Focus 580; The Evolution Explosion: How Humans Cause Rapid Environmental Change

We're going to talking about evolution in this part of focus on Ivy and it is the case I think that most people when they think about evolution they think about a process that is very slow and takes a very long time. Something on the order of millions of years. This morning our guest Stephen Palumbi He's a biologist says in fact that the pace of evolution has been picking up and that humans have been directly involved in that and that now indeed we see evolution in many cases occurring very very quickly. He writes about this in his book The evolution explosion how humans cause rapid evolutionary change that's a subtitle. It's published by WW Norton. Stephen Palumbi is professor of biology at Harvard University where he teaches evolution marine biology and molecular ecology and also does research on populations and molecular genetics of marine animals He's joining us this morning by telephone. And as we talk of course questions are welcome and all we ask callers is that you try to keep your comments brief and we ask that so we can keep things moving along and get in as many different people as possible but of course anyone is so welcome to

call the number here in Champaign Urbana 3 3 3 9 4 5 5 we also have toll free line. It's good anywhere that you can hear us and that is 800 to 2 2 9 4 5. 5 Professor Palumbi Hello. Hello there David. Thanks for talking with us. Thank you very much and Bracy and as I mentioned I think that and usually point out in the book that people do have this idea that evolution is this this is thing that you know it's it it grinds exceeding fine but it takes a long time and that it's something in fact Darwin believed I think at one point in you or you argue that he may have been right a lot of about a lot of things but this may be one thing that he got wrong that he thought it it had to take a long time. And in fact you say that there are plenty of examples all around us for rapid evolution. That's right and in fact we know evolution can take a long time in Darwin really focused on that. But but even he knew that that evolution could be really

rapid. He knew for example that domesticated plants and animals evolved very quickly under the pressure of human intervention and he called that artificial selection. Very different than natural selection. But the main difference was one of speed and the fact that humans were the ultimate cause of the evolutionary change in domesticated animals and. And. And if we just take. That is the starting point what we can see is that that happens all around us now not just under in cases where we we want to affect change but in a lot of situations in which our normal activities that are normal for us in a way generates an accidental evolutionary change and the fact that evolution can be fast really fast of happening within our lifetimes happening even over a course of a single year means means that humans are really affecting the evolution of species around us and in ways that matter to our daily lives. Well it's Or it also seems to be the case that even the pace of rapid this kind of rapid evolution

with human agency is picking up because of that. For example something like domestication of animals did take a long time but now we can point to cases where for example bacteria would develop antibiotic resistance and that something like that might happen as quickly as a year. Well that's right and and we have seen that over the last couple of decades. The antibiotic era just really started in the middle of World War 2 with the commercialization of penicillin but within a few years we were making penicillin on an industrial scale and it didn't take very long before bacteria started evolving resistance to it. So right now for example that has gone to such an extent that penicillin is useful for some things but a lot of major hospital infections are mostly resistant. Penicillin we've invented other drugs to sort of take their place. And so what we've gotten into is an arms race with bacteria the arms race is driven along by evolution and the point of the

book is to simply show that evolution is a biological process is something we really understand well enough to be able to come to grips with this arm or arms race see it for what it really is and then know what to do about it. Well I think also you point out the fact that it's something that we should be aware of and that perhaps we have not taken note of to the extent that we should and that when you look at some of the examples you know for example the classic story about the finches and their bills that Darwin wrote about and how it is over time that this can change in response to environmental conditions and one might think well that's that's nice and it's a benign process and it takes some time and that's you know that we're talking about bird beaks After all what's that got to do with us. And I think you're you're trying to point out to people and you write about it in this way that the real story of evolution has teeth and that there are real consequences that in fact have been have been cattle.

And yet the their day to day impact hasn't really been noted and that the fact that you would argue that this is evolution hasn't actually even been ignored. Well it hasn't and the trouble is that not only do we tend to think of evolution as being being slow but we also tend to think of it as being knocked out in Porton to what we really do. I mean what's really important to what we do with technology and and the changes it that brings to us and health and medicine and the environment those things really impact us and so we're worried about them. But evolution is an idea. And so we don't tend to think of it as being something that will really strike us at home. But when you begin to look at the examples that you can find you realize that in fact evolution does impact a lot of our a lot of our daily lives one of the examples that I try to bring bring to home in the book is. What happens when you take your your child your dinner one or two year old to the doctor because they haven't any ear

infection. They may be they may be in a lot of pain and crying and of course you're all upset because it's your kid and the physician might tell you it's a virus it's a viral infection it'll get better and they won't give you an antibiotic so you know any of any of us who have been parents know that you want that pink juice you know the MOC FACIL and because that's going to make your kid feel better and it'll stop them from hurting and you'll be able to sleep tonight. And yet more and more and more pediatricians are saying no I'm not going to give you the amoxicillin because it's viral and the antibiotic isn't going to cure this disease. So you're a parent what do you say. You know say OK you say well I want it anyway. Suppose it isn't viral suppose it's bacterial then just give this to me in case it's not viral. And the reason why that's not a good idea is that using antibiotics more than you should causes the evolution of resistance it causes the development of resistant bacteria in your

own kids so that when you really need those antibiotics they're not going to be useful because you've used them too much in the past. So that's a kind of example I think that a lot of people really really know about. They they've experienced it it's been a problem. I'm for them but they don't think of it as evolution and it but it really is. Well that then let me just take that one step further because I think it does go to what people think of when they hear the term evolution and they might say well if if for example E. coli develops resistance to a particular antibiotic that what we're still it's still E.coli right and that they have this idea that well we're talking about we talk about evolution is dinosaurs becoming birds and that that's a that's a fundamentally different thing with ECO. So it changes a little bit but it's still it's not like it's becoming something different. And would they would perhaps question applying the term evolution to this kind of

adaptation that we're seeing in this particular organism. Yeah. But it's it's it's not really a problem applying the term first. The term evolution just just means the change of something and we understand the biology of that pretty well by understanding how natural selection works on things. And how that leads to those. Organisms evolving over time. And this book is really not about dinosaurs turning into birds. This book is really about the changes that we affect around us. Those are evolutionary changes because they happen because of the rules of evolution that we know about and that's what I'm really concentrating on now. Does it mean that it helps us understand these other processes. I think so because most biologists and most people that that understand the ideas about how dinosaurs evolved into what are now birds realize that the same biological process was going

on there but it played out over a longer period of time. This book really just focuses on the short. Period of time because that's the period of time we're living in right now and we can see examples of evolution happening all around us if we ignore those examples. Then what we do is we create bigger and bigger problems that cost us more money and they cost people's lives. So you can you can sort of turn it around actually say that because people are unsure about dinosaurs turning into birds which they should not be. But but they are because they're unsure about that they don't want to teach evolution in schools. That means the students to learn about the basic biological process and then they're ill equipped to deal with these problems like the evolution of antibiotics the evolution of AIDS the evolution of leaves in a farmer's field for example is an evolutionary process that we need to allow people to understand. Band just and just real quick and I have a caller here and I will get to this caller in just a second but it's just so that people understand what it is that we're talking about the process we're talking about.

Just to review what we're talking about is that something that works because when you look at any population of individuals within that population there will be some naturally occurring variation that is one will be a little bit different from the other and if some of those variations due to a change in the environment become give that individual an advantage and if that variation is something that can be passed on genetically to succeeding generations then if if the environmental change continues long enough then what we'll see is a change in the individuals to accentuate that characteristic. That's right. And so we can see that happening over the short period of time and see how populations change from generation to generation. The example of Darwin's finches in the Galapagos they're a good example of that because it's a natural those are natural populations responding to the environment changes.

They change a little bit from year to year the cumulation of those little changes. If they were to happen all in the same direction for a long time would be big enough to call up to suggest that they were different species. So we can see how to connect the small changes to the larger changes. It's harder to see that in our lifetimes because those accumulations take longer. So this book really focuses on the things we can see right in front of us and why they make a difference to us. Our guest in this part of focus 580 is Stephen Palumbi. He's professor of biology at Harvard University. His book is the evolution Xplosion how humans cause rapid evolutionary change. It's published by WW Norton questions welcome 3 3 3 9 4 5 5 toll free 800 to 2 2 9 4 5 5 Let's go to Bloomington Indiana for color line number four. Hello. Hi I just want to expand on what some of the questions that David just asked

I think of late in late years the definition of evolution has changed. We do have a distinction I guess between what we call micro-evolution and macro evolution where microevolution requires no change in genetic material at all but simply the manipulation of existing genetic material in classic terms and that's not evolution. That's selective breeding we've been doing that forever and it is true as you said in the early in the broadcast. Darwin understood that. He knew that farmers could manipulate their breeding stock and that that's been going on forever and it isn't evolution. It relies totally on existing genetic material and it adds new it adds no new genetic material and end. And as you as you attempt to make the the the selective breeding changes greater and greater and greater you arrive at the species barrier. You do not cross a species barrier. As a matter of fact as we try to breed

species such as dogs and we get it further and further from the from the general interest into space. Characteristics of dogs you get you get problems with distemper and the deformations of the species barrier is still there and it's it's it's firm now it is true that in them in insecticides and certain things like that that there is a kind of a selective breeding that goes on. But that is still quite well within genetic variation in other words with a given given a whole bunch of insects you spray a field and there are a few of those insects that are just naturally resistant or immune to the insecticide that you're using. And those immune insects will proliferate. That's they don't they don't evolve. That is that they're existing within that they're operating within the existing genetic variation. I think that where you have

populations of viruses where there are there are virtually quadrillions of viruses and all they have to do to defeat an antibody is change the shape of their coat that is to say that there's a molecular coat that is coating the outside of that virus a genetic accident could happen that changes the shape of that coat. Now that could be what you really call evolution and it could defeat an antibiotic. Let's yeah let's give a let me give you made the same point raising the question of what is it. It is not evolution it is this. Yeah well let's let me go ahead and respond to the call. It it's an interesting distinction only and we can run it and see where it where it takes us. The caller is trying to make the distinction between changes that happened because of the sorting or the shuffling of naturally occurring variation and changes that happened because new variants arise by

mutation in the population. So every evolutionary biologist would call both of those evolution. That's right even if we didn't let's just focus on the role of mutation that's were really that's what the caller is really talking about that mutation is not playing a role in the process and so it doesn't doesn't count as evolution. And in fact mutation does play a role and we know so much about how some of these new traits evolve that we can identify the mutations that happened in a past population that gave rise to these new these new abilities. For example mosquitoes just I'll just take one of the examples that the caller brought up mosquitoes used to be very susceptible to organophosphate insecticides but in the mid-1970s somewhere in the world probably in southern France so it's not quite to clear a mutation happen that allowed in the Scioto to two. Take the organophosphate insecticide and keep it from affecting the

nerves of the insect mutation was a century a exaggeration of the number of genes in that insect for a particular protein. That new mutation was so good at resisting organophosphate insecticides that that mutation became very common in that population and that population has since spread all over the world. Now that's something that did not occur before the mid-1970s it occurred in a population by mutation and that the populations of mosquitoes have evolved since then. Another good example is in fact penicillin resistance that penicillin. Is broken down by bacteria because they have an enzyme now that takes the penicillin and breaks it apart. That enzyme didn't used to work on penicillin they used to work on something else but a mutation happened in it that allowed those bacteria that had the mutation to thrive in the presence of penicillin. So in those cases and there's many others we could talk about it is just the shuffling of

preexisting genetic variation that we see changing in the world we really are picking up new variants. It's not just viruses although I could give you lots of examples of viruses. The call is really right that happens very quickly especially in HIV. But we've seen those new mutations occur in bacteria in viruses in sex in WI and they all fuel evolution. So one way to look at it is not that there's a distinction between evolution that happens because the shuffling of variation and evolution that happens because of mutation but mutation generates the variation in a population that's the fuel of evolution and then natural selection is like the Pistons of the chains that generate the force. In natural populations and Windows variants are passed on to offspring then that's like that the gearbox of the differential in the engine and it makes the whole population move. Well we're operating on a mathematical probability. In other words we remember that a

mutation is simply a genetic accident. It is in the instructions for making something going haywire. And by just simply by accident and we have to assume that by accident this this this. The jumbling of the instructions instead of producing nonsense actually produced a better instruction than the original instruction and that only produced a better instruction. But he had targeted a specific. So in insecticide it targeted DDT. Now normally that resistance exists somewhere in the dip within the genetic variation of a life form. And those individuals that possess that resistance after an hour survive an attack of DDT and the rest of all of their all of their the other members of their species are wiped out and then only those who have that inherent resistance survive and proliferate.

If you're right that beach Asians are a genetic accident and you're also right and most of them are not going to be all of that useful. What we have seen in this case is that insecticide if we keep using that analogy using insecticide is such a strong ecological impact that when ever one of these mutations happens these accidents that that are usually bad but when ever one by an accident happens that is beneficial because it duplicates one of these genes that helps the insect resist the organophosphate insecticides that when that happens then evolution occurs and the odd thing is that we think oh that'll never happen because it's just so unlikely but it does happen. And one of the important lessons that you can gain by looking around the world and seeing what when evolution has happened is that you can see that it isn't that rare that when we have huge populations of pests and we're really stressing them with huge doses of a of antibiotics or insecticides then it's not that we rarely see these evolution the changes happen. It's we

always see these evolutionary changes happen there's not a single insecticide in the world that insects have not evolved resistance to there's not a single antibiotic that bacteria have not evolved resistance to. HIV as it is is a chilling but wonderful example of evolution because inside every single person the HIV virus accumulates the mutations necessary to overcome antiretroviral drugs and we can see him happening one after another after another as this virus in exhorter oblique defeats the drug. We try to use against it so. So it's important in this context to realize yes all of those all those things might seem very unlikely but we've seen them happen and when you see the unlikely happen over and over and over then you need to learn that lesson that in fact you should begin to predict it and expect it and use what you know about the process to try to defeat it. I have to jump in here because we're already at the midpoint and I have some other callers. It just strikes me that here the disagreement between you and the caller

it's not whether there is a in a phenomena recognizable phenomenon here because it seems undeniable that we have bacteria that have become resistant to antibiotics and we have insects that have been become resistant. Pesticide doesn't seem like we're arguing over the effect we're just arguing about we're going to call it. Well that may be true but one of the one of the things about that is if you if you if you don't know what is causing something you never know how to stop it. You never know how to affect the process to that you get to the point where it isn't bothering you as much. And I think that that's one of the that is the danger here that if we don't understand that it's the evolutionary process at work then then there's nothing we can do to predict when it's going to be bad when it's going to be OK. There's nothing we can do in advance to try to make it better. And what we can learn though if we understand it's evolution happening is we can we can organize our hospital so that it doesn't happen so quickly. We can change how our farming practices that it doesn't happen so quickly people are doing that but it's

easier if you recognize the fundamental biological process. Well then that gets to another basic question and that is what what we're taught as long as we intervene in the natural world to the extent that we do. This is going to happen and that the the only thing that we can hope to do is slow the process. Well I I'm afraid that's true. When I started this book I thought well I'll find some examples of when it really isn't happening. And I never did. You know we're not actually causing the evolution of elephants very much I suppose with more whales but that's because they're very long lived long live creatures but the kinds of organisms that spend their lives feeding on us are living with us are weeds and pests and diseases that have very fast generation times and very many of them are evolving because of our activities. Our guest Stephen Palumbi professor of biology at Harvard University. His book is the evolution explosion how humans cause rapid evolutionary change is published by. W Norton we are a little bit past the midpoint here we have other callers will get right too. They're both in Urbana So we'll

take them in the order they came in starting with line 1. Hello. Hello. Yes I mean I'm here. I was want to ask you something about genetics. Sure you get a shock when you mention that part of your title at the beginning they had someone on a month ago who was talking about the human genome project in relation to breast cancer. And she was adamant about ridiculing the human genome project because half of the people who had been tested with the gene that they had said was a cause of breast cancer didn't have breast cancer. And I would I tried to get her to admit on the air that he didn't have to be just one gene but she wouldn't. So I was wondering if you might want to clarify that there are multiple genes for the same outcomes sometimes and that even with just two genes like for blue eyes and brown eyes you certainly get a lot of different colored eyes.

Well this is certainly the case that that genetics can be a pretty complicated thing and I don't know very much about the genetics of breast cancer so I can't comment directly about that but. I do know from looking at other examples that there are plenty of cases in which genes may appear in one person and have one effect in the same copy of that gene could be in another person and not have that effect depending upon the variation they had in other parts of the genome. So it's it's not the case that every gene is a switch that turns a light on and off all by itself. There are switches that combine to turn lights on and off and that's exactly what I wanted to hear. Yeah OK I think that you just kind of misled the audience a little bit because he was just kind of being like a fundamentalist preacher there hammering on something and probably you have another point of view that is wrong. Thanks very much Paula. Thank you. I guess the overall point to take away from that again is this idea that as where we are starting to look at the human genetic material. Trying

to figure out what exactly does what parts do what. And we are starting to point to certain things and say well maybe we think this here has something to do with breast cancer and this over here has maybe something to do with heart disease and this over here maybe has something to do with all timers disease except we are a long long way away from making some connection between that and being able to say OK later this person is going to get breast cancer this person is going to get heart disease this person is going to get all Simers. We just don't understand well enough how well it works and how those things interact with the factors in the environment to which the person would be exposed. I think the bottom line as I understand it is that we're a long long way. I mean we know that genes play a role in disease but we're a long way from under. Standing completely. How exactly that works. That's right Bo. The other lesson from all of that because you know so much about our own genetics is that we do have a lot of variation in our own population across the world. There's there's lots of genes with lots of different variants and. And so even in in US there is genetic

variation for four important traits and whether or not you you get cancer or not you know the ability that you have for dealing with certain other kinds of environmental toxins that variation in how drugs are metabolize is very important now and in trying to to fine tune medical treatment so we can take this is a great example of the kinds of variation there is there are in other species as well it's not just us that has genetic variation it's everything. So that kind of lesson tells us that all over the world all over the planet in deep seas all up in the tops of the highest mountain there is this fuel for evolution to happen. And natural selection when it's strong can can create lots of evolutionary change using the existing variation like the first caller suggested or allowing new mutations that arise in these populations to thrive when it wouldn't otherwise. All right let's go to another herb. Color Line to yellow. Yeah I've got two questions I guess. I guess I'm trying to

see if your death would have been in a comment about them. One would be a couple years ago a couple of professors from Purdue came up with the Trojan gene hypothesis. I don't know if you're familiar with that but if you run through it they will jog my memory. OK. Yeah I had to do with the they were working. They simulated what would happen if another clean modified fish were released into the environment and on the fish they were looking at were matured more quickly than than the non modified fish. Right and they got they were also larger. And because of that they were sexually selected by the other fish. But the fact problem was that it. Only two thirds of the normal number of fish would get the

material in the first place. So what happened was the introduction of the genetically modified fish would in fact make that species extinct. Right now and I was just curious if you know or there were any more examples such as that that have been developed. It seems like you know a really good example of where you are trying to affect the evolution of the species could really cause a muff. Yeah that that particular example is is is a very good and in that regard there's been a huge amount of attention about what happens once we engineer new genes into domesticated plants and animals and whether or not that's something that we ought to pay a lot of extra attention to. One way to look at it is that like you're like you're suggesting that it really does add to the variation in the population than it really

does qualify as as a different sort of evolutionary change that we are injecting into into live populations. And then the Trojan gene problem where the the population is affected by this introduced gene in such a way that it it can go extinct is not something that that we've seen. But that's because we've been so far pretty lucky about the escape of these genes into the rest of the rest of the world. Just as big a worry is the escape of genes from crop plant say into weeds that allow the weeds to become herbicide resistant. So a lot of farms out in the Midwest and elsewhere right now are using crops that have engineered into them a gene for a life of resistance. Like I say it's a very strong herbicides that the crops can resist the herbicide So that means you can do a lot of we control without having to plow. The danger is that if we grow crops that have weeds

around them that are closely related to the crops that the gene will cross into the weeds and the weeds will become very very resistant. We haven't seen that happen yet even but it's early in the process. We have seen though that traits that are in crop selected by artificial selection have crossed it. We and I don't know the the literature all that well but I'm told for example you cannot grow rye in some parts of this country any longer because the weeds of rye are so good now because they have got the selected genes from the Rye crop that the weeds choke off the crop and it's no longer economically profitable so so we have seen the escape of genes from selected crops into weeds. We haven't seen the scape of genetically modified genes yet wholesale into weeds but many people are worried about that and trying to hope and ensure that it doesn't happen. Two professors Meir and Howard from Purdue Wright were

came to the conclusion they would only take one fish to infuse a situation to cause the species to get extinct. But of course in one's home. I was curious whether or not. You've looked into or or know much about the possibility that our culture really exists distrust source and that that they are having a I mean you talked about you're talking about affecting other species but what about the effect of our selection of of different cultures having an effect on our own genetic. Because I understand most of the time people will say that you know it takes too many generations right now. And I I really beginning to think that that's you know that's

short sighted and I'm wondering if you had much to say about going up and listen thanks. OK thank you. One of the other things that people say is that we're so good now it at controlling our own environment that we've slowed our own evolution that physically anymore we're we're stuck here you know because we live in houses and we wear glasses and and we have a nice food supply. And so our physical evolution is really slow down because we're buffering the environment from from ourselves but our cultural evolution is still rocketing along and one of the things I try to to say in the book and in a chapter about whether human evolution has stopped is that human evolution actually really hasn't stopped. It's not that that some of us aren't buffered from the environment but that all of us are in that the world is a very variable place and that many many people in the world are exposed to stresses and environmental problems that other people are really quite comfortable from and aren't

effected by. One of the really amazing things about the juxtaposition of the evolution of diseases in this topic is that there are some diseases that are only curable if you're rich enough because there are some diseases that have evolved to the point where the medicines to treat them are so expensive that we cannot afford them in many parts of the world. HIV is a great example. Again unfortunately we treat people in this country with. Triple drug therapy costs about $18000 a year per person to treat for HIV. That cost is just out of the question. A lot of central Africa and. In Asia where millions of people have HIV they cannot afford the drugs they do it's a per kilo so this is another example. So in those settings where diseases are still playing a major role in mortality the genetic variation we have for getting diseases or resisting them is really under strong evolutionary pressure so I

think in those cases the evolution of humans is still ongoing. It's because we're not all that good at keeping these environmental pressures from impacting people. Well continue will go to. Why number four for another Caller Hello. Hello. Most the time in this discussion you've been just talking about diseases and evolution on a very very genetic level. And it seems to me that I didn't didn't aboriginal peoples of the world have a very serious effect on on the evolution of all kinds of animals and it's going on even today considering the aspect of just where we're at here. The native peoples of America created a lot of fires for hunting and therefore they changed the type of plants and makeup of the area. In a more recent history in the seventeen hundred eighteen hundreds expiration to islands introduced rats and mice into these islands and totally destroyed

eco systems there that the last great genetic aspects of things. That's right and there's two things you can you can look at there and they're part and parcel of the same thing you bring up a really good point that that one of the impact that people have on the environment is introducing other species into the environment or controlling the distribution of species as you're putting it through to fire or you know just farm practices if farm practice anything anyway so that's that's an ecological effect. My take on that would be to ask what is the evolutionary effect of those ecological effects with the secondary secondary effect of what you're talking about. Yes exactly. And we know there are some. For example if you introduce a new insect into an area where its former host plant is not it will often evolve preference to a new host plant or introduce a new crop into an area and the native insects will evolve a preference for that new crop.

We've seen that kind of thing go on all the time. It's the evolutionary aspect that I'm personally interested in not just the fact there happen to be rats at a particular limit and where they were before. One of the rats would kill the birds who were the top of the ecological species on that particular island. That's right changing the entire ecological framework of what was on that island before it. They didn't have that kind of predator now they do that. That's right and that's really critically important and it's one of the one of the main things that we tend to do in the world around us. But that doesn't necessarily lead to evolution. There are examples of it and so what I was trying to do at least of the book is to focus on examples where that kind of ecological change results in evolutionary change. There is one example that I can usually point to and that's the Introduce an introduction of fish into different lakes and streams around the world in there. Small species of fish that are native in the streams small wild

guppies in Trinidad and in Central America for example and where there are where there are no predatory fish. The males are really brightly colored red and green and gold and they have long fins and they're just all happy males. And they they they succeed by attracting females who prefer to mate with the really brightly colored males. But you introduce predatory fish into these streams and the predatory fish are attracted to the brightly colored males as well they eat them up just as fast as anything. So what you get is the evolution of really dull colored fish in the streams because these introduced predatory fish have gone through it wiped out all the really brightly colored ones. So that's an example of the logical change then having an evolutionary effect on these environments I think. Thank you very much. Thanks. Bye again. Again I guess what we're going back to is the point I think you're trying to make is as the caller suggested it is true that human beings have as far as we know for a long

time have have altered the environment to the extent that their technology gave them the ability to do that. The thing that now is different is that our technology has given us the ability to alter the environment to an extent never before possible and in ways that are rare. More dramatic have more problematic consequences and stories that play out much faster than they did before and it seems the cautionary angle of the story that you tell is that we ought to think carefully about what we do before we do it because the consequences can be so significant. Well that's exactly right and you know what we've seen you know is that we'll invent something and it'll be very useful and then industrialize it to an enormous degree. DDT is a very good example it was it was first used in Naples by the Allied armies in 1943 and 44 and within a few years millions of pounds a month for being produced by the industrialized countries of the world and spread

all over the world to combat insects and that huge industrialization potential meant that all over the world insects began to evolve resistance to DDT. We see it over and over and over again that that evolution is is a consequence of this kind of chemical approach to to insects. We see diseases etc. and what we do is we invent them then we deploy them and then are surprised a few years later when something evolves resistance to them and scurry around trying to find something different. Instead it makes sense to say OK we're going to do this because in fact DDT saved millions of lives. But we're going to expect evolution to happen. We're going to build it into our plan for how we're going to use this chemical and it'll turn out that if we do that from the beginning we can slow down evolution hospitals right now are trying to slow down the evolution of antibiotic resistance by strategizing by not using the same antibiotic forever in the same place. They're cycling antibiotics using

some one time. There's another time in and that kind of approach can really get allow us to have a better handle on things like like disease we can't cure insects we can't control cetera that makes it cheaper for us we don't pay the evolutionary cost. And it's because we've taken a look at it OK. I'm not afraid of calling it evolution. Evolution happens. I'm just going to use my knowledge of it to actually affect this better better change. We just have a couple of minutes we have two callers. I don't think I'll be able to do them. Will at least try to get one in Urbana line one yellow light one. Yes. Oh well maybe you mostly answered my question I wanted to ask about an argument against some of the approaches to genetically modified foods like the ones like BT corn and Roundup ready you know herbicide resistant plants right. It seems like we could make a stronger argument against them if you could if you could make an estimate of you know to say that in 10 or 15 years these will be

mostly ineffective except that they were done you know until every damage by throwing off other things in the environment. Is anyone making is anyone who's opposing meis making such an argument. I hear a lot of people arguing about them. You know it worrying that they'll be directly dangerous to humans but I'd be a lot more worried about the environmental effects. Well it is a worry actually BT Corn is a good example or a pizzicato any of them. Insects can evolve resistance to those toxins. BT corn it has a gene in it that makes it bt toxin the BT toxin kills certain kinds of insects and those insects flee some of them are known to be able to evolve resistance to the toxic effects of that one protein. So so the danger is the worry is that by deploying BT crop so widely we're doing exactly the same thing we did with DDT creating evolutionary pressures to cause the insects to evolve resistance to these

to these toxins. Now there's been a number of theoretical and sort of arguments about how to slow that down and in fact many farmers now when they when they buy PTC they're required to plant a refuge that is a fraction of their field that does not have the seed. The crops grow up without the BP toxin. They're not allowed to spray insects take over that part of the field and grow up without the resistance genes for BT talks. They swap out the insects in the other part of the field and by doing that they slow the evolution of BT requiring. I've never heard of this. Well you look at up the companies that are selling BT seeds are home. Oh I see thank you again under those circumstances. The EPA has suggested a 4 to 8 percent refuge size and if you look look into it you'll see that that is really one of the major ways that the evolution of BT resistance is trying to be slowed because that is the

problem. It's a big expense to engineer these genes into crops and you don't want them to evolve to be useless in just a few years because one it doesn't pay off your investment and two you're evolving the insects to actually resist BT toxin which right now is a very good organic insecticide. We're going to have to stop I'm sorry to say because with that we've used our time for people who are interested in reading our more on the subject you can look for the book we mentioned it's titled The evolution explosion published by Norton and by our guest Stephen Palumbi He's professor of biology at Harvard University professor Palumbi thanks very much for talking. David thank you very much is a pleasure.