Defying Death...

14 April 2015
Presented by Chris Smith, Georgia Mills.


In this episode

00:57 - Gibbon calls decoded

Want to learn to speak gibbon? Their "hoo-hoo" calls have been 'translated' and the results are pretty interesting...

Gibbon calls decoded
with Dr Esther Clarke, University of Durham

The sweet, swooping song of a pair of Lar gibbons is what first intrigued Durham Lar GibbonUniversity primate researcher Esther Clarke. She set off for the Far East to study their elegant melodies, but then noticed something a little unusual in the quieter so-called "hoo hoo" calls that the gibbons were making, as she explained to Kat Arney...

Esther - Originally, I was interested in gibbon songs, which is what we know a lot about. They're very loud, long distance communication between groups. But while I was following them in the field, I noticed that they were making all these very quiet noises as well. Everyone seem to know about them as well. Everyone who had studied gibbons, but nobody knew what they meant and what they were for. And so, this gave me the idea to try to record some of these quiet calls and try to analyse them.

Kat - So, this is more like kind of gibbon chit-chat rather than shouting.

Esther - Exactly. This is the kind of talk amongst themselves, between close family members. It's not something you can hear from far away.

Kat - What sort of things do you think the gibbons are trying to communicate with these close range calls?

Esther - It's interesting because they make them all the time. So, I subdivided them into that 9 different contexts and I was able to analyse calls from 6 of those where I had a big enough sample size. These are things like meeting a predator for example, a ground predator like a leopard or a tiger, or an aerial predator like an eagle. Also, when they're feeding and when they're traveling.

Kat - So, let's have a listen to some of these calls here. Which one is your favourite first?

Esther - I have to say probably, the raptor is my favourite because actually, when I was in the field, the way I got them to make these calls was I had to show them fake predators. So, I made my own raptor model and I stuck it up in a tree and waited for the gibbons to see it. Initially, I thought it was a failure because they never have seemed to make any noise whenever they saw it. I thought, "They just don't believe it." All I heard were these tiny, tiny little "hoo-hoo" and I thought, "It's just totally ridiculous." and then I was lucky enough to see them with a real eagle owl. When I saw them, they made exactly the same noise. I realised that I had stumbled upon the actual raptor response.

Kat - So, let's have a quick listen to that....

How about another call when they notice something else?

Esther - Okay, so I can give you another example when they see a different type of predator. When they see a ground predator, a tiger or a leopard, the "hoos" are pretty much similar. They're louder and they come much more quickly. They're more intense and they're a higher frequency.

Kat - Let's have a listen to that one...

You mentioned that people have known about these kind of noises for a long time but never analysed them. I guess this is really a kind of the language that they're using to talk to each other.

Esther - I don't know if I'd use the word language, but it is definitely showing a complex form of communication. It's not just random noises that they're making, because we're finding in every contexts, they're consistently using the right as it were, type of "hoo". So, what's really interesting about it is that we typically think of the "hoo" as one type of call and this research has shown, it splits up to at least 6 and presumably many more different subtypes. And that means that their vocal repertoire is much bigger than we thought.

Kat - How did it feel to you when you first realised, "Wow! They're using the same call for the same thing, that means leopard"?

Esther - It was pretty exciting. When I showed them my model leopard for example, they got quite scared obviously because they really believe that it was a real leopard. That was a little disconcerting at first because they would be throwing branches at it and defecating at it and this sort of thing. But what's nice about it is when you're walking through forest and you hear gibbons in the distance and you can tell immediately just from listening to them what's going on with them. That's what I really liked.

Kat - So you can eavesdrop on the gibbons.

Esther - Yes, exactly.

Kat - Humans have a huge vocal repertoire, but obviously, we've evolved from ape-like ancestors as have the gibbons. When you think about human communication, you can hear, that's a man, that's a woman, you can hear different pitches in individual's voices. You have a different pitch, slightly different sounding voice to mine. Is that the same for the gibbons? Do they have their own personal tone of voice?

Esther - Absolutely, yes. So you can individually identify gibbons by their tone of voice. But also, what's interesting is that males are pitched higher than females and that's unusual among mammals because typically, males are lower pitched than females. And also typically, larger than females and that's generally why. In gibbons, there's no real difference in size between males and females at all. So, why it's quite puzzling that female voices are pitched so much lower.

Kat - Why is it that gibbons have such a limited range of vocal noises whereas humans can make all kinds of wonderful singing, shouting speech?

Esther - That's an interesting question. I think personally that gibbons have a lot more flexibility in their vocal tracts than we give them credit for. I think that the actual act of singing allows them to use more of their vocal tract potentially than other non-human primates. This is something that still needs to be tested, but we already know that the way that gibbons produce their song is similar to the way a human produces soprano song for example. I think that the more that we study them, the more we'll find that there is more flexibility. As much as language? No, I'm not sure about that, but definitely more than we know about right now.

06:10 - Finger lengths predict marathon times

Running a marathon anytime soon? The length of your fingers could predict how fast you'll be able to complete it...

Finger lengths predict marathon times
with Dr Danny Longman, University of Cambridge

If you're planning on running a marathon anytime soon, rather than thinking only Runningabout your feet you might also want to take a look at your hands! New research shows that the relative lengths of the index and ring fingers can predict your race performance. Graihagh Jackson jogged over to see Cambridge University's Danny Longman to find out how...

Danny - Testosterone stimulates growth of the ring finger whereas oestrogen, the female sexual hormone, stimulates growth of the index finger. So, if you have a relatively longer ring finger to index finger, that would suggest you had a more masculine hormone exposure within the womb exposed to a higher concentration of testosterone.

Graihagh - I'm now looking at my ring and index finger and they're quite close. My ring finger is not too far away from my first finger in terms of length. So, that might infer what about me when it comes to long distance running then?

Danny - Well unfortunately, it wouldn't actually be possible to measure just by looking but if you were to have a relatively longer index finger relative to your ring finger, that would therefore give you a predisposition to be more successful at sports due enhanced efficiency in development of your cardiovascular system, which could result in faster running times.

Graihagh - So, how did you look at this? How did you test this hypothesis?

Danny - We attended a half marathon race in Nottingham. The runners had just completed a half marathon, they extremely hot, sweaty and tired and were entirely bemused by the idea of having their hands photographed. But...

Graihagh - I can imagine. 'Give me a flapjack and some Powerade!' would be my initial reaction, I think.

Danny - Well, that was the way we bribed them. I gave them some homemade flapjacks in exchange for photographing their hands.

Graihagh - What did you find? The people with the comparatively longer ring finger to their index finger, were they better runners?

Danny - Yes. We found that in both men and women, there was a strong correlation between the ratio of their fingers and their half marathon performances. Now, this correlation was particularly strong in men. We found that men who were exposed to a lot of testosterone in the womb were on average, nearly 25 minutes faster when compared to men who exposed to a little testosterone.

Graihagh - That's quite significant and what about women? Was it as pronounced?

Danny - Well, there was still a significant relationship for women. It wasn't quite as pronounced. Women with higher testosterone exposure showed an improvement of approximately 11 minutes.

Graihagh - People with a short ring fingers in comparison to their first fingers, should they just throw in the towel now?

Danny - Well, although we did find a very significant relationship between a relatively long ring finger, the amount of difference in ability of this is explained by this genetic factor, is absolutely minimal compared to the effects that you can achieve through training, through diet, through a healthy lifestyle. We really do want to stress that this should not put anyone off running.

Graihagh - So, the longer your ring finger, the better the run you are, perhaps. So, what does that mean?

Danny - When these findings are considered within the context of our evolution, they suggest that endurance running ability may signal male reproductive potential and genetic quality to women.

Graihagh - Do you mean that women just would have found long distance runners sexier?

Danny - From one point of view, but what this study is suggesting is that in ancestral populations, ability to run long distances in these populations, where hunting was an important method of acquiring meat, could be one of these signals for portraying genetic quality.

Graihagh - What do you mean? People used to run down their food? I thought it was all bows and arrows.

Danny - Well, we're talking, very much, a lot earlier in our evolutionary history. Now, this persistence hunting is a technique by which hunters track and chase prey to the point of prey exhaustion. Tribes in the Kalahari in Africa and also the Tarimoro in northern Mexico are able to track down prey in this way. So, what we're proposing and what our study is suggesting is that the ability to bring back the meat and to be a successful hunter displays to women traits that are desirable in a potential partners such as intelligence to be able to track the animal, athleticism to be able to catch it, but also in generosity because this meat is then shared throughout the community.

Graihagh - And given this, that we would've been doing this sort of behaviour, and still are in some places, it sort of seems that we've been evolved to run half marathons at least once a week. What's happened? Because most people can't run for 20 minutes without tearing a tendon or something terrible.

Danny - Well, one perspective to answering that question would be to say that our lifestyle today is not the lifestyle to which we have evolved to perform. Humans evolved in much more stressful environments than we have these days. The technology that we have developed over the last 50 years is increasing in pace exponentially and it's actually shielding us from the environment within which we evolved. And so, the environment in which we lived today is a lot more sedentary and as a result of that, the levels of fitness that we perhaps enjoyed in the past are not necessarily enjoyed by the vast majority of the population today.

12:00 - Why are the Dutch so tall?

The Dutch are the tallest nation in the world, having grown a 20cm in the last 200 years. How did they reach such great heights?

Why are the Dutch so tall?
with Dr Gert Stulp, London School School of Hygiene and Tropical Medicine

The Dutch are the tallest nation in the world and, on average, they've grown a How Many Shells Tall are You?staggering 20 centimetres in less than 200 years. Height is determined by a complex interaction of our genes and our environment, but the driving force enabling the Dutch to reach their current lofty height may be down to a higher rate of reproduction among taller men, according to a new study from Gert Stulp from the London School School of Hygiene and Tropical Medicine. Kat Arney got the long and the short of it...

Gert - So, we got our hands on a very large dataset from the north of the Netherlands and the northeast, the tallest part of the Netherlands. And we basically examined whether height, if we control for factors like education and income, and health was related to the number of children.

Kat - So, that will tell you if there's some kind of natural selection, some kind of breeding effect going on.

Gert - Yes. If taller individuals would have more children, this might be part of the reason why the Dutch become taller because if taller individuals have more children and we know height is highly heritable, then it's plausible that the next generation consists of children who become taller themselves.

Kat - So, what did you find when you looked at all these data?

Gert - We found that above average height men had higher fertility compared to their shorter counterparts. In women, we found that average height women had more children compared to shorter and taller women. The effect of height was much stronger for men. So, if we combine these two findings for men and women, we can conclude that it's very likely that natural selection would favour taller heights.

Kat - So, that's kind of the family side of it. But obviously, height isn't just down to our genetics. What do you think may be some of the other factors that are on top of this genetic background? What are some of the other factors that may be increasing height in the Netherlands?

Gert - In the Netherlands, it has been suggested that our higher rates of consumption of milk and cheese have increased our heights and also, our good healthcare system and good access to healthcare, and very importantly, low levels of inequality in our society has also been attributed to our height advantage.

Kat - So, the Netherlands is very equal society. There's not that much difference between the richest and the poorest.

Gert - Yes. Less so than many other countries.

Kat - It seems very strange that something like inequality might be playing a role in height. How could that be?

Gert - Well, the reason is that if you are stressed for resources, either in nutrition or maybe when you have a higher risk of diseases, your body has to fight off these diseases or have to cope with the stress. That often comes at the cost of growth. So, we see sort of in poorer areas of society, that growth is stunted. So, children do not reach their full growth. Inequality have such an effect on height because if you have very unequal societies, this means that there will be a very large part of the population that is really stunted in their growth. Whereas in sort of more equal societies, you find it's less.

Kat - Do you think this could explain why some other countries that are very maybe similar to the Netherlands in terms of their diet, their environment, haven't attained this kind of astronomical height that the Dutch have?

Gert - I think that would be a very plausible explanation. Definitely, between the United States and the Netherlands, that would seem a factor. Interestingly, it has been argued that 150 years ago, the Dutch were almost as short as a European nation and at that time, the Netherlands was also much more unequal. Ironically, the Americans were the tallest western nation at that time and at that time, America was almost a much more equal than it is now.

Kat - You are an extremely tall man. You're well over at 6 foot tall and towering above me. I'm extremely small. So, when I go to for example, medieval places, they're kind of built for my sort of height. Have humans always got taller?

Gert - Indeed. If you look at historical times, we have become much, much taller and we think, how much taller can we get? But it's perhaps very interesting to also look a little bit further into evolutionary time because there are fossils found, from hundreds of thousands of years ago that actually were estimated to have heights of about 190 centimetres which is much taller than you and also many others living in western countries. So, it might very well be that our evolutionary heritage allows us for even more growth. Having said that, there is some evidence that the Dutch have stopped increasing in recent times which might suggest some biological limits to growth. That said, we also live in time of relative financial recession and it could very well be that when the environmental quality improves again, when things are looking up again, that the Dutch might even grow further and further, until a point that they're perhaps gravity will severely constrain further growth.

Georgia - A tall story indeed. That was Gert Stulp from the London School of Hygiene and Tropical Medicine.

17:08 - Digging up hominids with archaeologists

Palaeo-anthropologists in South Africa are inviting tourists to watch them at work excavating a new species of human ancestor...

Digging up hominids with archaeologists
with Professor Lee Berger, University of the Witwatersrand

A new species of early human ancestor is providing a tourist attraction with a difference. In a first of a kind initiative, scientists in South Africa are about to turn one of the world's most archaeological digimportant fossil sites into a live laboratory, where members of the public can look down into a cave where the two million year old remains of the members of a species of early human ancestor, called Australopithecus sediba, are being excavated by scientists. Professor Lee Berger, who discovered the site and is leading the project, took Chris Smith to the location, which is near Johannesburg...

Lee - We're at Malapa site where in 2008, my then 9-year-old son made the discovery of the first remains of what would turn out to be a new species Australopithecus sediba. A 2-million-year-old early human ancestor and this site since then has turned into one of the richest early human ancestor sites on the continent of Africa, if not, in the world.

Chris - What actually is the site? What's here?

Lee - What's here is an ancient cave. It was probably about 15 meters under the ground about 2 million years ago. The ground is eroded since then and collapsed leaving us with just the contents. The cave is like a big swimming pool that you'd fill up with concrete throwing bones intermediately into it and in this case, some of those and in fact, quite a lot of them, were skeletons of this early human ancestor species.

Chris - How did the skeletons get in there?

Lee - We don't know. We hypothesise right now that there were some sort of trap or attractant in here. Maybe if you imagine a pool of water that they desperately needed to get to. Whatever was causing them to go in here, they were taking a great deal of risk to do it and it appears that some of them were dying in the process.

Chris - How many remains of this ancient human ancestors are there here?

Lee - Well, we don't know the answer to that. That's why we're building this laboratory over the top that we've begun excavation. But so far, what is exposed on the surface have been two main skeletons and at least the remains of 4 other individuals that we found so far. But every time we open up a little bit of rock here and move a little bit of dirt, we see someone new. We're introduced to another one of these people that died 2 million years ago.

Chris - Why have you elected to build the laboratory here rather than take these remains to the laboratory?

Lee - The problem we have in Malapa is that as we began working here, we realised this was no ordinary circumstance. We had to have an environment that we could protect those fossils that we exposed as we were working. And so, that required us to build something very, very special here - a laboratory that would protect this remarkable fossil. We also then found out this wasn't just a normal type of rock that they were contained in. it was a rock that was preserving organic material.

Chris - And what is that?

Lee - Plant remains that are captured in it, seeds, things like that, even food particulates that are captured in the teeth around so we can see what they were eating. Maybe more remarkably, we think we've found fossil skin here too. So, there was a lot of reason to protect this site, but we also needed a platform then to take off large pieces of the site to work on them in the laboratory.

Chris - I wonder if - just so that people listening to this can appreciate when you say protect the site - can you describe the vista for people?

Lee - That's right. We're seen in the middle of about an 8,000-hectare pristine nature reserve where there's really nothing in here except game. I mean, there are leopards around us, there are zebras, there are wildebeest. All these type of animals here and it's a pristine environment. We're seeing at the head of a valley that we can look northward and see out into the Mahale's bird mountains with nothing but wilderness in front of us at that time. So, we had to build something very special here that I didn't want to be visible within the environment. On the other hand, this is an important site. It's a site that people will be journeying to for hundreds and hundreds of years. So, I want it to be spectacular. And I know that sounds like an oxymoron, something that's invisible and spectacular. That's why we went to so much design effort and ended up with almost an organic structure itself, almost a beetle-like structure that sits over this site. If you're a tourist, you can actually come and stand over to watch us excavate.

Chris - The easiest way to describe this will be a bit like a wigwam that's open at the bottom around the covering. So, it's keeping the weather off. It's keeping the sun and the rain off. And it means that you can work underneath this walkway because you got a suspended walkway here. It's a couple of metres - 2 or 3 metres above the ground - isn't it?

Lee - That's right.

Chris - Is that so, that you're saying tourists, are you going to bring people out here to look at you working?

Lee - Well, absolutely. Actually, within the next couple of months, you'll be able to come out here as a tourist and probably the only place on the planet you can see a discovery of a hominid live.

Chris - Can you tell us a little bit about the "people" who would've been the inhabitants of this environment who you're now finding two-and-a-bit, maybe just under 2 million years later in this pit in the ground?

Lee - If you imagine we were standing here 2 million years ago and they walked out of these trees around us, at a distance, you would say, "Those are humans". They walk on two legs. Until they got closer, you probably wouldn't realise what's bothering you but something would bother you. One would be the most striking thing - would be their height. They would probably only be standing about 1.3 metres tall. They also been more lightly built. They would've been quite grass or quite skinny. They had longer arms than we do, more curved fingers. So, they're clearly climbing something. They also would've moved a little different. Their hips were slightly different than ours and their feet are slightly different. So, their gait would've probably been a more rolling type gait, slightly different from the more comfortable long distance stride we had. As they got closer to you, you'd be struck by for the most obvious thing which would be, their heads are tiny. If you imagine, you take a man's fist and curled it up, that's about the size of their brain and that would strike you. There'd be almost this pinhead on top of this small body. And that would immediately make you recognise that this is not a human.

Chris - Where do we fit in to this story related to these individuals?

Lee - Well, we don't know to be frank. It's maybe just a late member of what we call the australopithecines, the australopithes, which are often considered to be kind of the root branch just before our genus that would give our eyes to us. They do share a lot of remarkable features that only members of our genus have like reduced dentition and the shape of the pelvis, and some other features of the hand.

24:03 - What is death?

How do we decide when someone is dead? Do we look at the heart or the brain, and do we need to redefine it?

What is death?
with Dr John Troyer, The Centre for Death & Society at Bath University

The impact of modern medicine is drastically changing our concept of death. SurgeryIncreasingly, people are being resuscitated successfully, sometimes hours after they first died. Does this mean we could defy death? And do we want to be immortal anyway? Philip Garsed hit the streets of Cambridge to canvass opinion...

Philip - Would you like to live forever?

Male - I wish but it's not possible.

Female - No, I don't think so.

Male - No, I don't think so.

Male - If I am healthy, yes.

Child - Not forever, but for quite long.

Male - No.

Female - Not really.

Male - No, not really, no.

Philip - Around 90% of the people in my tiny sample didn't like the idea of living forever, but why and could I change their minds?

Male - Life will become a bit of a bore if you live forever.

Male - I've seen so many terrible things that wouldn't please me.

Male - It's just too long.

Philip - If you could keep your health, would that change your mind?

Female - No. I don't think it would.

Female - Only what keeps my family going with.

Female - I'd like to live forever if I could stay young.

Philip - So, if science made that possible, you'd actually be really quite keen?.

Female - Yeah, definitely.

Georgia - It seems that most of us don't want to live forever. Although fear of the effects of ageing seems to be what's putting most people off. But the impact of modern medicine is changing things and increasingly, people have been resuscitated successfully sometimes hours after they've apparently died.

So, should this make us reconsider how we think about death? Could we continually resuscitate people throughout their life, defeat the maladies of ageing, and maybe one day, live forever?

And more importantly, would we want to?

Chris - It wasn't all that long ago that if you were dead, you genuinely were dead. But that didn't stop people trying though. In the 1700s, doctors attempted to revive drowned patients by tickling the backs of their throats with a feather, strapping them onto a trotting horse, even blowing smoke up the rectum or even for good measure, giving them a good whipping.

Well, reassuringly, today's methods of resuscitation are probably more comfortable and more effective. But as a result, the boundaries between life and death are becoming much more blurred. When is someone actually, medically dead?

With us is John Troyer. He's the Deputy Director of the Centre for Death and Society at Bath University. Hi, John.

John - Hello.

Chris - What is actually the definition of someone who has died?

John - The current definition is neurological or brain criteria. And so, when the person has complete or total brain death, which includes the brain stem no longer operating or functioning then you are dead.

Chris - A lot of those things that you've drawn on their though John, are very contemporary. They make use of modern medical definitions and medical assessments of people. What did people use to think in the old days?

John - For millennia, death was simply heart death. So, when your heart stop beating, you would die because there would be a lack of oxygen going through your system and that would cause death. In about the 1950s, it became understood that individuals could, in theory, be kept alive in a kind of comma state - this idea that you could have a person who someone seemed to be alive even though they were physically looking dead. And that was when we began the surge through the '60s, '70s and '80s, particularly in the western first world, the development of life support technology that could in fact restart a stopped heart or could in fact keep you on ventilation, artificial circulation, and oxygen input so that you could in fact keep a person who seem to not be fully functioning somehow alive.

Chris -   Of course, this is a moving definition because people were pretty comfortable that if you said someone was brain dead a few years ago, that meant they just had no brain function whatsoever. But then on this programme Adrian Owen sat here and said, "I'm about to publish a paper in the New England Journal of Medicine where I am communicating with a brain scanner with people that no one has spoken to 4 or 5 years or so because we thought they were brain dead.

John - That's right and the definition will not certainly change. I mean, we're using as sort of mid-20th century concept of death right now and if there's one thing that can be certain about the definition of death is that it will change as different kinds of sort of diagnostic tools become even stronger or new approaches to thinking through what is going on inside the brain when we think that a person is dead. The big questions right now is if a person who seems to be dead or is in a persistent vegetative state, is responding to stimuli, is that person still that person? Meaning, is there still a conscious person there or is it a response that is a response, but it might be different than what we think of as actually being the person, him or herself. These are the bigger questions that we're getting into now.

Chris - That's John Troyer from Bath University's Centre for Death and Society.

29:11 - Back from the dead

Two-year-old Michelle Funk was trapped under the ice for over an hour without oxygen. She made a full recovery, but how was this possible?

Back from the dead
with Dr David Casarett, University of Pennsylvania

In recent years, there have been a number of cases in which people have defied Icey pooldeath by surviving for hours without oxygen. The cells in our bodies need oxygen to survive; without it they begin to die and brain damage sets in within five minutes. Yet these patients have made a full recovery. What makes them special? David Casarett is a clinician at the University of Pennsylvania and has an interest in this field. He told Georgia Mills the story of a girl who had been submerged under the ice of a frozen river...

[Transcript to follow]

34:49 - Frozen in time: The truth about cryonics

Cryonics is the preservation of people at low temperatures, with the aim of resuscitating them in the future. So how does it work?

Frozen in time: The truth about cryonics
with Garrett Smyth, Cryonics UK

In theory, cryopreservation - the process of using low temperatures to preserve Cryonics Stabilization Equipmentpeople - is possible, but how would it work in practice? Garret Smyth is one of the first UK residents to sign up for the scheme; he's also the co-founder of the cryonics organisation, Cryonics UK. Cryonics UK have a specially-designed ambulance that cools and prepares patients for shipping to a long term preservation facility in America or Russia. They have been in business for over 5 years and he told Chris Smith how they are process a patient, starting with a specially-prepared ambulance...

Garrett - From the outside, it looks like a pretty regular ambulance. Inside, a lot of the stuff is the same, but there's an important piece of equipment, which is a container that can hold ice and water as well as also, so you can put the patient in there. They will, by this point, already have been put on a machine that compresses the chest, and the CPR.

Even though the person is legally dead, the blood is continuing to be circulated so that allows them to cool down quickly. But then as they get down near zero, one has to replace the blood with a medical grade anti-freeze or cryoprotectant as it's called. This has a slightly lower freezing temperature so you can get them down below zero. It also replaces a lot of the water in the cells. So, there isn't a sort of bottle of liquid in a freezer effect of expanding ice. The water comes out of the cells and we would take patients down to dry ice temperature.

Chris - That's about minus 60, isn't it?

Garrett - 78, I think. Then they're flown over to the states or if you choose Russia, where you're brought down to liquid nitrogen temperature. If it's all gone well, in the best of circumstances, you've actually got enough anti-freezing to stop ice crystals forming.

Chris - So, the whole thrust of this is  by getting the body temperature right down, really quickly, you reduce the rate at which any kind of decay or degradation of the tissue is going to happen so that they're then placed in this storage facility in liquid nitrogen, nearly minus 200 degrees C which means that they should "survive" in that pristine or as near pristine state as possible, until such time as they can be - well, for want of a better phrase, reanimated.

Is it possible though to store an entire human in this sort of way? Does the tissue not do what happens to a raspberry or a strawberry if dumped in the freezer and just explode?

Garrett - A raspberry and a strawberry are not very good models for animals due to not having a blood supply. Because of the blood supply, you can get very close to every cell in the body and replace - as I was saying - the water with anti-freezers, which stop crystals forming.The biggest thing so far...

Chris - But has anyone actually done this would say - if I took a hamster or a mouse and I anesthetised it and replaced all its body water with one of these cryoprotectants and put it in ultimately liquid nitrogen and then later, thawed it out, can I come up with a viable mouse that way?

Garrett - At the moment, not a mouse. A kidney has been done and it's a rabbit kidney so it's not going to be that big a kidney, but it is a proof of principle of being able to do it.

Chris - So, why hasn't anyone succeeded with a whole organism like a mouse or a hamster or even something bigger?

Garrett - When I say no one has done it with a hamster, as long as you don't get too cold. It has been done with a hamster. Audrey Smith at the Mill Hill Institute in London did it in the 1950s. There always seems to be someone stopping the research. It's very frustrating because really, without much research, it could be done properly and much better.

Chris - Because obviously, that's going to be fundamental to this working because if the current techniques are being employed, but you can't do this on an animal model, then there's not much hope for say, you as the UK's first person to sign up.

Garrett - One aspect of it is research and I entered it knowing fully that it wasn't done perfectly and the situation has improved a lot. They're now doing vitrification rather than freezing, which is a great improvement. They couldn't vitrify kidneys when I first signed up. So, it's an ongoing research and I joined in order to support the research.This is why I'm advocating we really should do more research. So, if you're going to make me wait a thousand years, as long as I'm kept in good condition, I'm willing to take the chance. I was listening to a programme the other day where they were talking about bringing back the dodo using 3D bioprinters and I was thinking, you know, because they can bring about the dodo, I'm going to be easy...

39:26 - You could live forever - as a robot!

Brain emulation is where you upload your brain to a computer and become immortal. But is this feasible and why seriously consider it?

You could live forever - as a robot!
with Dr Michio Kaku, City College of New York

Thanks to President Obama's brain-mapping project, it looks as though we could Robotbecome immortal by copying our brains and uploading them on to a computer, or even a robot. In this form, that "person" could hypothetically live forever. Michio Kaku is a theoretical physicist who's been looking into the possibilities and thinks this might be achievable within a generation or two, as he explained to Georgia Mills...

Michio - Well, the digital era has made possible several scenarios. The simplest one is to create a library of souls, whereby, you take a person like Winston Churchill and calculate the sum total of their credit card transactions, their video tapes, interviews, everything. You construct a hologram which then gives you a reasonable facsimile of having a conversation with Winston Churchill. And as more digital information is compiled, you're simulation gets better and better. So the library becomes a library of souls. But the big money as you mentioned is this billion dollar initiative by the European Union and by President Barrack Obama to create a connectome or a map of all the neurons of the brain which in some sense will give us a duplicate of our dreams, our personality, our soul. Our soul reduced to information. So, in the future, we're going to have two disks. The first disk will be the genome by which our genes can be reproduced forever, but the second will be the connectome with all the neural pathways of the human brain. And then when you die, your genome and your connectome live forever. And so, this is a form of digital immortality.

Georgia - We know how to map out someone's genome. How would you map out their brain, their connectome?

Michio - Well, there are several ways to do it. First is the slice and dice approach which is very crude, very primitive, whereby you use a microscope and a razor blade and slice the brain. That's been done with fruit flies for example but is very tedious. More recently is the optogenetics programme coming out of Stanford University whereby we can actually look at neural pathways for certain behaviours by lighting them up with a flashlight. This is amazing - using flashlights to basically work out the neural pathway to certain behaviours. And so, we think that it's going to take many decades but we will have a connectome with all the neural pathways of the human brain. And then the question is, well, who wants to live inside a computer? Rather boring, right, living forever inside a computer?

Georgia - Yeah, no thank you.

Michio - But you see, we will create surrogates. Surrogates are robots without a mind. They have perfect bodies that can live on Mars, Jupiter and are handsome, beautiful, gorgeous, immortal, and then the connectome of the computer communicates with the surrogate. So, it's as if you are inside the robot. And so, this could be the future of space exploration that our connectome will basically drive mechanical surrogates, will be superhuman, will be able to live on Jupiter and Mars, and different kinds of hostile environments. And we'll be able to explore the universe in this way, being immortal.

Georgia - So, once we've nailed this technique, we could just beam our brains anywhere in the galaxy I suppose.

Michio - Right. In fact, I see that even in the next century, consistent with laws of physics, because I'm a physicist, we'll be able to put the connectome on a laser beam and shoot the laser beam into outer space. It would take us one second to go to the moon, about 20 minutes to go to Mars, riding on a light beam and on Mars and on the moon would be a surrogate. And so, you would basically live your life as a robot on the moon, Mars or wherever. And so, this is the cheapest, most effective way of space travel. Forget the booster rockets, forget weightlessness, forget cosmic rays. Think about riding consciousness on a light beam...

Georgia - I love this idea of becoming a superhuman robot that can fly around in space and everything. But firstly, would it still be me? Would it not just be a copy and secondly, what about all the things that make us human like having sex, eating? Would they just disappear?

Michio - No. you'll be able to have super sex, you'll be able to have different kinds of phenomenon in sensations that you can only dream of today, and you'll do it in robotic form. Now the question is, is that really you? Well, if you define you as basically the wetware of your brain and the software that governs the wetware, then of course, then when you die, that's gone. That's not going to come back. But this is a very reasonable facsimile of you with all your memories, all your personality quirks, everything being digitalised and becoming immortal.

Georgia - Has there any science been done yet that might imply that this could actually happen?

Michio - Yes, on a primitive scale. We are children. Children when it comes to being able to map the brain. But with optogenetics, we've been able to actually look at the neural pathways for certain kinds of behaviours. This was once considered far beyond anything we can do and we do it. We used genetic engineering to modify the neurons of a certain pathway so that when you turn on a flashlight, it fires. It fires and by firing, you can actually trace the pathway for certain kinds of behaviours. With a flashlight, you can make a mouse for example chase its tail or a fruit fly take off. And this has changed the entire scientific landscape. In fact, the Nobel Prize will go eventually to the inventor of this technique because it has been a game changer.

45:46 - Is immortality a price worth paying?

We debate the consequences that an immortal population could could bring about...

Is immortality a price worth paying?
with Dr John Troyer, Bath University; Garret Smyth, Cryonics UK; and Dr Michio Kaku, City College of New York

With a growing population and 7 billion of us on Earth already, can we cope with an immortal population? John Troyer, Garret Smyth and Michio Kaku debate the pros and Bear in the Skycons with Chris Smith...

Garrett - I don't particularly want to be vitrified or suspended.That's really my last-ditch thing to do. I like being alive and I want to stay alive. 

Chris - I mean, the only thing that's bothering me Michio with what you were saying is that, fine, you end up in a computer and you exist. Aren't you going to be sort of stuck with 21st century thinking?

Michio - Well, one danger of immortality is stagnation that old thinking may begin to dominate all of society. That's why we have to make sure that we encourage creativity, innovation, youthful kind of thinking or else, we will in fact stagnate as a consequence. But think of all the benefits that we could have. One thing that separates us from the animals is that we have a culture and that is, that we can hand down information from generation to generation. Mama bear does not teach baby bear how to hunt in the forest other than by behaviour. There's no culture among animals. However, this culture will be enriched once we have the ability, not just with information, but the entire personality being preserved. And so, I think that society, instead of stagnating could actually benefit from this. Our culture will be greatly enriched once we have this kind of digital immortality.

Chris - John, are you comfortable with this idea over the whole preservation of the body because of course, as I mentioned at the beginning, there are 7 billion plus people on Earth? We're expecting that number to exceed 10 billion by mid-century. Surely, preserving ourselves in silico - in a computer - is better than preserving ourselves in the flesh.

John - There's a key issue for both, let's say, methods of preservation which is both the revivification or the bringing back. But also then the long term support and then how basically do you keep everything from degrading. How do you keep the information itself from breaking down over time?

Chris - Well, the other important point is I suppose Michio, is there not a danger if you exist as a computer programme that someone might infect you with a computer virus? 

Michio - Yeah, there's always a danger of hacking as well. What happens if somebody hacks into the memory of an Albert Einstein and corrupts it? So all of a sudden, you get nonsense coming out. That's always a danger. However, I think the risks are far smaller than the benefits. We're talking about enriching our culture.

Chris - So, there you go Garrett. It looks like you're going to have to preserve yourself until such time as you can exist in a computer programme.

Garrett - I don't think that an animatronic Winston Churchill would really be Winston Churchill. So, I really do plan if it all works out, to come back as me, as a biological me. I think if I could agree - whilst, I don't want to be a robot and I know a lot of people that don't, I would like to agree with Michio on how people living longer, whether or not people are cryopreserved, the anti-aging research will go on. One of our problems in the world is that people forget what the history and what has happened before. So of course, they're doomed to repeat it. 

Chris - But that's what Michio is sort of saying, that if we have this sort of collective knowledge then actually, we can have Winston Churchill on tap or Einstein to help us solve problems and then we won't actually arrive at that situation. Do you agree Michio?

Michio - Yes, I agree because I think as I mentioned, what separates us from the animals is the culture that we hand down generation after generation. But why do we have to lose that generation when they die? All that wisdom and knowledge essentially evaporates when people die. Why should it be that way? Why not benefit from this? And so, why do we have libraries? We have libraries because we opt to benefit from reading about biographies of the lives of famous people. But why not actually interact with these famous people? Now at first of course, the first generation of the library of souls is not going to be very good. However, as the decades go by, once we have the entire connectome then it will be indistinguishable. The library of souls will be indistinguishable from the real thing. No experiment can differentiate between an Einstein and the Einstein that's been digitalised because the connectome is identical.

Chris - Michio, thank you very much and that's where we must leave it. Thank you very much to Michio Kaku, John Troyer and Garrett Smith.

50:28 - Why are ripe pears juicer?

Unripe pears are dry, yet ripe pears are juicy so how do they become moist?

Why are ripe pears juicer?

Unripe pears are dry, yet ripe pears are juicy so how do they become moist? Philip Garsed put Dennis' question to plant scientist Sonia Dunbar, from Cambridge University...

Sonja - Fruit ripens to make it more appetising to creatures so that they will eat it and spread the seeds of the plant.

Philip - The animal gets a nice nutritious meal whilst the plant gets its seeds carried far away inside the animal before, of course, being deposited in some first class manure. Lovely, but what changes have to happen to our pear to change it to a lovely sweet and tasty fruit?

Sonja - The rest of the plant supplies the fruit with a sugar called sucrose. Some fruits like grapes break this down into two sugars called glucose and fructose. This is why fruits like grapes need to be left on the plant until they're fully ripe. Other fruits like our pear store the sucrose's starch which is not very sweet. And they then break it down into glucose and fructose later on. That's why a pear gets sweeter just sitting in a fruit bar.

Philip - But why does it get squishier as well?

Sonja - The texture of the fruit changes because of three enzymes called pectinase, cellulase, and lipase which together break down the fruit cells. Firstly, pectin is the material that helps glue the cells together. You might have used it to make jam. Pectinase unglues the cells. The second enzyme, cellulase breaks down a material called cellulose - the stuff that make cell walls stiff. Lastly, a third enzyme, lipase also lends a hand by breaking down the fats in the cell membrane. Combined, these enzymes make the fruit cells leakier and less tough. So the fruit is softer and juicier.

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