects on biodiversity. It's causing losses of biodiversity at precisely the time when we need the biodiversity to allow us to support a growing population. And the big problem is climate change is affecting the people that depend most directly on biodiversity because they're the poor of this planet. And those people are not being massively affected by climate change and we're buffered from it in the more sort of wealthy parts of the world. So from my point of view I think the big interesting thing is how there's now been a connection between development and biodiversity. Protecting biodiversity is essential for development, essential for social justice and poverty alleviation and that connection wasn't really made before. People thought that protecting biodiversity was like an alternative to development. But it's not the environment or development. The environment is the economy. It's what makes development possible. I think that's the big message that biodiversity is not like protecting some pandas so we can go and look at them. It's about protecting the systems that actually we depend on. I mean it's not as if life's going to end because of climate change but human life is going to become a lot harder. A lot of species are going to go with us and the poor of this planet and our grandchildren. So the unborn generations who don't have any say in how we govern the planet now are definitely going to have a much more impoverished life because of the actions of the last 50 hundred years. I think from the climate change point of view it's like how could you think that you were going to burn billions of years worth or accumulated carbon from a period when the earth was incredibly productive during the carbon if it was high temperatures, lots of rain. How could you think you'd burn or release that into the atmosphere over such a short period and it wouldn't affect the climate? I mean I don't think the onus from us should be to prove that climate change is happening. It's like releasing all that fossilised carbon into the atmosphere and something that's already at such a low abundance in the atmosphere increasing its doubling or increasing its abundance but it's already very rare. It seems to be a very dangerous thing to do. So I don't see how people could think that we wouldn't affect the climate in some way and we've got all the evidence that we are affecting the climate. The issue that I'm interested in is how those changes that are projected are going to affect the systems we depend on for our food and for our wellbeing and that's biological systems. I think it's important that we're mostly dealing initially with climate scientists in terms of understanding what the likely rates of change are going to be, the average changes across years in temperature and how that's being forced by greenhouse emissions. So understanding the mechanism by which the climate is changing is very important. But even if we have a great deal of certainty of exactly how much the temperatures can like to change in the next 50 years the upper and lower bounds of that, we still know remarkably little about how those changes are going to affect populations of organisms and communities and ecosystems. And I think although the idea of tsunamis and storms and floods looms very large in the public imagination, most people's experience of climate change is going to be by the way it affects food security, the way it affects ecosystems and organisms. And we know that organisms face environmental changes all the time. We know that they're dealing with the environment changing on a daily basis, on a weekly basis. The issue is how much climate change is going to take that beyond the bounds that they're used to experiencing. I mean, especially in season environments, organisms deal with wintertime and summertime and they have all kinds of interesting adaptations to cope with that. But what's happening with climate change is the extremes are increasing. We're getting more variable climates and less predictable climates. But I think what we really miss in terms of predicting how organisms will respond to climate change is how that's going to affect the types of outputs we rely on for our human economies, like farming, for food security, predicting when diseases are going to emerge, the emergence of diseases, the spread of diseases through invasions. We really need to understand the biology. And the difficulty there is that organisms experience the environment in a very local way. They experience it across metres, not hundreds of metres, and across hours and minutes. And they can change their behaviour to change how they experience the environment. They can choose where they lay their egg, so they can choose when they go into diopause. So they have a certain amount of plasticity to cope with the environmental change they're facing. But the issue is that the environment is changing in a much less predictable way from their point of view. These cues they were using are becoming no longer reliable cues that tell them when they should emerge to synchronise with other organisms or when they're going to be free from frost. So the persistence of organisms in most parts of the world depends on them being able to cope with environmental variation. But climate change is changing the way that variation is being experienced. And we know very little about how organisms experience that just as individuals, but on top of that you have the idea of genetic variation. The organisms actually differ in how they deal with the environment and that gives you the capacity for them to actually evolve in response to change. That's the main issue that my research really addresses is trying to understand what limits populations' responses to environmental variation. So I think one of the issues that we think about species as single units and this is why perhaps we've lost or missed this evolutionary aspect of responses to climate change. We know that organisms are distributed in space have limits to where they're found. That's determined by their niche, what they can cope with. But we don't know how much they vary across their range as individual populations. They've been responding historically to changes. What happens in Canada is different to what happens in Latin America. It could have the same species with a very broad distribution. But those populations can be very different in the niches they inhabit. So that in itself is testament to the fact that organisms have responded to environmental change across their distribution. They often have clines, they often have changes in characters which tell us that they can respond to some change. But what really fascinates me as a scientist is why at the edge of their distribution do they stop adapting. We know that over longer timescales organisms have been able to go into, I mean mammals return to the ocean several times and we colonize the oceans, became completely marine. So clearly these niche barriers can be overcome given enough time. But probably that happens only very rarely. So I'm really interested in what are the factors that limit how fast organisms can respond to change. They have this plastic variability so they have an ability to kind of use the environment in different ways. They respond to cues and they vary in the way they respond to cues. And that kind of plasticity gives you a resilience just without necessarily evolving. But also those cues can evolve. How you use the environment, how you respond to the environment can evolve as well. And we're really interested in understanding if the environment changes too fast, whether populations are not able to keep up with to track that changing environment sufficiently fast before their population declines. So this is a concept that's called evolutionary rescue. It's an idea that when a population is in an environment and the environment changes suddenly, under what conditions can it evolve, change the gene frequencies in its population to allow it to match that new optimum and thereby continue to grow and continue to be sustained. And fundamental to that idea is the idea that when the population experiences a new environment its growth rate declines because it's far from the optimum so many organisms are unable to grow as quickly or reproduce as quickly as they were before. So this feedback between your distance from the optimum of the population and your growth rate is really what determines the limit to evolution. It's the way that your growth rate declines as the environment changes and how much genetic change is needed to allow you to get to that new optimum. Because that genetic change, the time it takes for that to happen, that's all the time when the population is suffering reduced size. And that reduced size feeds back and reduces the genetic variation. So it actually makes it even harder for it to evolve. So it's a kind of like a, if you don't evolve quickly while the population size is still large and the population declines then you're losing variation to allow you to continue to adapt. So it's kind of like a bit of a sort of positive feedback. The rescue has to happen fairly early on we think. So we have very good theoretical models for the situations under which evolution can occur, the sort of maximum sustainable rate of adaptation. We look at populations and how they're distributed now and tell us all in the past what have they been able to respond to, how much they vary across their range and their niche which tells us the kind of range that they can clearly evolve into these new niches. But we don't know a lot of these key parameters like the growth rate, the amount of how strong selection is in the field, how it varies with the varying environment. We don't have good estimates in the real world of those things because actually they're quite hard to measure. But we don't even know very much about how much genetic variation there is within populations or between populations which is the fundamental engine that allows organisms to evolve. Without genetic variation, variation in reproductive success, there's no evolution. Evolution stops. So we need to understand more about how genetic variation is distributed across populations and within populations or across families essentially. And we also need to know how changing in one direction so evolving one type of morphology or one type of response may limit your ability to respond in another way. And this comes into this idea of trade-offs which is the idea that you can't be everything at once. And fundamentally that's why organisms are diverse, why they've gone into different niches and proliferated into the biodiversity that we see is because one species can't do everything. So they evolve a larger body size. It means they have a longer gestation time and they can't reproduce as quickly. So you have these kind of trade-offs that are involved throughout history. By understanding those trade-offs we can maybe start to understand more about what limits organisms are responding to environmental change. And we've actually got an incredible new ways of doing that now with next generation sequencing, a sort of genomics revolution has allowed us to study organisms in the wild and actually look at how the genetic basis of the variation that affects their fitness in natural populations and there's been some fantastic studies that have been done on that. Really from a biological point of view it's like we've just discovered the telescope like in the 16th century, you know. So we are now able to do things in a few weeks that previously would have taken several years. And so the ability to actually address these really quite difficult questions is now with us in terms of genomics but we need more and more studies in the field to actually tell us how what's really limiting organisms range. The degree to which their responses to the environment are affected by extremes in particular is a key issue. Like we know they respond in space but the experience environment in a very local, very temporally changing way that changes over time and what climate change is doing is it's increasing the probability of extreme events. So not only is the mean changing and the mean changing actually doesn't seem that much a few degrees but the probability of extreme 15 degree differences is becoming much more frequent. And what interests me is how do organisms evolve to things that they've never experienced before unless it once in the last sort of 5,000 years, that kind of temperature of that kind of event. How can they possibly have evolved with the ability to be resilient to that change? Yes, yes. I should say first of all that I think the focus on returning back to what I was saying before about climate scientists I think the focus on demonstrating there's been a temperature change and the surface temperature change or oceanic temperature change is all fine. We can look at biological organisms and see them responding to climate change. What we see actually when we look across thousands of species is their ranges of all shifting polewoods. So in the southern hemisphere they're shifting towards Antarctica and in the northern hemisphere they're shifting towards the Arctic. And they're becoming extinct to their southern margins in the northern hemisphere and shifting northwards. And that's a clear ecological response to climate change. Organisms are moving into habitats that are now becoming sysfal for them at the northern edge of their range in Europe and they're declining on moving up onto mountain tops and parts of their range. And that's something that we work on in butterflies because we know a lot about butterfly's ecology and about the habitats that they use, the interactions they have with other species and also about their historical distribution. So a lot of work has been done on butterflies in this area. So we know there are definitely across, there's a signature, a very strong signature across the globe of organisms responding to climate change by shifting. So there's definitely something going on. It's unequivocal. I don't have a meteor biologist who doesn't believe in changing. The question is how fast and how much is that average change interacting with changes on a very local scale. And that's something that takes a lot of work to understand because organisms are complex, they have individual behaviour that varies. Our butterflies, for example, that we work on are UK species of butterfly, the brown argus. And that's a butterfly that can change where it lays its eggs. And actually butterflies in general, if they choose to lay their eggs five centimetres off the ground, the eggs are going to experience a much lower temperature if they lay them on the ground. So five or six degrees difference on average. And that's work that's been done in the States on a checker spot butterfly. And that shows like an incredible ability of organisms to choose by the maternal behaviour to affect the microclimate that they're offspring are going to grow in. And knowing that on average across this latitude of the US, there's going to be a change of two degrees centigrade, doesn't tell you what the individual organisms are going to do on the ground. So there are definitely strong signatures of ecological responses. So organisms are shifting their ranges. For many of those organisms, we don't know if they're actually changing their habitat requirements or they're actually changing their niches, which is what evolution would do. It would change what their tolerances are. We can actually say that a lot of them are doing pretty much what they're moving to areas that would have been habitable before. So they're moving into areas which are just the same areas they were previously living in, do you see what I mean? So they haven't changed their niche. They're just passively, not passively, but they're tracking the change. But the general pattern that we see is actually that most generalist species are able to do that. So species that have large population sizes that don't have specific requirements for other species, don't have particular interactions with other species that they exploit. So in butterflies, some species are pretty generalist about the host plants that they use for their larvae to grow on. And others are a bit more specialised. They need certain types of habitat where these particular plants grow. And those organisms with very particular habitat types that they require tend to be not expanding their ranges or not shifting their ranges. And that seems to be because they're very limited by habitat availability. So you have this kind of double whammy of like the anthropogenic change of the environment causing things to have to move. But habitat loss on a local scale restricting their ability to shift their ranges. So most specialist species of butterfly actually declining, about 75% of specialist species, are declining. They're becoming increasingly trapped in sort of fragmented locally cool places rather than expanding their ranges into areas that are now suitable for them further north. And the butterfly species that we work on, the Brown Argus, is in a very interesting example because it seems to have shifted its range northward despite having particular habitat requirements. So in most of its range in the south that uses a host plant called rockrose, which is a Cystaceae family of plants. It's quite different. It's quite a particular plant that grows on short downland. But it's a specialist species in a way in that it uses mostly this host plant. And yet it has been able to shift its range northwards in Britain. It seems to have been able to do that by actually evolving to specialise on a different host in the new part of the range and so use that on geronaceae species like geranium, which are found in very different types of habitat, have a very different type of microclimate, we think, and a very different type of growth form, a very different family of plant. And yet it seems to have had an evolutionary response very quickly that's allowed it to colonise this new area. So that's one example. I mean there are lots of examples of changes in organisms but it's often quite difficult to distinguish those changes that you see in the field from just plastic changes and the idea they've just evolved to use the environment slightly differently, they haven't actually evolved. So there are lots of examples in mammals where they've shifted their range. But knowing the degree to which evolution is responsible for allowing that change to happen or conversely the degree to which evolution means they don't have to shift their ranges as much. Maybe they can just move half as far because they can evolve to cope with a warmer temperature. So when species are lagging behind and not tracking the environment exactly, is that because they've evolved locally? Often we just don't know. So there's a big knowledge gap in understanding the way that evolution allows resilience in terms of allowing populations to respond to climate change and rescuing them from just contracting and becoming trapped in local places. So it's a huge area that we don't really... Now that we have the genomic tools it's going to become a lot easier to demonstrate that evolution has actually happened. But just looking in the field and saying they're now here and they were there, things like mammals and birds, it's hard to bring them into the laboratory and rear them and show that they've genetically changed in these traits. And often the changes are things like changes in the way they react to the environment. So they're not... They're like changes in the genes that underlie the plasticity, which is much harder to detect when you put them in the lab. You have to test them under a whole range of conditions rather than just one particular condition and show that they're different. But pretty much whenever we bring organisms into the lab and rear them, we find that they do have all-genetic differences in most traits and certainly a lot of capacity to evolve in many traits. The thing that we don't really understand is how those traits correlate with each other and how that might limit their ability to adapt. The issue about whether or not the organism is going to be able to track the environment sufficiently fast I think in many cases they won't be able to. And we know for example that some tree species are still increasing their range in response to glacial changes, post-glacial expansions. Some tree species are moving quite slowly. Others are already where you'd expect them to be given the existing environment. But it's hard often to know exactly what's limiting a species in a particular place. It could be like every ten years there's a frost and that stops the sapling, kills all the saplings or often it's these extreme events that limit species ranges. But I think certainly the rate of, for many organisms, the rate of environmental change is going to be too fast. Again, we're slightly hampered in understanding that fully because we don't know how much it's going to change on a local scale. Organisms may well persist in places just because they're able to use moist microclimates or shaded. They might move to north-facing slopes or the south-facing slopes. So this comes back to the side of needing to understand this very local way that the environment is changing. Certainly, as I say in butterflies, 75% of the species we define as specialists, they have particular species they depend on, their ranges haven't tracked, they haven't responded to climate change. And that's basically what we're seeing across most species that have particular species they need to interact with because those species have to expand as well. And often those species, like if their plants might be limited by a soil type or by some other feature of the environment, not by temperature. And that will mean that unless they shift their niches to use different plants, they won't be able to actually persist in that place. I mean, there was a famous study done in 2005 by Chris Thomas, which caused a lot of discussion, where he modelled a species as a sort of single unit. Like I was talking about before, the problem is we assume that species have got the same niche everywhere. But let's assume that the species has basically got the same niche everywhere, which is basically quite conservative if you're saying actually giving it a lot of latitude to evolve because you're saying, well, every population has all the genes it needs to move, has all the tolerance necessary to move to anywhere in 50 years' time where there's going to be a habitat that can currently inhabit. If that habitat exists anywhere on the globe, then it can be there. So you assume there's no limitation in how fast they can move or their dispersal, there's no fragmentation, there's no oceans in the way. He basically suggested that 10% of species of which we had good estimates would go extinct even if they could get anywhere they wanted to be. Simply because those habitats would no longer exist. So without evolutionary change, 10% would be condemned to extinction. If you allow there to be some limitation in the rates of movement, that estimate goes up to about 35% of species within this century. There's a lot of assumptions in those models and they've been questioned a lot recently. They pertain to particular types of organisms and other people have challenged that paper based on looking at vegetation analyses and other types of organisms that may not have that particular limit. But certainly the best available information we had in 2004 suggested that we were looking at between 25% and 35% extinction if you allow some dispersal limitation. So if you allow that they can't get north of Scotland, they can't get up into further places in Scandinavia where there might be suitable habitats. But even if you assume there's no limits to dispersal, you still have all those 10% of species having nowhere where they can still live because of climate change. I worked a lot previously on understanding what happened post-glacially, so understanding what the consequences of glaciation were for species distributions. The issue with doing those analyses is firstly it's hard to see the things that didn't make it. So you've got a big ascertainment bias and you don't always underestimate the amount of extinction that went on in the past. You're also looking at species as single units, again, you're not really seeing. The idea of focusing on species extinction is a natural thing to do but it really understates what's really happening. In terms of understanding how ecosystems work, what really matters is the way that populations decline and communities change in their composition because species might still be found in the centre of its range but if it's contracting in all these peripheral areas, it's basically essentially locally extinct. That means it's no longer part of the ecological network. Those are much more serious in terms of ecological outputs than worrying about whether one species is still present somewhere on the planet or not. By the time a species is just found in one population, you've lost all that intra-specific genetic variation that's probably important for adapting or certainly important for adapting to change. So you're losing your capital in the sense of your ability to respond to change. But I think using species' extinctions is a really poor currency for understanding the effects of climate change and biodiversity, all the effects of habitat loss and biodiversity. But we can look at what happened in the past where mass extinctions happened because of rapid climate change or because of habitat loss. And I think what we generally see, I mean I'm no expert in this, but I think we generally see as similar types of organisms go extinct as those organisms which we now see on red lists that are very critically endangered. There's a lot of fantastic work being done by people like Georgina Mace looking at correlates of extinction risk in existing mammals and other people comparing it to past extinctions and other mammals. And you can see the same traits come up. If you've got a long gestation time, if you've got a large body size, if you're specialised in a particular type of diet, then you tend to go extinct much more quickly. Definitely carnivores. Organisms that depend on top of food webs, if you like, or at higher trophic levels tend to be more endangered. I mean there are some exceptions to the red list in terms of organisms which we should be really congratulating ourselves we've managed to make endangered, like cod. I mean cod have a huge rate of increase. They're one of the real outlaws. They don't have the life history of an endangered organism, but they are endangered because of the massive huge amount of pressure that humans have basically put on them. So it's often quite hard to actually, like in looking at what's happened in the past, it's actually quite hard to look at correlates of extinction now because we've actually already lost a lot of the species that were already vulnerable. So there's a big filter. So we're actually looking at an ascertainment bias where we just see the species now that probably are fairly resilient. In the sense that we're not perceiving the organisms which, so there were previous organisms that went extinct thousands of years ago or hundreds of years ago which we aren't included in our studies now. We can't study them, we can't include them. And that's also presumably true when we look at what happened in the past as well. The fossil record only records widely distributed species going extinct. Species that are highly localised and show particular interactions. I mean they are much harder to find evidence for and they've probably already gone. I guess it's like, in a way that ascertainment bias means that the rates of biodiversity lost are going to go down eventually because you'll lose the easy things that go first. It's like being burgled several times. The first time you lose your computers and your iPhone or the next time it's other stuff and by the time they've been there you've had three rounds of extinction you're only seeing the things that nobody wants, the things that are very hard to get rid of or hard to move. I mean the UN Millennium Assessment and the Millennium Goals is to reduce the rate of biodiversity loss but eventually it will be reduced. And ecosystems that have been highly degraded you find extinction rates go down because you lose the vulnerable species very quickly. People often say to me, well extinction there's what five mammals gone extinct or something like that. But really in terms of the, it's about what we're trying to conserve and what we're interested in and we're interested in the effects basically we're interested in climate sensitivity which is the degree to which a certain change in the environment is going to affect the way an ecosystem functions what it outputs in terms of things like water and rainfall and soil decomposition or pollination these kind of things that people try and put an economic value on and that involves understanding how communities are going to change. Now communities of organisms interacting it matters if that species is present at that point in space. Now if the population has gone extinct in that particular part of its range then that species is no longer existing in that community no longer performing that role. So species this is why it's really important to look at species that are actually quite common and actually quite widely distributed and then say well actually they're declining at a very fast rate and they're becoming much less common in particular places the chance of finding it if you go to this bit of habitat is much less common much less likely to find it now. I think one of the issues has been that biologists have kind of painted themselves in a corner a little bit because they argued for protecting very rare species like you know and then people said well these species look you know there's no way they're going to be protected look at tigers or pandas look at the amount of money that has to go into protecting those and you have to argue for their protection for a very ethical point of view and say well they've got a right to exist look at these beautiful animals or plants or whatever but by the time a species is really endangered it's only found in a couple of places that it can't really be participating in the ecosystems as a whole their value in terms of what they contribute to life and how the life depends on them because in most parts of their range their former range they're not there so they're not part of the communities of interacting organisms which is what is basically biodiversity it's this kind of you know you go into a rainforest and basically it's full of these organisms interacting and that's lost with population extinction is what matters for that situation and also if a population goes from being distributed across a lot of habitats and each population is adapted locally to that environment it's got a lot of genetic variation it's got a lot of genes that are present in some parts of the range that aren't present elsewhere the population shrinks down to a single remnant couple of populations you've lost to those unique adaptations across the range which are the testament of the history of evolutionary change over the last hundreds or thousands of years so it's that currency it's that genetic variation within the species that's going to allow us to allow those populations to persist where they are to actually still continue to engage in ecosystems without genetic variation there's no evolution so there's no capacity to evolve and what we're doing at the moment is we're reducing biodiversity at just the point where we need it to adapt we're forcing it with massive you know overconsumption and massive increases in population in the globe we're also huge rates of habitat loss as well as climate change so we're destroying the very capital that's actually going to allow us to adapt and actually have these ecosystems continuing to operate in the future so from the point of view of climate sensitivity I mean climate scientists are generating these fantastic estimates of exactly how the variation how much the environment's going to change but determining to what extent that's going to be catastrophic and over what timescale depends on knowing how allisms will react and that's really a very different question I mean how close are we to tipping points do the tipping points even exist and how do they vary on a local or a global scale how do they vary across ecosystems or in the marine environment versus the terrestrial environment these are all questions that only biologists can really address and a key part of that which we've been missing is the degree to which you can't assume a species has the same niche across its whole range it actually has the capacity to adapt and use the planet differently or use the environment differently and have different tolerances this idea of problematic interactions how species interactions are affected by climate change that's a really key issue that is hard because the world is complicated one of the things we really value about biodiversity is these interactions between species it's not just this species that looks like this and lives here it's actually the interactions it has with all the other things it interacts with in its lifetime and those things particularly in seasoned environments they depend on allisms synchronising their emergencies sometimes times or their behaviours with each other and often there's conflicts there because often that's natural and often like a plant is trying to prevent a butterfly laying its eggs on it and its larvae growing on its leaves so there's like a bit of an arms race between the two where one's trying to emerge particularly in the tropics you see the plants are trying to have their big growth of their leaves at a time when the insects aren't around and the insects are trying to match so they're trying to be around so they can produce a lot of young just at that time but it's rapid increase in biomass in the leaves and that it always uses kind of these environmental cues which is incredibly fantastic amazing things that organisms do to match so they can survive winters, they know when to go and they use environmental cues to decide when to go into diopause, when to hibernate and then when to emerge and the difficulty is with climate change those cues are no longer as coordinated as they were, they're no longer as useful so for example the temperature and the photo period so the day length is no longer has the same correlation that it used to have it has a different correlation and this means organisms may start to make mistakes and more and so not only for their own survival they have to actually come out at the right time to actually exploit their resources they have to emerge, they pollinators have to emerge at the same time as the flowers otherwise the flowers don't get pollinated and the insects don't get fed and that's a mutualistic interaction where both organisms actually have to share the need to be pollinated and to be fed but if you have a parasitic interaction or a herbivory type interaction where once a bird timing when they lay their eggs for their chicks to emerge for a time when they're a larvae around and caterpillars around that they can eat or insects around that they can eat so if these different organisms in different trophic levels use different cues which they do and previously that actually was fairly reliable then that becomes a real problem because you get them emerging at different times you're getting this thing called trophic mismatch which people have been working on very nice systems in great tits looking at a moth species they're trying to track the bud burst of the trees so they can grow their larvae and the great tits are timing with their clutches when they lay their eggs so that their chicks have got and they can feed their chicks for these larvae and those things are becoming desynchronised because they're evolving at different rates or reacting in different ways to the environment actually there are quite nice examples of humans using cues like when other animals do things to actually decide when to do things like planting rice in some traditional Chinese communities they use the arrival of birds beginning when birds start to nest it's a cue that's when we should start planting our rice because the birds have got a good sense of when it's going to be raining when it's going to be productive when the storms are going to finish so there's all these organisms using cues from each other and using cues to allow them to persist in places where the environment is sometimes harsh and those cues are all basically being they're changing and we don't know for how much organisms are going to be able to evolve in their way that they use the environment to actually cope with those changes and they're increasingly unpredictable nature of the environment these seasonal changes are periodic you can predict that it's going to be and maybe the first time having a first frost is a good indicator of when to flower but in the future it might not be like that and that's a real issue I think that we don't really understand well I was always fascinated by evolution when I was a child I've always been really interested in trade-offs actually and very interested in actually how behaviours evolve as well so behavioural ecology when I was a university kind of this idea that you're trying to optimise your decisions that you make and if you make this decision it compromises your ability to make another decision don't mean to think more generally about why this general question about I mean why do species have specialised niches why are species only found in one place and not in another place you know why in the past did you not just have one species that just does everything why do species evolve and acquire certain phenotypes and ways of doing things as they stop them doing other things we know evolution can achieve a lot but why are species limited in there in their distributions but I think the reason I got into what I'm doing now is really a lot of it was driven by by conservation and by being really quite shocked by the scale of biodiversity loss which I think is interesting because I think that's actually been downplayed in the media because there's been so much focus on addressing climate change denial and this idea of is climate change happening or not and if it is happening which obviously it is but if it is happening on a large enough scale to actually cause catastrophic change or not that's been a real focus of scientific research and rightly so but we know that habitats have been lost we know that biodiversity is declining in an alarming way and I think that kind of idea of the biological effects of human exploitation and human population growth, human overconsumption has been slightly lost in the story partly because people focus on species extinctions and not on the declines in abundance of species across their range and the interactions that are changing and partly because I think people don't value the nature as the thing that makes everything as possible the fact that the environment is the economy it's the thing that we all get everything from life is what we depend on and that life is being massively stressed we're losing biodiversity besides the time we need it the most and so I think I was really upset, anxious about that when I was a teenager and I studied biology because of that and I was also really fascinated by evolution and now it's really exciting that evolution is actually one of the key things that might or might not allow resilience to things like environmental change and it has done in the past and we need to understand how much it can temper those critical tipping points that we can predict or we can try to predict based on rates of climate change but really I mean I go into it because I find it absolutely fascinating really I'm a population geneticist so I try and understand how populations really how they respond to change how they're able to track a changing environment I was at a party actually and somebody asked me why I chose to study it was an astrophysicist and she said to me why are you choosing to study something that's so localised it's only found on one planet as far as we know and it's only existed for a very short period of time because I was thinking well I studied life it's an amazing thing to study because we're on this planet we might as well study life while we're here and she was like yeah it's a very localised phenomenon let's hope it doesn't stay it doesn't become more localised I mean I do do a lot of interacting with the public about these things and actually generally I think people are generally very concerned especially younger people, especially children something seems to happen to people when they get into their late teens early twenties someone seems to come back again in their thirties and especially when they become grandparents and they can sort of see the length of their grandchildren are going to be alive in 70 years time but there seems to be I think there's a period when the consumer culture gets people and they sort of trade this culture of disappointment driving their expectations so they seem to when you meet children who are like 7 or 8 up to about 13 they're really worried about the environment so I think there is already a great worry about it I think one of the problems that scientists have done is they present nightmares they basically make people afraid I mean people have often said Martin Luther King didn't say I have a nightmare he said I have a dream so it's aspirational and people really feel powerless so I think one thing scientists can do is say well look we know that this is a big challenge we know the planet is facing big consequences of what humans are doing but there is ways that we can improve things there's ways that we can reduce the impact I think scientists are fighting like a big well scientists, rationalists generally are fighting kind of like an industry that's basically trying to convince everyone that everything's fine we should just care on as we are and that's got a lot of money behind it and actually but I think the thing is it's not making us happy these things that we're doing it's consumption that we're doing I don't think they're happy happier than they were because of the consumption that they're doing someone said we're borrowing money we can't afford to buy things we don't need to impress people we don't care about but that machine is driving us to do that so I think what scientists can do especially biologists is to make people aware of how amazing how wonderful things are and communicate the reason we study these things because we're absolutely fascinated by them and I think actually why I spend a lot of time trying to communicate to people as a scientist is that we're driven by doubt we ask, I mean we're skeptics we question everything and I think we get we have to get across to the public the idea that scientists ask questions they don't come up with facts and dry sort of proof scientists are about asking questions and questioning everything and having doubt and every question it needs to be answered scientists are not ever certain of anything and I think the unfortunate thing is that lack of certainty which is what allows science to continue is sort of pounced on by people saying well this means they don't even know there's no consensus we know that to get 97% or a very large number of scientists agreeing on something is an incredibly rare thing to happen I think the real tragedy is that people are missing out on so much by not having this kind of approach to things actually thinking that science is about just dotting eyes and crossing teeth and proving things with a big stamp rather than actually sort of engaging with the world and trying to see beauty in it by understanding it more I think in this country particularly the media don't serve the public very well in terms of science I think they underestimate, I talk to people admittedly people who come to science fairs and things like that and come to the public engagement events we do here I talk to them about science a lot and I'm always incredibly impressed by how much they know the difficulty of course is they're the people that come to us if you go out and pick people around in the street it might not be the same story and I think with biodiversity it's a particular if you ask people in the street what biodiversity is most people don't know so I think we've really failed a scientist to get across you know that life is basically the thing that makes that everything is within it's the thing that makes everything possible like if I tell people that only one in ten of the cells in your body is actually human I mean the people are like shocked by that and that telling you that we are actually ecosystems ourselves we carry around tens of millions of organisms within us they're interacting in this ecosystem that we're just a platform for and people think well I'm me most of the cells in your body are not you at all so who are you and people get their mind swept by that maybe I'll show you this as well this is from a recent textbook on evolution which came out a few years ago it illustrates how much genetics has told us about the true of life and the history of life on this planet that we didn't know before and this is basically a tree based on neutral markers based on molecular markers which tells us about the evolutionary history of the planet and this point here is the what we think is the last universal common ancestor about five billion years ago and what this tells us first of all is that Darwin was absolutely right all life on this planet all existing life on this planet is related to a group of ancestors or a single ancestor five billion years ago and it also tells us there's a lot of biodiversity we know very little about this is biodiversity in bacteria these are all the eukaryotes all the forms of life that are multi-cellular most of them and these are the archaea and these are the bacteria these are three big kingdoms of life and what I usually do with the first years in one of their first lectures is point this up and ask them to put their hand up when they've seen where the animals are on this tree if you look on this tree very carefully here so this twig here of a tree of life this is basically all the animals that's not just all the mammals and birds that's also all the coral reefs and worms and all the mollusks and all the insects so you can see there's actually most biodiversity is not animal it's actually this sort of biodiversity we might find a handful of soil some of these things just a handful of soil, a world and a grain of sand so to speak actually we didn't know that there was this much diversity in soil in bacteria we'd try and grow from a load of soil we'd try and grow it on some agar and it wouldn't grow because it depends on quite complicated species interactions so these forms of life we can only find them when we actually sequence all the soil and find all the different lineages that exist in it and so we find a lot of evolutionary history we've actually nothing about it we focus so much in the last few thousand years on these animals here there's land plants here and you see they're flanked by algae what we call green algae two types of green algae though really divergent and red algae these are like kind of seaweeds but they're incredibly divergent fungi are here so these are all the fungi all the mushrooms they're quite closely related to animals but there's all this biodiversity that we know very little about and genetics is teaching us a huge amount about where the real evolutionary history is on the planet these small things that run the world especially in democratic systems is the public need to realise that they can actually do something and they can actually change how they spend their money or how they vote is actually going to have a huge effect convincing the government that these issues really matter and they matter for our children and for our grandchildren is really important so people, I think the most important thing is to make people not feel powerless I mean the environment has slipped off the agenda you know in politics certainly in UK politics maybe I shouldn't talk about this government in any detail you know DEFRA the people that are responsible for the sustainability of the ecosystems that we depend on they're basically the treasury they are the wealth of the planet the problem is we don't value that that wealth we value sort of financial wealth more imports and exports not the actual thing that makes that stuff possible