Ice Age Giants; Brazil with Michael Palin; Guts: The Strange and Mysterious World of the Human Stomach

The second episode of Ice Age Giants was about the large mammals in Europe during the Ice Age. Roberts started by visiting Transylvania where there is a cave that contains fossil cave bears. The caves also have patches of the walls that have been worn smooth by the bears passing through the caves. These bears were larger than grizzly bears, and were vegetarians. As with modern bears they hibernated, and the animals found in the caves are mostly those that didn’t make it through the winter. But the cave bear specialist showing Roberts these also showed her two that seem to’ve slipped down a steep slope in the cave & failed to make their way out – there are scratch marks in the mud on the cave walls that look like the two bears, an adult & a cub, failing to scramble back up.

Also found in this cave is a cave lion skull. These were one of the top predators of the European continent and mostly ate medium size herbivores like deer. But it seems this one, through desperation or foolishness, had tried to sneak up on a hibernating bear and found it still awake. They had done a CGI fight between the bear & the lion which looked very impressive but not quite real enough. The lion’s skull showed signs of damage from teeth which is why it was thought to have died in a fight.

Cave bears were common early in the ice age, but became rarer as the temperature got colder and eventually became extinct at the beginning of the last glacial maximum. But some animals thrived in the colder weather and the first of these that Roberts talked about was the Woolly Rhinoceros. These animals looked exactly as you’d expect – a rhino with wool, with a bigger horn than a modern rhino. A well preserved one has been found near a remote town in Siberia so they know what the wool looked like as well as the skeleton. Preserved woolly mammoths have also been found in this area, including a baby one that I’m pretty sure we’ve seen before in another Alice Roberts programme.

Both the rhinos and the mammoths were herbivores, and ranged over a wide area from England to Canada – due to how much water was locked up in ice at the time Britain was linked to the continent via a land bridge, and Alaska & Russia were also linked. You’d think that during the ice age herbivores would have problems in the winter due to snow, but actually there was little snow across this area again due to the amount of water locked up in ice sheets. The Mammoth Steppe, as it is called, was an open grassland with lots of flowering plants. This is known from work done in Canada examining the contents of fossilised ground squirrel nests. The squirrels hibernated and stocked their nests with food for the spring before they slept. The nests of ones that failed to make it through the winter obviously still have their spring food store in them when they are excavated and this lets scientists see what seeds and fruits were around at this time.

The last animal discussed were human species. Starting with Neanderthals who are known to’ve killed & butchered mammoths. The expert Roberts talked to thought that they probably did this by herding one down a dead-end gorge and then flinging rocks down from above to kill it. The CGI for this bit was a little less than convincing, which was a shame. The other human species at this time was our own one, and Roberts looked at evidence that they used the mammoths for more than just food. It’s though that they built houses from mammoth tusks (as the tent poles) with hides stretched over them for a roof. Roberts also looked at a piece of carved ivory, in the shape of a bison, from this time.

In the third episode of Brazil with Michael Palin he travelled through the south east of Brazil to Rio de Janeiro. First up was an old gold mine and a current iron mine – this region is a source of a lot of Brazil’s mineral wealth. The gold was mostly mined on behalf of the British (I almost said “by the British” but that’s very much not true). There was a brief stop off at a couple of places, one of which was a farm where a man had a cow with 5 legs and two digestive systems, which was actually mostly to show us how the rural poor lived I think.

Then on to Rio de Janeiro where the rest of the programme was set. Palin didn’t just visit the rich bits of the city but also the poorer areas. The Brazilian government is making a huge effort to clear up these areas and drive the drug lords out and drag the communities into the 21st Century before the World Cup and the Olympics. First armed troops go in for the “Pacification” and then there is investment in the infrastructure and projects like schools and boxing clubs for the youth.

And in last episode he visited places in the far south and the south-west of Brazil. He started by visiting a current heir to the no longer existent Brazilian throne … I hadn’t even been aware that Brazil had been an independent monarchy, apparently they’re descended from the Portuguese royal family. And from that leftover from the past he went on to visit an aeroplane making company, very much an example of Brazil’s future.

Palin then spent some time in Sao Paolo, concentrating mostly on the poorer side of the city, and also pointing out how many Japanese immigrants there are in this part of Brazil. He then went to a town that was like a theme park Germany transplanted to Brazil – Blumenau. Obviously they’d dressed up to do their traditional dances for the benefit of the cameras, but when he then talked to some of the residents of the area they were saying they felt German first & Brazilian second, even though they weren’t necessarily first generation immigrants.

And the series finished up with a trip through some of the more unspoiled areas of wilderness in the south. J commented while we were watching that one of the places was the sort of place an Ancient Egyptian might want to end up. Pantanal is an area of wetlands, that floods annually. The residents farm cattle and the wildlife includes species of ibis.

Guts: The Strange and Mysterious World of the Human Stomach was a programme we’d recorded a while ago, but I wasn’t sure if I was going to be too squeamish to watch. In the end it turned out to be mostly OK – just one sequence where I kept my eyes shut most of the time, and only a couple of contenders for “worst job ever” 😉

The thread tying the whole programme together was a demonstration Michael Mosley had done at the Science Museum. He swallowed a small camera which transmitted pictures from his digestive system over the course of the day. First it travelled down his oesophagus into his stomach, and spent a while there. They supplemented this batch of pictures with a set from a more high resolution camera on a tube that went down his nose, and he ate a selection of brightly coloured veg so that we could see them arrive in the stomach and start to mix with the gastric juices. Then after that second camera was removed he ate a large meal, and there were pictures of that being digested – most of what you could see was the veg, the steak had pretty much disintegrated by the time it got to the stomach. After that the camera moved through the small intestine, where we could see the intestinal villi which are little frondy projections from the surface of the small intestine to increase the surface area available for absorbing food. The stat they quoted was that the surface area of the inside of the human small intestine is about the size of a tennis court. Then the camera proceeded into the large intestine where it mingled with the faeces.

In between the various pictures of Mosley’s insides there were a series of short segments about related things. In the first of these he visited a historian who told him about the discovery of the composition of gastric juices. This was fairly astonishing – a doctor (William Beaumont) in Canada had a patient who had been shot in the stomach, and when the wound healed it left behind a small (inch or two diameter) hole in his flesh straight into the stomach. So afterwards the doctor did various experiments both putting things through the hole into the gastric juices to see what happened, and also drawing out some of the gastric juices to do other tests. Before that digestion was thought to be purely a mechanical process, but this doctor showed that the chemical action of the acidic gastric juices was a critical part of it. There was also a very brief segment just after this where Mosley dipped a coin in a beaker of artificially made up gastric juices and saw that it cleaned the coin.

Still on the subject of the stomach there was a segment about gastric bypass surgery. Which is the one I shut my eyes for most of – I can cope with pictures of someone’s insides, but not so much with surgical stuff stuck into someone. The operation we watched (or in my case listened to) was on a severely overweight man who’d had a heart attack in his late 20s, after a couple of years of unsuccessfully trying to shift the weight his doctors decided that gastric bypass surgery was the best option. I didn’t know before that what actually makes most of the difference after these operations is that there are behavioural changes. Partly because a hormone secreting part of the stomach is segregated from food so doesn’t do its normal job with increasing appetite, and partly because the bit of the small intestine that sends signals to say “full now” is closer to the stomach so the signal is sent sooner after eating starts. 6 weeks after the surgery the patient was saying he’d lost 3 stone, and had gone from never feeling full to being satisfied after eating quite small meals.

When talking about the small intestine there was a segment on perception of gastric pain, and the correlation with differences in personality. For this Mosley filled in a personality test then went through some pain tests (tube down the nose, balloon inflated in oesophagus till it hurt) while hooked up to blood pressure & heart rate monitors. The doctor doing the research was classifying people into either neurotic or extrovert categories, and he had found that the two groups had different responses to pain. Neurotics (like Mosley) showed reduced blood pressure and reduced heart rate. That’s not at all the expectation Mosley went into the test with – the textbook reaction to pain is increased heart rate & blood pressure, which is what extroverts show. The doctor was saying this has implications for treatment of gastric pain – different treatments will work better with different types of patients.

Moving on to the large intestine we had the two candidates for “worst job ever”. First up was the woman who cultures samples of faeces in the lab to look at the types of bacteria they contain. The ecosystem of the large intestine is very complex, with a large number of different types of bacteria. These can aid us in our digestion by breaking down the things we can’t, or they can be the cause of problems. She also talked about flatulence (which is a by-product of a healthy digestive system) and how the differing smells of farts is down to differing compositions of bacteria in the large intestine. Smelly ones are down to having more hydrogen sulphide producing species. Flammable ones down to having more methane producing species. Second candidates were the two people who were doing faecal transplants – in these faeces from a healthy person are mixed with salt water and put into an unwell person’s stomach via a tube down the nose. This can introduce a better mix of bacteria to the gut.

So this turned out to be quite an interesting programme, although I was somewhat glad that we ate our pudding during the other programme we watched on Wednesday rather than during this one!

Wonders of Life; Brazil with Michael Palin

The third episode of Wonders of Life had the theory of natural selection as its theme, but once again didn’t approach it from the direction I expected. Instead Cox started by talking about how the most important element for life is carbon, because of its versatile chemical properties that allow it to form large & complex molecules with a variety of other elements. These molecules include proteins (which are the building blocks of organisms) and DNA (the instruction set). So he started by telling us about carbon being formed in stars, and then talked about how carbon in the atmosphere gets into organisms. The first stage is photosynthesis – where plants take CO2 and energy from the sun and turn them into sugar (a molecule with a carbon backbone) and O2. From here Cox moved on to talk about how the carbon that the plants are made up of move through the food chain – a lot of animals eat plants, but they are hard to digest because a lot of the carbon is bound up in molecules like cellulose & lignin which are important structural parts of plants. Termites solve this problem by farming fungus in their colonies, which digests the wood they bring it and then the termites eat the fungus. Giraffes in common with other ruminants have a complicated digestive system with multiple stomachs, one of which contains bacteria which help break down cellulose. Other animals take the shortcut of eating animals instead of plants – there was some great footage here of a leopard coming to pay a visit to the (very open!) car that Cox & camera crew were sitting in. I don’t think I’d want to go on safari, that’d freak me out!

Having established how animals get their basic components (to some extent) and talked about foodchains, Cox now moved back to DNA and how come there are so many different sorts of organisms. First he gave a brief description of how DNA codes for proteins (with not much detail) and then we talked about what drives mutations. He name checked the sorts of causes, and showed us one – cosmic rays. That was a pretty neat experiment, I don’t know that I’d seen a cloud chamber before and it was cool to see the cosmic rays passing through the vapour in the tank! He then talked about the incredibly high number of combinations of possible DNA molecules that there are if everything was down to random chance – most of which would be instructions for organisms that couldn’t live. So there must be something that constrains the set of combinations, and that something is natural selection.

I found his explanations here to be rather muddy to be honest, perhaps because I would’ve approached the subject differently if I was doing the explanation, perhaps because it was a high level overview of something biological told by a physicist so something got lost in the translation. But we got neat footage of lemurs in Madagascar, so that made up for it for me (and I hope that other people watching it who didn’t know what he was talking about in advance found it comprehensible). The gist of it was right, anyway – that variation between organisms affects their chances of survival (like having a slightly longer thinner finger for an aye-aye makes it easier for it to dig out insects from trees so that makes it easier for it to get food and to stay alive). If something survives more, it has more offspring so there are more like it in the population. And over time these changes can build up (the middle finger of an aye-aye looks really very different to that of other lemurs), and if the population is isolated in some way from the rest of its species then they will become a different species and no longer able to interbreed with the originals. Isolation can be geographical (he showed us how the break up of the supercontinent Gondwana had left Madagascar isolated for tens of millions of years), but it can also be within a geographical area by lifestyle or habitat. (After complaining about his muddy explanations, I think mine probably are too, ah well.)

The fourth episode was all about size, and how the laws of physics affect the size of organisms and the size of organisms affects which laws of physics are important to the organism’s everyday life. He started by swimming with great white sharks (he was in a cage so quite safe, but frankly I would really rather not have that experience personally), and using them to illustrate how the effort required to move through water constrains the shape an animal is – sharks, as with fish and aquatic mammals, are streamlined. He also talked about how living in water allows animals to grow larger, because the water counteracts some of the effects of gravity.

This moved nicely onto a discussion of how on land as animals get bigger they need bigger skeletons to support themselves, and this constrains the sorts of shapes they can be (big animals are proportionally bulkier) and the ways they can move. He illustrated this with Australian marsupials, and worked in an explanation of how kangaroos’ locomotion is so efficient because their elastic tendons store the kinetic energy that they have when they land, and then use that to spring back up again. But the main point of this sequence was to show us the relative femur (thigh bone) sizes of various marsupials both living & extinct. As the length of the bone increases (so the animal is bigger) then the cross-section increases significantly more (i.e. a five-fold increase in length but a forty-fold increase in cross-sectional area) – this is because the mass of the animal has increased in proportion with its volume, and volume increases as the cube of length.

Cox then turned from animals our sort of size (i.e. mice to elephants …) where gravity is the dominant force, and moved to the much smaller scale of insects. Particularly amusing in this bit was him dropping a grape then a watermelon off a balcony to demonstrate that small things bounce and bigger things … don’t. He talked about how this is due both to smaller things falling a bit more slowly (due to friction with the air) and also because big things have more kinetic energy that must be released when they hit the ground (because it’s proportional to mass, I think). And this is done via exploding in the case of the watermelon. So gravity isn’t the big thing for an insect, instead it’s the electromagnetic force, which controls the interactions between molecules – like the way you can pick up a small piece of paper by wetting your finger so the paper sticks to it. This principle is what lets insects walk up walls or across ceilings.

He then went on to talk about what the smallest possible size for an organism is. First for animals – of which the smallest known is a wasp that’s about 0.5mm long, and is a parasite that lays its eggs in the eggs of a moth that feeds on & lays eggs on macademia nuts. And then for bacteria (skipping viruses because they’re not really alive) – where the smallest possible size is 2nm (I think) which is constrained by the size of atoms. You can’t be smaller than the volume necessary to fit all your cellular machinery, and those molecules are the size they are because their atoms are the size they are.

And then Cox talked a bit about how size affects metabolism, and how that in turn affects longevity. Smaller things have a higher surface area to volume ratio (because as something gets longer its surface area goes up by the square of the length change but its volume goes up by the cube). And this means they lose more heat than a larger version. And if you’re an endotherm (like people are) and generate your heat inside you, then the more you lose the more energy you must use to replace it. So smaller animals tend to have a higher metabolism and generate more energy from more food more quickly. Bigger animals both don’t need so much energy (if they’re endotherms) but also there are other constraints that mean that they need to slow down their metabolism. I think one of those was that it takes longer for things like nutrients to get through the circulatory system and so cells at the periphery can’t run too fast otherwise they’d burn up all their resources before they could be replenished (I’m not sure I’ve remembered that right though). Then Cox finished up by using crabs to illustrate that things with a slower metabolism tend to live longer (and this segment made J shudder because he hates crabs!).

The second episode of Brazil with Michael Palin was called “Into Amazonia” and covered (roughly speaking) the north west of the country, including the capital (Brasilia) and some of the indigenous people. The programme was bookended by the two tribes he visited – starting with the Yanomami who are very isolated and trying to remain so and ending with the Wauja who are assimilating some bits of modern Western culture while still preserving their own culture. The leaders of both peoples are worried about the impact that government projects (such as dams and mines) will have on their way of life, and frustrated about the lack of consultation.

Palin also visited one of the last remaining rubber tappers – rubber was a major export from Brazil before the British got hold of some seeds and grew rubber trees in Malaysia. A bit of a sad segment, because the industry has just dried up & gone away. As a counterpoint I think this was where he got to swim with the pink river dolphins, which right up till they showed up I had assumed were going to be some sort of euphemism (particularly with the solemn young man explaining how sometimes girls turn up pregnant & they say the dolphins did it)!

I’m not going to run through everywhere he went or everything he saw, but the other bit that stuck in my mind was Fordlandia. This was a planned town, with a Ford factory, and it was supposed to be a perfect America (this is back in the 1920s). But what it was was a perfect failure, and all the remains today are some abandoned ruined buildings in the jungle.

Wonders of Life; Brazil with Michael Palin

Well, Brian Cox’s Wonders of Life series really didn’t start how I expected it to do. I suppose in retrospect it should’ve been obvious that a physicist would talk about the physics & chemistry of life rather than the biology! This first episode was asking the question “What is life?”. He made a brief detour to mention that this question is typically answered by reference to a soul or other supernatural cause, but then started to talk about the laws of physics and how life exists as a result of the ways these laws work (in the same way that a star exists because of how the laws of physics work).

Life probably got started in hydrothermic vents in the ocean – which are alkaline environments. The ocean of the time (3.5 or 4 billion years ago, or so) was slightly acidic, so there was a proton gradient set up between the alkaline waters of the vent & the acidic waters around about it. The protons moving along this gradient releases energy. This is the same mechanism by which batteries work – in this case the heat of the earth’s core drives the setting up of the gradient, and because of the first law of thermodynamics (conservation of energy) all of this energy must be released when the protons move down the gradient. The hydrothermic vents are also rich in organic molecules, and the energy drives the chemical reactions between these molecules. And the first life arises from that chemistry. All life uses proton gradients to get its energy – he showed us pictures of mitochondria from a variety of animals, but the same is also true of prokaryotes (which have no mitochondria).

At first glance life violates the second law of thermodynamics – that the universe tends towards disorder. Living things are obviously complex and over the last few billion years they’ve got more rather than less complex. I never quite follow this argument (physics really isn’t my thing) but I think what it boils down to is that whilst an organism is more complex it’s achieved that in a way that disorders its surroundings more than they would otherwise be. So yes living organisms are localised pockets of complexity but the universe as a whole is still more disordered than before.

He then moved on to talk about how come life isn’t still just chemical soup in rocks. And what keeps organisms the same as their parent organisms. The answer is DNA – the instruction set for making an organism. I was much amused by his DNA precipitation experiment – take cheek cells, add detergent, salt and alcohol, and hey presto! you have white strands of precipitated DNA in the alcohol layer in your test tube. That’s pretty much the basis of a lot of molecular biology labwork – only you don’t use fairy liquid or vodka. He then ran through the basic high level structure of DNA and talked about how it codes for proteins. And then proteins are both the building blocks & machinery of cells and organisms. The great thing about DNA as a molecule to store the instructions is how stable it is – he quoted 1 error per billion bases (I think) when duplicating DNA which is a pretty low error rate. And relatively small differences in the instruction set are enough to generate very different organisms – he pointed out we’re only 1% different from chimpanzees, 1.6% different from gorillas etc.

The second episode was all about senses. After a bit of scene setting he talked about paramecium, which are single celled organisms that swim about using wee hairs (cilia) in their cell membrane. When it bumps into something in the water the little hairs reverse direction and it moves away again. It does this using proton gradients – normally there’s a difference between inside & outside the cell, and when the paramecium touches something the membrane deforms & this opens channels in the membrane and the proton gradient equalises. The energy generated by this is used to switch the direction of the cilia and to open more channels (I think) which means the change in direction propagates right round the cell. This is the basis of how all our senses transmit the information back to the brain – this is how nerve cells work.

Cox then spent a bit of time talking about how different animals have different senses (and different dominant senses). Different species therefore sense the world differently to us – our dependence on sight & hearing, and our ranges of sight & hearing, aren’t some objective way of detecting the world. Like all other animals we have the senses that we need for our evolutionary niche. In this bit I was particularly amused by the footage from some experiments on frogs – if a small rectangle is move past a frog in a horizontal orientation it goes nuts trying reach it & eat it. If the same thing is moved past in a vertical orientation, the frog doesn’t even seem to see it. When it looks like a worm, then it’s detected, when it doesn’t look like lunch it’s not worth wasting energy paying attention to.

He then talked about human hearing while sat on a boat near some alligators. The point of the segment was that despite the little bones in our ears looking like they’re designed for the purpose, actually they’re re-purposed gill arches. And part way through this long process of re-purposing the bones are the reptiles, whose jaw bones are also re-purposed gill arches. So the alligators were illustration …I still wouldn’t’ve got that close to them myself!

And obviously he talked about sight. Rhodopsin, a pigment that reacts to light, has been around in organisms for a long time – way back to cyanobacteria which have existed for a couple of billion years. And Cox demonstrated how simple a basic eye actually is – even a “camera eye” like ours (retina which does basic light detection, some sort of case with a hole in in front, then a lens in the hole. Obviously the devil is in the details, but one thing Cox didn’t mention explicitly is that eyes are believed to have independently evolved several times (the figure I remember is at least 40 times, but I don’t know if that’s right). He then went diving to see an octopus in its natural environment – which is another animal with a camera eye like ours (and it evolved independently). Octopuses are pretty intelligent, and Cox speculates that perhaps intelligence is driven by the need to process the complex images that our sophisticated eyes produce. I’m not sure what I think of that, in the same programme Cox also showed us a mantis shrimp that sees more colours and detects distance more precisely than people – but there was no talk about them being particularly intelligent.

As I said, not quite what I expected from the name of this series, but that makes it more interesting I think 🙂

We also started watching a series about Brazil with Michael Palin. I tend to be a bit wary of travelogues like this – sometimes the bits where the presenter joins in can cross the line between funny & cringe-making for me. Palin normally stays about on the right side of the line, but only just. But it’s still interesting to see the places & people.

The first episode was about the north-east of the country & was titled “Out of Africa”. A lot of people in this region have African ancestry – a lot of the slaves brought from Africa to the Americas ended up in Brazil. Palin quoted a statistic of 40%, and said this was more than ended up in the USA, which I was startled by. This has noticeable influences on the art & culture of the region – one notable example is the religion of Candomble which mixes African and Christian elements.

Palin visited a few different places in the region & a variety of different sorts of groups & events. The ones that particularly stick in my mind were the cowboys who were participating a race to catch bulls. And the national park that consists of a region of sand dunes that are blown miles inland to an area with heavy enough rainfall that there are lakes in the middle of the dunes – which looks pretty surreal.