Horizon: What Makes Us Human?; Royal Institution Christmas Lectures: Meet Your Brain

What Makes Us Human? was a recent episode of Horizon, presented by Alice Roberts while she was pregnant with her second child. So the frame was lots of gooey shots of little babies or shots of Roberts looking pregnant, and the meat of the programme was about some of the things that do or don’t set us apart from our closest relatives in the animal kingdom (chimpanzees, of course!).

One obvious difference between people & chimps is that we’re more intelligent than them. But actually the differences appear to be more subtle than one might expect. Roberts visited some researchers who look at co-operation in chimps & humans. Chimps will co-operate to get a reward, but if the reward is uneven – one gets more or one gets the reward before the other – then the chimps don’t care. Well, the one that loses out does, but not in a way that gets them their “fair” share. But if you do similar experiments with young children (toddler age) then an unequal reward gets shared out. Importantly this only happens if they had to work together to get the reward – co-operating means sharing.

Another difference is the helplessness of a human baby when it arrives on the scene. This is something that has had an “answer” for decades, but recent research has suggested the “answer” isn’t the whole story. Babies are born at the point where they only just fit through their mother’s pelvis, and it has been assumed that there are two selection pressures on the width of the birth canal – one is that wider makes it easier to have bigger headed babies, and the other is that narrower makes walking more energy efficient. So the theory is that women’s pelvises are at the sweet spot between easier childbirth with more developed babies and walking efficiently. But new research is suggesting that women’s walking (and running) is no less energy efficient than men’s despite a difference in gait because of the different shape of pelvis. So that may not be the explanation, you’d think if walking efficiency was the important factor then women’s hips could be wider. The new theory is that women’s metabolisms can’t continue to improve to keep up with the demands of their unborn child – babies are born at the point where their mother can no longer supply all their energy needs. Something about this segment left me with questions about whether there was more data than was explained, because it felt a bit pat & a bit too much jumping to conclusions.

When you look at a human brain & human nerve cells they show more connections (and dendrites) than other animals. Humans have more duplicates of a particular gene to do with dendrites than chimps & if you duplicate this gene in mice then you get more dendrites & connections – in the right proportion to explain the difference between humans & chimps. In this segment Roberts also talked to a scientist who is starting to map, to visually image, actual brains – at the moment he’s just doing mouse brains (very slowly) as they’re small. But eventually the plan is to be able to investigate a human brain this way. They end up with a colour coded three dimensional diagram of all the nerve cells in a brain with connections mapped etc. This looked cool, but I’m not sure how much it actually tells us in the long run – as I understand it brains are all unique in detail, even if similar in general. And does “neuron A connected with neurons B, C, D & E” tell us much about what any of these do?

(And am I cynical about Horizon’s presentation of science because I go in thinking it’ll be shallow, or do I go in thinking it’ll be shallow coz it often leaves me with questions?)

The Royal Institution Christmas Lectures are a series of lectures aimed at children and broadcast on the BBC. I used to watch them every year when I was a kid. We recorded the series in 2011, and have only just got round to watching them – that year they were about brains and the lectures were given by Bruce Hood. The first lecture in the series was titled What’s In Your Head? and covered the basics of what a brain is, how nerves work and the sort of modelling brains do to make sense of the world.

As it’s aimed at children I don’t think it covered anything I didn’t already know, but it did it with style and involved a lot of demonstrations – some of which were rather neat. For instance Hood & another scientist showed that brains work on electricity by disrupting the ability of the other scientist to move his hands properly using in electromagnet against the head. So the chap was clapping and then they switched on the moving magnetic field & he could no longer co-ordinate bringing his hands together. There was also a little bit about MRI scanners to look at brain activity – with a striking visual demonstration of how powerful the magnets involved are: a nurse went into the room with a spanner on a string and then the machine was switched on and the spanner swung up and pulled towards the machine.

Another bit was about how the brain sets up patterns as it learns about the world and how that can lead to being disconcerted by new experiences – like if you eat grapes then your brain learns that round, green, sweet is a pattern associated with grapes. The first time you meet a green olive, you see round and green and then your brain fills in “sweet” because that’s the learnt pattern. So when you eat it you get a nasty surprise. This example particularly stuck in mine & J’s heads coz until recently neither of us ate olives (I’ve somehow acquired a taste for them over the last couple of years) – so the “yack!” reaction he was talking about amused us πŸ™‚

Ice Age Giants; Australia with Simon Reeve; TOWN with Nicholas Crane

The last episode of Ice Age Giants looked at why there are none of these large animals left. The first half of the programme concentrated on North America where there were the greatest proportion of extinctions. Roberts started by talking about the idea that it was people – we were treated to a proper true crime documentary moment where the voiceover was all “but beneath the peaceful streets of this Tennessee town lies a dark secret” etc etc. And saw how there is an excavation pretty much in someone’s back garden – of mastodon bones that look to have been hunted & butchered by humans. So was it people? Roberts pointed out the problems with that theory – not many people in North America at the time, lots of megafauna, and a few thousand years of overlap of people & megafauna.

So what else? How about the floods that created the coulees (also known as the Channeled Scablands) in Washington (the state). These features of the landscape are vast vast canyons that have been scoured out of the rock, but there’s no sign of a river. The theory to explain what caused them is that as the glaciers melted a great lake of meltwater was formed in Montana which is known as Glacial Lake Missoula, this was penned in by a dam formed by the melting glaciers. When it broke through it did so catastrophically and the water rushed to the west of the continent carving its way through the rock as it went. This happened several times as the glaciers advanced & retreated, I think she was saying a couple of hundred times over just a few thousand years. This would’ve killed anything in it’s path (and created what still looks like a blasted landscape today). But that can’t’ve killed all the animals, it would just’ve got the ones in its path.

How about climate change? This isn’t a case of it just getting a bit warmer all over – the melting of the ice sheets released more water into the rainfall systems, so the world got wetter as well as warmer. Still not quite that simple, the swamps that the glyptodonts lived in dried up & became desert because the rainfall moved north as the ice sheets retreated and the more southern regions warmed up. Roberts now skipped across to Europe and the woolly mammoths & woolly rhinoceroses of the Mammoth Steppe. These enormous herbivores relied on the dry grasslands to provide them with sufficient food all year round. As the world warmed up, and got wetter, forests grew where there had just been grassy plains. And it started to snow in the winters on the Mammoth Steppe. Woolly rhinos couldn’t cope with that – snow covers the grass and makes it harder to find, it’s also hard to walk through so you need more energy to move around and so more food. So that’s what killed off the woolly rhinos – an Ice Age Giant killed by it snowing too much, not at all what you’d expect.

And now we circled back to the mastodons of North America. There is research being done on fungal spores in soil that can indicate how many herbivores have left their dung on the land – if you look at soil from the past you can estimate herd sizes (or at least changes in herd sizes) over time. And these show that the large herds of mastodons & other herbivores died out before the climate change changed the vegetation (which you can tell by looking at seeds & pollen in the same soil samples). So probably not climate change as the whole story here. Roberts then talked to a palaeontologist who thinks he has an answer for the mastodon extinction. He has looked at the types of injuries on female mastodon specimens, and also looked at the types of mastodon that show signs of butchering. In modern elephants (which are close cousins of the mastodons) preferential hunting of mature adult males destabilises the herd structure. Normally a dominant male swoops in to a female plus offspring herd when the females go into heat and mates with the females. He also suppresses the behaviour of the adolescent males. When there is no dominant male, the younger males that still live in the female herd will go on a rampage when the females come into heat – and can injure females & calves (and each other) in the process. This palaeontologist thinks he sees evidence of this happening to the mastodons, so it was people that caused their extinction but in a very slow process caused by preferentially hunting solitary adult males which they wouldn’t’ve been able to see happening.

Last up for extinction were the woolly mammoths – which survived on a remote island north of Sibera until around 2000BC (when people arrived on the island). Apparently from the evidence on this island the mammoths were becoming dwarf mammoths … by mammoth standards anyway. Roberts talked a little bit here about the potential cloning of mammoths that is now becoming possible due to the extraction of DNA from very well preserved frozen specimens.

And Roberts ended the programme with a romantic notion of how we’ve also saved some of these Ice Age Giants – like horses. They became extinct in America, their ancestral home, but survived across Europe & Asia and were then domesticated. She was talking about it as a beautiful partnership, but I’m afraid I was amused by it rather than moved by it πŸ˜‰

Anyway, I greatly enjoyed the series. The CGI wasn’t perfect (something always looked a little off about the way the animals moved, and there was a lot of repetition of sequences that made it a bit too obvious it was generated) but it was good. And the science was presented in an un-sensationalised way – lots of “we think” or “this is a possible explanation” rather than grand solutions to mysteries.

Having finished watching Brazil with Michael Palin (post) we started to watch another travelogue we had been recording – Australia with Simon Reeve. We’re both pretty sure we’ve seen Simon Reeve present another programme in the past, but neither of us can quite remember what it was.

In the first episode of this series he started in central Australia then headed south to the coast followed by west to Perth. In central Australia he focused on an animal you don’t expect to be the subject of a programme on Australia – the camel. Camels were brought to the country as a means of transport, being well suited to the desert conditions in the centre. With the advent of cars they weren’t needed any more & were released to the wild where they now roam freely. Unsurprisingly they cause a lot of damage to the ecosystem and to the farms in the region & so they are regarded as pests. Some farmers just shoot them when seen, but Reeve talked to one farmer who was rounding them up and selling them back to the Middle East for food & for racing.

Next Reeve went to visit a winery – a vast commercial winery with gallons & gallons & gallons of wine in big tanks, supplying relatively cheap wine to supermarkets across the world (this was owned by Hardys). This segued neatly in to a segment about how water is a limited resource & it’s being over used in Australia as a whole. Reeve then visited another limited resource – tuna, which is being overfished in the seas near the Australian south coast. He visited a facility where they’re trying to breed tuna in captivity, which involves conning the tuna into thinking they’ve migrated by changing the lighting and so on as it would change if they really were migrating.

From there to resources that are booming – he visited an area which has a modern day gold rush & talked to some weekend hobbiest prospectors, and also visited a huge commercial mine. Next, Reeve visited a village where an aboriginal community lives having been moved off their land when the mining companies discovered resources underneath it. They haven’t been compensated for the loss of the land, nor have they earnt anything from the metals being dug up from under what they still regard as their land. Reeve said that the situation is complicated & the government is trying to help, but the aborigines are still living in third world conditions.

From there he went to the other end of the spectrum – he took a train to Perth where he visited some British ex-pats who are living the dream. The man he spoke to had been a bin man in Sheffield, he’s now teaching people to drive trucks so they can work for the mining companies. His pupils earn more than he does, but he earns about Β£60k and has a big house with a pool etc, just what he came out to Australia for. And the episode finished up with Reeve visiting an airport where “fifo” commuters fly from – that’s “fly in fly out”, the commuters work in the mines (doing things like driving trucks for lots of money) and live in Perth getting back & forth by plane.

The second episode covered the north of Australia, which is particularly sparsely occupied. He started out in a national park (Kakadu) helping to trap & cull cane toads. These are a non-native species that was introduced to eat beetles that were pests … they didn’t eat the beetles, and being poisonous & non-native they have no predators amongst the native animals. So they’ve spread & are killing off the wildlife in the park which dies trying to eat the toads. The cull seemed a bit like it would just make the people doing it feel like they were trying – if there’s millions of toads then catching & killing a couple of bin bags full won’t do much good.

Moving towards the east Reeve visited the Australian army, first one of their tank regiments then he spent a bit of time on patrol with a unit doing observation in the outback. This segment reminded us that Australia is actually right next to Asia, rather than being a stray bit of Europe stuck in a southern ocean. In the bit with the patrol they talked about how the unit was mixed race & that this didn’t cause problems in a way that made it sound like that was an unusual situation. They also talked about how the aboriginal members of the team were vital in teaching everyone how to live off the land – they made green ant tea for Reeve, which apparently was quite nice … not sure I’d’ve been keen to drink it. The follow up to this section was a visit to an asylum centre, Australian law is that asylum seekers must live in these detention centres while their application is processed which can take months or years. Reeve spoke to activists on the behalf of these immigrants who say that conditions in the centres aren’t good – lots of the inhabitants self-harm or commit suicide. Reeve spoke through the fence to some of the inhabitants, who’d come from the sorts of places you’d expect – Iraq, Afghanistan etc.

From there we moved on to the slightly more cheerful subject of another aboriginal village which owns resource rich land. Whilst it looked as depressing as the place in the first episode the ray of hope here is a young woman who has set up her own company with the long term plan of the village itself doing the mining on the land closest to them. At the moment she rents 4 bulldozers out to the company who’re doing the mining, which I got the impression was proof of concept.

And the programme finished with another couple of segments looking at the natural world – first Reeve joined some scientists who were taking samples of the stinging tentacles from box jellyfish. These jellyfish are extremely poisonous, and live in shark & crocodile infested waters. From the way the scientists were acting (and not letting Reeve do much but observe) they weren’t exaggerating the dangers. The venom from the stings is useful for drug research – there’s a lot of complex biochemistry involved that does things like target the actual poison to particular areas of the body and other stuff like that. So understanding it might help make better more effective drugs.

Last up was the Great Barrier Reef. Changes in the water (due to increased use of fertilisers etc on land) have lead to destabilisation of the ecosystem there, and Reeve was shown how people are culling the starfish that are killing off the coral. He also joined a ship pilot who guides coal ships through the reef – there’s not much room to spare & it’s a dangerous task, but the wealth generated by the coal industry means that they are still permitted to run their ships through the area.

In our quest to free up some space on the PVR we’re watching all the programmes we have recorded in HD first – and only recording new stuff in SD. Just before that decision we started to record TOWN with Nicholas Crane in HD so it’s come up to be watched a little quicker after airing than I think we might’ve got round to it otherwise. It wasn’t quite what we expected, guess I didn’t read the description that closely when I set it recording. Instead of being about towns as a general thing each episode is about a particular town.

The first episode is about Oban, a town on the west coast of Scotland that’s where you go if you want to get a ferry to the Western Isles. And the main theme of the programme was that that isn’t all there is to Oban, that the town is itself a worthwhile place to visit.

Oban wasn’t a town until comparatively recently so his talk about the history of the place started off with nearby Castle Dunollie which was the seat of the Chief of Clan MacDougall until 1746 when the Clan Chief moved to a new house nearby. Surprisingly “Battle of Culloden” and “Jacobite Uprising” weren’t mentioned during Crane’s discussion of this. I had a little poke around on wikipedia and it seems like the 1746 move was a coincidence as the MacDougall Clan Chief wasn’t involved in that Jacobite Uprising, but I’d’ve thought that was worth mentioning on the programme just to say it wasn’t involved. Oban became a town after this – the first industry in the town was tobacco but this collapsed once the ship that brought the tobacco over from Virginia sank. After that the primary industry in the town was whisky, Crane visited the distillery which is still making whisky today. In the 19th Century Oban was finally linked by road & rail to the rest of the country. It was a tourist destination, partly due to the links with the Western Isles but people did visit the town itself. Queen Victoria was one of those tourists. After that it fell into decline & most people who visit aren’t stopping, just moving on to the ferry. One more recent bit of history is that Oban was where the first transatlantic telephone line ran to, and this was an important link between Washington D.C. & Moscow during the Cold War.

In terms of the modern town Crane spent a bit of time looking at the major employers in the area. Oban is the hub of the postal service for the Western Isles, and everything there has to be run like clockwork to match up with the ferry services. Another major employer is the granite quarrying operation a bit north of Oban – all the people who work there commute by ferry because there are no road links to the quarry. Crane also visited a few of the cultural offerings of Oban. He met a local painter who paints a lot of the landscapes around the area. He also visited a cΓ¨ilidh bar where there is a traditional band & traditional dancing. And he also ate at a gourmet restaurant which is on the harbour so that the fish & shellfish are very very fresh.

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” πŸ˜‰

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!

Ice Age Giants; Wonders of Life

Ice Age Giants is a new series presented by Alice Roberts about the large animals that lived during the last ice age. It’s a nice blend of Roberts talking to various experts & looking at fossils, and cgi of what they think the landscape & animals look like. Of course I always wonder what we’re wrong about looking at stuff like that, but it’s cool to see.

The first episode was all about animals in North America. She started with Smilodon fatalis, the sabre-tooth cat – this segment mostly concentrated on how it killed its prey. The sabre teeth are actually pretty fragile (relatively speaking) and one might think that they would be easily broken by getting stuck in struggling prey. They also can’t kill the way modern big cats do – like lions – because they actually suffocate their prey by crushing the windpipe between their jaws or pinching the nose shut. But if you look at the width that a sabre-tooth cat’s mouth can open (to an angle of 120°, twice as wide as lion’s) and the big boned & heavily muscled front legs then another hypothesis becomes apparent. The cats killed by pinning down their prey (to keep them still) then slicing through the throat & ripping out the windpipe or cutting the various arteries there.

Roberts then moved on to talking about the Shasta ground sloth – a large (grizzly bear sized) relative of modern sloths. She visited a cave that had been a ground sloth lair with a palaeontologist who studies these animals – the cave contained a very large amount of sloth excrement. Apparently it hadn’t rotted because the conditions in the Grand Canyon (where this was) are so dry. They looked at bits of this & could see that sloths clearly didn’t digest their food all that well (bits of twig & so on still recognisable). And there was even a large pile near the back of the cave that had distinct layers and so on running from ~40,000 years ago through to ~20,000 years ago – a bit like the geological record in rocks.

Next up were glyptodonts, an animal I’d never heard of before. In the cgi sequences they looked a bit like massive armadillos or turtles on steroids. According to the palaeontologist Roberts talked to these creatures are often found belly up – if they die in water then the weight of their shells makes their body flip over & they sink to the bottom upside own. They had a reconstruction of two of these fighting – they don’t just have massive armoured shells and armoured tails, they also have little armoured hats that look about right for protecting the brain as two of them clash together in a dominance fight (a bit like stags).

Roberts then went to look at large standing rocks with a scientist who is looking at the weathering/wear patterns on the rock. He thinks that the smooth patches must’ve been polished by animals rubbing up against the rocks to scratch their backs as the wear patterns don’t look like any of the other possible causes he’s investigated. The lower bits & bobs could’ve been many things (including modern domestic livestock), but the 14 foot high patches were almost certainly mammoths! The Columbian Mammoth was bigger than the Wooly Mammoth of Europe, and was even taller than modern elephants. And they weren’t hairy, I had no idea you got bald mammoths.

And the last segment of the programme was about the La Brea Tar Pits. Which as soon as she said the name I remembered I knew of them, but I’d forgotten till I was reminded. These are in California, and are a source of natural asphalt. It’s sticky (obviously) and sometimes creatures get trapped in it and die – and to date 3,000,000 specimens of 600 different species of fossils from the era of the ice age have been found in these pits. I don’t think they’ve actually dug through much of them – there was one batch found when an oil company was digging up the tar, and another batch was dug up when some where wanted to build a car park. They’re still processing this batch – it was moved in blocks so they can now excavate it properly. So they aren’t just finding the big animals (which include sabre-tooth cat kittens!) but also the little ones like snails & beetles and such. And this is generating a lot of useful information about the general environment and climate in the area during the ice age period.

Once upon a time I wanted to be a palaeontologist, but I’m not really an outdoorsy enough person to do the work. But you can picture me watching this programme filled with glee and bouncing up & down a bit going “oooh, look at that, isn’t that cool?”. And there’s another episode next week! πŸ™‚

We’ve now finished watching Brian Cox’s Wonders of Life, the final episode was mostly looking at the physical & chemical properties that make life possible on our planet. The ingredients that make it home, as he put it.

So he started out with water, and explained hydrogen bonds. These form because water molecules are polar – the electrons in the molecule are more around the oxygen atom than the two hydrogen atoms. So the oxygen atom has a slight negative charge & the hydrogen ones are slightly positive. These means that bonds called hydrogen bonds form between the oxygen of one molecule and the hydrogens of another. Which makes a body of water not just a bunch of separate molecules but instead it’s a more cohesive thing. This makes water a good solvent (I’m not sure I followed this, but I’ll take his word for it), and so it carries many of the other nutrients we and other life forms need. Its solvent properties also make it a good place for our own internal chemistry to happen – and all living things have a large percentage of water. The cohesiveness of water also gives it surface tension. Cox demonstrated this by looking at pond skaters, which live on the top of water supported by surface tension. Surface tension is also how water moves through plants, all the way from the roots to the leaves.

Next up was light, and he started by looking at all the ways that the light from the sun is harmful concentrating mostly on talking about UV. UV light damages DNA and can burn skin, so most animals and plants have some sort of adaptation to prevent this. Humans (and other animals) use melanin, which is a brown pigment that is particularly good at dissipating the energy of the UV radiation. Cynaobacteria evolved a different way of dealing with light – they absorbed & used the energy. The coupling up of two energy using systems to take the energy of light plus CO2 and turn it into sugars (ie food) and O2 appears to’ve evolved only once – plants do it too using organelles which are descendants of cyanobacteria that now live inside plant cells. And this provides the third of the ingredients we need for our sort of life – oxygen. He went into a cave with a sulphurous lake to look at the sorts of organisms that life in oxygen-free environments – slimy ones, it seemed.

And the last of his ingredients was time. Both the sort of time that gives us our circadian rhythms and gives the monarch butterflies their navigational systems, and also the sort of time that gave us a chance to evolve. If you look at the history of life on this planet there’s a loooong couple of billion years before you get beyond single celled organisms. Even a billion years to get from simple cells (prokaryotes) to complex cells (eukaryotes). Cox was asking “is it necessary to have all that time?”, and saying that we don’t know because we only have one sample so not enough data. I’m not sure I agree – there’s clearly random chance involved in whether or not the right mutations came up, so it could’ve happened immediately or it could never’ve happened. So I don’t think the length of time it did take is significant or necessary. It’s just indicative of how rare a chance it is – because each of the big jumps (non-life -> life, simple -> complex cells, single celled -> multicellular, development of photosynthesis etc etc) has only happened once despite the four billion years available (a third of the age of the universe, don’t forget).

Overall I’ve enjoyed watching this series. It really wasn’t what I was expecting (though I’d find it hard to tell you what I was expecting) but in retrospect it’s obvious that a physcist would tell us about the physics & chemistry behind the biology. And it was more interesting for me because it wasn’t what I was expecting. I did feel he was stronger on the physics & chemistry than the biology which sometimes felt a bit like he was saying things he didn’t quite understand. A bit like me talking about physics to be honest πŸ˜‰

Prehistoric Autopsy; Lost Kingdoms of South America

The last episode of Prehistoric Autopsy was about Lucy – one of the most famous fossils of our ancestors (and the only individual (as opposed to species) I’d actually heard about before this series). She was a member of the species Australopithecus afarensis and lived a little over 3 million years ago. She was discovered in the early 70s, and at 40% complete was one of the most complete specimens of a hominid from that era.

This programme felt like there was a bit more padding than the other two – not quite as much to tell us about, partly because there’re fewer fossils available to figure things out from. But there was still quite a lot πŸ™‚ From the bones that do exist (both Lucy’s and others) they can tell that this species was bipedal & walked upright – even tho they don’t have the foot bones they can see the shape of the knee joints and the pelvis. This is corroborated by data from some preserved footprints, that are presumed to be Australopithecus afarensis because that was the only primate species that’s been found in that area at that time. Experts have analysed the shape of these footprints and compared it to both human and chimpanzee footprints in similar material. The Australopithecus afarensis footprints are much more like the human ones – they have a non-opposable big toe, and the pressure patterns (like deep heel prints) are similar to human ones.

They also showed us the pelvis bones of chimps, humans & Australopithecus afarensis – you can see the difference between the chimp one & the other two really clearly. But the differences between the Homo sapiens one & Australopithecus afarensis one are much subtler. The scientist Roberts was talking to also pointed out that you can see changes in the birth canal – Australopithecus afarensis would’ve found it harder to give birth than a chimpanzee because the canal is not as wide, due to the demands bipedalism puts on the shape. But not as hard as a modern human – the brain size of Australopithecus afarensis is still pretty small, only a little bigger than that of a chimp, so the fit would not be as tight nor would it require quite as much changing of position from the baby on the way out.

Australopithecus afarensis may’ve used tools. This was a pretty controversial piece of evidence – and Roberts & McGavin didn’t agree on how plausible they thought it was. And it was nice to see how that was presented – there wasn’t a feel of some fake monolithic “the opinion of the scientists”, it was presented in a much more true to reality way. Some scientists think this, others aren’t convinced, everyone’s interested in seeing more evidence. Actually the whole series has done well on this front, they took great care to tell you about the caveats and where the evidence was slim. Lots of “we think because of reasons” and less “we know”.

Anyway, back to the tools – there’s an animal bone, found in the same context as a juvenile Australopithecus afarensis, which has two parallel grooves on it. In the grooves are fragments of hard igneous rock (as opposed to the sandstone that was encasing all the bones). This may be evidence that Australopithecus afarensis used sharp rocks to butcher meat (in some crude sense). But it may also have been due to accidental trampling of a dead animal that drove a stone against the bone. Given chimps use tools like twigs, it wouldn’t be that surprising if Australopithecus afarensis did – but really there needs to be more evidence than a single bone.

They also had a segment on how Lucy might’ve communicated – which was probably via facial expressions as well as vocalisations, because pretty much all primates do that. To illustrate this they showed us a little bit about some new research starting on Japanese Macaques, which has the eventual goal of seeing how many different facial expressions they can tell apart (and I think they have hopes of figuring out what they mean, not sure how though).

The model they built looked really good, as all of them have. They said at the end of the programme that the models were going out touring museums round the country, but when I looked it up we’d missed all the dates (because we time-shifted the programme by 3 months). A shame πŸ™ Although apparently the exhibition was aimed at kids, so maybe it’d’ve been a bit shallow. There also doesn’t seem to be a tie-in book for the series, another shame – I’d’ve bought it πŸ™‚ I did find another Alice Roberts book on Human Evolution, so if I like the book of hers we have (when I get to it) then I’ll pick that up.

Having finished up Wartime Farm last week we started on a new series – this time something that we’re only time-shifting by a couple of weeks. The series is Lost Kingdoms of South America, which is clearly inspired by the previous BBC series called Lost Kingdoms of Africa. The primary difference between the two series (as well as which continent they’re on) is the presenter – the African one was presented by Gus Casely-Hayford, who is an art historian whose family come from Ghana. The presenter for this current series is Jago Cooper, who is an archaeologist who specialises in South American cultures but not (as far as wikipedia tells me) from South America. So that gives a slightly different tone to the programmes (not better or worse, just a different perspective).

This first episode was about the Chachapoya people of Peru. Who I must confess I’d never heard of before watching it (although it became clear I should’ve at least known the name). A good start – because I’d sort of assumed we were going to get first the Aztecs, then the Incas then perhaps the Mayans, you know all the peoples we’ve all heard of before. Instead we got an intriguing people whose society really wasn’t the same as our expectations for the place & time.

The Chachapoya lived in the north of Peru, in the Andes, from about 400AD until around the time the Europeans arrived on the scene. The name we use is the Incan name for them & it translates as the Cloud People because of their high altitude villages & towns. Cooper interviewed an archaeologist in Lima who said she thought only about 5% of their sites have been properly excavated, if that. So there’s a lot still to find out.

One of the themes of the programme was that when thinking about these people we really need to take our Western preconceptions and throw them away before we can understand them. For instance the first thing we think is “but why did they live so high?” – because that’s the altitude that was best for cultivation of maize & potatoes. They lived where they could grow their food, which is a perfectly sensible thing to do. And why did they live somewhere so remote? It wasn’t remote for them – both because the people were more willing to travel further between settlements, and because the rivers and the geography of the Andes at that point combined to funnel trade from the Amazon Basin to the Pacific Coast through the lands of the Chachapoya. So not remote, but on a busy trade route. Cooper showed us some artifacts found in Chachapoya sites that included things like feathers from birds only found in the rain forest in Brazil.

Early in their culture they buried their dead up in caves on mountain cliff-faces. These were astonishing – Cooper needed the help of modern equipment and experienced mountaineers to get to these caves where the bones lay. But the floors of the caves were worn through repeated visits, so this didn’t seem to be a case of burying your dead somewhere out of the way. Later they mummified their dead – and this is why I feel I should’ve heard of them, because I knew there were Peruvian mummies, I just didn’t know which culture made them. Which is poor, really – but now I do πŸ™‚ These mummies weren’t like the Egyptian ones which were buried & left to last out eternity in their tomb. These mummies were carried around from place to place in bags, and sometimes taken out & displayed in some fashion. A very different relationship with the dead.

Another difference in their society from what we might expect is that they don’t appear to have had a hierarchy – the Spanish had referred to this in writing from the time they arrived in South America, but there’s also evidence for it in the archaeology. The villages that’ve been investigated don’t seem to have elite housing – all the housing is the same sort of shape & size. I wasn’t entirely clear how they can tell that the one larger building most villages have is a ceremonial site & not an elite site, but they were clear that this was the case. There are also no signs of elite burials – all the dead that have been found are treated in the same. This is pretty unusual for a human society.

They also don’t seem to’ve been bloodthirsty in the way that the Aztecs & the Incas are – no human sacrifice was mentioned, nor ritual bloodletting. And in another difference from the “canonical” South American civilisation story they were conquered & dispersed by the Inca before the Spanish arrived. The Spanish actually allied with the Chachapoya to fight against the Inca. Although the Europeans did deal the final blows to the Chachapoya way of life – both through converting them to Christianity, and via the diseases they brought with them.

Prehistoric Autopsy; Wartime Farm

The second episode of Prehistoric Autopsy was all about Homo erectus, and they were building a model of Nariokotome Boy. This is a 1.5 million year old near complete Homo erectus skeleton & the most complete one ever found. They started off with context, again – Homo erectus only died out relatively recently, but was around for 2 million years, which is the longest of any human species. It’s also one of the first hominids that can be thought of as human, and we and all the other ones that were around in the recent (geologically speaking) past are descended from them. They also lived outside Africa, and were the first hominids to do so.

Homo erectus co-existed with several different hominid species over time – they talked in detail about one, Paranthropus boisei. The skull they showed had a massive jaw, a skull ridge and very flared cheekbones to fit the chewing muscles behind. A diet of particularly solid things seems plausible, like nuts and seeds. As well as that sort of food there’s evidence of wear from grasses on their teeth.

They showed us research into the climate over the time period – I loved this bit, there’s just something so neat about being able to find out what the world was like so long ago with such a simple concept. They do it using samples taken of the sediment on the ocean floor. It’s laid down layer upon layer over time, and you can look at things like the sort of mud it is and the sorts of plant seeds/pollen you find in it to build up an idea of what the weather and landscape was like on nearby continents. We got shown a particular example of a core where you could see a colour change in the mud from top (~5000 years ago) to bottom (~10,000 years ago), and told us that the changes correspond to a change in the nearby climate (East Africa, if I remember right) from wetter to more dry. Over the 2 million years that Homo erectus existed the climate seems to’ve undergone lots of swings between hotter & colder or wetter & dryer conditions and they speculate that why Homo erectus survived and the other hominids didn’t is that Homo erectus was more adaptable.

And that they were more adaptable because of their bigger brains and because of the different way they interacted with the environment around them. There’s evidence that Homo erectus used fire, and they cooked their food (at least at the end of the time period, I wasn’t clear if there was no evidence from earlier on or if they hadn’t done the analysis (yet)). Their tools are more sophisticated than earlier hominid tools – instead of just breaking rocks for a sharp edge their tools are carefully shaped and show evidence of being planned and involving skill to make. So Homo erectus seems to’ve had the cognitive ability to shape the environment to suit themselves, rather than put up with the environment they find themselves in. There’s also evidence that they took care of older members of their groups – a skull has been found where the individual lost their teeth a few years before death, and quite clearly wouldn’t’ve survived without help.

Because of the model building the programme also spent some time discussing the probable physique of Nariokotome Boy. Homo erectus show many adaptions for running, and were probably lean and hairless (to the extent that modern humans are hairless, I mean). Because of the lack of hair they’d’ve had dark skins to protect themselves from the UV of the African sun – and this limited their spread north, they don’t seem to’ve got the low melanin mutation that permitted us to live in more northern climates. Also in this section they showed us evidence that Homo erectus may’ve suffered from tuberculosis, which is astonishing – it is a disease that we get from cattle originally, and was assumed to’ve become a human disease only more recently when modern humans started living in close proximity to cattle because they’d become herders. The marks and signs on the Homo erectus skull they were looking at (not Nariokotome Boy, another one) were very similar to the ones on a modern human who’d died of TB, so seemed convincing evidence. Which raises all sorts of interesting questions.

We also watched the last episode of Wartime Farm, which unsurprisingly covered 1945 and the immediate aftermath of the war, as well as wrapping up with a “what we’ve learnt” segment. So they were mostly concentrating on the fact that once the war was won, that didn’t mean life returned to how it had been pre-war – not only did people still need fed, but in some ways the situation was even more precarious because Britain was close to bankrupt and couldn’t afford to import food yet the fields were becoming less fertile due to a lack of manure and from being over-farmed. They also talked about the celebrations that people had (and the thing they dramatised was a firework elephant, which was awesome πŸ˜€ ). And they harvested the wheat crop they’d spent the year growing, using a brand new combine harvester (well, 70 year old one …).

This was a good series, although I’ve struggled to write more than a paragraph per episode. I’m not quite sure why, but I guess partly because there was a lot of “look at how we did things” which isn’t easy to transform into text. I did feel that they spread it all too thin, perhaps they couldn’t do it half the number of episodes, but I do think they could’ve cut it down a bit. The format of half-dramatising, half-telling still feels like it shouldn’t’ve worked, but they pulled it off very well.

Prehistoric Autopsy; Wartime Farm

Last night we watched the first part of Prehistoric Autopsy which was all about the Neanderthals. This is a three part series presented by Alice Roberts & George McGavin plus a whole team of experts – the format is that they have a “lab” set up with various different experts & they demonstrate some of the research that’s been or is being done about three different human/ancestral species and use this knowledge to build a life-size replica of the species in question. It suffers a little from “staged conversations” syndrome & an almost complete lack of on-screen chemistry between the two primary presenters but other than those two niggles it was a fascinating programme.

So they started by giving us context for Neanderthals – not that long ago by palaeontological standards we weren’t the only human species on the planet. If you go back to ~70,000 years ago there were 4 species as well as Homo sapiens: Homo floresiensis (who died out about 12,000 years ago, which is about the same time as the Chinese were starting to make pottery), Denisova hominin (who I’d never heard of before, wikipedia tells me this is a branch from Neanderthals), Homo neanderthalensis (Neanderthals, died out around 30,000 years ago), Homo erectus (died out around 70,000 years ago). Neanderthals moved out of Africa & lived in Europe, then Homo sapiens evolved in Africa and independently moved into Europe later on.

They then talked us through lots of different evidence for what the Neanderthals looked like & how they lived, whilst at the same time showing us the building of the replica (based on an actual individual skeleton). Lots of fascinating things, quite a lot of stuff I didn’t know before, so I shan’t try & list everything that made me think “ooh, neat” πŸ™‚ I knew that there’d been work that showed we (northern Europeans) are more related to Neanderthals than you might think, but I hadn’t realised that they’d actually sequenced the whole Neanderthal genome. And the data they showed for relatedness was quite impressive – looking at 500 people of West African descent & you see under 2% relatedness to Neanderthals (with a nice normal distribution) and then looking at 500 people of Northern European descent and you see 2-4% relatedness to Neanderthals (again, nice normal distribution that doesn’t overlap the West African one). Looks pretty clear there was interbreeding going on in Europe 30,000 years ago.

Neanderthals also had more culture than one might’ve thought – there’s a painted shell with a hole that looks like where you’d put one if you were making a pendant, that was found in association with Neanderthal remains. There’s also a cave-painting that has had some of the paint dated to ~15,000 years before the first signs of Homo sapiens. They spent some time considering if Neanderthals could talk, too – but that was a little less convincing. They also looked at how Neanderthals hunted, and how they made clothes. You can tell from tools found that they must’ve scraped hides to make them pliable for making clothes, and you can also tell this from the arm bones of the skeleton. You could also tell from the wear on the teeth that they worked the hides with their teeth too.

Oh, and thinking of teeth – one of the really neat bits was that there’s a group that have examined Neanderthal teeth from a skeleton of a young girl, using a synchrotron. The images generated allow them to see and count the growth lines in the teeth – at a resolution of 1 per day. That means they could count up how long the girl had lived since her teeth came in, and instead of the 6 years estimated from the state of the bones it turns out she’d lived for about 3 years. So Neanderthals matured at a much quicker rate than us, and they speculated in the programme that this might be part of why we still exist and are thriving & the Neanderthals aren’t. That we have more time to learn while we grow up, and this makes us more adaptable & gives us an edge in competition.

I could ramble on for longer, but I shall stop there. I’m looking forward to the other two programmes when we get to them & I’d definitely recommend watching this one if you have the chance (and are interested in that sort of thing).

The other programme of the evening was the seventh episode of Wartime Farm – covering 1944. We had carrier pigeon training (because they were extensively used during the war in particular to relay messages during the D-Day landing), POWs being used as farm labour (the expert on this segment was a German chap whose Grandad had been one of those POWs which was a neat touch), the troops gathering pre-D-Day, basket making, flax harvesting. Oh and some terrible German bread – bread was never rationed here, but it was in Germany. And in desperation there were recipes for wartime black bread that were appalling – the one they demonstrated was silage, grass clippings, sawdust, fermented rye (better hope for no ergot!) and honey. It looked a bit like black bread once it had been cooked, and they ate it and said it didn’t taste too bad – but pretty much it was the sort of thing you’d eat if you were reduced to eating grass, this was at least a palatable way to do it.