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AnimalsTranscript
00:08The biggest living thing that exists on this planet is a plant, like this giant sequoia
00:17tree in California. Plants, whether they are enormous, like this one, or microscopic, are
00:28the basis of all life, including ourselves. We depend upon them for every mouthful of
00:35food that we eat and every lungful of air that we breathe. Plants flourish in remarkable
00:44ways. Yet, for the most part, the secrets of their world have been hidden from us. Until
00:58now. Now, we have new groundbreaking technology that enables us to enter their extraordinary
01:07world and see their lives from their perspective.
01:19This series will reveal the extraordinary and dramatic ways in which plants behave. And
01:32we will explore the challenges demanded by the very different landscapes in which they
01:38live. The tropics. The richest and most competitive place in which to survive. The bizarre water
01:53the world. Where giants fight ferocious battles. And plants eat animals alive. Deserts. Up. The
02:11world of extremes. Seasonal lands. Where survival
02:23the world depends on precision timing. And everywhere we will explore the critical and intimate
02:31relationships between plants and animals, including ourselves. Join me in a world that takes
02:43you by surprise. See our planet as never before. From the plant's perspective. This is the green planet.
03:09of image.
03:35To be continued...
03:53I'm in Costa Rica, in the heart of a rainforest, the richest and most dynamic environment
04:00on Earth. Rainforests only cover a very small proportion of the Earth's surface, yet they
04:07contain over half of all known species of animals and plants.
04:14Up here, the forest canopy is bathed by life-giving sunlight. The branches of the great trees carry
04:28rich, flourishing sky gardens. Home to countless different kinds of beautiful plants.
04:43Each species has evolved its own exquisite solution to the challenges of survival. This
04:56forest world may look peaceful, timeless and unchanging, but that is far from the truth.
05:06This is a battlefield. Throughout this forest, plants are competing ferociously with one another
05:17to claim the light. The battle is at its fiercest on the forest floor, where only two percent
05:33of the sunlight filters through. Plants here have to bide their time.
05:44Their opportunity comes when an old tree dies.
05:53When that happens, sunlight floods the forest floor for the first time in perhaps a hundred years.
06:19The seedling's wait is over.
06:26The seedling's wait is over.
06:30They have to claim a place in the canopy.
06:33But it's not alone.
06:39Rivals are everywhere, each with its own survival strategy.
06:57Some plants, like this monstera, stretch out divided leaves to collect what light they can.
07:10This vine is groping blindly around with its tendrils.
07:19Its attempts to reach the light by hitching a ride.
07:26Its tendrils are highly sensitive to touch, and a suitable target is in range.
07:44Got it.
08:06The vine tightens its grip, and begins to haul itself upwards.
08:15But it's now overtaken by the forest's fastest growing tree, a young balsa.
08:29Its giant leaves are already 40 centimeters across, and are stealing the light from its rivals below.
08:38But the boss of battle is not yet won.
08:43Other different vines are lying in wait.
08:57Each is armed with dozens of claw-like hooks.
09:05If just one hook gets a grip, the vine will be able to smother its victim.
09:41There's no other one in the house.
09:45But the balsa is defended by a shield of slippery hairs.
09:55The vine's hooks just can't get a hold.
10:02The balsa brushes them aside and continues to rush skyward.
10:15Leaving the losers in its shadow to fight among themselves.
10:24This balsa has won its battle for the light.
10:33And it's done so in a little over a year.
10:39Most trees would have grown an inch or so in that time.
10:43But this one is already 30 feet, 10 meters tall.
10:53Balsa's owe their success to the special character of their wood.
10:58If this section of tree trunk came from a hardwood tree, it would be really quite heavy.
11:04But as it is, it's from balsa.
11:07And it's really very light.
11:11And that's because of its internal structure.
11:17Under the microscope, balsa wood looks like a honeycomb.
11:21It contains more air than wood.
11:25So not only can it grow very fast, but it gets the maximum height for minimum weight.
11:34But fast growth needs something else.
11:38Fuel.
11:39And lots of it.
11:51That fuel is created in a plant's leaves as they soak up the sun.
12:07It's a process called photosynthesis.
12:13A chemical reaction that is the basis of all life on Earth.
12:24Leaves are covered by thousands of microscopic pores called stomata.
12:31When open, they extract carbon dioxide from the air,
12:35and using energy from the sun, combine it with nutrients to build the plant's tissues.
12:45And critically for us, the process releases the oxygen that we and all animals need in order to breathe.
13:05But for plants, there is a downside.
13:08These precious energy-packed leaves attract predators.
13:14In every shape, size, and agility.
13:35A sloth can only move slowly.
13:39But you don't need speed to gather leaves.
13:43And it eats nothing else.
14:04The plants here are under constant attack from all kinds of leaf eaters.
14:11But the most voracious by far is hardly ever seen.
14:16It consumes 50,000 leaves every day.
14:21It's created this great clearing in the forest.
14:25And it lives just beneath my feet.
14:36It's called Leuco agaricus.
14:42It's neither animal nor plant.
14:46It's a fungus.
14:50It lives five meters underground.
14:54Far from the leaves that it devours.
15:00To get them, it employs the best leaf gatherers in the tropics.
15:11Leaf-cutter ants.
15:13Leaf-cutter ants.
15:19Millions of them provide the fungus with its food.
15:22And in return, the fungus cultivates tiny mushrooms as food for the ants.
15:33The fungus releases chemical signals that tell the worker ants what type of leaf it wants to eat.
15:43Scouts are sent out with the latest orders.
15:55Worker ants will travel hundreds of meters to find the right kind.
16:02Today's crop is being taken from a young bixar tree.
16:09Just a few years old and still battling to reach the canopy, it can ill afford to lose any of
16:15its leaves.
16:34Between them, the ants can demolish a large leaf in a matter of minutes.
16:44The sound of cutting attracts more ants.
17:01Now, the pieces are carried back to the underground fungus.
17:12The ants can run at speeds of two meters a minute.
17:19And each can carry a load ten times its own weight.
17:38It's a river of leaves across the jungle floor.
17:44Part of a vast network that extends for miles through the forest.
17:58To avoid congestion, worker ants dig trenches around obstacles.
18:31Thousands of pieces are delivered every hour to the waiting fungus.
18:48Feed by such a continuous supply, the fungus grows rapidly, filling the chambers in which it lives.
18:59So the ants excavate more space.
19:06It seems that the fungus has the upper hand.
19:11And the bixar tree will not survive.
19:19But it fights back.
19:24Using chemical warfare.
19:29The bixar tree floods its leaves with toxins that could kill the distant fungus.
19:37As the ants carry the fragments back, they are themselves poisoning the fungus on the tree's behalf.
19:49It's a long-distance attack.
19:59As the poison takes effect, the ants sense that their fungus is weakening.
20:15And they respond to its signals by changing to another source of leaves.
20:26So the plant's chemical response forces the ants to constantly switch from tree to tree.
20:39Strike and counter-strike.
20:44And that ensures that enough leaves remain uneaten for each tree to recover.
21:07Once the plant becomes adult, it can switch its energies from growth to reproduction.
21:20The tropical forests of the Americas stretch from Mexico to the southern reaches of the Amazon.
21:27They contain more than a hundred thousand different species of plant.
21:32Each with its own particular survival strategy.
21:39One species that has adopted a grow-fast lifestyle flourishes throughout this vast region.
21:50The balsa.
21:53But it has to pay a high price for doing so.
21:57The lightweight wood that enables it to grow at such speed is not strong and is easily broken.
22:06Few balsas live longer than twenty years.
22:11This one is approaching the end of its brief life.
22:15So the time has come for it to reproduce.
22:25It has used a huge amount of energy to produce some of the most extravagant flowers in the forest.
22:31In immense numbers.
22:42Each is the size of a human hand.
22:51As night falls, the tree prepares an enticing treat.
23:04This is a kinkajou.
23:07A kind of fruit-eating raccoon.
23:14Each flower is filled with huge quantities of exceptionally rich nectar, supercharged with sugar.
23:32Irresistible.
23:42The kinkajous drink so greedily that they get pollen all over their faces.
23:51So, as they move from tree to tree, they carry pollen with them.
24:03But the balsa leaves little to chance.
24:07The nectar might appear to have run out, but this is just the first round.
24:14Now, the balsa refills its flowers, enticing the kinkajous back to repeat the process.
24:21Seven times a night.
24:25Pollination is complete.
24:31And the kinkajous, they also get well served with over a hundred pints of nectar in just a few weeks.
24:43Both plant and animal do well out of this arrangement.
24:50But in the tropical world, that isn't always so.
25:00Borneo.
25:07Here, on the slopes of Mount Kinabalu, live plants that eat animals using pitcher-shaped leaves full of water.
25:25Insects are attracted by the expectation of nectar, but tumble into the pitcher, where they're drowned and absorbed.
25:40On the lower slopes of the mountain, a plant grows that has no leaves at all.
25:46Or even a stem.
25:51All that can be seen is this.
25:53A bud.
26:02It is a parasite.
26:12The rest of its body lies within the tissues of a liana on which it feeds.
26:23After about five years, the bud finally opens into a monstrous flower.
26:32It now has only a day or so in which to be pollinated before it starts to wither.
26:41Its petals are the color of blood.
26:46Their surface is tough and warty.
26:55It appears to have fur.
27:00Even whiskers and teeth.
27:07At first sight, it might be mistaken for a dead animal.
27:13This is Rafflesia, the corpse flower.
27:22A metre across, it's the world's biggest flower.
27:29And this one is a male.
27:34From its center comes the pungent odor of death.
27:47It's a scent that might not appeal to every animal.
27:57But it's very attractive to carrion flies.
28:02They lay their eggs on rotting flesh.
28:18The scent lures the fly deep into the flower in search of meat.
28:29The fly finds nothing.
28:32The Rafflesia, however, has the fly exactly where it wants it.
28:41It's stuck pollen to the fly's back.
28:56If this male Rafflesia's strategy is to work,
29:00the fly carrying its pollen must now visit a female corpse flower.
29:10Such as this one.
29:22Success.
29:41Once pollinated, plants are able to produce seeds, the next generation.
29:47But once again, there are animals all over the forest that are eager to make a meal of
30:00them.
30:09The Malay Archipelago, a vast tropical world of a thousand islands.
30:23It's home to giants, the tallest trees in the tropics, many of which live for centuries.
30:37They produce seeds in enormous numbers, but only do so when the time is right.
30:47This individual hasn't produced a single seed for nearly a decade.
30:51But in the last weeks, it has become festooned with more than 10,000 of them.
31:02Each seed has the potential to produce a giant like its parent.
31:13But success will depend on timing.
31:32Seed hunters are gathering.
31:39Bearded pigs.
31:49But these seeds have been produced by a dipterocarp.
31:55Trees that create the tropical world's largest seed nursery.
32:06After years of waiting, thousands upon thousands of individual dipterocarps have synchronized
32:13to produce the next generation, all at exactly the same time.
32:35And now, these seeds will face the dangers below together.
32:43We'll see.
33:05Bye.
33:26By releasing billions of seeds all at the same time,
33:31they swamp the pigs and any other animals
33:34with more than they could possibly eat.
33:58And that buys time for some of the seeds
34:01to take root and sprout.
34:30The tree's strategy has worked.
34:34But a seedling will have to overcome many more dangers over the years
34:39if it too is to become a giant.
34:48And there are many ways in a tropical forest by which a tree's life can be ended before
34:54it reaches its prime.
35:00The northernmost tip of Australia.
35:06This is the world's most ancient rain forest.
35:27Battles between animals and plants have raged here for 180 million years.
35:40So the plants have had time to develop effective defensives.
35:47This is a poison arrow tree.
35:51One of the tropical world's most heavily defended plants.
35:58It's trunk is tall and slippery and exudes a poisonous sap.
36:07It appears to be almost invulnerable.
36:16But even so, just as this individual reaches maturity,
36:22its life has become endangered.
36:28Each monsoon season, it is invaded from above.
36:40It attracts hundreds of shining starlings.
36:47Its immense smooth trunk makes its high branches above a safe place to nest.
36:53But over the years, this has created a major problem for the tree.
37:03After feeding, the starlings return to the nest to digest their food with inevitable consequences.
37:16Every year, they produce almost a quarter of a ton of droppings.
37:24The toxic chemicals they contain create a dead zone that completely surrounds the tree.
37:38The toxins are absorbed by its roots and travel up through the trunk and into every leaf.
38:02The tree is slowly dying.
38:08It has become a victim of its own success.
38:14It has been poisoned.
38:23Now, a new battle begins.
38:27One to claim the tree's dead body and the vast amount of nutrients that it contains.
38:35It's a battle that is fought throughout the natural world,
38:40involving a group of organisms that we rarely notice.
38:46Here, on the floor of a tropical rainforest, it's dark, it's humid, and it's hot.
38:54Ideal conditions for fungi.
38:58We normally think of fungi as things like this, mushrooms of one kind or another.
39:04But these are just the fruiting bodies.
39:09They exist, for most of the time, hidden in the leaf litter and the earth as a network of fine
39:16white threads.
39:19The threads of competing fungi envelop their victim's body, releasing enzymes which digest the tree's tissues
39:27and unlock the nutrients within.
39:32There are a million or so different species of fungi in the tropics.
39:38Some feed on dead plants.
39:41Others eat them alive.
39:44And some reveal their existence in an eerily beautiful way.
39:59In Africa, in the Congo, this is known as chimpanzee fire.
40:10The mysterious bioluminescent glow becomes brighter as the fungus digests the tree.
40:22When fungi have fed sufficiently, they develop their reproductive organs.
40:27The mysterious bioluminescent glow is more than just a few years.
40:56Each
40:57can produce literally billions of spores, the tiny particles that carry the
41:05species' genetic blueprint. Each spore like this has the potential to kill a tree.
41:36The spores are so light they can be carried by the slightest air currents.
41:51At least a billion float above every square meter of rainforest.
42:06Recently, it has been discovered that these spores do far more than just bring death and decay.
42:14They are, in fact, at the very center of the rainforest's life support system.
42:29High in the humid air, the spores combine with molecules of water.
42:48Gradually, they collect into droplets which, when they are heavy enough, fall...
42:53fall...
42:56and rain.
43:36Over two and a half meters of rain falls every year in a rain forest.
43:50And in the center of almost every rain drop, there is a fungal spore.
44:10The world's rainforests are the richest and most dynamic environments on Earth.
44:16Built on complex connections and relationships.
44:24But these connections, competitive or collaborative, are now becoming increasingly fragile.
44:47When Charles Darwin was exploring the tropical world nearly 200 years ago, he wrote this in his diary.
44:56Among the scenes which are deeply impressed on my mind, none exceed in sublimity the primeval forests undefaced by the
45:10hand of man.
45:12He would struggle to find such a place today.
45:30Today, 70% of all the world's rainforest plants grow within a mile of a road or a clearing that
45:38we have cut into the forest.
45:44And this is creating new battlefields in the tropical world.
45:51Alien armies of identical cultivated plants now stand where thousands of different species once grew.
46:08We have planted vast regiments of crops in order to provide ourselves with food and other commodities.
46:17And the ancient forest has been reduced to ever fewer isolated fragments.
46:28All, however, is not lost.
46:31The fragments can still be sanctuaries, keeping alive the intimate relationships within them.
46:40Their size is nonetheless critical.
46:53This is the seven hour flower.
47:07This plant produces its flowers at night.
47:10They open at about six o'clock and each blossom only lasts that night.
47:18It opens for about seven hours and then it dies.
47:24But during that time, it provides food for one particular animal.
47:29A bat.
47:30And here it is.
47:50During the seven hour flower's flowering season,
47:55Underwood's bat feeds almost exclusively on its nectar.
48:00It is the plant's primary pollinator.
48:07It might seem that this is a fairly evenly balanced relationship.
48:13But not so.
48:15The bat likes this nectar because it's sweet.
48:20But it's not very nourishing.
48:23So the bat must visit hundreds of flowers a night.
48:29And it pollinates them as it feeds.
48:39But if a patch of forest becomes too small, with too few flowers, the bats will disappear.
48:46And without the bats, the flowers can't reproduce and will soon die out.
48:54The partnership is broken.
49:06Life in the forest depends on countless close relationships.
49:11But they are increasingly under threat as forests become more fragmented.
49:17The solution, of course, is to join these remaining fragments together again.
49:22Thirty years ago, I came to this exact spot.
49:27This land belonged to a scientific research establishment.
49:31And it was covered with grass being grazed by cattle.
49:35The scientists got rid of the cattle and allowed nature to take its course.
49:41Just look at it now.
49:53This new forest has become a bridge that connects several fragments,
49:59allowing plants and animals to both renew old connections and create fresh ones.
50:16Of course, we urgently need to protect what healthy forests still remain.
50:26But looking forward, we must take what may well be our last chance to re-establish the lost rainforest.
50:38And help the tropical world to heal itself.
50:45It will take the cooperation of nations around the world,
50:49but it is the only way in which we will be able to preserve the treasures of the tropical rainforest
50:56for future generations.
50:58And with it, ultimately protect all life on this, our green planet.
51:23The aim of the green planet team was to take the viewer into the world of plants so that it
51:29could be seen from the plants' perspective in a way that had not been possible till now.
51:35That meant developing an entirely new camera system.
51:45And this is the Game Changer.
51:48A specially designed robot camera that we affectionately call the Triffid.
51:59The Triffid started life in the garage of an American ex-military engineer, Chris Field.
52:05I've seen quite a few of these Planet Earth-style documentaries, and they always absolutely blew my mind.
52:10Especially the botanic time lapse really spoke to me.
52:13In his spare time, Chris spent a decade building elaborate motion-controlled time-lapse camera rigs and teaching himself how
52:22to film plants.
52:25Plants often behave like animals in so many ways.
52:29And being able to see it through time-lapse is one thing, but using the motion control brings you into
52:33that time scale.
52:39And we could really see the potential in how we could use this sort of movement to bring plants alive
52:45and film them in the same way that we film animals.
52:50Soon, Chris joins the team in a quiet corner of the Devon countryside, and the robot army begins to take
52:57shape.
52:59After 40 years of filming time-lapse, these rigs have opened up a whole new world for us.
53:06So it'll be like hovering around something with a drone or helicopter, but in a time-lapse speed.
53:14The holy grail for us is being able to take this technology out into the wild,
53:19trying to get the same sorts of dynamic moves in some of the most extreme environments in the world.
53:26So what we needed to do was develop this technology even further.
53:31Six months later, the Triffid is born.
53:37And with slight trepidation, they hand me the controls.
53:41So that makes it go away.
53:44And this makes it come back.
53:47And this sends it up.
53:55I think I'd better hand it over to the experts.
54:00Now it's time to put this new member of the team properly through its paces.
54:07The aim here is for Ollie to find a target, aim for it, and fly through it, as if he
54:12is a tiny fly going through a hole in a leaf.
54:15Easier said than done.
54:17Oops.
54:18I'm trying to find a target.
54:21Whether the kit's going to stand up to that sort of use, and the abuse that we throw at most
54:27pieces of kit, has yet to be seen.
54:29In the studio, it seems to be working pretty well.
54:33But this is only a dress rehearsal.
54:35It's time for the Triffid to face the challenges of the Costa Rican rainforest and leafcutter ants.
54:49We want to film the journey all the way down the trunk and along this buttress group and down to
54:57their nest.
54:59The team and the Triffid need several days of dry weather.
55:03But a storm can hit at any moment.
55:06And rain is one thing the Triffid does not like.
55:11The conditions that we're working in now are a little bit more challenging than the studio.
55:18All the ground is really bumpy.
55:21We've got loads of plants in the way.
55:23I know we're making a series about plants, but sometimes they're a complete pain in the neck.
55:30The Triffid needs to be programmed to capture images from 7,000 different camera positions on the ants' trail.
55:40Just one drop of rain on the lens, or a wobble, and the whole process will have to start again.
55:47I think this is when we're going to find out if our ambition outweighs our ability.
55:55For the crew, the ambition is certainly high.
56:02Fortunately, it's all down to the Triffid now.
56:14We've been filming the ants with the Triffid for eight days now, and we're on our third set-up.
56:21It's pretty slow going.
56:24While the Triffid seems to be handling the pressure well, for the crew, trying to take a tree's eye view
56:30of ants is turning into a bit of a nightmare.
56:35Wake up. Film ants. Go to sleep.
56:39Dream of ants. Wake up, film ants. Sleep.
56:42Dream of ants. Wake up, film ants. Go to sleep. Dream of ants.
56:50After two weeks in the jungle, ambition and ability finally come together.
56:55For the Triffid, at least.
56:58Thousands of individual images creating a single extraordinary time-lapse.
57:05One that follows a river of leaves across the jungle floor from a unique perspective.
57:15For the Triffid, this was just the beginning.
57:20Take a bow, Triffid.
57:29Next time on The Green Planet, the wonder of water worlds.
57:36Where plants hunt, go on the move, fight, and create the air we breathe.
57:51The Open University has produced a poster that explores the vital role that plants have for our planet.
58:00To order your free copy, call 0300 303 4200 or go to bbc.co.uk forward slash green planet and
58:12follow the links to The Open University.
58:18Into those water worlds here next Sunday at 7.
58:21Later tonight, see Beauty Offworld looking up for the first time in 2022.
58:26The new Sky at Night is across on BBC 4 at 10.
58:30Here next, a demanding house guest tests her sister's patience.
58:33The new series of Call the Midwife continues in a tick.
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