- 18 minutes ago
How flowering plants transformed barren prehistoric landscapes, outcompeted ancient species like conifers, drove the evolution of animal life, and eventually sculpted human history.....
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00:00:08I spent most of my life trying to understand the forces that shaped our planet.
00:00:12And as a geologist it always seemed to me that rocks were right at the heart of things.
00:00:22But now I'm discovering it's not only volcanoes and colliding continents
00:00:27that have driven the Earth's greatest changes.
00:00:31Because at crucial moments in its history another force has helped create the planet we live on.
00:00:39Plants.
00:00:42It's a whole new story about the Earth.
00:00:46Revealing how from its earliest history plants have shaped our world.
00:00:55So far we've seen how plants and their ancestors began by producing a life giving atmosphere.
00:01:02And breathing oxygen that was made two and a half billion years ago.
00:01:10They'd harnessed light from the sun bringing energy to the world.
00:01:15And they'd formed the fertile soil.
00:01:18Allowing life to colonise the land.
00:01:30But the next chapter will take us even further.
00:01:33Because a powerful newcomer to the plant world was on its way.
00:01:37It would conquer every corner of the planet.
00:01:42It would shape the very surface of the Earth.
00:01:45And it would drive the evolution of animal life.
00:01:50Including our own ancestors.
00:01:53This is its story.
00:02:16These buildings are nearly a thousand years old.
00:02:21The largest religious site in the world.
00:02:24Covering 200 square kilometres.
00:02:29This is the temple of Angkor Wat.
00:02:32In Cambodia.
00:02:36I'm here to witness the importance of one of the most powerful symbols known to humankind.
00:02:45A symbol central to an ancient Buddhist ceremony.
00:02:53Flowers.
00:03:02You see lotus flowers and jasmine just arranged beautifully up there.
00:03:08The lotus, the big ones, and jasmine, a trail of little flowers.
00:03:12See how the lotus petals are all folded in amongst themselves.
00:03:16The different layers representing the various levels of heaven.
00:03:22For these monks, flowers have a crucial role.
00:03:27And this is just one ceremony.
00:03:30From one religion.
00:03:32Flowers are central to cultures throughout the world.
00:03:37They're deeply woven into all our lives.
00:03:44The making of someone's soul.
00:03:46It remains to be heard of grace.
00:03:46The sharing of us is widely shown to thee in outreach.
00:03:47The lukeác association of the quiet land.
00:03:47Oh, with that sierry, often así I'll give out the training to physically proud.
00:04:06From oneulent.
00:04:11But it's not only a human obsession, because since they evolved, flowers have been the
00:04:18driving force for the whole of life on Earth.
00:04:25They've become enmeshed in the lives of virtually the entire animal kingdom, in all its rich
00:04:31diversity.
00:04:32From the smallest insect to some of the largest mammals, they've all been shaped by flowers.
00:04:38But how did this happen, and why?
00:04:48The emergence of flowers is one of the biggest turning points in Earth's history.
00:04:55To understand how they changed our planet, you need to go right back to a prehistoric
00:05:00time.
00:05:04To the moment when the very first flower appeared.
00:05:12Up until around 140 million years ago, the Earth was very different.
00:05:18The animal kingdom was dominated by dinosaurs.
00:05:23And the separate continents we know today didn't exist.
00:05:27Instead, there had been a single huge continent, Pangaea.
00:05:39I'm heading for a place that's about as close as you can get to that ancient supercontinent.
00:05:46It's in the remote South Pacific, 1500 kilometres from Australia, the island of New Caledonia.
00:06:09Looks like paradise, doesn't it?
00:06:12I mean, what makes New Caledonia just so interesting is that it's like a Noah's Ark of ancient plants.
00:06:18I mean, this little journey is going to take us back in time 140 million years.
00:06:32Because this part of the world is so isolated, it gives a glimpse of the plant world before flowers existed.
00:06:41Back then, the plant kingdom had two mighty rulers.
00:06:45One of them was the tall conifers, like this prehistoric species of pine.
00:06:56Look at these trees.
00:06:58Bizarre, aren't they?
00:07:00They're huge.
00:07:03Aricaria, cook pine, named after Captain Cook, who explored this corner of the world.
00:07:10You know, pine trees are a family of conifers that are among the oldest in the world.
00:07:14So when the dinosaurs were around, these were nature's real giants.
00:07:20What made flowers so revolutionary was the limitations of the ancient plants that came before them.
00:07:30To reproduce, conifers like these relied on the vagaries of the wind.
00:07:41This is pollen, the male sex cells of conifers.
00:07:46Each grain has to be magnified a thousand times to really see it.
00:07:53The two air sacs, one on each side, catch the breeze.
00:08:00With luck, the male pollen will be blown to a female cone on a nearby tree.
00:08:05But for that to happen, each conifer needs vast amounts.
00:08:13It's very wasteful.
00:08:16Up to ten billion grains have to be released by a single tree.
00:08:25The other big player back then was the ferns.
00:08:32Their method of reproduction was also restricting.
00:08:38Because ferns evolved in wet, swampy conditions, they needed water to transport their sex cells.
00:08:47And they use a surprising device.
00:08:51What they do is they release a sperm, which swims through the water in the mud to a nearby plant
00:08:57and fertilises its egg.
00:09:01Under a microscope, you can see that by thrashing around, the male sperm cell can propel itself through water.
00:09:10It's able to swim for over two hours.
00:09:16It's amazing to think that a plant produces something like a human sperm.
00:09:23But the downside was that ferns had to live near water.
00:09:28It was hugely limiting.
00:09:32All this meant something was lacking in the world of Pangea.
00:09:39It was a big diversity.
00:09:40There were few species of ferns and even fewer types of conifers.
00:09:48Just 1% of the range of plants we have today.
00:09:55And the animal kingdom was also limited.
00:10:02Scientists have found evidence of 700 different dinosaurs.
00:10:08It sounds a lot, but today there are over five and a half thousand species of mammals alone.
00:10:15There was little variety.
00:10:18It was a monotonous green world.
00:10:23And that's how life on the planet would have continued.
00:10:42140 million years ago, somewhere in Pangea, one plant of one species happened to chance on a new way of
00:10:52reproducing.
00:10:53And it would change the earth forever.
00:11:02I've pushed further into New Caledonia's jungle.
00:11:14The plant I'm after is really rare, which is why I've come so far.
00:11:21This is the only place that you find it.
00:11:23It's died out everywhere else.
00:11:26Mind you, amongst all of this, it's like a needle in a haystack.
00:11:39It looks like the leaves.
00:11:44Now what?
00:11:46Got them.
00:11:49I've come all the way around the world to find that.
00:11:52That is the Ambarella plant.
00:11:59Ambarella trichopoda is the closest living relative of the first flower to evolve.
00:12:06All flowers today have descended from its ancestor.
00:12:19Botanists believe it began when a single plant mutated to leaves that became petals,
00:12:25which instead of being green, were probably white, like those of Ambarella.
00:12:31We now consider them to be the very first petals of the very first flower.
00:12:38To grasp the significance of this plant, you have to imagine a scene in some primordial forest where everything is
00:12:46just completely green.
00:12:48And then there's this flash of colour, a glint of white.
00:12:52Some chance mutation.
00:12:54And the thing is, it's scurrying amongst it.
00:12:56It's a little beetle.
00:12:57Certainly not a bee, because bees haven't evolved yet.
00:12:59But a beetle spies this dash of white and scurries across to have a look.
00:13:03And then munchies on these little white buds that are just packed full of pollen.
00:13:11But not all the pollen is eaten.
00:13:14Some sticks to the beetle.
00:13:17And on it goes to other plants.
00:13:23Unknowingly, it's become a courier, delivering pollen from plant to plant.
00:13:29Pollinating them as it looks for food.
00:13:38Plants had evolved an ingenious way of reproducing.
00:13:41They no longer relied on haphazard methods like the wind for conifers or water for ferns.
00:13:50Instead, it was reliable.
00:13:53Insects carried pollen directly to other plants.
00:13:57It was the birth of flowers.
00:14:04It's hard to grasp just how revolutionary this was.
00:14:07You know, I'm used to thinking of momentous changes in the earth as occurring through huge events.
00:14:13Vast continents colliding or mountains uplifting.
00:14:17But this was the tiniest of events.
00:14:20A subtle alteration of how a plant looked and a chance encounter with a curious beetle.
00:14:26And on the back of that, the world changed forever.
00:14:40Back then, the supercontinent of Pangaea was splitting up.
00:14:46Smaller continents were forming here.
00:14:51Creating countless new landscapes.
00:14:56With new climates and environments.
00:14:59Rising mountain ranges.
00:15:03And dry, inhospitable deserts.
00:15:08For conifers and ferns so dependent on wind and water, the new landscapes were impregnable.
00:15:17But for flowering plants, it was the chance they'd been waiting for.
00:15:22Because they had a powerful in-built advantage.
00:15:34This is a monkey puzzle tree.
00:15:37And like most conifers, monkey puzzles live for hundreds of years.
00:15:42And crucially, they don't reach sexual maturity until they're forty.
00:15:49Now, this is a campaign flower.
00:15:52Which in the shadow of this thing looks pretty puny.
00:15:56But the campaign flower has a last laugh.
00:15:58Because this, like most flowers, matures much quicker.
00:16:02In fact, the campaign flower can reproduce after just four months.
00:16:07It means that in the time that it takes this conifer to produce just one generation, the flowers can go
00:16:13through a hundred and twenty generations.
00:16:19What's so fascinating is the impact that this has got on evolution.
00:16:23Because every time there's a new generation, there's a possibility of a genetic mutation.
00:16:28A mutation that might give a characteristic that helps survival.
00:16:32So the faster the life cycles, the more species can adapt to new environments.
00:16:38Which, of course, is crucial to our story.
00:16:53140 million years ago, these rapid life cycles help flowers exploit the most hostile environments.
00:17:01Just like Tangkwa Karoo in South Africa.
00:17:09Because beneath this desert is a hidden carpet of flowers.
00:17:15Each year it rains for just two months.
00:17:20The plants only have this brief window to reproduce.
00:17:24So how do they ensure they're pollinated in time?
00:17:39The evolved colour.
00:17:52Each type of flower that you see is using colour in a struggle to get noticed by insects.
00:17:58And there isn't much time.
00:18:00In a few weeks or days the rains will be gone.
00:18:03And if these flowers aren't fertilised by then, then the plants will die.
00:18:07And the opportunity to reproduce will be lost.
00:18:12Hundreds of different flowers.
00:18:15Dozens of different colours.
00:18:17Whether it be orange gazanias.
00:18:20Purple dew flowers.
00:18:22Or the red balloon pea plant.
00:18:26And it wasn't random.
00:18:27Many used a different, specific colour to attract insects.
00:18:35They became targets.
00:18:37Using insects to transfer the right pollen to the right plant.
00:18:41Even over great distances.
00:18:47And flowers evolved a clever way to enhance this colour.
00:18:54To the naked eye, a petal looks smooth.
00:18:58But magnify it a thousand times and you can see its real structure.
00:19:10It's not a flat surface at all.
00:19:14Instead, the petal is made up of countless nodules.
00:19:20Each acts like a tiny prism.
00:19:23Which reflects and diffracts light.
00:19:27It gives the petal an iridescence to attract passing insects.
00:19:42And in their use of colour, flowers went even further.
00:19:46And in their use of colour, flowers went even further.
00:20:14It's a heck of a contraption, isn't it?
00:20:16A special camera to give you a kind of insects view of what a flower looks like.
00:20:26That's nice. Look at that.
00:20:28Insects and this camera can see a part of the light spectrum called ultraviolet.
00:20:35That's normally invisible to us humans.
00:20:50The camera reveals how flowers that appear plain to us look completely different to insects.
00:21:04And the markings are really important because they're like airport runway lights that guide the insect down onto the petals.
00:21:12Like neon signs that say, free food here.
00:21:26But once the flowers were pollinated, they still faced a big challenge.
00:21:32Because their offspring then had to make it through the rest of the year.
00:21:38Here in the Karoo, that could be ten months of drought.
00:21:44To survive, flowers perfected another trick which had a powerful impact on life on Earth.
00:21:53Seeds.
00:21:56Because seeds are this remarkable ability that we don't normally think about.
00:22:02These are seeds of the can of indica flower.
00:22:06And this, this is an empty shotgun cartridge.
00:22:10I'm going to pack the seeds in where the lead pellets would have been.
00:22:14Yeah.
00:22:41Oh, it's gone right through.
00:22:46Look at that, that looks perfectly intact.
00:22:54The story goes that during the Indian mutiny of the 19th century, soldiers used these seeds
00:23:01instead of lead shot, they're hard enough to be blasted out of a barrel and through
00:23:13wood.
00:23:17These seeds are so tough, in fact, that it's said that despite being fired from a gun,
00:23:23they can still germinate.
00:23:26Sounds unlikely, I know, though we'll see.
00:23:32But a tough shell wasn't all, because seeds from flowering plants developed a further
00:23:38evolutionary advantage that no other plant possessed.
00:23:49It all starts at the moment of pollination.
00:23:56Having been delivered by an insect, two cells from the pollen burrow deep into the flower's
00:24:02ovary.
00:24:04Here, one fertilises an egg to create an embryonic plant.
00:24:14But, and here's the clever bit, the second cell from the pollen does a completely different
00:24:20job.
00:24:22instead of becoming a new plant, it grows into a food source for the fertilised egg.
00:24:28a kind of packed lunch.
00:24:31It's called double fertilisation, and it's unique to the seeds of flowers.
00:24:46It meant seeds could lie dormant for months or even years until conditions were right.
00:24:56As for my canna indica seeds, well this is how they fared.
00:25:02Despite being blasted from a shotgun, four weeks later, here they are now, successfully germinating
00:25:11into a tiny flowering plant, remarkable.
00:25:21By 100 million years ago, flowers were redrawing the global map of where plants could live.
00:25:30They were turning once infertile areas into oases of life.
00:25:41And it wasn't just about plants.
00:25:45Because these flower oases were now luring animals too.
00:25:50There was one ability above all that gave flowers the power to do this.
00:25:58Plants can do something unique that marks them out amongst all other living things on
00:26:02the planet.
00:26:03planet.
00:26:03Their leaves can capture energy from our nearest star, the sun, and turn it into food.
00:26:14And the total amount of energy photosynthesis brings to the earth is staggering.
00:26:38I know this is a bit odd, but just imagine that this little scooter and all the fuel it uses
00:26:43represents
00:26:44And it's all the energy that the USA consumes in just one year.
00:26:50Now imagine that you take all the plants in the world, all the trees, flowers and grasses.
00:26:57All the jungles of forests and savannas, and you add up the total energy harnessed by plants from
00:27:03the sun every year.
00:27:06It's not two scooters worth, or ten.
00:27:10It's all of this, 40 times the amount of energy consumed by America every year.
00:27:23It's 100 trillion watts of energy every year.
00:27:30Astonishing as this is, flowers took all this energy and went even further.
00:27:36An adaptation that would have enormous repercussions for the animal kingdom.
00:27:43They developed this ingenious method of making the sugars available to the pollinators.
00:27:48And if I take this syringe here and just slide it delicately in here, I can show you what
00:27:56they came up with.
00:28:02It's this really sweet tasting liquid.
00:28:05Nectar of course.
00:28:06One of the most energetic sources of food on the planet.
00:28:10And something animals found utterly irresistible.
00:28:15The nectar from this bird of paradise flower has three times the sugar concentration of Coca-Cola.
00:28:27Flowers were now pumping bite-sized packets of liquid energy into the food chain.
00:28:35And this began driving the evolution of entirely new insects.
00:28:44Just take a look at this.
00:28:46Isn't it beautiful?
00:28:49For me this is one of the most incredible fossils ever found.
00:28:53I mean it's such an intricate detail.
00:28:55The material is amber and inside it is a bee.
00:29:05It's a very primitive bee that got stuck in liquid tree resin.
00:29:10Which then solidified and preserved the hapless insect.
00:29:19Bee fossils like these began appearing roughly 100 million years ago.
00:29:26And what they show is the incredible impact flowering plants were now having on evolution.
00:29:34What I love about this fossil is that it's like a snapshot of an ancient past just captured
00:29:39in time.
00:29:40And it makes you realise that there was a particular point when bees first arrived on Earth.
00:29:48Bees evolved from carnivorous wasps.
00:29:51Which had turned their backs on meat in favour of pollen and nectar.
00:29:58As they evolved their whole bodies became covered in hair to collect more pollen.
00:30:07They developed sophisticated compound eyes with hundreds of tiny lenses to spot the flowers.
00:30:17Inside were special cells to detect UV light.
00:30:24There are more types of early bees in South Africa than anywhere else in the world.
00:30:28So it's thought they originated here.
00:30:30And if you think about it, without the power of flowers, you'd have no bees at all.
00:30:39But by creating insects to pollinate them, the flowers introduced a new problem for themselves.
00:30:48There was a risk that after an insect picked up pollen from a flower, it would then travel
00:30:53onto a different species of flower and fail to fertilise it.
00:30:58The pollen would be wasted.
00:31:02The solution of flowers was inspired.
00:31:08Down under these cliffs on the South African coast, you can see what they came up with.
00:31:17This lovely pink flower is Orpheum frutescens.
00:31:21Which flourishes here in these salty conditions near the sea.
00:31:25But what's truly amazing about this plant is that it struck up this exclusive relationship with a particular bee.
00:31:34Orpheum flowers don't contain nectar.
00:31:36The payment they provide is pollen.
00:31:39But strangely, they keep it locked up.
00:31:43Special twisted stamens stop it being stolen by visiting insects.
00:31:49All that is, except one.
00:31:51The female carpenter bee.
00:31:54Only she has the key.
00:31:59Let me show you what the bee has to do using these tuning forks here.
00:32:04When the bee lands on the flower, it changes the rate at which it beats its wings.
00:32:09To just the right frequency.
00:32:11From this note.
00:32:15To this one.
00:32:19Middle C.
00:32:21And it's these vibrations that are the key.
00:32:25Unlocking the stamens, which open up at the top here.
00:32:28And just shower the bee with pollen.
00:32:33Oh, look at that.
00:32:35Look at the amount of yellow pollen on there.
00:32:38Fantastic.
00:32:43Now watch the bee do the same.
00:32:46Hitting the middle C note.
00:32:49With the beat of its wings.
00:32:53And unlocking the pollen.
00:32:57No other insect does this.
00:33:00It's incredible, isn't it?
00:33:01One single species of flower.
00:33:03One particular type of bee.
00:33:05Have evolved together to give this intimate partnership.
00:33:13It ensured that a flower's pollen was successfully taken to a plant of the same species.
00:33:22But these increasingly tight relationships between insects and flowers had another impact on life on Earth.
00:33:28Because they led to tighter and more isolated populations, that started creating gaps in the overall ecosystem.
00:33:37This in turn encouraged new species to evolve, filling in those spaces.
00:33:45Flowers were now driving a huge increase in the diversity of life.
00:33:51And they were fueling this increase by pumping nectar into the food chain.
00:34:02The insects, bees, butterflies and moths, such as the hawk moth, were eating it with long probing tongues.
00:34:13There were new species of birds, like the calliope hummingbird with beaks perfect for trumpet shaped flowers.
00:34:23And predators, such as these toucans, that ate the pollinators.
00:34:29Between 120 and about 90 million years ago, all thanks to flowering plants, evolution had entered the most explosive phase
00:34:39in the Earth's history.
00:34:52By now, Pangaea had split up, creating the continent so familiar to us today.
00:34:59And flowers dominated them.
00:35:02They had conquered the ancient conifers and ferns and covered half the Earth.
00:35:13But it wasn't just life they were changing.
00:35:17Because they started altering the very shape of the planet itself.
00:35:28This is Ha Long Bay in Vietnam.
00:35:32I'm here because it's evidence of how flowers unleashed some of the most powerful forces on Earth.
00:35:40This whole landscape just dwarfs you.
00:35:44You can see these pinnacles of limestone just soaring upwards. Limestone that you get all over Vietnam.
00:35:50And it gives this really distinctive, even iconic landscape called karst.
00:35:57The thing is when you look at things as huge as that, you look for huge geological processes to create
00:36:03them.
00:36:03But, you know, it's not always the case.
00:36:10That's because 90 million years ago, flowers began to build an empire across the planet.
00:36:19In a totally unexpected way.
00:36:26They did it by creating vast tropical rainforests.
00:36:44Almost all the trees are really giant flowering plants.
00:36:49You can see one here in flower.
00:36:52And all the trees are doing one thing.
00:37:02Breathe out on a piece of glass and it's pretty obvious that there's moisture in your breath.
00:37:07And in a funny kind of way, plants are breathing out moisture too.
00:37:10It's just much harder to see.
00:37:15But take a look at this.
00:37:17If I tie a clear plastic bag over this big leaf,
00:37:21then we should be able to actually see the plant breathing away.
00:37:27And all we need to do now is wait a couple of hours.
00:37:39Look how much moisture this single banana leaf produces.
00:37:47It's losing water or transpiring through tiny pores in the leaf called stomata.
00:37:58Close up, you can see the veins of the leaf which transport water around the plant.
00:38:05Leaves of flowering plants contain four times more veins than other plants.
00:38:18Because they share the same type of special vein leaves, trees like these act as kind of giant water pumps,
00:38:24drawing moisture up from the soil and pumping it out into the atmosphere.
00:38:28Some of these trees chuck out five tonnes of water every day.
00:38:42All this transpiration meant that 90 million years ago, flowering plants were creating more clouds.
00:38:54which led to more rain.
00:39:01Water that, when it fell, was then drawn up from the forest floor by the same trees,
00:39:07forming a self-sustaining cycle of almost perpetual rainfall.
00:39:14In fact, 80% of the water in the rainforests came from the flowering plants themselves.
00:39:24In this new age of rain, water became an ever-powerful sculpting force.
00:39:33And today, you can see its effects in an astonishing hidden world.
00:39:54Deep beneath the rainforest in central Vietnam are the caverns of Hang Song Dung.
00:40:01We are the first British film crew to explore them.
00:40:11ang song dung is the largest cave passage ever discovered.
00:40:16Anywhere on earth.
00:40:43This single carbon
00:40:46is nearly two kilometres
00:40:48long.
00:40:50All carved from solid
00:40:51rock by nothing more than
00:40:53water.
00:41:02All of which
00:41:04has trickled down from a single
00:41:05source, the vast
00:41:07jungle above.
00:41:11It's a relentless force that has carved out
00:41:14a dozen enormous caverns.
00:41:19An underground
00:41:20monument to the power of
00:41:21flowering plants.
00:41:33And deep in this labyrinth, this wood
00:41:36for me is perhaps the
00:41:37greatest of all the wonders of the plant
00:41:39world.
00:41:51Here, at the heart of the cave,
00:41:54a whole rainforest.
00:42:08Where the roof has collapsed, flowering plants have made their home.
00:42:17200 metres
00:42:18below ground level.
00:42:25It is like a lost world.
00:42:27And the thing is, just a few
00:42:28minutes ago, there was me in a
00:42:30kind of cool, dark cave
00:42:32and ejected into this.
00:42:34This place was streaming sunlight.
00:42:37Hot
00:42:37and sticky rainforest.
00:42:42And where there's water and light,
00:42:45flowers have produced life.
00:42:59plants such as this banana
00:43:00flower thrive, which
00:43:03in turn attracts butterflies
00:43:04and other animals.
00:43:08It's a thriving ecosystem
00:43:10here.
00:43:11And the whole thing is fed, really,
00:43:13everything, this whole food chain
00:43:14is fed by the flowering plants.
00:43:23Flowering plants have created
00:43:25a small but perfect version
00:43:27of the rainforest
00:43:28above.
00:43:36Look at that mist.
00:43:39There's a whole weird
00:43:40microclimate in here.
00:43:42Clouds of moisture
00:43:43envelop everything.
00:43:45And the plants just soak up
00:43:47that moisture, just draw it up
00:43:48and then pass it out.
00:43:51So that kind of cycle
00:43:52of transpiration that we see
00:43:54on a big scale up in the tropical forest
00:43:55is kind of captured in
00:43:56miniature down here.
00:44:04Caves formed under all
00:44:06the world's great rainforests.
00:44:09And this extra water
00:44:10even began to transform
00:44:12the global climate.
00:44:16As water evaporates,
00:44:19it absorbs heat
00:44:20and cools the planet.
00:44:22The Amazon rainforest alone
00:44:24keeps its whole region
00:44:26five degrees colder.
00:44:28Across the planet,
00:44:30water injected into the water cycle
00:44:32was eroding deep canyons,
00:44:35carving high mountains,
00:44:38and sculpting the karst towers
00:44:40so iconic of Asia.
00:44:47It's extraordinary, isn't it?
00:44:49Especially when you think
00:44:50that all this comes not from
00:44:51huge forces deep underground,
00:44:55but in part from
00:44:55tiny changes
00:44:57on the leaves of flowering plants.
00:45:0665 million years ago
00:45:0765 million years ago
00:45:08was the age
00:45:09of the rainforests.
00:45:13They'd spread from the equator
00:45:15to cover most of the earth.
00:45:18It meant three quarters of all plants
00:45:21were now flowers.
00:45:23a rich, lush home
00:45:25for millions of new animals.
00:45:29The dominance of the flowering plants
00:45:32seemed unassailable.
00:45:35But it was not to last.
00:45:43A 10-kilometre-wide asteroid
00:45:46coming from deep space
00:45:48was on a collision course.
00:45:58It hit the earth
00:46:00with a force of a billion Hiroshima bombs.
00:46:0470 billion tons
00:46:06of pulverized rock
00:46:08were blasted
00:46:09into a low orbit.
00:46:14Scientists called it ejecta
00:46:16and traveling
00:46:17at supersonic speeds
00:46:19its friction
00:46:20with the atmosphere
00:46:21heated the earth up
00:46:22by over 200 degrees Celsius.
00:46:27It spontaneously triggered
00:46:29fires across the land.
00:46:37It was one of the worst
00:46:39mass extinctions
00:46:40in the history of the earth.
00:46:45And famously killed off
00:46:47the dinosaurs.
00:46:57But less well-known
00:46:58is the immediate impact
00:46:59on plants.
00:47:03scientists believed
00:47:05that for them
00:47:06the effect of the asteroid
00:47:08was also devastating.
00:47:12Not only were there fires
00:47:14but the ejecta
00:47:16created clouds
00:47:17of nitric
00:47:18and sulfur dioxide
00:47:21which fell
00:47:23as acid rain
00:47:27destroying plants
00:47:29is from the roots up.
00:47:48I think it's really hard
00:47:49to imagine
00:47:49what the most recent
00:47:50and powerful extinction event
00:47:52must have been like
00:47:52but perhaps the closest
00:47:54you can get to it
00:47:55is like a newly erupted volcano
00:47:56like here in White Island
00:47:57New Zealand.
00:48:02I think it's just
00:48:03a desolation really.
00:48:05The bleakness,
00:48:06that sense
00:48:07that life's just been
00:48:09obliterated.
00:48:14For plants
00:48:15the aftermath
00:48:16of the asteroid impact
00:48:17must have been similar.
00:48:20Here on White Island
00:48:21vegetation has been
00:48:22incinerated
00:48:23affected by successive eruptions
00:48:26and the volcanic fumes
00:48:28create acid rain
00:48:29just like after the asteroid.
00:48:32For flowering plants
00:48:34it was a disaster.
00:48:35That close,
00:48:36almost inseparable
00:48:38relationship with insects
00:48:39was now their Achilles heel
00:48:40because even if a flowering plant
00:48:42had survived
00:48:43the initial calamity
00:48:44it needed a specific animal
00:48:46to pollinate it
00:48:47and often
00:48:48it's simply been wiped out.
00:49:01But flowers
00:49:02weren't beaten yet.
00:49:05All those evolutionary devices
00:49:07that had allowed them
00:49:08to thrive
00:49:09on a hostile planet
00:49:10in the first place
00:49:11now became
00:49:12their ultimate tools
00:49:13for survival.
00:49:17Coloured petals
00:49:18to attract a few
00:49:20surviving pollinators.
00:49:22Nectar
00:49:23to repay them
00:49:25in desperate times.
00:49:29Above all
00:49:30flowers could rely
00:49:31on those superb
00:49:32survival capsules
00:49:33that could have been
00:49:35purpose built
00:49:35for just such an apocalypse.
00:49:39Seeds.
00:49:51Now, following the asteroid impact
00:49:54seeds help flowers
00:49:55to re-colonise the earth.
00:49:58And as they did so
00:50:00once again
00:50:01flowers formed
00:50:02an inseparable relationship
00:50:04with animals.
00:50:06The dinosaurs had gone
00:50:08but another type
00:50:09of animal
00:50:10had replaced them
00:50:12mammals.
00:50:18This time
00:50:19flowers use mammals
00:50:20to help them
00:50:21distribute their seeds.
00:50:32Here in Thailand
00:50:34this whole floating market
00:50:36celebrates the clever
00:50:37evolutionary device
00:50:39flowers came up with.
00:50:42More sophisticated flowers
00:50:44developed a really
00:50:45sneaky way
00:50:46of spreading their seeds.
00:50:47A method
00:50:48that didn't just
00:50:49disperse it metres
00:50:50but kilometres.
00:50:52And to do that
00:50:52they again
00:50:53harnessed the hunger
00:50:54of animals.
00:50:55They developed fruit.
00:51:03What is that?
00:51:05This is Dorian.
00:51:07I cast you here.
00:51:09OK.
00:51:09Yeah.
00:51:11You can't come to Asia
00:51:13without trying
00:51:14the smelliest
00:51:15most notorious
00:51:16fruit on earth.
00:51:18Beautiful.
00:51:20I hope it tastes
00:51:21better than it smells
00:51:23though.
00:51:25There's the seeds
00:51:26in there.
00:51:29And then there's
00:51:30flesh.
00:51:31Textures.
00:51:37They're all laughing.
00:51:38They're laughing.
00:51:40It's like an off
00:51:41avocado really.
00:51:44I think that's what
00:51:45they call an acquired
00:51:46taste.
00:51:48The botanical
00:51:50definition of a fruit
00:51:51is that it must
00:51:52actually develop
00:51:53from the flower
00:51:54itself.
00:51:56The fleshy
00:51:57coating was once
00:51:58the ovary
00:51:59as it grew
00:52:00around the
00:52:01maturing seeds.
00:52:03Lovely.
00:52:04Incredibly sweet.
00:52:06Very subtle.
00:52:08Isn't that great?
00:52:09Just the way
00:52:09all of them hide
00:52:10this inside
00:52:11this little seed.
00:52:15You can see why
00:52:16some warm-blooded
00:52:17mammal or bird
00:52:18would want to
00:52:19eat this.
00:52:19It's just
00:52:19packed with
00:52:20nutrition.
00:52:21And of course
00:52:22as you do that
00:52:25you swallow
00:52:26the seed.
00:52:28And then later
00:52:29on you pass
00:52:31that out somewhere
00:52:31miles away
00:52:33dumped in some
00:52:33little dollop
00:52:34of manure.
00:52:35And that's
00:52:36really the point
00:52:36of all of this
00:52:37different types
00:52:38of fruit,
00:52:38all this diversity
00:52:39is designed
00:52:40to attract
00:52:41animals to
00:52:42eat it.
00:52:55Fruit is one
00:52:56of the most
00:52:57remarkable
00:52:57transformations
00:52:59in nature.
00:53:02What begins
00:53:04is an advertisement
00:53:05for an insect,
00:53:06a flower,
00:53:07becomes a
00:53:08protective covering
00:53:10for the seeds
00:53:10inside.
00:53:13And then a
00:53:14final burst
00:53:16swells into
00:53:17the juicy
00:53:17flesh of a fruit.
00:53:3655 million years
00:53:38ago, one group
00:53:39of early mammals
00:53:40was evolving
00:53:41that relied
00:53:42almost entirely
00:53:43on fruit.
00:53:45In fact,
00:53:46without it,
00:53:47they'd probably
00:53:47never have
00:53:54existed.
00:53:55It was an
00:53:56animal which
00:53:57would directly
00:53:57link flowers
00:53:58to our human
00:54:00story.
00:54:05They live
00:54:05here in
00:54:07Thailand's
00:54:07Khao Sok
00:54:08National Park.
00:54:09Somewhere
00:54:10in these
00:54:11trees,
00:54:11there are
00:54:12primates.
00:54:15I'm sure
00:54:17that up
00:54:17you see the
00:54:18trees,
00:54:18the branches
00:54:19moving,
00:54:20but trying
00:54:21to pinpoint
00:54:22the actual
00:54:23gibbons
00:54:23is really
00:54:25tricky.
00:54:27Oh,
00:54:27there's one.
00:54:30Do you see it?
00:54:31It's kind of
00:54:31silhouetted,
00:54:32and the branches
00:54:33just up there.
00:54:36Yeah,
00:54:37it's moving.
00:54:40my first
00:54:41gibbon.
00:54:43The primates,
00:54:45lemurs,
00:54:46monkeys and
00:54:46apes,
00:54:47evolved an
00:54:48inseparable
00:54:49partnership with
00:54:49the fruit from
00:54:50flowers,
00:54:51and it determined
00:54:52their whole
00:54:53anatomy.
00:54:55Primates have
00:54:56got the perfect
00:54:56tools for
00:54:57reaching fruit.
00:54:58They've got these
00:54:59really strong
00:55:00hands,
00:55:01which along
00:55:01with their
00:55:01powerful chest
00:55:03and shoulder
00:55:04muscles,
00:55:05allow them
00:55:05to get up
00:55:05into the trees.
00:55:08All these
00:55:09are important
00:55:09traits that we
00:55:10human primates
00:55:11have inherited
00:55:12today.
00:55:15And all
00:55:16came from the
00:55:17need for the
00:55:17first primates
00:55:18to reach the
00:55:19fruit of
00:55:20flowering plants.
00:55:26Norberto
00:55:27Asensio is a
00:55:28primatologist.
00:55:29He studies
00:55:31the crucial
00:55:31role fruit
00:55:32plays in
00:55:33the diet
00:55:34of monkeys.
00:55:36For most
00:55:37primates,
00:55:38fruit is
00:55:38important.
00:55:39It's part
00:55:39of their
00:55:40diet,
00:55:41somewhat.
00:55:42Is it the
00:55:42core of the
00:55:43diet,
00:55:43the essential
00:55:44core,
00:55:44do you think?
00:55:45I would say
00:55:45so.
00:55:46I would say
00:55:46so that most
00:55:48of the primates
00:55:49will have
00:55:4970 to 90
00:55:51percent of
00:55:52their diet
00:55:53on fruit.
00:55:55But back
00:55:56then,
00:55:56flowering plants
00:55:57created a
00:55:58problem for
00:55:58themselves.
00:56:01primates were
00:56:02so hungry
00:56:02for fruit,
00:56:04they would
00:56:05pick it long
00:56:06before the
00:56:06seeds inside
00:56:07were mature.
00:56:10It meant
00:56:10seeds were
00:56:11being wasted.
00:56:15So flowers
00:56:17came up with
00:56:18a solution.
00:56:25When fruit
00:56:26was ripe,
00:56:27they made
00:56:27it sweet,
00:56:28juicy and
00:56:29brightly coloured.
00:56:31It was a
00:56:31colour-coded
00:56:32time delay.
00:56:34And it
00:56:35encouraged primates
00:56:36to take only fruit
00:56:37that was fully
00:56:38mature.
00:56:43Norberto studies
00:56:44how this colour-coding
00:56:46drove changes in
00:56:47our ancient
00:56:48ancestors.
00:56:50Before now,
00:56:51primates,
00:56:52like all mammals,
00:56:53were colour-blind.
00:56:56This made spotting
00:56:58ripe fruit difficult,
00:56:59as I'm about to find out.
00:57:02Let's do an experiment.
00:57:03Here you have glasses
00:57:05that are going to turn you
00:57:07into a simple
00:57:08mama.
00:57:09Let's see.
00:57:11Oh, gosh.
00:57:14The glasses simulate
00:57:15colour-blindness by removing
00:57:17red from the picture.
00:57:20I can kind of tell
00:57:21the difference
00:57:22in contrast
00:57:22between some of them.
00:57:25That's gone
00:57:25a very funny
00:57:26shade of
00:57:26bluish-ness.
00:57:28The interesting ones
00:57:29are these reds.
00:57:30These reds don't...
00:57:31I mean,
00:57:31I know they're red,
00:57:32but they just don't
00:57:32seem red at all.
00:57:34It's just...
00:57:35Overall,
00:57:36it's just got
00:57:36a kind of very
00:57:38almost bland
00:57:38greyness to it.
00:57:45For primates
00:57:46to perceive red,
00:57:48they had to evolve
00:57:49a more sophisticated
00:57:50vision system.
00:57:53In the retina
00:57:55are special
00:57:56photoreceptor cells
00:57:57that detect colour
00:57:58called cones.
00:58:01There are
00:58:02150,000
00:58:03per square millimetre.
00:58:06Early mammals
00:58:07only had two types
00:58:09of cone,
00:58:10one for green
00:58:10and one for blue.
00:58:13It meant
00:58:14they were colour-blind.
00:58:16But primates
00:58:17evolved a third type.
00:58:20It was sensitive
00:58:21to red.
00:58:24Now they could
00:58:25spot ripe fruit.
00:58:27Colour vision
00:58:28helped give primates
00:58:30the advantage,
00:58:31kick-starting
00:58:32the evolutionary
00:58:33journey that
00:58:34resulted in us
00:58:35humans.
00:58:37That's why
00:58:38we have colour
00:58:38vision now
00:58:39and we have
00:58:40this wonderful
00:58:41rainbow of colours
00:58:42that we can see
00:58:43now and enjoy.
00:58:50Fruit drove the evolution
00:58:52of so many of the traits
00:58:53of our ancient ancestors,
00:58:54but this symphony,
00:58:55the ability to
00:58:56see if fruit
00:58:57was ready to eat
00:58:58or not,
00:58:59had given primates
00:59:00perhaps for the first
00:59:02time on our planet
00:59:03this capacity
00:59:04to see in full
00:59:07glorious technicolour.
00:59:08You know,
00:59:09something that I think
00:59:09we just take for granted.
00:59:20Since they'd evolved
00:59:21140 million years ago,
00:59:24flowers had transformed
00:59:26our planet.
00:59:27They'd come to dominate
00:59:28the plant kingdom,
00:59:30sculpting the earth itself.
00:59:34Above all,
00:59:35flowers drove the evolution
00:59:37of animals,
00:59:39especially primates,
00:59:41shaping our human evolution.
00:59:56It seems to me
00:59:57that we're rather
00:59:58animal-centric,
01:00:00that by being members
01:00:02of the animal kingdom
01:00:02ourselves,
01:00:03we somehow see them
01:00:04as the thing
01:00:05that's at the heart
01:00:06of driving changes
01:00:07to life on earth,
01:00:08but I don't think
01:00:10that's true.
01:00:11Most of the big changes
01:00:13to life on the planet
01:00:14are being brought
01:00:15around by flowers.
01:00:16They're the ones
01:00:17that are more manipulative,
01:00:19more inventive,
01:00:20more powerful
01:00:21than any of the animals
01:00:22that they're interacting with.
01:00:23Most animals
01:00:24are only here
01:00:26because of flowers,
01:00:27including us.
01:00:29It's an intriguing thought
01:00:30for next time
01:00:31you're out doing the roses.
01:00:35Next,
01:00:36we reveal the epic battle
01:00:38between the forests
01:00:39and their greatest challenger,
01:00:41a new type of plant,
01:00:43the grasses.
01:00:45It was a conflict
01:00:46that would set the world
01:00:47on fire.
01:00:49The victor
01:00:50would force
01:00:50our ancient ape ancestors
01:00:52out of the forests
01:00:53and into the savannah
01:00:56and go on to trigger
01:00:58the birth
01:00:59of human civilization.
01:01:04Guest
01:01:05on fire.
01:01:34The purpose
01:01:34of Quran
01:01:34You
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