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Australia: The Time Traveller's Guide -

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(generated from captions) 4.5 billion years in the making. A land as old as the earth itself.

new world you might expect. Australia. It's not the brave in Australia, When Europeans first arrived everything was new and different. no old buildings There were few ancient relics, and little obvious history. a kind of separate creation. They saw it as a young country, further from the truth. Nothing could have been

(Roars) inhabited continent on earth The oldest, flattest, driest in prehistoric times. is a puzzle put together that unlock the mystery And the clues across Australia's sunburnt face. can be found scattered

And this is an amazing country. My name is Richard Smith. every rock has a history, For a scientist like me, against the odds. every creature a tale of survival the earth's deep history, If you've ever dreamt of exploring

Australia has got it all. billion years on the big island So join me and spend a few at the bottom of the world. to get the big picture. It's a great place Of all continents on earth, of our planet none preserved the great saga quite like this one. and the evolution of life jump in a car Nowhere else can you so simply to the dawn of time. and travel back

and worn, If Australia seems a little tired over the course of her long life. it's because she's seen a lot happen 4.5 billion years ago. began with the earth's fiery birth fumbles of life long ago We passed the first Australia's ancient shoreline. in the waters skirting is the Palaeozoic. GPS: Your destination We've seen the planet itself to pleasant... change from poisonous to swim in the seas. ..and the first animals begin of a continent, But in terms of the lifetime is still an infant. Australia and the world around it Gondwana motherland... Still attached to the greater on land. ..and still a blank canvas of slime and bacteria Save for a thin smear along the soggiest of margins... for over four billion years. ..all the continents had laid bare behind us, Now with 90% of earth history all of that was about to change.

The tremendous explosion of life of the Cambrian that began in the oceans at the dawn of the Ordovician, were still going strong six great periods the second of the that make up the Palaeozoic. And it was in Ordovician oceans experimentation began as well. that a second wave of animal One that ultimately Australian's coming ashore. would lead to the first now crowded with life, With the seas onto land were not far away. the first tentative footsteps just one of an exotic collection Now at the time Australia was South America and Antarctica of lands including India, Africa, supercontinent Gondwana. that today we call the about here, right on the tip... Australia's position was just and mostly underwater. ..just north of the equator around the planet Oceans were rising across parts of Central Australia. and seawater movement flooded in know today as the Simpson Desert At the time the sea of sand we of the Larapinta seaway, was slap bang in the middle a tongue of warm ocean water the country. that licked right across

have been a bumpy boat crossing. Back then this bouncy drive would As the rising waters swept in a rich bloom of plankton... they carried fish to swim in the sea. ..food for some of the earliest right above me. And they swam right here - Larapinta seafloor lie tumbling The last vestiges of the old hills of the Simpson Desert. from the top of the mesa-shaped like this, Even in the best of seasons unforgiving landscape. the Simpson is a harsh, (Rattling) to find the world's earliest fish Now you probably wouldn't expect in the dead centre of the driest on the planet today. inhabited continent hill in the Simpson Desert But it was on the side of this lay waiting to be discovered. where the fossil of Arandaspis bony head-plates it left behind - We only know Arandaspis from the was a fish with a simple tail enough to tell that this and no real fins. have jaws or even teeth... Nor did fish like Arandaspis whatever morsels they could find. ..they probably just slurped in the significance of this fish - But don't underestimate with a backbone... this was an animal vertebrates, ..and being one of the first back to an animal like this. we can all trace our ancestry ruled these Ordovician seas... But giant invertebrates was just a bite-sized snack. ..and to them, Arandaspis to swimming out of danger, While the first fish took soon be flexing their leg muscles their invertebrate foes would in a different way. and head for the seaside... Time to put the foot down ..in the Silurian. of the Western Australian coast, On a remote stretch the 21st-century Indian Ocean Silurian shoreline. eats away at an ancient have exposed the burrows Wind and water movement in the sandy coastal cliffs. of long-gone animals of the burrows remain a mystery. The original inhabitants attracted by such rich pickings But not the predators along the prehistoric shoreline. are revealed in the rocks Clues to their identity of nearby Kalbarri National Park.

My goodness, what a view. has sliced a spectacular gorge Here the Murchison River deep into the Silurian past. back in the Silurian The Murchison Gorge wasn't a gorge at all, of course. estuarine flood plane It was a vast from the hills in the distance, with rivers winding down carrying sand into the sea. in the history of the planet But for the first time down there those Silurian shorelines were alive with animal activity. to take the kids to the beach. This may not have been a good time were massing in the shallows. Armies of sea scorpions as eurypterids, Known to palaeontologists as long as a man is tall these giant arthropods could grow and they bristled with armoured legs and fearsome claws. Far less threatening was this bloke. Kalbarria was probably an ancestor of modern crustaceans and grew about as long as a king prawn. Whether in search of food, a safe place to mate or simply to avoid the nasty neighbours, Kalbarria clambered ashore... ..and left clear imprints of its many tiny feet in the rocks. A descent into Murchison Gorge takes you back to those ancient Silurian shorelines for a walk in the footsteps of prehistory. All in a days work for Kalbarri ranger Mike Paxman. It's amazing the amount of time that goes past to make so many layers in a gorge like this. MIKE: Each one's different, it has its own character. Down here it soon becomes clear that the sea scorpions followed Kalbarria ashore. This is what we call 'track central'. I can see why. Yeah. There are tracks everywhere. This is probably the best site in the park to look at these eurypterid tracks. Your animals come through here. So in shallow water? Shallow water. OK. Then slipping and sliding as it comes around the corner. That's exactly right. But here, I mean, I can see clearly, there's this kind of sloppy looking track here. But once you come over here, you start seeing really discrete footprints, clear graphic demonstration of a creature walking out of the water and onto dry land. Where we are here in the depth of the gorge, we're in the oldest of the Silurian sediments in this area. Quite an historic little spot you've got here. Very, very. The Kalbarri trackways are the oldest direct evidence for animals on land. And even though these formidable beasts could not stray far far from the water's edge, a beachhead had been established. So this seems to be how the animal invasion of the land began - with a scary assortment of arthropods with attitude, slinking and scuttling ashore onto the wet sands of a new frontier. But this wasn't just a continent to exploit - there was a whole planet for the taking. Waiting beyond the breakers were all the wide brown lands of earth. As the Silurian progressed, the entire Gondwanan juggernaut as Australia welded on at the northern edge, began to drift into the Southern Hemisphere. Australia, already under animal assault, found itself centrestage for the waves of invasion and conquest that would follow. But animals were not going to get far inland without help from plants. They too came out of the sea... ..first as slime then as low-spreading things that clung to dampness. Algae and fungi captured the shoreline, followed by tiny forests of lichens, liverworts and mosses, pioneering the move inland. That was the big deal about the Silurian, of course - it was the first time that the earth turned green. Today we take for granted the plants around us. It's their oxygen we breathe, their food we eat. But the land can be a tough, dry place to live... ..and any plant going to make it big out here needed a thick skin and a little internal fortitude. Just such a plant first took root somewhere around here. If you thought that this was just another ordinary roadside cutting on a pretty but ordinary country road, well, of course, you'd be dead wrong. It was here near Yea in Victoria that fossils of some of the world's earliest land plants were found. Indeed these rocks contain the first signs of the greening of Gondwana. Just amazing. This is Baragwanathia, thought to be the oldest true land plant in the world. Not much to look at perhaps, but with green leaves and a stem to carry sap internally and to support its weight, the world above water was its oyster. In life, it would have looked much like this. This is a lycopod or club moss, as was Baragwanathia, rising out of the water in a coastal bog in Queensland today. These are the direct descendants of the green revolutionaries who changed the face of the planet. If you look closely, you can see many of these Silurian-aged plants still clinging on in damp corners around the country. Here's a rainforest Selaginella, a tropical tassel fern... a club moss in Tasmania, even a Psilotum in Sydney. Plant life had by now engineered a solution to the ultraviolet radiation that had been sterilising the earth's surface... ..an ozone layer built from excess oxygen. With the natural ozone sunshade now high in the sky, barren continents became viable real estate. Finally there truly was life on earth and not just in the sea. The low-spreading thickets provided the perfect humid cover for other arthropod forms like millipedes, centipedes and mites to make the transition to land complete. Some molluscs even brought their own homes because it was still not a very welcoming place. While life was exploring the fringes, most of the Gondwanan supercontinent was dry, probably still quite bare and almost certainly windy. The Larapinta seaway had receded, leaving much of what is now Central Australia resembling the Sahara Desert. And that desert in the dead heart became mountains. Titanic, tectonic forces operating over a span of 150 million years, buckled the earth and pushed great folds or rock into the air. In their heyday, Central Australia's MacDonnell Ranges would have been a mountaineer's dream, as high, it's thought, as any on earth today. But Australia would never experience mountain-building on this scale again. After a near eternity of erosion, the diminished remnants of the MacDonnell Ranges still run in long, jagged ridges from one side of Alice Springs to the other. From the air, they protrude into this ancient landscape like the bony skeleton over which the dry skin of a tired continent is draped. All other continents boast mighty mountain ranges... ..the Rockies, the Alps, the Andes, the Himalayas - but they are all relative newcomers and mostly still growing. What sets Australia's landscape apart is its venerable antiquity... ..and its great flatness. Australia is actually quite remarkably flat and when you look at it from space, it's not just flat but it's apparently saucer-shaped. It's a saucer that holds many secrets for geologist Lisa Worrall. Her interest is not so much the bedrock of the outback but the story of all its eroded remnants, accumulated over a vast gulf of time. We know parts of Australia have been exposed for millions if not billions of years. We're part-way through an ongoing geological story. The rivers that in Australia mostly drain inland are actually losing or have lost the ability to carry sediments out and down into the seas, so inland Australia is filling up with sediments. Outback Australia is drowning in sand. Head towards the coast in any direction from the Red Centre and you cross oceans of these old, weathered sediments. It's the sort of landscape you should expect from the flattest continent on the globe. Travelling north-west, it's 1,000km before you reach the next significant patch of high rocky ground... ..the Kimberley. While mountains were still pushing skywards in the continent's heart, up here in Purnululu National Park, others were already wearing down to nothing. (Man sings Waltzing Matilda) Epic tales of erosion and recycling lie behind most geological features in the Australian landscape. The sands and gravels that made the Bungle Bungle Ranges started arriving here about 375 million years ago... ..dumped by rivers that wore away highlands far older and now long-gone. This landscape was already second-hand long before the rocks began eroding away into the famous striped beehive domes we see today. The distinctive striping of the rocks here is a dead giveaway to how the Bungle Bungles were formed, layer by layer as mighty rivers washed sediment from distant mountain ranges to fill the basin. Alternating layers of pale gravel and sand stained by a living skin of bacteria provide the stripes... ..and a new phase of weathering and erosion is creating the distinctive shapes. This unfolding landscape is a two-tone testament to change... ..left as a parting gift by rivers that ran down into a Devonian tropical sea. 300 dusty kilometres to the south of the Bungle Bungles and you can run down to that same ancient sea... ..once home to some of the most spectacular tropical reefs on the planet. Surprisingly, you can still visit these reefs today.

I'm standing at the base of the Great Devonian Barrier Reef. These towering limestone cliffs were once towers of life, rising into the clear, sunlit waters of a colossal reef system

that once circled the Kimberley. In both size and significance, the Devonian reef rivalled modern Australia's Great Barrier Reef. Its limestone ramparts were once festooned with crinoids and corals, sponges and sea squirts and many other creatures still found clinging on in tropical waters. That Devonian life is gone but the great reef walls still stand to this day. It's easier to see from the air. In the same way that the Great Barrier Reef fringes the Queensland coast today, the Great Devonian Reef skirted in a sweeping curve around the Kimberley hinterland for perhaps 1,000km. Reef after reef line up across the landscape as if a giant bathplug had been pulled. These days freshwater crocodiles guard the only water left... ..dry-season pools left by the monsoonal streams that drain and dissect the old reefs. At Tunnel Creek, one such stream has carved its way right through the Devonian limestone range. It's a deliciously cool change from the sweltering heat outside... the very heart of the reef itself. ..and offers dark access to of reef-building organisms A whole suite above me. built this Great Devonian Reef remains in the rocks still - You can see a lot of their ghostly sponges, stromatolites, corals, called 'stromataporoids'. strange extinct things here weren't the things But the real stars of the show that swam around outside it. that made the reef but the things was the great age of the fishes. Things with fins because this that for the first time, It was in the Devonian fish filled the oceans... ..fish of all shapes and sizes. and sizes we see today. Just not quite the shapes (Bird squawks) fish of the Devonian north-west Like the reefs themselves, the are amazingly well preserved... ..protected in limestone nodules nearby Gogo Station. scattered across Ow. Devonian style. This is reef-fishing, just a hammer and a lot of luck. No messy bait required - around here - You don't get a lot of bites yields a fossil strike. about 1 nodule in every 100

a Gogo fish But whenever you catch it's always something special. That's a lot of bone. GAVIN: Oh, wow. that's some very large plates. That's a lot of bone there, that is, Gavin? So what do you think probably a big arthrodire. It's clearly a large placoderm, were the placoderms. Kings of the Devonian seas of Arandaspis. Fish had moved on since the days to go with their bony head-plates. Now they had jaws, fins and teeth

covered in these bony plates... The front part of the body was be pretty much shark-like. ..and then the tail would very agile, successful predators. They were in fact, sensory system. They had a highly developed electro-sensory perception Some of them had like modern sharks and rays. been preserved in fabulous 3-D. Many of these fossil features have Oh, look, there's some ridging. the fossils from being crushed. The Gogo nodules have protected might be a Holonema? Do you think it gonna clear it up. A nice bath in acid's and scrub it with a toothbrush. And soak it in some water a shower at night, No, if I'm not getting Hmm. this fish certainly isn't. the limestone nodule It's only once in the lab is dissolved away in acid that the fossilised fish within in astonishing detail. come back to life... brain cases, bones and fin rays, Scales, teeth, eye sockets, well preserved for their age the fish are all so fabulously can be made out. that even soft body bits these are pretty sexy fossils. In more ways than one, particularly interesting Well, this one here's few male fossils that we have, because it's one of the because it has this clasper. and we can tell that Very much like a shark. What, like in a shark? oldest confirmed male appendage, This bony tube structure is the impregnating a female. a fishy willy for for vertebrate life The Devonian was an important time underway with many biological experiments vertebrate sex. including the all-important a bit of a hit or miss affair... Even today sex in the sea can be precision and plenty. ..a trade-off between Without coupling and live birth... sink or swim on their own... ..vulnerable progeny destined for success on land. ..not a strategy oldest preserved mother with child This is a portrait of the world's to prove it. and we have the fossil discovery to date. This is perhaps our most famous and this is the real kind of This is the mother fish you could have live birth. clincher we had that here, right round the bottom, And it's this little structure and that is the umbilical cord to her unborn embryo. which is attaching the mother My goodness, that's the world's we know of. earliest umbilical cord earliest evidence It is. It's the world's of live birth in any vertebrate. making all the right moves... Our backboned ancestors were sociable, smart and sexy. ..already on the road to becoming And they were everywhere. fish were swimming in the waters We know that the same sorts of at the same time... of Australia's east coast more hazardous conditions. ..though under slightly had been a construction zone The eastern seaboard of Australia ever since the Cambrian. ran in a broad arc Far offshore, a line of volcanoes of colliding tectonic plates. along the edge Now imagine if you will... of volcanic islands ..that this is the line of the old Australian plate. running down the eastern boundary old Australian mainland. And over here is the sea that was filling up with sand Now, in between them is a shallow thickened, it hardened into rock. and mud and ash, and as it Now, these two plate boundaries into each other, were constantly shunting more of this fresh rock was pushed and every time they did so, and shunted and piled up of the Australian mainland. along the eastern side shunt by shunt... So piece by piece, Australia rose from the sea. ..the highland of eastern (Thunder rumbles) newly constructed east, As rain fell on the towards the sea, rivers ran back down and billabongs filing the freshwater lakes of the new coastal landscape. of those Devonian rivers Throw a line into one plenty of fish and you would have caught to this. that looked almost identical Whoa! Hi, big guy. Aren't you something special? Look at you. truly special - Now, this is something a living link to our fossil past. Neoceratodus forsteri, It's the Queensland lungfish, I hope. and I'm trying to hold him, of a handful of lungfish Now, he is the most primitive that still swim on planet earth. Think about it for a moment. These guys were already ancient history 100 million years before the first dinosaurs walked the earth. And if you're worried about that fish-out-of-water thing... ..these guys are called 'lungfish' for a reason - they're built for it. There you go, matey. Off you go. Thank you. When lungfish moved from the sea into freshwater in the Devonian, they brought with them the ability to breathe with or without gills when the going got tough. It's the skill that stands these remarkable living fossils in good stead. They live on in just a few river systems in South-East Queensland. And when oxygen levels fall, they can switch to gulping air from the surface. It's a strategy that has doubtless allowed them to struggle through

more than one Australian drought. Not all fish have been so lucky. As far as we can tell, drought is a problem that has plagued the country for at least 360 million years. We know this because in 1956 the local council sent a bulldozer to smooth out a bad bend on the Canowindra to Gulgong Road. Well, the bad bend in the Canowindra to Gulgong Road is still here and you wouldn't know it to look at it, but I've just parked right on top of one of the most spectacular Devonian freshwater fish sites in the world. The roadworks inadvertently lifted the lid on Australia's oldest-known billabong. When a palaeontological team returned to open the site... Can you turn that round, so we can get the light on it? ..thousands of fish tumbled out. They were lying on the slabs just as they had been the day they all died together when their waterhole dried up. Like their saltwater Gogo cousins, many were armour-plated placoderms. There were lungfish here as well... ..and another related group of fishes with four-lobed fins... ..that we humans should be very thankful for. Of the 4,000 or more fish uncovered on these Canowindra slabs, this one is special. It's been given the name Canowindra grossi, after the town of course, but its real claim to fame are the features that it shares with those fish-like animals that were leaving the water behind. Its reptilian-looking head had nostrils, suggesting it too could breathe with both lungs and gills. And it was one of the lobed-finned fish, a group with four limb-like fins with a bony internal structure we can recognise in our own arms and legs. It's not hard to imagine that somewhere in the drying Devonian billabong at Canowindra, at least one of those fish might have got away... ..by walking onto land. And this is why. Hard evidence in the form of fossilised four-legged footprints of about the same age and found near the Genoa River in Victoria. It was a different Genoa River but these early fish-like tetrapods, about 1m-long, were among the first animals on earth to feel the sand between their toes. It's astonishing to think that it was from a spot very near here that to the best of our knowledge, some of the world's first animals with four legs walked out of the cool water and made their mark on the land. It's not hard to see how the evolution of walking limbs might have come about. Many Australian fish species today are still testing out ways of getting about without swimming. This is the aptly named handfish... ..hopping and skipping its way along the Derwent Estuary in Tasmania. And this that master of the tropical mangrove, the mudskipper. However they'd managed it in the first place, the first amphibians walked out into the botanical wonderland of the Carboniferous. The Carboniferous saw all sorts of new plants putting down roots and pumping out oxygen at levels the planet had never seen before. Huge forests, especially in the Northern Hemisphere, helped push up oxygen levels in the atmosphere to 50% higher than today. The extra oxygen saw some invertebrates grow to enormous sizes. It allowed millipedes the size of snakes to scuttle across the land and insects as large as seagulls to take to the air. The rich insect pickings on offer must have favoured the spread of the amphibians now moving through the landscape. But like their froggy descendants today, these ancestral four-legged animals needed to return to water to reproduce. Sometime in the Carboniferous, the first reptiles overcame this limitation. Wrapping their eggs in a membrane blanket with a hard outer shell, reptiles could take a watery egg with them on their travels. It was a solution so successful that it allowed the many contemporary lizards of Oz to still claim the arid Australian outback as their own. There was yet another Carboniferous legacy left out here. The greening of the earth began to at least partly turn Australia red. The highly oxygenated atmosphere began to rust the iron-rich soils and rocks of the outback. And some rocks out here are bigger than others. It's very impressive. It's a fabulous monolith, isn't it? It's justly famous for being the largest bit of rock, lump of rock, in the world. Yeah, and it's just gorgeous. And it's very red... ..the colour of weathered iron minerals like hematite. Many of the rocks of Australia are rusted. We know that we had oxidising rocks back to around the Permo-Carboniferous. That colouration of the landscape is in fact, very old and very persistent. But at the end of the Carboniferous, just as world-domination lay within the reptiles' grasp... ..the changing world threw up another great climate challenge. The drift of Gondwana saw Australia heading south... ..and getting colder. It was more than just the location... The earth had slipped into another ice age. And Australia was covered in more ice than it would ever see again. By the time we reached the Permian, a deep chill had settled in. Ice carved it's calling card on the country... ..nowhere more clearly than the Fleurieu Peninsula in South Australia. The bedrock here was scoured by glaciers. All these long scratches and grooves in this smooth surface were gouged by rocks and debris being dragged along on the bottom of an ice sheet flowing in this direction. And here is one of those rocks that did all the scraping, a simply enormous boulder just dumped here. What these rocks are telling us is that clearly, if you look to the south of Australia back in the Permian, you wouldn't have seen the open ocean we see today. If you looked back that way, you would have seen the mountains of Antarctica. (Footsteps) It's incredible to think that if you travelled to Australia in the early Permian, the landscape probably looked much like this over I at least the southern half of the continent. Evidence for ice can be found stretching across the country from the Kimberley to the coast of Tasmania. But this cold landscape was not frozen solid like Antarctica. It was seasonally cold, more like a Northern Alaska or Canada. Well, Permian Australia might have been freezing cold, but it was far from lifeless. These remarkable rocks on Maria Island are just stuffed to the gunnels with shellfish. And nearly everyone of the animals in the rocks here and in the rocks behind me and the cliffs in the distance, belonged to one species of clam... this one, called 'Eurydesma'. What Australia's Permian ocean lacked in diversity, it made up for with abundance. Life crowded the seafloor. It was the same story on land. And the proof can be found hidden underneath Australia's moist eastern seaboard. Much of it right under modern Sydney. Beneath the eucalypt forests that surround the city of Sydney today, lie cool climate forests, far more ancient. Welcome underground, gentlemen. Ground floor, the Permian. I'm heading deep into a coal mine at Helensburgh on Sydney's southern outskirts. The seems of rich black coal here have been mined for longer than any other in the country. What you are looking at here is the exhumation, half a kilometre underground, of the dead black graveyard of a vast, swampy forest that once stretched right across the Sydney basin. It's hard messy, noisy work, but there's treasure in this coal - the raw energy of fossilised sunlight. Half the energy used to light Australian homes, fuel industry, cool beer and power this program, comes from Permian plants buried faster than they decomposed over a quarter of a billion years ago. When scientists look closely at these coal seems, they found something not seen in the Australian forest growing so far above me today. The fossil leaves they encountered were found in alternating, repeated layers. Every autumn it seems these now-blackened Permian coal forests were once a riot of colour. One tree above all others, dominated the Permian forests... ..Glossopteris. Glossopteris had solved another part of the problem of reproducing on dry land by encasing its embryo in a protective, seedy shell. So successfully it turns out, that fossilised Glossopteris leaves are the botanical signature of all Gondwanan lands. The planet had come of age in the Permian. Here was a world with great oxygen-producing forests inhabited by animals with four legs. Insects had taken to the skies and the seas were brimming with animals. Life on earth was going swimmingly well... ..and then suddenly, everything went diabolically wrong. Well, the Permian came to a sudden and very sticky end right here at the greatest extinction boundary in the planet's history. Now this black coal is the last coal to have been deposited anywhere on earth in the Permian, the last of the great Gondwanan Glossopteris swamps. But it also marks the bitter end for over 80% of all species alive on the planet at the time. This truly was... the world's greatest cataclysm. This figure is conservative... ..some estimates have 95% of all species dead and gone... ..wiped out in a geological blink. The trigger it seems, did not come from outer space but from underground... ..a massive volcanic eruption in Siberia pushed CO2 levels sky high, and the planet into a runaway greenhouse crisis. These were the days when our living earth nearly died. Acidified and stagnant, great swathes of the ocean festered... ..toxic bacteria took over from plankton and deadly hydrogen sulfide spilled into the skies. But with change, even of the calamitous kind, comes opportunity... ..and the earth would soon echo to the thunder of giants. Out of the chaos of the Permian disaster rose a new world order, one ruled by reptilian teeth and claws. (Roars) It's time for the age of dinosaurs Down Under. Dive into a secret history where monsters roared with an Australian accent. Set course for the wild years. You wouldn't want to miss them for the world. Closed Captions by CSI