David is joined by Professor Kate Trinajstic to discuss modern-day palaeontology, and how ecosystems and species evolve and react to environmental change.
Palaeontology is the study of the history of life on Earth through fossils, a fascinating branch of science that enhances our understanding of extinction, biodiversity, evolution and preservation, and how to respond to climate change.
Professor Kate Trinajstic is a vertebrate palaeontologist and Curtin Research Fellow, who specialises in armoured prehistoric fish. Her work focuses on how early vertebrates evolved an internal skeleton and complex musculature, how lungs developed, and how teeth and jaws evolved.
She is accomplished in a variety of micro-analytical techniques, including synchrotron and neutron scanning of fossil materials, which have opened up exciting new avenues for non-destructive investigations of the structure of fossils.
Her primary field work is in the Kimberley region of Western Australia at the world-famous Gogo fossil site, which was once an ancient barrier reef teeming with fish.
In this episode, Professor Trinajstic discusses how palaeontology can inform our response to climate change, how she uncovers and analyses fossils, her fieldwork at the Gogo fossil site and the discovery she made that reset the evolutionary calendar.
Australians find mother of a fossil
The First Vertebrate Sexual Organs Evolved as an Extra Pair of Legs
The challenges and opportunities for research in paleontology for the next decade
Email thefutureof@curtin.edu.au.
Curtin University supports academic freedom of speech. The views expressed in The Future Of podcast may not reflect those of the University.
Music: OKAY by 13ounce Creative Commons — Attribution-ShareAlike 3.0 Unported — CC BY-SA 3.0 Music promoted by Audio Library
You can read the full transcript for the episode here.
Intro: 00:00 This is The Future Of, where experts share their vision of the future and how their work is helping shape it for the better.
David: 00:10 I'm David Blayney. The discovery of dinosaur bones in the late 18th century brought the field of palaeontology into the public eye. Since then, paleontological research has helped us understand extinction, biodiversity, evolution and preservation. Today palaeontology can help us respond to climate change by providing insight into how species react to environmental change and how they evolve. With us today to discuss this topic is Professor Kate Trinajstic, a vertebrate palaeontologist and Curtin researcher who specialises in armored prehistoric fish. Thank you very much for coming in today, Kate.
Dr Trinajstic: 00:52 Thank you. It's lovely to be here.
David: 00:53 What can we learn from looking at 350 million year old fish?
Dr Trinajstic: 01:01 We can actually learn quite a lot. The fish I work at, as you said, were ancient armored fish, but they're the first jawed vertebrates. Now, vertebrates are animals with a backbone and jawed vertebrates are the group that we ourselves belong to. And a lot of the things that we take for granted as being structures within our own body - our basic ball plan or plan about our body - 90% of it had already evolved in those fish. So we're seeing the first evidence of animals with a differentiated backbone. So they have different structure in their vertebrae, in their neck and a neck joint. They have different thoracic or chest vertebrae, different tail vertebrae. We also see animals that had the first jaws with teeth and also the first set of paired fins. So they're your pectoral at the front and your pelvic at the back. And these go on to become our arms and our legs. So we're really seeing in these fish the first steps as to how ourselves evolved.
David: 02:22 How has life on Earth previously responded to climate change and changes in the environment, and what have we learned from this?
Dr Trinajstic: 02:33 Well, unfortunately, what we've learned is that when there's actually really major climate change, we have mass extinctions. There've been five mass extinctions in the past. When we look at our biodiversity we can say that the majority of life on Earth has already become extinct. So looking back in the fossil record tells us what our past life was, how it's responded to different conditions, and what survived, what's evolved and what's not there anymore. So it's very important to look back. When we're now looking at at questions with climate change, we've got fantastic supercomputers, we can do modeling, we can try and predict what's happening into the future, but it's not going to be until we get into the future that we can see whether or not this modeling works. So looking into the past and looking into the fossil record and the rock record, we can actually say what different climate changes they were and how the Earth and how the animals responded to those changes.
Dr Trinajstic: 03:51 And when you think about animals, if their environment is changing, they've only got three options. They can move to better conditions, they can adapt and try and survive in the conditions that they're in, or they go extinct. And when we look at our Earth now, we see that over millions of years, the continents have changed through plate tectonics. And so those roots of migration have have changed. One of the ways that marsupials got to Australia was that they walked through South America, across Antarctica, in a time when it was warmer and into Australia. And then when the continents separated, it was only in Australia that they were able to survive. So as the continents have changed, as we've got more cities and more areas that we've cleared forests, we're destroying those migration patterns, which is limiting the ability for our animals to move. We also know that animals do adapt.
Dr Trinajstic: 05:08 They can adapt to climate change over millions and millions of years. So ...
David: 05:15 Not quite the timeframe that we're facing right now.
Dr Trinajstic: 05:19 No, no. So one of the things that the fossil record can tell us is the timing of things. So climate change has happened in the fossil record. It has happened in, in the world before, but it appears that now is happening at a faster rate, which again, limits animals' and plants' ability to adapt. And so we are looking at the potential of moving into another phase of mass extinction. And we know that it takes millions and millions and millions of years to recover from a mass extinction.
David: 06:06 Are we ... so we're not quite in the mass extinction yet, but we're, we're sort of trending that way.
Dr Trinajstic: 06:14 It's hard to, it's hard to say, because one of the things about mass extinctions is that you look back. A mass extinction has to be that a huge number of animals across all species go extinct over a period of time. Well we can't actually determine a mass extinction has occurred until it has in fact occurred. And we can look back and say whether or not it meets the criteria for a mass extinction, which is, it has to be global, it has to affect all animal taxa and plants - so we are looking at not just one group of animals going extinct, but all of the groups, so insects and mammals and reptiles and and everything. So it's very difficult when you're going through something to actually determine whether or not you are actually in the midst of an extinction event. What we do know though, is that we are losing animals at an increased rate compared to what we have seen in the past.
David: 07:28 A lot of things have changed since the late 18th century. Palaeontology is no doubt ... it's, it's not an exception. How has palaeontology advanced with technology?
Dr Trinajstic: 07:42 It's actually advanced a great deal. And I often think of this - I don't know if you saw Jurassic park, the first one - I'm probably showing my age now where it ...
David: 07:53 no, unfortunately I haven't. I've seen clips of it.
Dr Trinajstic: 07:56 Okay. But you open with Sam Neil kind of crouched on a rock with a paintbrush and he's brushing off a little bit of dirt and things from, from bones. And I think a lot of people think that's what palaeontologists do. I've never used a paintbrush in the field. I've used a sledgehammer, a jackhammer, a diamond bladed at chainsaw, but never a sledgehammer or never, never a paintbrush.
David: 08:28 Couldn't you break the bones if you use a sledgehammer?
Dr Trinajstic: 08:32 Hopefully not because the bones that I'm working with are actually encased in what we call carbonate nodules, which are basically little round circular pieces of limestone. They look a bit like hotdog rolls. And so the, the fossil is kind of like the hotdog and it's protect it by, by the roll. So you hit the roll with the, with the hammer and it opens up and you see a fossil on the inside and up in Gogo, which is in the North of Western Australia. We get these nodules and about every 50 nodules you crack, you get one that has a fossil fish in it. And you're right, it usually cracks along the plane of the fossil and you end up with half the fossil on one side of the rock and half the fossil and the other. So you get superglue or Araldite and you glue the two bits back together again and usually - or you used to - then put those into a very weak solution of acid, which is basically vinegar. And that would take away all the rock and you'd end up with a little mound of bones and then you have to try and piece all those bones together like a jigsaw puzzle.
Dr Trinajstic: 09:50 Now we can actually use Synchotron and Neutron, which, both of these beams are run by an ANSTO or the Australian Nuclear Facility. And they're like when you go down to the hospital and you get a CT scan or an x-ray and basically the x-ray penetrates your skin and you can see the bone. We're looking at really powerful x-rays. With synchotron, the x-rays are by electron beams, where electrons speed up and change direction they emit an x-ray charge, and neutron beams, which again, as you hit a neutron beam onto the surface, it can penetrate it and then it bounces back and scatters and gives you an image. And so, just like when you go to the hospital and get a CT scan and we can put together a three dimensional image of our insides, we can do the same things with fossils. We can put them through these powerful beamlines and then get a 3D image of what's in the rock.
Dr Trinajstic: 10:57 That means we're not risking destroying any of the fossil. We can virtually remove the rock by a computer. And then if we want, we can get a 3D print out of the fossil at any size we wish.
David: 11:14 And what's the benefit of that as opposed to ... presumably there's a risk of damaging the fossil by using acid, isn't there?
Dr Trinajstic: 11:22 Absolutely. And one of the things that we didn't realise before we started using the synchrotron is that we were in fact damaging some of the structures. So acid and cartilage aren't a very good mix together and even some of the really fine bone. So within our fossils there's a type of bone called perichondral bone, which forms on the outside of cartilage and it's only one cell layer thick. And so it didn't go through the acid baths terribly well. We used to get little bits of it out, but not much.
Dr Trinajstic: 12:03 So using Synchrotron gives us a better idea of these really delicate structures inside. The other thing we can do is actually see inside the bone. So it's paleohistology. Now what that allows us to do is see the cells spaces inside the bones. The other thing is that with fossils their bone didn't resorb as much. So, as we grow, our bones change shape and they change shape by taking away a layer of bone and then putting down another layer in a better shape. A lot of our fossils are like trees, so they just keep building up bone layer upon layer upon layer, and you get growth rings. Now when you virtually section this bone, you can count the growth rings and so then you can work out approximately how old the the animal is.
Dr Trinajstic: 13:10 You can also start to look at negatives. So what were the spaces? So when there's holes running through those bones, we kind of go, well that's where the nerves were. So you can use your computer program to fill in those holes and work out where the nerves were, where the blood vessels were. And also looking at the brain case and reconstructing some of the soft tissue things that aren't usually preserved in a fossil. The other thing that we used it particularly was to look where muscles are attached. So the old fashioned way was to get the bone out and have a look for rough surfaces on the bone and where there was a rough surface or a scar, we'd say, okay, well there's a muscle that used to go there. And so that's how we started to try and add the muscles to the bone and worked out what the animal looked like.
Dr Trinajstic: 14:06 What we found when we used Synchotron to have a look inside the bones was, we could see there were disruptions if the bone cells, we have muscles became attached. And we saw that there was a lot more of these disruptions than there were muscle scars. So that means that we were actually underestimating the number of muscles that they were present in in fossils. So now we've got a much better and more accurate idea of where the muscles were and that way we can get a much better idea of how these animals moved and walked and interacted with each other and with the environment.
David: 14:47 How long have we been using Synchrotron technology for?
Dr Trinajstic: 14:53 In geological terms, in an instant. In our terms? I first used Synchotron for ...
David: 14:59 Footnote in the book of history.
Dr Trinajstic: 15:01 That's right. I first started using Synchotron in 2010 where I used a European Synchotron facility in Grenoble, in France. And in 2011 we started the trial runs at the Australian Synchotron. So it's fairly new technology. Other palaeontologists have been using it a little bit before then, but not much before around about, you know, 2006, 2007 for paleontological work. And it's been a lot more recent for the Neutron Scanner. So this is fairly new technology and it's improving rapidly. In 2010 I took my fossil over to France. I put it in the Synchrotron beam and I came back 27 hours later and the last time I went, I put my fossil in the Synchrotron beam and I came back in three hours. So this speed and the data that we're getting is amazing. And of course we need the supercomputing facilities to then get that data. I think last time I walked away from the Australian Synchrotron, I walked away with nearly four terabytes worth of scanning data.
David: 16:31 And of course you need to have a big computer to be able to process that and turn that into usable information.
Dr Trinajstic: 16:36 Yes. And a whole lot of postdoctoral students who actually know how to drive a computer far better than their professor.
David: 16:44 And looking at the, you know, we've been looking at some of the new technology. Looking at the, the super new technology, what are we, what are we seeing being used now? What's just over the horizon or do we not know yet?
Dr Trinajstic: 17:02 I'm not sure that we know yet. I mean the, the latest thing that we're doing is the neutron scanning. And that's really in its infancy. So I think that that is an area that we will probably make some great advances in. One of the things that we're still limited in in both neutron and synchotron from the fossil point of view is size. So when we want to get really high definition, so see things at a cellular level, we can only put in a very small sample. So what's over the horizon, I guess, is that we will be able to put in and larger samples and get finer and finer detail.
David: 17:52 Petabytes of data.
Dr Trinajstic: 17:54 Petabytes. Yes. So we'll need much, far more post-doctoral and PhD students who know how to try that computer to, to realise that that information.
David: 18:05 Well I guess if you're a smart person with computers and I guess there's a, there's a spot for you in palaeontology.
Dr Trinajstic: 18:11 They certainly is. And I think that's showing us too, that right across the sciences, there is more and more multidisciplinary skills required. So when you think about the scanning that we're doing, they've been devised by physicists. When we're getting the data that's people who have got really great computing skills. And skills and visualisation. When we looking at what data we're putting in there, we're looking at biologists and geologists and people who are actually going out and looking at out Earth and our environment. So we're seeing really all of these skillsets coming together to solve some of the big problems that we're facing in the world today.
David: 19:01 Well, that's worlds away from the image we have of the paintbrush on the bone. What is the most significant thing that you've discovered in your research?
Dr Trinajstic: 19:13 The most significant thing that I discovered, I discovered with my colleague, Professor John Long, who's now at Flinders but it was at the Melbourne Museum at the time, and we found a fossil embryo inside one of the fish. Now, that's kind of nice, and you kind of think, how cute, you've got a little embryo - sweet. But then it's kind of like, hang on a second, we've got an embryo inside a fish. What does that tell us? Now, the most significant thing about that was when we looked really closely, we actually saw a little umbilical cord. So that tells us that this fish had life birth and it brought back the story of live birth right back to the evolution of the jawed vertebrates. Prior to that, the idea of live birth occurred in sharks and the only fossil evidence we had of that was 200 million years in advance.
Dr Trinajstic: 20:18 So we bought back the story of live birth to the actual origin of the jawed vertebrates. The other thing we had to think of was if you've got live birth, you've got internal fertilisation. Where you have internal fertilisation, you have to have sexual dimorphism. And we didn't have any fossil evidence of any kind of physical attributes that separated males from females within our, ancient armored jawed fish. And there's actually a great line in one of the publications from the 1960s that said, despite an exhaustive search, they had been no evidence found of any sort of male reproductive organs. Now what you do in science, is you go back and look at this evidence and you question it. So we went back and had a look at those original fossils and we actually found that the areas that they had thought was a pelvic girdle, which supports the fins, were in fact the male clasper organs, which have a very thin rod of bone running up them and that the pelvic girdles which support the fins were actually further up the body and very well separated.
Dr Trinajstic: 21:47 Again, this is really quite unusual when you have a look at shocks. The male claspers are attached to the, to the pelvic fins, so they're a modification of the pelvic fins. When you have a look at most animals, they've got four sets of limbs. Or vertebrate animals. So you've got arms, legs. If you're a cow, you've got front legs, you've got back legs. If you're a fish, you've got front fins, back fins. We've got a separate set of paired organs outside of that zone. So here we're seeing that even though these are jawed vertebrates - they're on our evolutionary lineage - they were able to produce an additional set of paired appendages outside of the normal area that we would find those. So again, we question this, we have some other fish that were more primitive, that everyone thought couldn't have had internal fertilisation, because it had no pelvic fins. But once we found male claspers, separated from pelvic fins, we thought, well, let's go and have a look at these. And so we found that these animals absolutely had no pelvic fins, but they did have these additional set of paired male appendages. So it's really kind of turned what we thought about the evolution of paired appendages completely on its head and where those appendages could form. And so we're seeing that there was a lot more flexibility of where you could kind of 'punch out' a set of paired appendages from your body early on and greater much greater complexity than we had ever thought.
David: 23:46 And when was this discovery made?
Dr Trinajstic: 23:50 Like many discoveries, each step was made over a number of years. So we first found the mother fish in 2008. Then we found more embryos in 2009. Then we found the male claspers later in 2009. Then we went on a exhaustive search and we found that the separation of the pelvic fins and the appendages - that was published in 2011 - and then 2015 we found the paired male claspers in a fish that didn't have pelvic fins. So a lot of little steps to finally get the whole picture of what was going on.
David: 24:51 This discovery in the grand scheme of things is pretty fairly recent. Why is that?
Dr Trinajstic: 25:00 We've been investigating this fossil site in Australia really since the 1960s and, and we meaning the scientific population rather than me individually. The site was actually found in the 1940s by Curt Teichert from the University of Western Australia and he brought back some of these fish to the museum there and he had no technique of getting them out of the rock. Then in the 1950s expedition from the British museum who'd been working in the eastern states, sailed into Albany, came up to the university for a day, saw these fossils and thought, I think we know how to get them out. Took a couple of samples back to the British Museum and that's where they developed the acetic acid technique, which removed the bone from the rock. The fossils were absolutely magnificent. They're three-dimensionally preserved and original bone, so you can basically glue them together like a model aeroplane and they look absolutely magnificent on display. So a joint expedition was planned between the Western Australian Museum, the British Museum of Natural History, which was then called, and the Hunterian Museum. And they came out and literally bought three tons of these fossils out and most of them went back to the United Kingdom to be worked on with the agreement that a number of the specimens would come back to the Western Australian museum, which they did then in the 1980s no, 1970s, Sir David Attenborough went up to that site and featured it on his Life on Earth series. Then my supervisor, professor John Long, got an Australian research council grant and did postdoctoral work up there in the 1980s. And at that time we were collecting large amounts of fossils and getting a diverse fauna. So when you think about this reef, this great Devonian reef, which is about 375 million years old, we've got everything up there. We've got all of the fossils, but we've also got all of the structure of the reef. So the big limestone ranges are actually the reef. So we've got a complete environment there and that's very, very unique. It also stretches over 350 square kilometres. So we've got a lot of space to cover. We've been going up very regularly now since the 1980s and every trip, we find something new.
David: 28:04 So there's no risk we're going to run out of things to discover I guess, because the techniques are changing all the time.
Dr Trinajstic: 28:09 The techniques are changing all the time, but also this area is just so rich that we haven't been on a trip that we haven't found a new specimen that nobody has seen before. And it's really amazing because you do hit that rock with your sledgehammer. It opens up, you look down and you realise that you're casting your eyes over something that hasn't seen the light of day for over 375 million years, and you're the first person to actually see that, and then when it's a new species or a new specimen, it's even more exciting. And we actually call those out our star specimens. And normally what we do is we wrap them carefully and we put them into boxes and we kind of truck them down to Perth. But if you're a star specimen, you get wrapped up in plastic. You may have to sacrifice some of your clothing because it goes into your kind of carry on bag and it gets the star treatment. It gets to actually fly down to Perth with, with you. Yeah, so I don't know what else is up there, but we're finding new and wonderful things all the time. And one of the things that the Synchotron has showed us is the amount of soft tissue we have preserved up there. And soft tissue in the fossil record is incredibly rare. And now we're finding that we don't just have the bones in these ancient fish, but we have all of the musculature preserved as well.
David: 29:56 So WA's quite a hotspot for palaeontology then?
Dr Trinajstic: 29:59 Absolutely. the fauna that we're finding in the Gogo formation is actually recognised as one of the 10 best fossil sites in the world. And most West Australians don't even realise we have it.
David: 30:12 What's on the horizon for your research?
Dr Trinajstic: 30:16 I'm still very interested in the soft tissue preservation. So I'm trying to map the muscles. So getting through all of that scanning data, looking at combining where we have muscle preservation, that also, as I said earlier, where we see on the bones, those areas where the muscles attached, so that for the first time we can accurately reconstruct the musculature of these fish and then work out how they moved and how they functioned. Particularly, I'm also interested in looking at how things change through their lifespan. So, as I said, we've got embryos, but we've also got juveniles and teenagers and adults. And when we reconstruct the muscles and their bodies, we can see if their shape changes where they grow, and also see whether or not they're occupying different parts of the reef and acting in in different ways. The next stage is to really understand the total fauna and how it interacted and really get an idea of how one of the first reefs worked in the world. And if we can understand how it worked and what happened, it might give us some ideas of how we can save some of our reefs now, which are under threat.
David: 31:59 Well, I think we'll leave it there. Thank you very much, Kate, for joining me. So long and thanks for all the fish.
Dr Trinajstic: 32:05 Thank you. It was a pleasure.
David: 32:07 And thank you for listening. You've been listening to the future of a podcast powered by Curtin University. If you have any questions about today's topic, please get in touch by following the links in the show notes.