Well guess as Dr Robert Hagen astrobiologist at the Carnegie Institution and author of the book Genesis talking about the genesis of life in outer space and the 2nd special guest talk about the most incendiary aspect of the evolutionary theory the application to you and me our special guest is Carl Zimmer biologist author of the book Evolution talking about how humans humans probably evolved from a common ape like ancestor according to the fossil evidence and also the voluminous evidence given to us by d n a and biotechnology so an exploration today we talk about evolution and out of space and evolution of our own bodies. Well our 1st special guest today is Dr Robert Hagen of the Carnegie Institution outside Washington d.c. He's an astrobiologist author of the new book Genesis and we are talking about how the 1st spark of life began on the planet Earth about 3 and a half 1000000000 years ago. The 1st question for you is how did you 1st get interested in science as a youth Oh man I would so excited about nature when I was young we had a house in Cleveland Ohio the back onto a swamp and my brother and I would go tramping back we collect butterflies and we collect frogs and we collect crayfish and at night I love looking up at the sky and the stars and so my parents bought me a telescope and this was really small but I got what your larger telescopes that end up building my own but love looking at the sky and looking Saturn with my favorite nature just turned me on when I was in high school I moved to northern New Jersey and northern New Jersey is just a gold mine for mineral their famous Mineral County and I got out teacher who pointed me in the directions that go to Franklin New Jersey go to Patterson New Jersey collecting minerals and that's what really got me into mineralogy which is my main field right through college Ok now you are an expert in an area that is not familiar to the average person and that is something called astrobiology So what is astrobiology Oh that's right biology is one of the most amazing new integrated fields in finance it's the study of the origin of life the distribution of life in the universe and also discusses what the future of life might be in the universe this is a field that has been brought to life by major new funding through NASA and announced Astrobiology Institute which is based at the Ames Research Center in California. Ok so your book is entitled genesis of the scientific quest for life's origin Let's begin now in the year 953 with an experiment done by a graduate student under the direction of his advisor by the name of Stanley Miller could you tell us a little about that experiment and how that led to a paradigm shift with regards to how we view Genesis but Professor what a transformation at what Stanley Miller young 23 year old graduate student at the University of Chicago did mentor it with Harold Yuri who had won the Nobel Prize for the Discovery up to tear him to be hydrogen isotope of heavy water so you know he was incredibly famous Miller well known you know what came to your Ian said I want to try and experiment to make the molecules of life from nothing more than a primitive atmosphere now you had proposed the primitive atmosphere consisted of hydrogen methane which is the natural gas you burn on your stove and ammonia that's the strong smelling chemical from ammonia cleaners and you mix those together with water and just ran a lector box through a piece of glassware and lo and behold in just 2 or 3 day is that clear colorless the Lucian began turning shades of pink and then Brown and then black gunk started getting deposited on the side of the glass where Miller had made a whole range of organic molecules that were basic building blocks of life mean acid to make up protein sugars that make up the hydrates of all sorts of molecules that form cell membranes called limpid and not only that a few cases they're called these are the molecules that are key components of d.n.a. And r.n.a. Many of the most fundamental building blocks of life just appeared out of a simple primitive atmosphere and looks like lightning Ok so let's back up a bit over talking about is getting a flask with horrible chemicals like ammonia methane hydrate. Him sending a spark through it essentially replicating what they thought was the early atmosphere of the earth bombarded by x. Rays and lightning bolts and so on and so far and bingo out of that came the building blocks of proteins amino acids so what was the reaction of the scientific community which before that experiment was really. Basically had no theory as to how organic chemicals could form out of nothing it's true that the bombshell the scientific community looked at this and thought Wow this must be how life originated in just a couple of days you can go from a simple atmosphere to the building blocks of life then given millions of years the early ocean we're just going chock a block then. That working out of molecules and that was what led to this idea of the primordial soup An early. Just the right building block for life that people thought she it's going to be a matter of 10 or 20 years they will know everything there is to know about the origin of life that's a little overly optimistic and taken with a lot longer and we're still a long way from knowing but this was the 1st experiment that that little experiment on the path to believing that there is a chemical origin of life going from the simplicity of a geochemical world to the complexity of the biochemical world Ok so back in the fifty's they thought that the early atmosphere of the earth was a hostile brew of ammonium methane hydrogen and things like that however today we're not so sure today many groups have proposed a different scenario for the formation of life on the earth very similar of course to what Miller and you're a had but with a different chemical composition of the soup what is now the leading theory as to what the atmosphere in the oceans look like back then well one thing about the atmosphere is that yeah I do. Yeah of an atmosphere of hydrogen and methane is much to what's called me do you think we'd think that it was a much more chemically neutral atmosphere including things like nitrogen that dye nitrogen gas that makes them of the right atmosphere today perhaps them feel to perhaps other might or components like carbon monoxide maybe a little bit of methane maybe from hydrogen but not as to make way reactive and the atmosphere that Miller proposed Nevertheless when you put Shop Fox through any of those that matures you still get very interesting products for the basic concept of the miller your experiment is certainly valid but there are other environments as you suggest. Ok now I'm the Alvin submarine which was used to probe the Titanic writing on the bottom of the ocean and also to retrieve the hydrogen bomb dropped off the coast Apollo Marise Payne back in the 1950 s. Was also used to investigate what are called Volcano vents and some people say that perhaps a volcano events is where life started it's one theory but could you elaborate on that theory yeah the idea here is that life requires a couple of simple ingredients requires water some kind of water rich environment it involved it requires energy of some kind no Miller said lightning other people think about light but you also have the energy from the earth and you require carbon and other carbon compounds that are called organic molecules one of the most exciting environments on Earth 3 of those ingredients come together are the deep ocean and the hydrothermal vents or the plaque smokers as they're sometimes called on the bottom of the ocean and these were discovered in the late 1970 s. But right now it is diving in the submersible how it went off the Pacific coast completely unexpected to find not just the hydrothermal vents be under the smokers if you will with all sorts of mineral rich hot fluids coming up but the final living community far right below the influence of the front where it's totally dark all the time and you know life right because of all that energy coming out of the ocean floor now when we talk about energy we realize that we mammals get our energy by eating plants so we mammals could not have been the 1st form of life on the earth but plants in turn get their energy from sunlight in a very complicated process come full photosynthesis which also could not have been the original energy generating device because it's very complicated and we're time . You know about creating life from nothing almost So you're saying essentially that the energy supply could have been obvious very caustic environment on the bottom of the ocean that's the theory and here's why people think that might be though in our body the energy for example from plants or from sunlight is kind of routed through a process that's called oxidation reduction reaction to their reaction just like it occurred in a batter your flashlight battery you're basically transferring electronics from one group of chemicals to another and that exact same problem that's occurred deep on the ocean floor because very what are called reducing the fluids to come out from that if you lower the ocean surface and they get very oxidising water in the ocean and that the oxidation in the reduction together causes chemical reactions just like in a battery just like in your body that's what we think the very 1st energy for life was just like a battery trip invited to earth. Ok now the astronomer Fred Hoyle had a different theory in fact he was quite the contrary and within cosmological circles and he said the following that the Earth is 4 and a half 1000000000 years old roughly speaking and during the 1st 1000000000 years was the age of asteroids and meteors constant bombardment by debris from outer space for about a 1000000000 years we see that on the moon even today and as a consequence if life formed in the oceans the oceans would have boiled off and therefore life could not have gotten started within the 1st 1000000000 years or so after the age of meteors ends. Pingo life gets started very soon so he says this means that life could not have started on the earth they came from outer space in the form of spores so he called this the panspermia theory but what do you thoughts about the panspermia theory at 1st glance that sounds like a pretty crackpot idea you know why it's being heated from outer space but a lot of Spite of they're now taking this very seriously I think there are 2 possibilities one is that life is a cosmic imperative it arises everywhere and it arises very quickly I put scientists they like to write comes about in a 1000000 years 1000 years there's one very famous writer in the field even the takes 2 weeks Well that's true in light but of reason on earth and there's no problem but if life does take hundreds of millions of years we have a planetary neighbor Mars that was applicable long before Earth much less in the way of bombardment by meteorites much more open I mean in terms of its temperature early on and if out there like we now know that from these recent discoveries by now the miners with Abbottabad hundreds of millions of years before it's very possible that life arose on Mars and then there's this amazing mechanism if mind gets hit by asteroid something that 10 or 20 or 30 kilometers across. Will be it's been shown Don't be rocks thrown up into space and those rocks would be relatively unheated relatively unstressed they could contain microbes and those microbes could then be brought to Earth by meteorite. A group of scientists that are giving very serious consideration to the idea that one. Is Mars life because Mars was habitable earlier and we may know that if in the next decade or 2 when we go to Mars and we look specifically for life we might find life right fossils like Life On Mars that represent I answered so if you want to see a martian you should simply look in the mirror. Now let me ask you a question that's bothered me for a long time and that is the Earth is roughly 4500000000 years old but there's only one d.n.a. Molecule rearrange in different ways of course but there's only one d.n.a. It has a t.c.g. As the building blocks nucleic acids that's why we can eat anything on the earth we can eat sea urchins we can eat insects we can eat plants even though we're separated by a tremendous evolutionary distance because we're all made out of the same molecule Now if there's 4 and a half 1000000000 years old. And life gets started pretty quickly that how come it didn't start again with another d.n.a. And again and again why do we see different d.n.a. If we only see a t c g we only see a certain set of amino acids and that's it we've had not just a few 100000000 years we've had 3 and a half 1000000000 years of quiet oceans with no meteor impacts to speak of so why don't we have many d.n.a. Like robots you know that's such a great question that a lot of us are asking the question of why is the chemistry that we see in life today and evitable Well I don't watch the alternative way well. Why don't we you know the explanation that's most often given is why put the competition and once that 1st successful self replicating cell with all of its proteins and d.n.a. That failure fission very powerful mechanism once we got started but if I did enough you know microbes can divide that our field one and 2 then went on 8 and in a matter of weeks the earth was populated by that extremely successful self replicating well and that's ate everything out you don't have a chance if you want the 1st on the block to know how to live and know how to reproduce then you are going to get eaten because you are food Well let me ask the question then food depends on proteins proteins in turn depend upon a template that is d.n.a. Template to create the protein but there are many proteins that nature has not used there are many proteins that you can create that nature is not even thought of so why didn't another d.n.a. Get off the ground that was uneatable unedible that it was based on proteins that simply cannot be digested by our d.n.a. And it's not based on a.t.c. G 4 nucleic acids but it's based on a different sat you know. Hardesty or whatever and it creates proteins that are undigestible by our cells and therefore the 2 life forms should co-exist but if it's well I think partly that life has been very tough on the bollock you'll elect for example I may use the right both d.n.a. Used to be on the right but I don't particular sugars either sugars with 5 crap out of and there are dozens of different sugars with 5 coming out why those turns out there's actually a an advantage to those molecules because a particular shape and people are shown that if you try to use other molecules they don't work so to a certain extent the molecules that white you are the best molecules for the chalk but also I think life is incredibly good at taking various other potential molecules and eating them it's just amazing how life is used all different kinds and you think that if environment that has energy life has learned to eat but I think it's just what you get one kind of life and stablished it's really hard to get a 2nd competitive system going it's sort of like the ultimate monopoly you know you can imagine some company makes the best car of the best computer and other companies try to get started but if that 1st company is so huge and so large it just swallowed up the competition and nothing else we got going sort of like the diamond monopoly have to be or you know there's never been another big company making diamonds because the pure write them all up and swallowed up the competition Well the reason I ask you this is because in science fiction movies we always see aliens from outer space that want some very specific things 1st of all they want to eat us meaning that they can digest our proteins which I find remarkable 2nd of all they don't want to mate with us in which case they have basically the same d.n.a. As us literally so they can interchange d.n.a. Sequences with us and I find this rather impossible but what you're saying is that in some sense d.n.a. Really is preferable and that. Maybe when aliens from outer space land on the earth they're going to have d.n.a. Which is very similar to ours you know what you're saying I think it's possible that some aspect of biochemistry will be very very similar maybe even d.n.a. R.n.a. But I think there will be very important differences but one thing we have what's called the genetic code and that basically are that the reach an addict letter that match up to different amino acids the building blocks the protein I think that code may be wildly different if even if there is a code of their world that it would be but very different from ours so I can't imagine there being that kind of unity but there are some a chance of in some chance a chemical event and the origin of life I think there are also some aspects of origin that are going to be very similar for world the world Ok well if you say that if another d.n.a. Got I think around in our d.n.a. B.c. Ate up that d.n.a. And then what happens when Alien d.n.a. Reaches the earth will our d.n.a. Consume molecule for molecule their d.n.a. Or vice versa perhaps their d.n.a. Will consume ours Well it's a really good question it depends on the building block molecules I can imagine alien d.n.a. I can imagine alien proteins that are totally poisonous to us and vice versa it's also very possible that life on other worlds started with an opposite and there is a very curious characteristic of life on Earth that the sugar molecules used in d.n.a. And r.n.a. Are called right handed and the amino acid used in proteins I want to call left handed mirror image molecules that I body used in fact that's what it for dieting there's a new product out you can buy left handed sugars which treats sweet but the body can't digest them so this is one kind of artificial sweetener which gives you no calories it's a great invention it's a great idea so if there were an alien life form that happened to be reversed and they used less kind of sugar. And right handed I mean that they could need we could need them I think we'd probably get along Ok now let's get back to the Miller experiment because there's a huge gap that we have left unfilled Miller show that I mean no masses in some sense are for free we see them in nebulous in outer space we see them in the cores of meteors from outer space I mean no acids are out there you know to space however d.n.a. Is extremely complicated if you look at a d.n.a. Molecule you say to yourself My God look at that thing and it would have taken an awful long time if for Miller to get a d.n.a. Molecule off the ground if he had done his experiment for maybe a 1000000000 years in that little test tube that maybe he would have gotten one d.n.a. Molecule off the ground so there's missing steps now so some people say that before d.n.a. There was already a before or and a there was a even more primitive structures even before r.n.a. So what do we know about the gap between the amino acids that are for free that we see in the Miller experiment and r.n.a. And d.n.a. This is probably the single biggest uncertainty in question but there's so many great ideas out there for one thing as you say I know a. Very complicated molecule and it's hard to imagine how it was that the finest from scratch in the people out of the middle step of that may have helped the minerals that attract right there's the minerals that are attracted to. Out there in the Genesis I described an experiment by a person at our laboratory guy named Nick Lachey who realized that you could build up an r.n.a. Like molecule from very very simple building blocks little like what all molecules the kind of things that are produced when you know it's not. When you talk about so the fire that you know. If you put it in water under just the right circumstances will form tiny little stack that molecule and those stack if there are just the right environment will attract the base is the 4 letters a t.c. And g. Of d.n.a. And those bases can light up on top of each other and you can actually make a r.n.a. Like molecule from scratch on the primitive earth now it's very possible I think that this is the sort of intermediate step where you build something that simple from simple building blocks and that mimics what's going to become more and more complex you add layers of complexity gradual one step at a time the next idea is very very powerful and and it's now being studied experimentally that's the kind of thing people look for you go from simplicity to complexity through a process known as the merchant Now if you go back back way back into the past and what do we know about the most primitive d.n.a. Or r.n.a. On the earth profess that the wonderful question of the how to do it what our defense think the most primitive biochemical features what are the chemical fossil that we find in modern life that point to the earliest life and I think the conclusion of unambiguous there are a few chemical pathways that are buried in every single living thing one of those that are in a way the ability for hour a day not only to store information and pass it on from one generation to the next but also for irony to improve the lives of certain reactions another is a cycle of what is known as metabolism that it taking energy of atoms from the surrounding and building up new molecules there's something called the trick acid like all the things they built into every living thing and there are a few other chemical pathways be ability to take nitrogen and convert it to ammonia for example that's also fundamental that's the way of using. Element nitrogen and biological systems so there are a few chemical pathways that we find in every living thing and those we believe are the most primitive chemical pathways that point out something about the earliest life and where are these organisms that are the most ancient most primitive forms of life they are they at the bottom of the ocean right now the most primitive organisms that we know are all in a very extreme environment in places where do you get if you have very high in places where it's very cold you know deep hydrothermal vent and people have to idea that one of the possible very real possibility that wipe originated in one of the extreme environments The other possibility is that life originated near the surface like Stanley but we would think but because of those they are the asteroids and meteors and comets they kept blasting the surface the only life that survived at those last insult but life that had it acted to the deep hot protected environment within the Earth's crust but you're white those are the most primitive organisms that we see today and that completes our interview with Dr Robert Hagen an astrobiologist and author of the new book Genesis Stay tuned now for the 2nd half of exploration. Welcome once again this is Dr meets you know Kaku professor of theoretical physics at the City College and the Graduate Center of the City University of New York and this is exploration every week and exploration we discuss the fascinating world of science and today we are celebrating the 150th anniversary of the theory of evolution the Origin of Species published by Charles Darwin 150 years ago and then next year just are celebrating the 200th anniversary of the birth of Charles Darwin and again on exploration in the 1st half we brought on an astrobiologist in the old days the whole concept of astrobiology was a contradiction in terms but because of the work of Stanley Miller and many others we now believe that the ingredients of life the ingredients of life or in some sense for free in out of space and perhaps life can spontaneously occur all by itself according to the work of many people including Dr Robert Hagen our 1st special guest he's the author of the book Genesis and he's an astrobiologist at the Carnegie Institution that was our 1st special guest and our 2nd special guest in this section of exploration is Carl Zimmer He's the author of many acclaimed books and his latest book is called simply evolution and perhaps the most intriguing aspect of all this debate is how this applies to human beings you know when Charles Darwin 1st published Origin of Species that created quite a splash it was a sellout However he refrained from talking about the evolution of humans but to him but to him it was obvious obvious that humans are well in some sense like animals and that many of the parts of our body evolved from the parts of the bodies of our neighbor. Ring species for example the great apes and Charles Darwin even put a place where humanity evolved from and that is Africa so why did Charles Darwin select Africa as a birth place of human beings before then some anthropologist said that perhaps Europe was the cradle of all of humanity in fact that's why the word Caucasian has an origin some people thought that the Caucasus mountains was the origin of humanity Charles Darwin said no it's Africa because that's where you find species that look like us the apes in Africa you see so many varieties of monkeys and if we evolved from a certain species there were probably neighboring species simultaneously existing with us and that's why he selected Africa as the cradle of humanity Well you can imagine that even today even today a 150 years after Darwin's theory it's still controversial even though Darwin's theory is the foundation of modern medicine you cannot practice modern medicine today and do research without understanding evolutionary theory the theory of d.n.a. And how it applies to all of us so in other words the miracles of modern medicine depend on the theory of evolution by Charles darling. Well Carl Sagan had a book years ago talking about the brain and maybe you can comment on this he had a theory that there are 3 layers to the brain the back of the brain he called the reptilian brain because the brain in some sense is a museum of all the early stages of our evolution and we originally came from the reptiles So at the very base of the brain is a very simple reptilian brain then he said the center of the brain is the the limbic system the emotional brain the the monkey brain the social brain and then the front part of our brain is what really makes reasoning and abstract thought possible and that's the cerebral cortex and that that's what makes us human has this held up that book by Carl Sagan was several you quite a few years ago has that pretty much held up that the human brain in some sense has an evolutionary heritage from the animal kingdom. In the basic outlines yet this 3 part theory the brain came up in the 1950 s. It was originally proposed by Dr Paul MacLean. And. You know I'll just now look at it as a little too simple a version of what was happening you know there's not one distinct reptile part of our brain but certainly you can see the evolutionary heritage. Of our past in our brains and particularly the way our brains develop I mean for example the 1st vertebrates were basically like sort of sardines without a head they just had a little spinal cord with a slightly swelling tippet the end but you can actually look at the genes that are expressed as that tip of the spinal cord starts to form in these funny little fish and you see that actually they're the same genes that help to structure our own brain and they play a lot the same role so you can see. 500000000 year history of our brain and the way that our brains develop and similarities between our brains and the brains of other animals Ok well you have an article in the latest issue of Discover magazine called Where are we going why are our brains so big who was the 1st human Why do we walk upright and other great mysteries of human evolution so let's start the story about 6 to 7000000 years ago in Africa when many scientists think that we 1st began to split off from the chimpanzees and the apes so tell us a little bit about the evidence for what happened in Africa 6 to 7000000 years ago and why did we split off there are 2 primary kinds of evidence so you can look at what is fossil. And if you look for fossils of Hama did that is. Apes that are more closely related to us than to other living apes you if you go back you can find you can find hominids all over the old world going back about a 1000000 years and then further back a gets a little harder to find a little harder before about a 1000000 and a half years they're all in Africa and then the oldest one that's been found is somewhere between 6 and 7000000 years old that was found in the Sahara and it's called the hell anthropos it was actually just announced last year it's quite a tremendous discovery and really very important when. You have that as oldest evidence of hominid evolution going on in Africa but you can also look at another kind of evidence you can look at the evidence in our own d.n.a. You can compare our d.n.a. To the d.n.a. Of other apes our closest living relatives are chimpanzees and bonobos which look like chimpanzees but they're actually different species anyway they're basically sort of our 1st cousins and if you compare our d.n.a. To theirs astonishingly similar if you look at the parts of the human genome where there's a code for proteins. They're different. It's very hard to find between them as different as we may look on the outside in fact they are about 99.4 percent identical So obviously we're very closely related to chimpanzees and so you can then look at those differences to try to figure out how it is that we split off and what makes us uniquely human and you can then look at the d.n.a. Of people in Africa people in Asia people in Europe and you can see that the root of the family tree of the human family tree is in Africa so we all came out of Africa and I understand that d.n.a. Is also a clock that we know more or less the rate at which mutations build up within d.n.a. And given that rate we could then calculate when we split off from different other species of life on the earth could you elaborate sure. Over time. Species genome picks up little mutations and a lot of those mutations actually don't. Bring much harm or much benefit they just kind of pile up in the background and so they seem to pile up at a pretty steady rate depend the rate may change from species species but there are ways of figuring out what that rate is so if you then look at human d.n.a. And the chimpanzee d.n.a. And gorilla d.n.a. And orangutan d.n.a. And then kind of line it all up and you calculate the clock you can get an estimate of how long ago the ancestors of say chimpanzees and humans diverge to. And this is really just starting to come together now these the molecular clock estimate because. You need a lot of a lot of data you need to look at a lot of gene sequences and so there are for example you know recent recent estimates that humans and chimpanzees their ancestors diverged say about 5000000 years ago plus or minus a 1000000 years so that still overlaps with that the fossil evidence says and it also helps to show just how close through laded humans and chimpanzees are Ok Now one of the big questions Why did we separate off from the chimpanzee line or the common line what benefit did did it give us and so tell us a little bit about what happened when we 1st began to diverged from our cousins. Right well this is sort of the mystery of mysteries this is a that question that everybody wants an answer to scientist included and it's hard to really get a good answer for it when you don't have as much evidence as you'd like to work with I mean this fossil I told you about Sal anthropos incredibly important fossil but when you look at it really it's basically consist of some fragments of the skull and a few bones from the rest of the skeleton and that's about it. You know we need so much more information to really get really good answers to that but you know you can make you can make them hypotheses and then you can test them in the future. So you know there used to be this thought that well you know since we're humans and we're so wonderful and so special and so unique that there must have been some incredibly profound. Reason that we diverge from other apes which were must be of course the very stupid and inferior so people would look for reasons that would be sort of sufficient So for example there was an idea that the jungles began to dry up in East Africa and then you had the Savannah and so that our ancestors sort of strode out into the savanna became people could walk on 2 legs and therefore became totally different from other chimpanzees. And other apes I should say. The problem is that the earliest hominids didn't live in Savannah and that they lived in woodland. Dense woodlands or like with women but in any case not the savannah so that whole kind of theory falls apart. You know that there may have been other reasons that we began to dive or you know we didn't live in dense jungles anymore so you know maybe we needed to sort of walk from tree to tree and pull down fruits they were hanging from those trees or maybe just to stand up in a tree to pick fruit is not very heroic kind of scenario but you know huge changes in evolution are often based on these tiny little shifts in diets or other ways of getting a living Ok so now we begin to walk on 2 feet for whatever reason and that of course freed up our hands so tell us a little bit about our hands and our thumb Why do we have thumbs anyway and one of them is good for well you know I'm easily thumbs and but think they look a lot different than ours I mean we can you know you can touch touch your fingertips with your thousands which gives you a huge amount of dexterity you can do all sorts of things with your if your hands thanks to the way that your films are arranged. There must be some connection between the changes that happened in human hand and. Things that you would use that kind of hand for most importantly making tools so the question then becomes well. What is the history of tools and that's a nother pretty murky question the oldest evidence of. Hominid tools is 2600000 years old these are stone tools when I say tool they don't mean a power source something I just mean basically a chipped stone that you could use to like break open a bone and get the marrow out or put your carcass to get some meat off it you couldn't get with your fingers or your mouth now before that there could have been other tools that just weren't preserved in the fossil record and an important thing that scientists now recognize is that chimpanzees and other apes are not dumb and this extends to using tools for example chimpanzees can make all sorts of tools they can make sandals out of leaves they can make little hats they can fish termites out of nests they can they can do all sorts of things they can even use stone tools although they can't use them they can't manufacture them the way we can so they might have been a long supreme history of tool making that we only start to see about 2600000 years ago and now that's of course talk about the brain it used to be thought that because we're smart then we use tools but if the human brain develops relatively late on this scale then perhaps it was the other way around perhaps tools help to make us in the sense that those Jim Pansies or ape like or animals that could use tools had a had a better survival advantage over those cousins that did not have the ability to use tools so tell us now allude about when did the brain start to get larger and the big question is What are your thoughts about why well. Talking about the brain people often think that all that happened in human evolution is that it got big like that you know you stuck an air pump in the skull and just pumped it up and it got bigger and bigger and bigger now certainly the human brain is enormous you know mammals generally kind of follow a general pattern of the relationship of their brain size to the body size we humans don't fit into that pattern our brains are about 7 times too big for our bodies if we were a normal mammal clearly we have big brains but we also have brains that are different in other ways I mean they're they have a different kind of organization so some regions of the brain humans are bigger. In chimpanzees Some are smaller there is a different kind of wiring that goes on we're only just trying to figure out what those differences are so big important question as well. Was there some sort of reorganization going on in the small hominid brain before it started becoming big because the brains only start to become big in the fossil record around 2000000 years ago so this is well over half a 1000000 years after we start seeing the 1st stone tool so you know what was going on before then it's hard to say now there are a lot of different theories that you know some of your listeners may remember from your previous shows that people have put forward about why brains got big one is sort of the Peacock theory that it's a kind of way of attracting make in the same way that a peacock uses tail to attract females because there's another idea that. That sort of it's called Macchiavelli and intelligence named after Macchiavelli in the sense that our ancestors were just trying to figure out what everybody else is thinking and trying to manipulate them for their own ends. There are other ideas about for example parasites lots of different theories. I think that one the most interesting ways of thinking about it is to think about. Think about how the home life of a hominid 2000000 years ago. They are by then you're starting to get much more towards Savannah kind of existence and you've got these bands of hominids moving around together and they've got they've got tools and they can get different kinds of things with their 2 of they can get they can dig up roots for example which has 2 birds that have lots of energy in them they can get at lots of food stuff but you know you need to be an adult to get that stuff and what you can do then do is bring it home and feed your kids so now your kids aren't having to go scrounge for food themselves they can get this wonderful amount of food from. From their parent this provides an opportunity for the evolution of bigger brain because that more energy can be there dedicated to growing these big brain then to just kind of you know. Get in get out and get out of the family and looking for food yourself so I'm I think I kind of like to look at the kind of kitchen side of the equation Ok well let's let let's talk about some more theory is there a whole bunch of theories about why we became intelligent when we look at she has an antelopes we find that they are delicately crafted to to excel at high accelerations of very quickly and so why is it that the cheetah and certain antelopes are such finally crafted aerodynamically stable animals and well we realize there's an arms race an arms race going on between predators and prey so perhaps there was an arms race among humans but of course humans aren't competing against anyone there are no more Neanderthals out there so who are we competing against perhaps we competing against ourselves other tribes other groups of humans and therefore there was a selection pressure because we competed against other humans what are your thoughts this is a really interesting area of research going on right now and it's fascinating to watch it develop it pulled in a lot of elements from psychology even from economics there are all sorts of ways of understanding this process and a lot of people think that's maybe really a key to understanding this this transition and human evolution in a sense that. You do have these different groups you have bands that were roaming around maybe 100150 strong. That. Would be competing for resources with other bands you see this going on with tempted to paint these today that they will wage the battle with each other for you know the good food treats for example. So the question then becomes well. How what what makes for a good group what makes for a group that's going to be able to hold together that's going to be able to. Compete against the other groups and so you know what that may be involved maybe a sort of really good social intelligence in other words being able to work cooperatively being able to to understand what other people are thinking in order to work together to hunt for example or to fight off an intruder for example so you could be getting this kind of group selection as it's called where certain groups are favored over other kinds of groups and then turn would influence. Who gets to reproduce and who doesn't and that would actually influence the shape of our brain and built into this is something else really interesting is morality you know if you look at apes they do have their basic moral systems they have a sense of fairness and they punish each other for breaking certain social rules. It could be that are much more elaborate than them around the merged as these groups were competing with each other from around they would keep moral system would keep a group cohesive even as people kind of competing with each other for mates and so on it would keep keep these groups from falling apart. Ok And yet there's another theory some a spin off of the Peacock theory if you take a look at humans we are much more intelligent than necessary we don't have to understand calculus and we don't understand how to we don't have to go to the moon all we have to do is survive in the forest and if you take a look at peacocks of course peacocks feathers are totally unnecessary so it is the female the female that chooses males who are extra healthy who can afford to have these fathers' And so this other theory says that it is the woman the female who decides that she wants to have a smart man now if you take a look at dating habits most women say that they want a man who's who's smart who wants to date a man who's not so smart they can be taken advantage of and if you take a look at high school a lot of the women there seem to prefer the quarterback over the half back so it's not necessarily the muscles it's the smarts the social smarts that are important in that game well that's a theory what are your thoughts. It's every new interesting theory because sexual selection is very important in the animal world I mean that that's what does give us the peacock tail that gives us the Roosters coma gives us all these sorts of extravagant display. You know I I'm a little skeptical about this theory just because. There's not have been that many sort of rigorous tests that I mean and you can and you can think of them from . Counterexample that would have to be addressed I mean it's true that. It's true that some girls might like to date the quarterback as opposed to the rest of the football team but the foot rest of it all team probably does pretty well just getting dates and you know if it's intelligence that we're talking about then you know why is it that the that guy in the computer lab isn't getting any dates at all you know it's it's it's an interesting idea but I'm waiting to see sort of how it emerges. Now when I was watching the movie The x. Men the other day it was mentioned that homo sapiens co-existed with the Neanderthals and that recent d.n.a. Evidence show that we actually enter when we mated with the Neanderthals However I think that the d.n.a. Evidence seems to indicate the opposite So tell us a little bit about the Neanderthals and the fact that we coexisted with them and that d.n.a. In fact has been extracted from the Neanderthals. Neanderthals as far as telling how this can determine probably descend from a common species that they certainly. Neanderthals as far as we can tell. Descend from a common ancestor that lived. Somewhere between half a 1000000 and a 1000000 years ago. Now our ancestors remained in Africa the Neanderthals and their ancestors moved out of Africa and into the Near East and into Europe and they survived there for what looks to be several 100000 years they had brains as big as ours or bigger they were incredibly strong and rugged they were master hunters they don't seem to have displayed the kind of creativity that aren't sisters did they seem to be pretty much set in their ways in terms of how they made tool. How they hunted and so on but that worked pretty well I mean they survived ice ages that would have killed most of us but the question then is well what happened in the energy used to be thought that Neanderthals just became modern european that it was just a process of evolution that steadily. Led from the entered call to European That's not likely to be the case now now looks like that Neanderthals went became extinct that Africans came out of Africa maybe say 50000 years ago 50 to 70000 years ago and started replacing the species that they encountered like Neanderthal Now there's been a lot of talk about well maybe Neanderthals were able to interbreed with that with our ancestor with what are called modern humans and you know this pops up in things like X.-Men for example. Well you can actually look at Neanderthal d.n.a. If you find particularly well preserved skull or other fossil of Neanderthal and scientists have actually found 4 different samples of the enters out the n a and they have been able to compare the genes there with the genes of modern humans and it turns out if you look at the start of a family tree you can draw with that information the entertainers are all going off on their own branch their numbers are closely related to Europeans than they are to Asia for example so it really does look like they're off on their own Now if you look at the bones of Neanderthals and the bones of some of the earliest European cities and you do see some. Evidence that maybe there was some interbreeding sometimes you see a modern human that has a really kind of rugged looking jaw there was one has just recently reported that 37000 years ago 37000 years old in Romania and it has a kind of an inner child look to it even though it's clearly a modern human so maybe there was a little interbreeding going on but if there was that didn't mean that. That there was that much going on. And that completes our interview with Carl Zimmer He's a science writer writes for Discover Magazine He's the author of the book Evolution and we have been talking about the human brain and the already gins of human evolution in light of some rather remarkable fossil discoveries and also d.n.a. Work which helps to pin down the all rejections of the human race and so once again the author was Carl Zimmer author of the book Evolution. Well I'm afraid that Sid for exploration once again our 1st guest was Dr Robert Kagan author of The Book of Genesis he's an astrobiologist at the Carnegie Institution in Washington d.c. And the 2nd special guest was Carl Zimmer author of the book Evolution talking about how evolution affects all life on Earth including human beings and if you want to copy of today's program called the Pacifica program service add 180-735-0230 That's 18735 ohm 230 for a copy of today's program once again this is Dr Michio Kaku professor of theoretical physics for exploration good day. Plug plug must. Come. Soon. Hearing the dread that. This process was designed to deliver the global justice this is the police bad. As well as European Union the United States. But the then all these big banks. Are making this says more than. The fact that President Trump has knighted States out of the Paris climate for world look at what the u.s. Is doing while it's still here that. Indigenous After best seller murdered in. The. Protests. That the government is president of all of our lives right now but that doesn't mean that we will stop fighting fighting for the lot for. Canada should stay from the Access pipeline to the Alberta tar sand. Canada. Climate Action. We brought Indigenous you delegation that are impacted by tar sands infrastructure. 25 to the. Predictions. We look at explosively Washington Post experts say in the history of war in Afghanistan no matter. Well the Bosphorus now democracy no doubt for the war and peace report I mean the good men were broadcasting from the un climate summit in the dread Spain back in the United States House Democratic lawmakers are expected to unveil articles of impeachment today charging President Trump with abuse of power and conduct they say presents a clear and present danger to national security and the upcoming 2020 election the New York Times reports the articles are expected to center on 2 charges that trump violated his oath of office by elevating his personal political concerns over the national interest and that trump stonewalled congressional attempts to investigate his actions the ongoing impeachment inquiry centers on how Trump pressured the Ukrainian president to investigate Trump's political rival Joe Biden and his son Hunter the New York Times reports the House Judiciary Committee was working overnight to prepare the Articles of Impeachment this all comes after the House Judiciary Committee.
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