Old rocks, old humans, old sharks, and links to today
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ABC Listen. Podcasts, radio, news, music and more. An opal-hearted country, a willful lavish land. All you who have not loved her, you will not understand. MUSIC

Part of the last verse of Dorothea McKellar's My Country in today's science show. So why is Australia an opal-hearted nation? And then we'll bring you the human ancestors, the hominid species found as fossils in our wider region, and then sharks. Hello, I'm Robin Williams, and we start with my partner, Dr. Jonathan Newby, and those unique gems.

Regular science show listeners will know that I recently visited the opal mining town of Lightning Ridge, part of an investigation into the opalized monotreme fossils, which revealed a whole new age of egg-laying mammals, including our favorite new ancient monotreme, the Echidnopus. But while I was there, I became a bit obsessed by the mysteries of opal itself.

Why are opals so good at making fossils? In fact, what even is precious opal? Why is Australia virtually the only place that has it?

And does that have something to do with the world the ancient monotremes lived in? So this week, a special bonus story from Lightning Ridge all about opal. And we begin with paleontologist Jenny Brammel, who is showing us more of her favourite opal fossils from the fabulous collection at the Australian Opal Centre.

This piece is a favourite of mine. This is a backbone from a dinosaur that has a lump on one side that doesn't belong there. This is a paleopathological feature. This dinosaur would have had either an injury or some sort of medical problem that probably gave it quite a painful existence.

Who'd have thought that your sore back would get preserved as a jewel? I know, you probably wouldn't trade for immortality, but some people might if they could. Yeah. Now this little bone here is actually a monotreme backbone. We have quite a number of monotreme post-cranial bones. So they're the bones from the body rather than the head of the animal. Oh, that's quite an extraordinary one.

down the bottom is that opal wood so that one is terrific it's from caroit in queensland

So we're looking at a sort of a rich chocolatey brown piece of wood where the brown material is ironstone that's replaced chemically the original wood. And then offset against that are all of these tiny streaks of green and lilac and blue, which are the precious opal that had filled the voids within the shrinkage cracks. So yeah, it's another favourite. Really beautiful.

You seem to love these fossils. Have you got opal fever? Yeah, I do a bit. So I came here first in the 1990s as a uni postgrad student looking for opalised mammal fossils. I can't say I've found many opalised mammal fossils because they are unimaginably rare. But I've been searching for 30 years now.

And coming here and being invited underground by miners to look for fossils meant that I had the rare privilege of seeing opal sparkling from the walls of a particular mine. And I didn't know at the time how rare it is to even see that.

But that night, as I went back to camp and shut my eyes as I lay down in my tent, I just saw the colour of opal on the inside of my eyelids and that was it. I was gone. So I'm an opal tragic. I love it. And I think if you see somebody with opal fever looking at or holding a piece of opal, you can see that the whole world has disappeared for them and that their eyes and their mind have gone into the opal.

So there's a real connection. I actually think there's some really interesting neurochemical things happening there. I really do think that there's something that happens neurologically when you love opal and you look at it that is really good for you. Opal really isn't like other gems. It ripples and it dances, shifts its colors and entrances.

It's our national gemstone. 95% of the world's precious opal comes from around the Great Artesian Basin in Central Australia. And yet...

Believe it or not, scientists didn't really understand how it forms until 2014, when the mystery was solved by a Frenchman. My name is Patrice Ray. I am a professor of geology at the University of Sydney. Patrice became obsessed with Australia as a boy when he saw a French TV show about opal mining in Coober Pedy. And I do remember thinking, oh,

Those people, you know, they dig a backyard and even if they don't find any gemstones, they end up with this beautiful underground house and some of them have a swimming pool. And I thought, this is a great way to make a living. This is a 10-year-old's dream, eh? Exactly. In 1995, the kid's dream partly came true. He moved to Australia and ultimately the geology department of Sydney University, whereupon he discovered hailstorms.

little we really knew scientifically about opal formation. I was not only surprised, but I was embarrassed. I mean, we know so much about gold and uranium and copper and diamonds, but why so much opal in Australia and not the rest of the world? I mean, I could not believe it. And I thought this is too good to miss.

So he took on the challenge, which you'd think should be easy. Opal is made of silica, which is common. Sand is silica, quartz is silica, they're everywhere. So why not opal?

But it took Patrice 10 long years until finally he cracked it, the geological recipe for opal. And the biggest clue came from unexpectedly far away, Mars. And then I started to read about the discovery of opaline silica on Mars. Yep, you heard it. Opal was discovered on Mars. So what did Mars and ancient Central Australia have in common?

Ingredient one, basalt. Basalt is volcanoes. Yeah, exactly. Volcanic basalt is full of the silica you need for opal. Ingredient two, acid. On Mars, the weathering occurs on the very acidic condition, condition that does not exist on Earth because the presence of limestone buffers that acidity. And then I think this is where the pin dropped. There was no limestones in the rock making the Great Artesian Basin.

To explain, limestone is like nature's antacid. You can't have acidic conditions if there's limestone around. But if Central Australia lacks limestone, it's one of the few places on Earth that can mimic the acidic conditions on Mars. So the question was, OK, how do acid conditions form on Earth? And it

And in most of the cases, the acidity is released through the oxidation of a mineral called pyrite. And it turns out that the pyrite is the product of biology.

There was a particular type of bacteria and what those bacteria do is to release or to poo, if you prefer, pyrite. And where do you find lots of anaerobic bacteria to poo pyrite? At the bottom of swampy bodies of water.

And there was just one time and one place on earth where that unique combination of volcanoes, swamps, and no limestone came together. Central Australia, beginning 135 million years ago. At that time, Australia is still part of Gondwana. 135 million years ago, Australia detaches from the rest of Gondwana. It is still attached with Antarctica.

And Australia and Antarctica move eastward. Heading east, the continent moves over a subduction zone, sucking central Australia down into a bowl shape, creating an inland sea. And on the east side, we have these massive volcanoes delivering lavas and volcanic ashes into central Australia.

The rivers, instead of flowing out to the edges of the continent, flow inland toward the sea, forming vast deltas of shallow lakes and muddy swamps. So it's very smelly, it's very muddy, it's very cold. Finally, Australia was a lot closer to the South Pole then. The seas were too cold for reefs to grow, hence no limestone.

Volcanoes plus acidic conditions in the absence of limestone equals opal. Not quite yet. So let's say that I'm Echidnopus. I'm living my best life back in the Cretaceous.

and I fall into a river and I drown. How do I become a fossil, a fossil opal? All right, so you are transported first through your river, you are transported into muddy layers. And the first thing that happens is that those bacterias, they will eat all the flesh. And through these anaerobic bacteria activities around the bones, we're going to deposit a lot of pyrites.

That fossilisation initially did not involve opal. It involved carbonates. My personal journey to gemstone status occurs in two phases. First, my bones fossilise as common carbonate. Then, from about 97 million years ago, the inland sea dries up.

Fresh rain seeps through the rocks into my anoxic bones, bringing oxygen, which reacts with the pyrite to make acid, which dissolves the carbonate and releases the silica as a gel, seeping through any cracks in the rocks.

And molecule by molecule, the carbonate is replaced by silica. And if the pH is in the right balance, what you deposit are precious opal. And you transform these dull carbonate fossils into a beautiful gemstone fossil. It does blow my mind.

that it was such a rare circumstance and such a rare landscape that allowed these gemstone monitoring fossils to come to us today. It is just impossible. They should not be there. I wonder what would happen if Australia was only 10 degrees north. I wonder what would happen if we did not have that subduction zone. I wonder what would happen if the conditions were not right for those bacteria to form.

I mean it's just simply impossible this gemstone to exist and yet it does. And the fact that we have these beautiful fossils add to the story, I mean it's just amazing. It is amazing. A unique confluence of landscape and time that alchemized living creatures into some of the most exquisite jewels on the planet.

They should be celebrated, part of our national heritage. And that's exactly why Jenny Bramall, Director of the Australian Opal Centre, has been working so hard behind the scenes to bring some exciting news

After more than 25 years of planning, in 2025 the Centre's collection will finally be housed in a grand new architecturally designed museum befitting its significance. Yeah, we're very excited about this. So what we're looking at here is an architect's rendering of what the future new Australian Opal Centre will look like. It's going to be quite incredible. You will enter the building through a short underground tunnel and

and you'll emerge into a space that's about twice as big as you can tell from the outside. It's about 65 metres long by 30 metres wide.

And right across that 30 metre span are big trusses and in between the trusses are skylights. So when you walk in through the end of the building you'll see gorgeous filtered light coming down from the skylights across a massive exhibition space. What we can see in this illustration is the malkaffs which are the ventilation chimneys that allow this building to breathe passively.

But they actually look like the kind of towers that you find in medieval tiny hilltop towns around, say, Tuscany, which I've been to, or parts of the Middle East. That's a really good observation because these are based on a Middle Eastern technology that's been used for hundreds, if not thousands of years, that have kept people

buildings that are in very hot, arid environments cool through the years. What made you decide to go with a bold architectural vision and what is your vision for this place? The original committee right from the beginning set out to build something that would elevate Australian opal. Australian opal is internationally recognised as an incredible natural treasure.

And here in its site of production, we're so casual about it. That's one of the things that we love about living here and being here. We have a laugh, we work hard, we play hard, but we're actually treating this incredible gemstone as if it were a sheep's fleece. It is actually so rare and special. So people wanted to elevate it by creating a home for it that acts as a pedestal to promote it.

and put it onto a truly global and international quality sort of stage. So from the beginning, there was a concept to get excellent architects and to deliver a building that was significant as well as its content.

In a future stage, we're going to actually build an underground Gondwanan garden. So we're going to have a garden within this building that is planted with perhaps wallamai pines, certainly tree ferns and ferns. This is something that people are very excited about. And once stage one is up and running, this is what we'll be fundraising for moving forward, our beautiful Gondwanan garden.

Well, it must have been incredible after the 25 years of planning to finally see that hole be dug and the foundations about to be laid. Absolutely. Is there anything else like this in the world?

In terms of a centre that is cultural and scientific, completely dedicated to a gemstone and a gemstone fossil, absolutely not. This is globally unique. Yeah. So it's going to be up there on the sort of level with much larger institutions, with generalised collections like the

like the Smithsonian, for example. Or on a specialist level, places like the Gemological Institute of America have a museum with a gemstone collection. But this is unique in the sense of the architectural significance, the incredible scientific and cultural significance of the content, and then the fact that it is being completely built of place. When will people be able to walk in the door?

At this stage we're looking at probably late first quarter, early second quarter of 2025. So it's very soon. At the moment we're getting into the stage of thinking about things like this incredible fossil collection we have, which items go on display first?

We can't have it all out at once. So what stories do we tell when the doors open? And what do we keep? Because there's lifetimes, multiple lifetimes of temporary exhibitions and changing exhibitions that we can offer over time. So yeah, it's an exciting time at the moment. It is. Can I put in a vote for Wee Warasaurus? Sure. Okay. Wee Warasaurus will be in there when the door opens. Yeah. Palaeontologist Jenny Bramall with John O'Kanubi at Lightning Ridge.

And so to a quick comment from paleontologist Professor John Long on some of those amazing conclusions on opals and evolution we've had on the Science Show in the past two weeks.

Yes, it was quite a wonderful discovery, Robin, all these amazing opalised fossils of early monotremes, which today, you know, we've got just the platypus and the echidna, but the fact there was a huge diversity of them and some of these other mammal types that are being discovered that lead towards the other groups of mammals of today. So, yeah, it's a fascinating work Tim's doing at the moment. Shows you that Australia is far more than just the funny old place at the end of the earth. Yeah.

That's right. So many big discoveries are coming out of Australia, not just mammals, but fish and amphibians and all sorts of things that are just changing our perspective on the big picture of where evolution started for many of these groups. And more from Professor John Long of Flinders University later in this science show on Radio National. But now we turn to our hominid ancestors as we're discovering ever more species all over our region.

The bone man who knows them best is the renowned Dr Chris Stringer at the Natural History Museum in London. The amount of work that you've done, Chris, over the years is so extensive, it's almost impossible to pick a reasonable 20 or 30 examples. But it's been fascinating to look at the ways in which, for instance, you've connected with other parts of the world. And let's start with Dragoman and your place in the story.

Yes, it's an amazing story, and we haven't really got to the bottom of the early history of this fossil, but for those who don't already know, this fossil from China, the best preserved ancient human fossil from China, it's been named a new species of human, Homo longi, dragon man, and I was asked to collaborate with Chinese colleagues about five years ago now on describing it. It had an interesting early history, and allegedly,

It was actually discovered in 1933 in Harbin in northeast China. And at that time, the Japanese were occupying the region and they commandeered a group of Chinese people, laborers, to work on building a railway bridge across the river at Harbin. And one of these guys was digging in the river deposits and he found this fantastic fossil skull.

And it was only a few years after Peking Man had been found. So he knew it could be important. He didn't want the Japanese to get their hands on it. So he put it in his rucksack and took it home. And he wrapped it up and put it down a disused well.

which is apparently what you do in China if you want to get rid of some treasures or hide them you put them down the ditch as well so he did that. Okay fast forward now to about ten years ago and this guy supposedly is on his deathbed and he hasn't told anyone about this skull up to them because he's ashamed of having worked for the Japanese so he's kept quiet about the whole thing he tells his grandchildren to look down the well sure enough they find this beautiful skull still well preserved

And I was involved in studying it. It was announced at a press conference in 2018, but suggesting it might be Homo heidelbergensis, this early human species. So we began working on it a bit later. And it soon became clear to me and some of my Chinese workers that it was not a Neanderthal. It wasn't Heidelbergensis, certainly wasn't Homo sapiens. It had a great big brow ridge and it's huge in size. It's the biggest fossil skull I've ever seen.

And it was something different. Our analysis suggested it represented a third main lineage of humans in the late Pleistocene. So we had been evolving in Africa as Homo sapiens. The Neanderthals have been evolving Europe and Asia.

And this group, Homolongi, Dragon Man, whatever you want to call it, have been evolving in East Asia. So a number of other Chinese fossils also grouped with the Dragon Man skull. Where did the name come from, Dragon Man? From the Dragon River. And of course, dragons are very special for the Chinese, so it was a great name.

So that, of course, brings up another interesting question, because we do know there is another lineage of humans in the Far East called Denisovans. So the Denisovans are known mainly from DNA from the original cave in Russian Siberia. And so Russian archaeologists have been digging there for over 50 years and had found fragmentary fossils. Nobody really knew what they were. There were some big teeth.

But when Svante Palma and colleagues got their hands on these specimens and extracted DNA, they discovered, to everyone's amazement, that it was a new kind of human, not a sapiens, not a Neanderthal, but something else which became known as Denisovans. Svante, by the way, got the Nobel Prize for his work. He did, deservedly so, yes, that's right.

So this lineage of Denisovans we know has been in that region for at least a couple of hundred thousand years. And there's a jawbone from the Tibetan Plateau of China, which based on its fossil proteins seems to be a Denisovan. And there's now more bits and pieces that are being put into that group. And so the big question is, well, we've got a separate lineage based on DNA, Denisovans. We've got a separate lineage based on fossils, Dragoman and his group,

Aren't they the same thing? Well, we can now say with a high degree of certainty they are. So this is that third lineage. So we've got whole genomes from this lineage and we've got some beautiful fossils. And it does seem to be a third lineage of humans and it interbred with Homo sapiens, just as the Neanderthals interbred with Homo sapiens. And interestingly, there was even interbreeding down in Australasia.

because people today in the Philippines, Australia, Papua New Guinea, have quite a high level of interbreeding showing in their DNA from Denisovans. So they've got like Neanderthal DNA, as Europeans have got and Chinese have got, but they've also got quite a lot of Denisovan DNA. So the Denisovans, we assume, were living down there as well, even though we haven't got a single fossil from down there. They must have been living on some of those DNAs.

regions, maybe Sulawesi, Sumatra. Some people reckon they were even moving towards New Guinea, but we haven't found the fossils yet. So that's another mystery. But the dragoman group must have been widespread because they're right up in northeast China, where even today it's extremely cold winters, you know, minus 16 degrees in Harbin today. So these people were coping with really cold conditions, but apparently they were also down in subtropical conditions in Southeast Asia. So a whole lot to learn about them.

You mentioned the Neanderthals before. One lineage of Neanderthals, or is there a bit of a cousin somewhere? Yes, well, the Neanderthals were varied, but not as varied, it seems, as the Denisovans must have been. So we reckon there were at least three different groups of Denisovans in that region, because the DNA that you find at a small level in, say, Tibet or China...

from Denisovans seems to be different from what you find in the Philippines people and different to what you find in Australia and New Guinea. So there were at least three lots of Denisovans and they diversified over probably three or four hundred thousand years. For the Neanderthals, they're much more unified in their DNA. We've got ancient Neanderthal DNA from Atapueca at about 400,000 years, but

But when we get to the later ones, they're all quite closely related, much more so than the Denisovans seem to be. And it might just be that we haven't found more distinctive Neanderthals. And interestingly, a paper is coming out this week that does show a distinct Neanderthal lineage in Europe about

50,000 years ago from a site called Grot Mondran in the Rhine. That's quite recent. Yeah, 50,000. We've now moved on a long way. So the Neanderthals at 50,000 had unsuspected diversity in Europe. Not as much as the Denisovans. We're still talking closely related, but a divergence maybe 100,000 years ago of a Neanderthal lineage that then somehow remained separate somewhere in Europe.

and survived until at least 50,000 years ago. And there's a fossil from Grot Mondrian. They've nicknamed him Thorin, a male individual. His skeleton has been discovered at this cave. And his DNA shows he's distinct from the other known late Neanderthals. So somehow...

We know that Homo sapiens was very varied across Africa. It looks like even in Europe there was unsuspected diversity, although on a smaller scale, in the Neanderthals. And they were making distinctive stone tools. So it looks like they had kind of separate cultures that ran alongside each other. But more sophisticated than people thought.

The more you look at them, the more interesting they become. Oh, yeah, that's right. I mean, if we were talking 20 years ago, I would have been talking about this behavioural gap between us and Neanderthals, that they were, if you like, inferior. They probably weren't as clever. Their brains weren't as high quality as ours. Their technology was simpler. They didn't have things like art and jewellery and complex behaviour. Maybe they didn't even have full language. Well, now, I don't think anyone would really argue that, but we know from a number of sites that Neanderthals have got complex behaviour.

I mean, there's a mysterious structure deep in a cave, Bruniquel in France. 300 metres into this cave, in complete darkness, explorers discovered these structures made out of stalagmites. So they've dated them up to 175,000 years ago. So this can only have been made by Neanderthals at a date like that.

And what basically the Neanderthals did 170, 176,000 years ago was to go down there with artificial lighting, so they must have had torches to even be able to see what they were doing, and they went and systematically broke stalagmites to a set size, and then they dry stonewalled these stalagmites into two oval structures, and no one knows why they did it. So this is deep in a cave in darkness. They had lighting there. There's clearly evidence of fires around these structures.

but the French archaeologists hadn't yet excavated the inside of these structures, so we don't know if they were living there. Seems a strange place to live, but this was a cold stage, might have been actually a reasonable place to live. There was running water going past it.

There might have been hibernating cave bears, so you've got food not far away. So these dry stone walls, which are about a metre tall, were actually part of a hut structure and the rest of it's rotted away. Other people think these might be some ritual significance. Maybe they were worshipping the cave bears and built these structures. So we don't really know. But that shows the complexity of Neanderthal behaviour.

And to do that means planning an organisation and pretty certainly complex language because you've got to have a group of people to do this. You've got to get people down there with torches and keep the fires burning and go out and collect these stalemites to a set size, then bring them back and build these walls. That must require language. I don't think they could have done it without proper language. Indeed. If I can leap across...

Back to our own district, just north of Australia, Homo florentiensis, the hobbit in other words, which lived quite recently, they thought in the beginning, about 18,000 years ago. That's almost co-evil with human beings. And any idea where that may have originated from and what line? Yeah, that's another big mystery. So the favoured theory is that it's a descendant of Homo erectus, so this earlier species which we know was on Java.

it somehow got to Flores and then it dwarfed down in size. So this process of island dwarfing, we know it happens for large mammals. So alongside Homo floresiensis on Flores, there are these tiny stegodons. So these elephants have shrunk down to the size of large dogs. So this process happens to mammals and on

On the main theory, it happened to these humans as well. So Homo erectus got to Flores maybe a million years ago and then shrank down in size to become Homo floresiensis. So that's the leading theory.

But there are a few things that don't quite fit. So the most complete skeleton has got some odd features which you find in fossils from Africa that are more than two million years old. So the shape of the pelvis, the shape of the shoulders, the body proportions, the small brain, minute bones in the wrists look much more like creatures more than two million years old than like what we suspect Homo erectus was like.

So there is a minority opinion, which I'm sympathetic to. It's even weirder for Resinensis. It's actually a descendant of something that was pre-human, and it got out of Africa before 2 million years ago, and we've got no trace of it. And it got all the way over to the islands of Southeast Asia, and possibly also to the Philippines, because there's a thing called Homo Lusinensis on the Philippines, which looks like a similar dwarfing process.

And then, having died out everywhere else, it then survived on these islands until the last maybe 50,000 years. And what happened to them? Well, it's likely that Homo sapiens spread into the region and they disappeared around that time. But we don't have as much detail as we have for, say, Europe and the Neanderthals.

The invasion story yet again. Yes, the invasive species of Homo sapiens. That's what Robin Dennell has called us. Yes, yes. A short history of you and yours. Chris Stringer at the National History Museum in London. The Science Show on Radio National.

So let's leave the past for a bit and look to the future and meet a youngster, Jiayi Fang, winner of the runner-up award in the recent Bragg Prizes for Science Writing. She's still at school, but really has a vision for our possible destinies. A choice. Two doors. What'll you do? Here's her essay. You've been teleported to an enigmatic portal. This is the end. There are two doors and you don't know which one to choose.

One door guides you to an alluring future. Envision a rich, biodiverse tapestry of galloping gum trees, pirouetting plants and walking whales. The other door guides you to a grim future. Envision no kaleidoscope of colour in flora and fauna, no animals and no plants. At all.

Of course, both opinions are unrealistic, but green certainly can be the new grey in an ever-changing world if we choose to stay in the portal, our world, and make it better together by building a collaborative community promoting the conservation and protection of our biodiverse environment. There's all this talk about biodiversity, but what even is biodiversity?

In simple terms, biodiversity is all the magnificent and interesting types of life discovered on Earth and can include a plethora of different biological organisms such as bacteria, animals and plants.

It assists humans in sustaining life with all of the biological organisms teaming up within ecosystems to provide essential medicine, shelter, food and clean water to all. Unfortunately, humans are increasingly threatening this biodiversity by clearing forests, over-exploiting and burning fossil fuels. One million.

1 million animal and plant species are threatened with extinction, which leads to a loss of biodiversity, according to the Global Assessment Report by the Intergovernmental Platform on Biodiversity and Ecosystem Services in 2019. This is because of our actions. Even our smallest actions can act as the catalyst for change. Let's not wait for politicians to enact a bill which will probably take another 100 years, let's be honest.

Let's initiate action in our communities now. So what can we do? Often I find myself wondering if I could even do anything so young. I'm here to tell you we can do so much together. Real action, real change, real reform for our planet. More than politicians arguing for change at least.

Firstly, let's start small. We can all follow the three R's of reduce, reuse and recycle and encourage our neighbours to do the same in order to save energy, reduce the amount of waste heading to disgusting landfills and most importantly, reduce air and water pollution in our natural world.

According to the United States Environmental Protection Agency, "overwhelming acid levels in our waterways force soils and trees to degrade in health while aquatic and plant communities are dangerously exposed to the atmospheric nitrogen from pollution, detrimentally threatening the diversity of such species."

The more people you encourage to participate in undertaking the three R's, the less pollution there will be, and consequently, a drastic reduction in the loss of biodiversity. I'm involved in my school's environment committee, and we recently came up with the idea of using appealing, humorous posters to motivate students to reduce, reuse, and recycle. It worked. By the end of the week, all the recycling tubs were full. Teamwork makes the dream work, after all.

Secondly, whole communities can band together to volunteer. This can be through bush care and need generation programs that typically every local council runs to a monthly cleanup. I am a volunteer with my local council where I see the true meaning of many hands make light work. There are volunteers of all ages, old and young, coming together to look after the bush by plucking out weeds and planting native species to reinvigorate, yet conserve, the natural space.

My local area is well known for its turpentine ironbark forest, but unfortunately 99.5% of that has gone to clearing land for houses. Completely gone. As volunteers, we've recovered a small fraction of that eradication, but we aim to bring back the biodiversity.

Additionally, I participated in Clean Up Australia Day with my community where we collected over 30 bags full of rubbish found littered near shops and even bushes. It was only one day of cleaning up, yet we did so much as a team. Thirdly, we need to educate the wider community on what we've learnt through working together as a community to tackle the environmental crisis.

Recently, I was involved in Osgrin's Youth Leading the World program, which taught me about the little things we can all do to prevent biodiversity loss and initiate an impetus for action. I will now use that knowledge to unlock society's understanding and compassion for this Earth. You've been teleported to an enigmatic portal. This is the beginning. There are two doors, and you know exactly which one to choose.

Ultimately, you choose none of them, opting for the portal, so you can create the green from the grey with us right beside you. Because people power makes the dream power of conserving and protecting our beautiful, biodiverse environment in the 21st century. Zhang Yi, well done. Thank you. Thank you. It was such an enjoyable ride.

What made you write that? Presumably your enthusiasm for aspects of biology, but you seem to be quite determined. I've always had a passion for the environment, especially growing up around the bush and now going to a school where there's beaches everywhere. I noticed that plastic pollution is such an issue and we really need to step up our game.

And how many of your other pupils at your school are keen on this? Actually quite a few because I recently started an organisation which aims to target youth and bring them together to help create change. So I've been doing that for a couple of weeks now since September with a few of my excellent co-founders and we've gotten a lot of people from school and they're really interested in helping this world become better.

Mavs, how old you are? I'm 15. 15? Yeah. When are you going to be 16? Next November. And I hear you know Emma Johnston, who was at the University of New South Wales as Dean of Science, and then she went Deputy Vice-Chancellor at Sydney. Yes.

And now she is the new Vice-Chancellor of the University of Melbourne and one of the great marine scientists of Australia. Yes, so I was invited by Ocean Youth, which is a youth initiative of the Ocean Earth Foundation, to attend the Global Nature Positive Summit, which is run by Tanya Plibersek.

and through there she was the emcee of the ocean dialogue event and she was really inspirational and just like guiding the whole event and talking about how her interest from marine science stemmed and particularly there was this one moment where she asked for the young people in the room to raise their hands and it was just like eight people because it was the ocean youth people and I think that really shows the impact that youth can really have and how marine science can also have an impact on this world.

Good luck and thank you. Thank you so much. It was really fun. Jiayi Feng from the Northern Beaches College, runner-up in the Junior Bragg Prize for Science Writing. A determined 15-year-old, don't you think? And so to sharks. Should we conserve such creatures? Well, just look at Professor John Long's new book, The Secret History of Sharks.

Well, it's called The Secret History of Sharks because up until now, no one had ever written a book about the long prehistory of sharks. You know, they go back 465 million years. Think about it, older than trees, even older than the rings of Saturn.

So sharks have been around a long, long time and the oldest fossil sharks are tiny little scales from Central Australia. So it's another one of these groups we can say might have originated in Australia.

We'll talk about how wonderful their design is. In fact, a lecturer when I was learning zoology called dogfish, which is small shark, if you like, just like Mozart, wonderfully designed, perfectly formed and so exciting. But how did they survive five extinction periods? Their amazing ability to adapt. All we can say is that at any point of time when a mass extinction event struck the Earth...

There were enough sharks in different environments that the ones that were hammered at these mass extinction events were often in the shallows, the shallow coastal continental shelf seas got hit hardest by changes in sea level, dropping or cooling of the oceans. But sharks in deeper waters were always able to bounce back and then repopulate those shallows. And that's one of the theories.

How do you do your work just finding tiny scales or tiny teeth, although some of the teeth are as big as a plate, but how do you infer so much from these little shards?

It's because sharks have unique tissues. I mean, we all think of cartilage that we have in our ears and our nose and our hip joints. And sharks have a skeleton made of cartilage, but it's not the same cartilage as in a human body. It's a unique kind of cartilage that they evolved that's quite special called globular calcified cartilage. And it's not only very light, but it's also quite strong so they can attach powerful muscles to it.

So when you look at sharks teeth and scales, they also have different kinds of tissue from regular fish and different structures. So you can study the evolution of scales just by looking at their structures, let alone the rest of the fish, but you can only infer so much from scales and teeth.

Luckily for us, there are a few sites around the world with perfectly preserved, complete sharks that are just nature's artworks. They're just beautiful things to look at. They inspire you and they tell us so much about the evolution of sharks. In your book, you describe, talking about teeth, there's a particular species seem to be producing teeth.

during a lifetime hundreds of teeth. How does that happen? Well, sharks actually have a unique kind of structure in their jaws. They produce teeth all through their life and shed them. So a shark can produce up to 20 or 30,000 teeth in a lifetime and shed those teeth which make them excellent fossils. That's why certain rocks are just packed full of sharks' teeth. If you dissolve them, you can get microscopic teeth out in abundance.

That's one of the superpowers, I talk of shark superpowers, not only their ability to make lots of teeth, but also the way they can shape their teeth, the dental plasticity to make teeth that are sharp,

teeth that are dagger-like, teeth with serrated edges like a steak knife for cutting into flesh, or teeth that are rounded and for crushing up things like clams. So some sharks even have what I call the Swiss Army knife dentition, where you have pointy grasping teeth at the front of the mouth and crushing teeth at the back. So you can eat just about anything. And that's why that some of these sharks are likened to the rats of the Mesozoic era when dinosaurs lived because they were found everywhere. They're very abundant and very adaptable.

You talk about some of these sharks. Yes, there are hundreds of species have lived over the last, what, 450 million years. But just now in the Australian Museum, you've been in front of an audience with a great big tooth of the megalodon, is it called? Yes, its full name is the totus megalodon, but everyone just calls it the meg or megalodon. And it was the largest predatory shark that's ever lived, probably about 20 to 25 metres in length.

And we're actually extending its body size from previous estimates because recent new research on it, published only this year, showed it had a much slender body form than we previously thought. It did not look like a big white shark on steroids, as every B-grade movie depicts it. It was more like a basking shark with a long, slender tail. It swam at a slower speed than white sharks on cruising speed because we can calculate that from its actual scales.

And we know from its huge jaws and teeth that it had the most powerful bite of any creature on Earth, even more powerful than a T-Rex. Why didn't it survive?

We think because it was so large, the oceans started cooling around 3 million years ago. There was a megafaunal extinction event in the oceans of the world. So there were far more species for baleen whales around at the time and now many of those went extinct. Other forms of predatory sperm whales went extinct like the leviathan with upper jaw teeth as well as lower jaw teeth. Many of the giant marine turtles and large seabirds went extinct. So

At that time, the environment was under chaos, cooling of the oceans, food chains kind of slimmed down a bit and Megalodon just couldn't cope. So the white shark took over its niche. What about those Darth Vaders of the fish world, the placoderms? Why didn't they win, covered in all that protective armour? Placoderms ruled the roost for about 70 million years in the oceans. They had armoured plates covering the front of the head and the body.

And some of them like Dunkleosteus, the Darth Vader you just mentioned, would have been up to five to seven meters in length. But towards the end of the Devonian, sharks were increasing in numbers and they gave placoderms a really good run for their money. And one of the things I discovered in writing the book, I say that by the really end of this Devonian period, when placoderms went extinct, sharks had actually outnumbered placoderms in both diversity and abundance. And I think

When the mass extinction event hit the end of the Devonian and the environmental chaos with oceans cooling and anoxic basins and everything, the placoderms went extinct, but the sharks sailed right through to a new golden age where they would become the most abundant fishes in our oceans. Three more questions and then I'll let you get to your audience and sign books. But what did you find...

I know you've found many things in gogo but what about your shark discovery there? Well I was really excited back in 2005 after I've been searching this amazing fossil site in north western Australia since 1986. It produces three-dimensional perfectly preserved Devonian fish that's given us many nature papers about breakthroughs in evolution like the origin of sex and so on.

But there were no sharks at Gogo after all the British Museum and Australian expeditions. Over 60 years of collecting there, we had many species of fish, but no sharks. And I found the very first one by hitting a nodule July the 7th, 2005, about 11 a.m. Never forget it. And I looked at a hand lens up close at this rock and I could see little shark's teeth. I knew I had the first Gogo shark. And we were able to acid prepare those cartilage bones and teeth out of the rock.

And then the big discovery was that the bones of this shark, which were made of this calcified cartilage, but they were mineralized in the fossilization process. We studied it in thin section and with CT scanning and we could find remnant bone cells between the matrix of the cartilage. So it kind of was a clue that sharks would have had bone earlier on in their evolution, but were losing it as they gave way to a completely cartilaginous skeleton.

And what made you go into that cage and face a white shark?

I told my publisher and my agent that if I got this contract for this book, I would go cage diving with white sharks so I could observe them, but I've always wanted to do it. And admitted on that day, I was wearing my brown underpants as I slowly backed myself into the cage and then saw this beautiful creature, this big white shark just circling around the boat and coming up close to the cage. I

I lost my fear fairly quickly. That first day I was two hours in the cage, mostly by myself with a few people coming and going, and just got to watch these sharks. And over the course of four days, I saw maybe seven or eight different sharks. I realised how beautiful, how individual they all were. They wear their battle scars. They're all different. Some of them are tagged. Many of them have names.

One of them, IMAX, had been coming back to the same site in the Neptune Islands for 15 years every year. And he was about 30 years of age. And he had a slight scoliosis in his tail. And to me, he was like the Richard III. He was kingly. He was like the Richard III of sharks. He was beautiful to watch. As you well know, a colleague of mine called Anne Jones has done a series about the Hollywood movies that tell you all sorts of

misleading things, lies if you like, about nature. How much did you loathe the Jaws film? Well, it was so scary I didn't really watch it again after that. A terrifying film. And let's face it, sharks don't go out with the intention of killing humans. They're just creatures that like to chomp things and taste them. They actually have taste buds behind their teeth, which is something I didn't know until I wrote the book and dug into their research about them.

So often humans just get in the way when they chomp and taste things. But the aftermath of Jaws was horrendous on the white shark populations of North America in particular. They lost about 79% of the population in the North Atlantic. And at the time, we didn't even know anything about their reproductive biology. For example, that those populations take 26 to 31 years to sexually mature. And they only have a small number of pups when they give birth.

So it will take many, many years, many decades to get that population back to where it was. And even today, they're still an endangered or threatened species. Brilliant book. Congratulations. Thank you, Robin. I'm glad you enjoyed it. Dr John Long is Professor of Pellantology at Flinders University in Adelaide, and his book is called The Secret History of Sharks.

And so to the crisis in services for mental health patients. So many nations are struggling to cope. And in East London, Professor Ian Tucker is researching ways technology could help. So I'm focusing primarily in the areas of community services and peer support.

So we know there's a lot of evidence for the value of connecting people to other people who can support one another, who may have been experiencing similar challenges with their mental health. And digital technologies offer significant potential there because they can help.

connect with lots of other people, you know, far more than they may have connected with were they to be accessing kind of in-person kind of local kind of services. Run by the National Health Service here in the UK and also the voluntary sector, charity sector. It's a good kind of collaboration where a local doctor can prescribe you or to link you through a link worker to a range of local social community-based activities and services.

That can be anything from like a local choir or a gardening group or a walking group or a particular exercise, running, yoga or something. That's been a real priority area and developed significantly in the last three, four, five years in the UK and also internationally. So there's big areas, I think, in Singapore as well. Very little work on tourism.

digital access within the social prescribing space so far. And we've done some research around that recently. So during the COVID-19 pandemic, a lot of these services did try to provide online access because they had to, otherwise it was no access.

That when we're talking about digital access there, we're primarily talking about video calls, Zoom, Teams and things. Some of that has fallen away and we're trying to understand now what works effectively and how digital can be used in that social prescribing space. So, for example, maybe there are certain conditions that people might have, such as social anxiety, where they don't feel well enough to access in-person services and actually being able to engage and access something online can be from the

comfort and the safety of their own home can be really beneficial. I should say, though I'm primarily talking about it from a mental health perspective, it is very much around physical health as well. So it might be people with mobility issues that digital online access can be really beneficial. It's a huge range. And when you consider, for instance, you mentioned the National Health Service, that is struggling for all sorts of reasons.

support, finance, and just plain overload. So how are you navigating that sort of chaos?

Well, I guess, unfortunately, the way that I'm not employed by the NHS, so I don't have to navigate it sort of on a day-to-day basis as such. But yes, you're right, there's huge pressures on the National Health Service in the UK, and I'm sure on health services globally. Unfortunately, there's increased mental health need, you know, rates of mental ill health are rising. So demand is rising, but supply is limited here in the UK. There's significant pressures. And the new Labour government is obviously finding a lot of challenges in terms of balancing the books and funding. So it's a challenge. And

One of the benefits and one of the, I think, the successes of something like social prescribing is it's a collaboration between the NHS and the voluntary sector. So the actual activities, the therapeutic activities that are delivered, that people engage with, aren't delivered by the NHS. You don't lose sight of people with people.

No, I mean the NHS lose sight of them. Well, you know, I mean a machine could take over and you don't see a human face for weeks on end True, so I guess it depends on what part of the digital landscape you're looking at there So something like social prescribing that's about like online access and there's still people there Yeah, so if you're doing an online yoga class, you're seeing someone else. Yeah, so the people are more part of it in that space and

I guess in something, whether you're referring to maybe something more like an app, because we know there are thousands and thousands of apps available designed to support people with their mental health, that you might potentially lose sight of people there, I guess, possibly, because that's a far more individual engagement. Can I just ask you about prevention? Because, you see, there are some brain people and psychology people who are suggesting that if you are going to rely absolutely on a little machine next to you,

And you just look it up on the screen, ping, but you don't have to remember it because you depend on the machine. Is there a way of training that sort of learning, that sort of discretion so that people's

are allowed to grow rather than just turn into custard? I suspect we need a lot more neuroscientific research to answer that in detail. I'm not sure that will turn our brains to custard necessarily, but we don't yet know the impact of that and I think we definitely need to be focusing on that.

course. In the one sense, having all this information to hand immediately is a great thing. Imagine all the things you can learn. I guess it's about how you do that and then trying to make sure you don't just over-rely on it and therefore don't feel you have to remember anything yourself. Professor Ian Tucker at the University of East London, hoping tech will make up part of our lacking in psychological therapists and even social cohesion.

Well, have you ever seen a news story and thought, hmm, what's the science behind that? Chances are the chronically curious science reporter, Belle Smith, has thought the same. Join her each week as she puts the question to people in the know to reveal the science behind new discoveries and current events. It's called Lab Notes, and you can find it in the Science Show podcast feed online every Tuesday afternoon. Production by David Fisher. I'm Robin Williams.

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