Seven Worlds, One Planet

An Andean bear scans the cloud forest in Ecuador in search of fruit (Photography: Chadden Hunter. Copyright: BBC NHU)

Produced by BBC Studio’s Natural History Unit, Seven Worlds, One Planet tells the story of earth’s spectacular continents and how they shape the extraordinary animal behaviour and biodiversity we see today. With the fifth of seven episodes set to air this Sunday (November 24), the series uses new technology, including boundary-defining drone techniques, to capture unique perspectives, new species, and never-before-seen animal behaviour.

Professor Iain Stewart, Director of the University's Sustainable Earth Institute, acted as a scientific consultant to the programme while Dr Lucy Obolensky, Lecturer in Postgraduate Education in the Peninsula Medical School, provided medical advice having previously worked with Sir David on Planet Earth and One Planet.

<p>Sir David Attenborough at the premiere of Seven Worlds, One Planet (Credit David Parry, Press Association)<br></p>
<p>Dr Lucy Obolensky&nbsp;and Sir David Attenborough above The Alps in BBC Planet Earth II</p>
<p>Iain Stewart Seven Worlds, One Planet</p>

FREE PUBLIC TALK: The Making of Seven Worlds, One Planet

The Sustainable Earth Institute is hosting a free talk by Jonny Keeling - Executive Producer of Seven Worlds, One Planet - on Thursday 5 December 2019. He will be discussing how the series was made, giving a behind-the-scenes view of the four-year, seven-continent production adventure.

Professor Iain Stewart, who supported the producers of the series, will introduce the talk and chair a Q&A session.

Find out how to register your place at the event


Episode 4: Australia

Dr Lucy Obolensky - The Australian Outback (hot, vast and harsh):

In 1860 The Victorian Exploration Expedition to Australia, led by Robert O’Hara Burke (1820-1861) and William John Wills (1843-1861), aimed to make the first transcontinental crossing of Australia. Setting off with 19 men, 23 horses, 27 camels, 6 tonnes of wood, a cedar topped oak table with chairs, rockets and flags, a chines gong and 16 gallons of rum, 18 men died and only returned alive to Melbourne.

Do we still underestimate the challenges of this unforgiving environment? As an expedition medic, your main concern in this terrain is heat illness. Heat illness encompasses a spectrum of disorders from mild being heat cramps to severe heatstroke. It occurs mostly in unacclimatised individuals who are volume depleted and carrying out excessive work.

The severity of heat illness depends on three main factors:

  • The environmental temperature and humidity;
  • The activity undertaken and duration of exposure;
  • The ability to thermoregulate.

Some are more at risk of heat illness and those risk factors include: extremes of age – young and old; concurrent illness; obesity; certain drugs such as diuretics, beta blockers or illicit drugs like ecstasy; lack of fitness; alcohol intake in the heat; previous heat illness.

Once the body starts to heat up your thermoregulatory mechanisms are lost. At temperatures greater than 41°C there is a disturbance of the cellular lipid membranes and alteration to chemical bonds within cells.

Dehydration increases sodium/potassium pump activity which increases metabolic rate and this leads to further failure of compensatory mechanisms for dissipating heat. Multi-organ failure ensures affecting kidneys and brain initially.

Patients with heatstroke have up to 75% risk of mortality so recognition early is key. Initial signs may be heat cramps or heat rash followed by heat syncope. At this point, treatment is possible through cooling, rest and rehydration.

Of the four mechanisms of heat transfer (conduction, convection, radiation and evaporation) evaporation is the most effective. Spray your patient with water and fan them to cool them down. If available put wet, cold sponges in the groin, armpit and back of the neck. It should be noted that paracetamol does not work as an antipyretic in heat illness.

Signs of more severe heat illness, progressing to heat stroke include a drop in blood pressure, severe headache, dizziness, temperature >40.5°C, nausea and vomiting. The skin may also become dry as the body loses its ability to sweat. At this point urgent treatment is needed with intravenous fluids and rapid, active cooling.

As with all aspects of remote medicine, prevention is better than cure. Educating your team on heat illness: how to acclimatise; how to drink the right quantity without under or over hydrating and how long it is reasonable to stay in the heat before taking regular rest breaks is essential to the prevention of any heat illness particularly heatstroke which carries a high mortality.

On expedition as the medic, ask yourself:

  • Are your team at risk of heat illness?
  • Are you all prepared for hot climates?
  • Have you educated your team?
  • Do you need to adapt/change daily goals?

<p>Iain Stewart and a koal</p>
Professor Iain Stewart with a koala
<p>Lucy Obolensky camping in the outback</p>
Dr Lucy Obolensky camping on the Manja track (Photo Angus Fowler)

Professor Iain Stewart - Australia and the Koala:

200 million years ago, the supercontinent of Pangea began to fragment. One by one, great land masses began to peel away. By 90 million years ago, the last two conjoined twins, Australia and Antarctica, broke apart. As a new ocean crust ocean opened up between them, both embarked on very geological different journeys. Antarctica drifted south and turned to ice. Australia headed north and turned to dust.

Australia’s northward push into ever warmer latitudes would have significant consequences for this land and anything trying to live on it. During the time of Pangea, the vast southern lands had been covered in temperate Glossopteris fern forest, but as it ventured into drier climes the fern forest died away, save for a few tiny pockets. It was replaced with bare red land and the one tree that thrived in these new arid conditions. The eucalyptus. Its a tree that today accounts for almost 80 percent of the forest in Australia.

For Australia’s cargo of animals, it was a brutal case of adapt or die. Only a few were able to evolve quickly enough to survive. And the classic case of that rapid evolution is the iconic Aussie teddy bear, the koala.

Technically it’s not a bear at all, but a marsupial. Anatomically, though, it’s basically a chewing machine. Having evolved to munch pretty much only on the Eucalyptus tree - a very chewy tree at that – most of the Koala’s head is designed for smelling and eating, using all its teeth and facial muscles to drive its powerful jaws.

Go back 20 million years old and you find that fossil koala remains are about half the size of the modern animal. In just a snapshot of geological time the koala’s dependency on the flourishing Eucalyptus forest had allowed it to become huge, with a gradually bigger and bigger face.

The eucalyptus trees didn’t only change the koalas’ machinery for eating but also for communicating. A bubble of bone inside its head acts as an echo-locating chamber that’s very good at picking up low frequency vibrations. The weird sounds they make transmit long distances, crucial because where they live the trees are far apart.

So, the koala’s teddy bear face reflects the dramatic climate shift that Australia has undergone, turning from verdant forest to mostly red dry desert. With its northward drift, the progressive drying of the island continent, it’s unlikely alliance with the flourishing tree helped secure the koalas future. Normally, animals that confine themselves to a single source of food end up as evolutionary cul-de-sacs. But in the case of the koala, these furry parasites really lucked out.

And it’s an evolutionary journey that is still in motion. As the fastest moving continent on the planet, Australia has moved so far north that it’s now colliding with Asia. With one continent grinding directly against another, it has forced up many of the volcanoes of Indonesia, even whole islands, such as Timor. And on the Pacific side, in Papua New Guinea, it has thrust up entire new mountain ranges as high as Europe’s Alps. As it does so, fresh evolutionary alliances are being forged.

So, Australia’s natural history isn’t over, not by any means, because the island continent’s future is to effectively become the southern margin of Asia. A remarkable continental makeover for a piece of planetary real estate that started life in the depths of the southern hemisphere. It is all down to the slow and steady movement of the one continent that’s always been considered quiet and stable.

Episode 3: South America

Professor Iain Stewart – from salt flats to savannah:

It’s one of the most truly extraordinary landscapes on Earth. The Salar De Uyni. The biggest salt flat on the planet, stretching out across the Bolivian altiplano plateau, 3700 metres up in the Andes mountains of South America.

In winter, especially during the snowmelt of late March, water ponds on the Salar’s flat surface, turning the land into a vast natural mirror. But at this altitude, any runoff from the mountain is subject to the cyclical and seasonal evaporation, laying down layer after layer of salt brine. 

A stunning white vista made all the more remarkable because this vast expanse of high plateau was originally part of a complex of great lakes at low altitudes, which gradually became uplifted over millions of years as the Andean mountains themselves began to rise.

The upheaval of the Andes has shaped South America’s natural history, not least by creating some of the world’s most rich, unique and biodiverse natural habitats. The continent is a true patchwork of ecological zones: from deserts, flooded plains and savannah, to lofty salt flats, cloud forest and mountain peaks. And at the continent’s heart, a vast rainforest that overflows with life: the Amazon.

That Amazon basin is itself a creation of the towering Andes. Before the Andes, the main rivers on the continent flowed in the opposite direction to today, westward into the Pacific ocean. When the mountain barrier started to rise it diverted rivers to the north, where they flowed out into the Caribbean, creating a huge expanse of wetlands close to the growing mountains.

Later, further uplift blocked the route north and forced the rivers to converge towards the Atlantic. From around 20 million years ago, the resulting wall of high mountains disrupted rain-bearing air masses. With the increased rainfall on its eastern flank, more and more sediment flowed off the Andes in new rivers that drained down into the Amazon basin. And with that flow came nutrients that enriched the Amazon forest and its flora.

With the growing Andes on one hand and the flourishing Amazon on the other, South America saw the development of an astonishing diversity of life. 

Many species are still only found on this continent. Species like the xenathrans – armadillos, anteaters, and sloths – found in diverse habitats across South America, not only in the rainforest but also in the savannah-like regions of southern Brazil and Argentina. Or the iconic llama, restricted to the steep Andean peaks and high salty plateau.

Few animals are better suited to the high-altitude mountainous terrain of the Andes than the llama. Unlike other hoofed animals, their feet have two toes. The bottom part of the foot is divided in two and is covered by a tough leathery sole. Because of these flexible pads, llamas have an amazing foothold on rocky and slippery ground. What’s more, they have unique blood that adapts well to the poor oxygen in the high elevations where they live. Llamas have more red blood cells (haemoglobin) per unit volume of blood than any other mammal. So their bodies are super-charged with oxygen.

These clever adaptations make llamas perfectly at home in the Andean high lands. But they didn’t originate in the mountains. In fact, they are not even from South America. Instead, they evolved in the low plains of North America. They are living proof of a dramatic tectonic union of the two continental Americas which fundamentally shaped the destiny of South America and its wildlife.

For it is the llama, perhaps more than any other animal, that highlights the remarkable biological transformation of the South American continent. When their ancestors first appeared in North America, about 40 million years ago, the northern and southern Americas existed as separate continents. Slowly, plate tectonic motions were edging them closer together and, by around 30 million years ago, an intervening archipelago of scattered volcanic islands linked up as stepping stones between the two approaching land masses.

And so it was that, 3 million years ago, that a narrow land bridge emerged and the llamas crossed into South America. Their arrival was part of an epic intermingling of species – the Great American Interchange. In reality, it wasn’t an especially even interchange; roughly half of today’s South American species are derived from North American forms, including cats, rabbits, bears, deer, and foxes. In contrast, only 10% of North American animals are descended from South American – armadillos and opossums being the most successful.

It seems that North American animals were more robust. Perhaps the relative isolation of the South American animals made them more vulnerable when new species encroached on their habitat. Whatever the reason, North American carnivores flooded south to find a wealth of large and lumbering herbivores.

In among the bloody northern invasion, the formation of the Central American isthmus dramatically increased animal and plants both north and south. But it was South America in particular that witnessed a true transformation in its biological wealth. And of course, among the most successful arrivals was that most quintessential of all South American mammals, the llama, now long extinct in the north, and gradually adjusting to the new heady heights of the Andean peaks.

<p>Lucy Obolensky rainforest<br></p>
<p>Iain Stewart salt flats<br></p>

Dr Lucy Obolensky – working in the rainforest:

The rainforest is an incredible place to visit: the sheer magnitude of everything there (trees to bugs!) and biodiversity is just incredible. The noise can be deafening at times with sounds of every variety of species. That said it is one of the most challenging places I've ever worked, and the jungle is definitely not my forte!

Keeping your kit dry poses one of the biggest challenges. All medical equipment needs to be kept in sealed containers in waterproof bags in waterproof sacks! Bites, stings and rashes are common as well as the more serious tropical illness such as leishmaniasis. Knowing what is potentially serious and what is not is important, especially when evacuation times are long, and you never want to make an evacuation in the jungle at night if you can help it.

Public health is essential in this environment, ensuring everyone stays well including hygiene and keeping their kit dry and in good condition, but also avoiding hazardous snake, scorpion or spider bites. Getting lost in the jungle at night is both incredibly easy and incredibly dangerous. Leaving base camp at night, even for a pee, is a big undertaking: stray to far and when you turn around everything looks the same and you have no idea where you came from.

A trip to the rainforest is an amazing experience, but what I class as Type 2 fun – you enjoy it more once get home again.

Episode 2: Asia

Dr Lucy Obolensky – the body's battle with altitude:

The Himalayas are one of my favourite places on earth. The spectacular scenery and enormity of the terrain is one of the most impressive sights you can take in. But living at altitude above 5000m is harsh and unsustainable for human life in the long term.

Travelling to high altitude initially gives symptoms of acute mountain sickness (AMS): nausea, headache, sleep loss and dizziness. If you do not spend time acclimatising to the altitude, AMS can quickly progress to the fatal conditions of High Altitude Cerebral Oedema (HACE) or high altitude pulmonary oedema (HAPE), which means increasing fluid on the brain or lungs respectively.

Acclimatisation is key to avoiding this and ascent rates should be 300–500m per day with a rest day every third day. Climb high, sleep low is the mantra we abide by.

Even once acclimatised life is difficult. Your heart beats faster, your breathe faster and become dehydrated quickly. The body is chronically deprived of oxygen and carrying out simple functions can prove challenging. Nothing heals at altitude and risk of infections (skin or Gastrointestinal) are increased.

Again, public health with good hygiene and base camp cleanliness is vital to ensure successful trips to altitude.

<p>Professor Iain Stewart with a&nbsp;carmin (<i>etroplus suratensis</i>)</p>

</p><h4>Beautiful view of mount Ama Dablam, Himalayas - Getty Images</h4>

<p>Dr Lucy Obolensky on expedition in the Himalayas</p>

Professor Iain Stewart – origins of a dramatic continent:

For fishermen in the backwaters of Kerala, southern India, the prize catch is a fish that is locally called carmin. For scientists, that fish is a distinctive type of cichlid – Latin name etroplus suratensis – whose peculiar anatomy reveals the evolution of an entire continent.

The peculiarity of the etroplus cichlids comes from a couple of anatomical quirks – multiple anal fins and a head that masks an enlarged swim bladder, the sac that controls its buoyancy. They are traits shared by only one other group of fish, the closely related paretroplus cichlids. But they live 4000km away, in Madagascar.

Now, etroplus cichlids can tolerate slightly salty conditions but they’re essentially a freshwater fish, so one thing’s for sure – they didn’t swim to India. Instead, it’s not the fish that moved – it was India.

120 million years ago, just before the emergence of the first cichlid fishes, India was located way beyond the equator in the southern hemisphere, tucked snugly in beside Madagascar. Then about 90 million years ago, as the southern fragments of the great supercontinent of Pangea began to break apart, India and Madagascar went their separate ways.

Over the next few tens of millions of years, the piece of continental flotsam destined to be the Indian subcontinent sped northwards, closing the stretch of ocean ahead of it. By 50 million years ago, its leading edge had reached the southern margin of the vast landmass of Asia.

As India slowly ploughed into the bulwark of Tibet, Nepal, and China, the immense power of the collision twisted and contorted solid rock as if it were plasticine. The result was the rise of the greatest mountain range on Earth – the Himalayas.

Hidden in amongst towering peaks up to 8000 metres high are tell-tale signs that the region’s crumpled rock strata began as muddy sediment on the deep ocean floor. Those clues can be found in hard, black nodules that fall from soft grey shale cliffs along Nepal’s spectacular river gorges. The nodules break open to reveal curious coiled stones which the locals call ‘saligrams’, traditionally worshipped as manifestations of the Hindu god Vishnu and sold at roadside stalls to passing tourists. Geologists know them better as ammonites, the fossilised remains of an extinct member of the squid family.

Their modern-day version would be the Nautilus. And just like the today’s Nautilus, these creatures didn’t live in the mountains.

150 million years ago, back in the Jurassic age when dinosaurs roamed the land and India was still conjoined with Madagascar, these ammonites were swimming around in the deep ocean. Similar marine fossils have been found right across the Himalaya, including at the top of Mount Everest, meaning that rocks that started out at the bottom of the ocean now form the roof of the world.

So, as India collided with Asia, the Jurassic floor of that ancient ocean which geologists call Tethys was gradually thrust up to form the planet’s most formidable mountain barrier. It is a barrier that has had a profound effect on the course of the natural history of the region. Because mountains this high can’t help but interfere with the climate.

Mountains create their own weather, and the bigger they are, the bigger the weather they create. So, as home to the biggest peaks on the planet, it’s no real surprise then that the Himalayas produce one of the most important weather systems on the planet – the Asian monsoon.

Every year, moisture-laden winds from the Indian Ocean feed intense monsoonal air masses that sweep across the flat lands of India and Bangladesh and slam into the ramparts of the Himalaya. As much rain falls in the Amazon basin in a year as empties on the slopes of northern India and Nepal during monsoon season, dumped by thunderhead rain clouds struggling vainly to climb over the Himalayan peaks.

The resulting torrential monsoonal deluges loosen snow and ice from mountain ice-fields and thundering avalanches deliver glacial debris directly into bloated milky-white headwaters, which twist and plunge through gorges that bite deeply into the mountains. These sediment-laden rivers flood out and spread their cargo of liberated ancient sea floor over the great plains of India, Pakistan and China on their way to the distant ocean.

Driven by the monsoon rains, the rivers and resulting nutrient-rich soils shed from the Himalayas have helped to create and maintain Asia’s astonishing richness of natural and cultural diversity. The margins of its mountain heartland set the fragmented geological template for an abundance of amazing species, whilst its extensive fertile plains support the livelihoods of three billion people.

Few living in their shadow, however, probably appreciate that this extraordinary legacy is 100 million years in the making – the epic consequence of an unstoppable landmass meeting an immovable object. And revealed in a story written into the bones of a rather remarkable fish.

Episode 1: Antarctica

Professor Iain Stewart – the geology of Antarctica:

March 1912. The Plymouth-born explorer and adventurer Robert Falcon Scott and his team are returning from their ill-fated attempt to be the first to the South Pole. Blighted by frostbite, snow blindness and malnutrition, and man-hauling 16 kg of rock samples, they still take time to ‘geologise’ the Transantarctic Mountains. Ultimately, it would cost them their lives. Almost eight months later, when their frozen bodies were found, Scott’s rock samples were carefully laid out. He had clearly considered them precious cargo.

Scott had been persuaded to collect the rocks by a young English palaeo-botanist, Marie Stopes. Later in life she would find fame as a pioneer of women’s rights and family planning, but in the early 1900s she was an expert on ferns and seed plants from Carboniferous times, 300 million years ago. Certain that such rocks would be found in Antarctica, she had pleaded with Scott to take her on his expedition. He refused, but promised to bring her back some samples.

When analysed back in England, Scott’s samples were found to be packed full of plant debris. Many of the leaves were from a fern-like tree called Glossopteris, indicating that in the Carbonifeorous age, this icy wasteland had been carpeted with fern forest. The spores of these trees couldn’t be transported great distances but Glossopteris had been found in Carboniferous strata right across the southern hemisphere, from India to South America. All those land masses must have been welded together, including, now, Antarctica.

And, 255 million years ago, much of what is today icy wasteland must have been covered in lush temperate forest.

Southern Right whales – the third largest whale species on the planet – spend most of the year in Antarctica feeding, but in August they journey over 2000 kilometres north to breed along the edge of Australia’s Southern Bight. The deep waters here mark where the once conjoined twin continents of Australia and Antarctica finally split apart.

90 million years ago, volcanic activity from deep within the earth’s mantle gradually created a new ocean seaway between Antarctica and Australia. As they spread apart across a mid-ocean ridge, Australia drifted northwards leaving Antarctica sitting all alone over the south pole, still temperate and forested.

But that isolation created an unusual effect in the waters around it. Without land in the way, ocean currents circulating that huge mass, got stronger and deeper, creating the circum-Antarctic current and cutting off the continent from warm waters to the north. In just 1 million years, Antarctica changed from a temperate forested land, to one entombed in ice.

Amazing to think that if I’d been walking along here, 90 million years ago, there would have been no cliff, there would have been no ocean. Instead, I would have been able to take a single step from here directly on to Antarctica.

Dr Lucy Obolensky – being a medic in Antarctica:

Depending on the trip/expedition you are joining it may be useful to have some polar experience first as an expedition member, rather than the medic, to get a feel for polar climates and its potential hazards.

The main issue of Antarctica is the remoteness and evacuation considerations. Know where you are going to be and where your nearest medical point of contact is for a) minor illnesses and injuries, and b) definitive medical care. Plan how you are going to evacuate to each of these.

Regarding medical kit, consider what is appropriate to take and what is necessary. If you are remote then defibrillator and airway kit are unlikely to be appropriate, if you are trekking then going light weight will be key.

Making evacuation decisions early is vital due to the length of time and logistics to organise this, so if you are a junior medic or have little polar experience then explore options of having a top cover call available from the UK to discuss emergency cases.

Ensure you are fit and have appropriate kit to keep yourself well and ensure good public health of you and your team with education of cold related injuries, camp hygiene and perhaps consider a buddy system.