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Ten million species
live on planet Earth.

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Each one is remarkable.

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But none can survive on its own.

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All life depends upon connections.

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Unexpected, invariably complex,

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beautiful relationships between
millions of plants and animals.

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Starting in our jungles.

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Wow!

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It's a different world.

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Why do jungles have more animals
and plants than anywhere else?

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And why can't this mighty brazil nut
tree survive without an orchid

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and this nimble little rodent?

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Connections like these
form the planet's great ecosystems.

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They're vital for all life.

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I want to show you our world
as you've never seen it before.

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DISTANT BIRD AND ANIMAL CALLS

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Central America.

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The narrow isthmus of land
joining two vast continents.

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This is Pipeline Road in Panama.

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Named because it runs alongside
an old pipeline that was put in

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during the Second World War
to get oil from the Pacific

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through to the Atlantic Ocean.

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And it cuts through some of the most
pristine rainforest in this part

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of Central America, and I have to
tell you that amongst birdwatchers,

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this is a hallowed place.

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It's world famous.

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FAINT BIRDSONG
AND GENTLE HUM OF CRICKETS

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Semiplumbeous hawk.

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Green honeycreeper.

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Blue-crowned motmot.

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Black-tailed trogon.

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I've been out here
since first thing this morning,

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that's about five hours,

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and during the course of that time,

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I've seen or heard
75 different species of bird.

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Some of them
are quite tricky to identify -

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I've just got glimpses
through the trees.

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If I was to stay out here all day

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and work really hard,

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I might see as many
as 200 different species.

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During Christmas of 1989, a party
from the Audubon Society came here

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and recorded no fewer
than 357 different types of birds.

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It was a new world record, set
in this area of rainforest in Panama.

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To put that in context,

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the most anyone has ever seen in
Britain in a single day is just 143.

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And it's not just birds.

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In this tiny reserve, there are
twice as many mammal species

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as there are in the whole of the UK,

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3 times more butterflies
and 13 times as many frogs.

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Perhaps this astonishing diversity
is shown best

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by the richness
of these superb birds.

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LOUD VIBRATING

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Hummingbirds are nectar feeders

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so they find these dishes
of sugar solution irresistible.

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But it's not just the individuals
that are so dazzling,

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it's the sheer variety.

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Blue-chested hummingbird.

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Long-billed hermit.

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Violet sabrewing.

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Black-throated mango.

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And white-necked jacobin.

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There are 59 different species
of hummingbird in Panama's jungles.

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The almost bewildering variety of
life that you find in rainforests

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is exhibited by almost every animal
and plant group that lives there,

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and it's the same in rainforests
all over the planet.

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It's the remarkable thing
that sets them apart

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from the rest of our
terrestrial ecosystem,

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and it's a profound example
of what we call biodiversity.

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The number of different living things
in a given area at a given time.

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The big question is why?

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And it's a question that's been
vexing scientists for decades.

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Why are there so many different
living things in the rainforest?

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In Asia, rainforests cover
hundreds of islands -

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some small, some vast.

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New Guinea,

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Java, Sumatra.

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Amongst them, some of
the remotest places on the planet.

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Across the Indian Ocean, Africa and
the rainforests of the Congo Basin.

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Further west still
and we reach the Americas,

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home to the Amazon rainforest,

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the largest unbroken expanse of trees
in the tropics.

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Together, these jungles form an
emerald band that circles our globe.

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CLAP OF THUNDER

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Here on the equator,
there are virtually no seasons.

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It's hot and wet all year round.

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Humidity barely drops below 90%...

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..and the sunlight is more intense
than anywhere else on the planet,

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day in and day out.

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All of this rain and all of this sun

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results in a phenomenon
on a scale unseen anywhere else.

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It's happening here, in these leaves,
in all of these billions of leaves.

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And even if you're a really
hard-nosed biologist,

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really pragmatic about life,

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it's nothing short of miraculous.

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It's the chemical process
of photosynthesis.

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What plants are doing is combining
two very abundant ingredients -

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carbon dioxide in the air, and water.

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Two ingredients that are
almost impossible to combine.

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If we take carbon dioxide and water
and mix them together,

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even under great pressure,
all we get is fizzy water.

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On the other hand, when plants
mix carbon dioxide and water,

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they get something else.

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They get food.

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They get sugar.

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More of these sugars are produced
in a given area of rainforest

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than in any other habitat
because of the sheer quantities

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of water and solar energy.

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In fact, the energy captured
by rainforests in one year alone

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could power the UK
for over a million years.

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All of that energy

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is turned into food,

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quite literally out of thin air.

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It's a bit like
the botanical equivalent

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of turning water into wine.

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Photosynthesis might explain
why there's so much life here.

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But it doesn't explain why there are
so many different types of life.

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There's one very special animal
that I'd like you to meet.

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She's a leafcutter ant,
and she's an ant with a challenge.

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You see, her problem is that
she can't digest leaves on her own.

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She needs to take them
back to her nest.

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But what possible effect
could a tiny pest like her

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have on this immense forest?

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There are plenty of plant pests
in temperate forests,

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but there's one crucial difference.

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Temperate forests have winters

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and each winter, the cold
kills off creatures like the ants

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and they have to rebuild
their colonies

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and start from scratch each spring.

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But here in the rainforest,
there is no winter

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and as a consequence, the plants here
are under almost relentless attack.

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Our ant is just one worker
among thousands in a single colony.

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Each ant deposits her leaf fragment
deep within the nest.

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There it will be composted
and turned into a fungal food

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for the whole colony.

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Added together, the impact of all of
these thousands of ants is enormous.

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It's relatively easy to work out

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just how much these ants
are harvesting.

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We know there's around a hundred
thousand in every nest,

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and scientists counted

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the number of journeys they made
every day carrying pieces of leaf.

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374,200.

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They also measured the leaf area -

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the total being carried each day
by the ants - 11 square metres.

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Multiply that up and during
the course of a year,

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it adds up to 3,855 square metres

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and that is 20% of the leaf cover

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that's produced here
in the area of the forest

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where these little guys are foraging.

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That's one fifth
of all of the leaves here

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destroyed by nothing more than ants.

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And that's just the ants.

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Grasshoppers, caterpillars,
slugs and snails...

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everything seems to be
eating its greens here.

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Wherever you look in the forest,
it's almost impossible to find a leaf

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that hasn't been attacked by pests.

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The simple fact
that there's no winter

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to kill off these pests
is a huge problem for plants.

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So to stand any chance of survival,

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every single plant
in the rainforest is armed.

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And many are filled with toxic
chemicals which render them inedible.

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All of this has had a profound effect

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on the evolution of
the animals that live here.

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Take a closer look at these
creatures. What do you notice?

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Many of them are plain weird.

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They're unlike anything else.

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And one of the strangest of all
is found here in Latin America.

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Here it is,
and what an amazing animal.

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Really charming as well.

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But if we take a closer look at it,

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you can see exactly
what I mean by weird.

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This is a female three-toed sloth.

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And she's embarking on a 20-metre
vertical climb to find food.

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She is charming, but she's also
quite unlike any other animal.

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So why is she so weird?

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Well, it's a direct result of
a very peculiar diet.

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You see, she is a very fussy eater.

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Feeding on only one or two trees,
the leaves of which are tough

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and full of toxins.

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But her gut has evolved
to host bacteria

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which are specially equipped
to break down

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these otherwise inedible leaves.

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It's a slow process.

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Digesting this salad can take weeks.

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She gets so little energy
from this diet

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that she's forced
to keep her movement to a minimum.

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She's almost become
part of the forest furniture.

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So much so that other creatures
have started to move in.

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She's the ideal home
for a colony of sloth moths.

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The way she looks, the way she eats
and the way she moves

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are all a result
of having to overcome

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heavily defended leaves,

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and THAT is why sloths are so weird -

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they're specialists.

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In order to survive in a rainforest,
you need to be a specialist.

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There are no jack of all trades here.

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The battle between plants
and animals goes on every day

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and it's this battle that creates
the jungle's biodiversity.

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Let me show you what I mean, with
one of the most toxic plants of all.

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This a passion flower vine

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and its leaves are laced with
a pretty toxic defence.

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Cyanogenic glycoside molecules,

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and when they break down,
they form cyanide.

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As you might imagine,
it works wonders

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because cyanide is every bit
as dangerous to insects

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as it is to us humans.

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Well, that is to the majority of
insects, but not all of them.

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These are caterpillars from a species
of butterfly called Heliconius doris.

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They have evolved
a unique internal body chemistry,

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to do what few other creatures can -

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counteract
the plant's deadly cyanide.

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They even incorporate the poison
into their own bodies.

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And after metamorphosing
into the adult butterfly,

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their bright colours
advertise their toxicity.

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Very clever.

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As one of the few animals
that can eat these leaves,

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they have this food source
pretty much all to themselves.

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But the downside is,
they can't eat anything else.

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They are wedded to this vine.

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The adult butterflies will not
lay their eggs on anything else.

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But of course, plants evolve too.

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This is a different species
of passion flower vine.

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It grows in exactly the same patch
of rainforest as the first.

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And were it to arm itself

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with exactly the same cocktail of
cyanide as that first plant

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then clearly it wouldn't be able
to protect itself

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from these Heliconius doris
caterpillars, so it doesn't do that.

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It's changed very subtly the type of
compounds that it's got in the leaves

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that produce the cyanide.

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And as a consequence of that,
it's totally toxic

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to this species of caterpillar.

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A victory for the vine, perhaps?

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Except THIS is a never-ending battle.

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Another species of butterfly
has evolved.

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One that can cope
with the different toxins.

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Introducing Heliconius cydno.

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Its wing patterning is a little
different to that of doris.

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But the most important changes
are internal.

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Because each of these
butterfly species

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has evolved to be able to eat
a different type of vine.

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The battle between plant defence
and caterpillar attack never stops.

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The result?

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A proliferation of species
of both vine and butterfly.

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In fact, each species of plant
and tree in the rainforest

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has ended up with
its own specialised pests.

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It's become
an evolutionary arms race.

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Just as pest pressure
is driving the diversity of trees,

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00:25:23,080 --> 00:25:29,320
the diversity of trees is driving
the diversity of tree pests.

248
00:25:29,320 --> 00:25:33,600
And it's not just the pests,
it's their predators too.

249
00:25:33,600 --> 00:25:37,240
Animals like this praying mantis
are continually evolving

250
00:25:37,240 --> 00:25:39,360
to try and outwit those pests,

251
00:25:39,360 --> 00:25:42,920
which, in turn,
are continually evolving

252
00:25:42,920 --> 00:25:44,760
to try and outwit the mantis.

253
00:25:44,760 --> 00:25:48,440
If conditions in the forest here
remain stable,

254
00:25:48,440 --> 00:25:53,720
and new species have time to evolve,
one thing is for certain.

255
00:25:53,720 --> 00:25:57,960
This rainforest will become
a whirlpool of biodiversity.

256
00:27:01,920 --> 00:27:06,520
Now, it's easy for us to think
of biodiversity as a wonderful thing.

257
00:27:06,520 --> 00:27:10,480
But the pressures
that create this biodiversity

258
00:27:10,480 --> 00:27:13,720
make the rainforest
a very dangerous place.

259
00:27:15,640 --> 00:27:18,360
Especially when it comes to
the survival

260
00:27:18,360 --> 00:27:21,040
of the forest's youngest inhabitants.

261
00:27:23,680 --> 00:27:27,360
Let's think about it
from the plant's point of view.

262
00:27:38,280 --> 00:27:42,520
I've collected about
15 different types of tree seed here,

263
00:27:42,520 --> 00:27:45,640
all of which have come from
this small patch of forest behind me.

264
00:27:45,640 --> 00:27:49,920
Now, imagine that each of these seeds
represents a tree.

265
00:27:52,480 --> 00:27:57,040
And imagine that the forest
was made up of a single species.

266
00:27:57,040 --> 00:28:00,840
Like this one,
that the locals call prischaco.

267
00:28:05,400 --> 00:28:07,840
What you'd have is a monoculture.

268
00:28:14,480 --> 00:28:18,520
But in the pest-infested rainforest,
this doesn't happen.

269
00:28:18,520 --> 00:28:19,800
And here's why.

270
00:28:21,640 --> 00:28:26,280
You see, imagine you're a seedling
trying to germinate and grow here.

271
00:28:26,280 --> 00:28:28,280
We know that
each of these tree species

272
00:28:28,280 --> 00:28:31,120
has a highly specialised set
of herbivores which attack it.

273
00:28:31,120 --> 00:28:34,240
So this one will be accessible to

274
00:28:34,240 --> 00:28:36,880
all of the herbivores
living on these trees.

275
00:28:38,360 --> 00:28:40,280
Not a good situation at all.

276
00:28:40,280 --> 00:28:45,120
But what if you were a different
species of tree germinating here?

277
00:28:45,120 --> 00:28:50,520
Then you wouldn't be susceptible
to this particular set of herbivores,

278
00:28:50,520 --> 00:28:53,680
and that would confer
a real advantage to you.

279
00:28:53,680 --> 00:28:55,720
Then there's a far greater chance

280
00:28:55,720 --> 00:28:57,760
that it would prosper
through to maturity,

281
00:28:57,760 --> 00:29:00,480
that it would survive. And in fact...

282
00:29:02,840 --> 00:29:05,680
..if another tree species
were to grow here,

283
00:29:05,680 --> 00:29:08,480
it too would enjoy
the same advantages.

284
00:29:08,480 --> 00:29:12,480
Reduced susceptibility
to this type of herbivore attack.

285
00:29:15,400 --> 00:29:19,800
The strategy spreads like wildfire
through the forest.

286
00:29:19,800 --> 00:29:22,240
What we end up seeing...

287
00:29:24,320 --> 00:29:27,000
..is a complete mosaic of species.

288
00:29:32,000 --> 00:29:34,640
A seedling
is far more likely to survive

289
00:29:34,640 --> 00:29:36,920
if it germinates in isolation,

290
00:29:36,920 --> 00:29:42,560
far away from the parent tree,
surrounded by different tree species.

291
00:29:44,440 --> 00:29:49,240
So how do plants get
their precious seeds away to safety,

292
00:29:49,240 --> 00:29:52,840
away from
their set of voracious pests?

293
00:30:04,760 --> 00:30:08,680
To find the answer,
I'm going to the jungles of Borneo.

294
00:30:13,720 --> 00:30:17,760
Home to some of the largest animals
in any rainforest.

295
00:30:38,480 --> 00:30:44,160
In the Kinabatangan river,
a group of pygmy elephants.

296
00:30:55,720 --> 00:31:00,640
Among the herd is a baby,
born only a few weeks ago.

297
00:31:15,880 --> 00:31:18,040
Nearby, in the Sepilok sanctuary,

298
00:31:18,040 --> 00:31:21,760
this young orang-utan
is just days old.

299
00:31:26,440 --> 00:31:30,480
They don't know it, but these
youngsters are incredibly important.

300
00:31:32,160 --> 00:31:35,360
Because not only
are both species rare,

301
00:31:35,360 --> 00:31:39,360
but both will play a crucial role
in this ecosystem.

302
00:31:44,840 --> 00:31:46,320
Orang-utans.

303
00:31:46,320 --> 00:31:49,920
Absolutely extraordinary animals.

304
00:31:51,240 --> 00:31:54,840
So easy to see why we generate
so much affection for them.

305
00:31:54,840 --> 00:31:57,920
And when you look into their eyes,

306
00:31:57,920 --> 00:32:00,800
it's like a reflection
in a not-so-distant mirror.

307
00:32:03,160 --> 00:32:05,000
But there is another reason

308
00:32:05,000 --> 00:32:08,480
why we should value
both orang-utans and elephants.

309
00:32:09,880 --> 00:32:11,920
If you're a tree, seed dispersal

310
00:32:11,920 --> 00:32:15,720
and germination
is a pretty risky business.

311
00:32:15,720 --> 00:32:18,240
After all, you're covered with pests,

312
00:32:18,240 --> 00:32:20,800
all of which want to gobble up
those seeds

313
00:32:20,800 --> 00:32:24,520
or snap up any tasty
germinating seedling.

314
00:32:24,520 --> 00:32:28,960
Your only chance is to get your seeds
as far away from yourself

315
00:32:28,960 --> 00:32:31,600
and those pests as possible.

316
00:32:31,600 --> 00:32:33,640
The question is, how do you do it?

317
00:32:38,880 --> 00:32:40,000
There's a clue.

318
00:32:45,240 --> 00:32:48,160
This young orang-utan will grow to be

319
00:32:48,160 --> 00:32:51,320
the heaviest arboreal animal
in the world.

320
00:32:52,760 --> 00:32:58,200
And this pygmy elephant will grow
to be nearly three metres tall.

321
00:33:01,280 --> 00:33:04,120
By most standards, that's not pygmy.

322
00:33:18,080 --> 00:33:20,560
They both face the same problem...

323
00:33:22,000 --> 00:33:24,040
..how to find enough food.

324
00:33:32,960 --> 00:33:34,080
The solution,

325
00:33:34,080 --> 00:33:39,120
as the baby is starting to realise,
is that they never stop moving.

326
00:33:54,360 --> 00:33:58,560
She will have to work hard
to keep up with the herd.

327
00:33:58,560 --> 00:34:02,200
You see, these elephants
are on the lookout for fruit.

328
00:34:08,520 --> 00:34:13,720
Overhead, orang-utans
search for fruit in the canopy.

329
00:34:22,720 --> 00:34:26,600
And thanks to their agility,
they can reach almost all of it.

330
00:34:32,920 --> 00:34:34,920
But for the young elephant,

331
00:34:34,920 --> 00:34:38,000
even low-hanging fruit
can be just out of reach.

332
00:34:48,400 --> 00:34:50,360
Her mother shows her how to get them.

333
00:35:04,440 --> 00:35:09,440
But what's important here is that
this elephant can smell some fruit

334
00:35:09,440 --> 00:35:11,680
from well over a kilometre away.

335
00:35:13,720 --> 00:35:15,720
And there are some plant species here

336
00:35:15,720 --> 00:35:19,960
that have specifically evolved
to attract elephants.

337
00:35:22,040 --> 00:35:24,880
For instance,
this jackfruit is so large

338
00:35:24,880 --> 00:35:27,760
that nothing else
can really deal with it.

339
00:35:33,880 --> 00:35:37,800
His huge gut will take a couple
of days to digest that meal,

340
00:35:37,800 --> 00:35:42,680
by which time he may have travelled
over ten kilometres.

341
00:35:47,240 --> 00:35:50,680
Between them,
the orang-utan and the elephant

342
00:35:50,680 --> 00:35:53,800
disperse thousands of species
of fruit.

343
00:35:58,480 --> 00:36:02,680
Not only will the seeds be supplied
with ready-made fertilizer,

344
00:36:02,680 --> 00:36:06,760
they will germinate safely away
from the threat of attack

345
00:36:06,760 --> 00:36:09,720
from the mother tree's pests.

346
00:36:26,840 --> 00:36:30,240
Rainforests,
more than any other ecosystem,

347
00:36:30,240 --> 00:36:35,120
rely on animals to spread their seeds
over large distances.

348
00:36:43,720 --> 00:36:47,560
But paradoxically,
this has created a nightmare.

349
00:37:29,520 --> 00:37:35,280
It's not often you get the chance
to walk 30 metres up in the treetops.

350
00:37:39,160 --> 00:37:43,400
This canopy walkway certainly gives
a unique perspective

351
00:37:43,400 --> 00:37:45,240
on the diversity of the rainforest.

352
00:37:46,480 --> 00:37:49,520
It's been built in Sabah in Borneo.

353
00:37:49,520 --> 00:37:51,680
Look at this!

354
00:37:51,680 --> 00:37:53,360
Wow!

355
00:37:57,240 --> 00:38:03,120
There's no doubt that there is
a huge range of species here.

356
00:38:03,120 --> 00:38:06,640
But the flipside is that
in any given area,

357
00:38:06,640 --> 00:38:10,440
there aren't that many individuals
of each of those species.

358
00:38:14,880 --> 00:38:16,920
This tree is just coming into flower.

359
00:38:18,360 --> 00:38:23,640
But the thing is,
if I look around the forest here,

360
00:38:23,640 --> 00:38:26,280
I can't see another of these trees.

361
00:38:28,160 --> 00:38:29,320
No.

362
00:38:30,640 --> 00:38:33,200
And this is bound to present
a challenge

363
00:38:33,200 --> 00:38:35,640
when it comes to sex, to pollination.

364
00:38:35,640 --> 00:38:37,840
But it's a challenge
that nature has risen to.

365
00:38:40,560 --> 00:38:41,840
The simple problem is,

366
00:38:41,840 --> 00:38:44,920
how do you cross-pollinate
to fertilize your seeds

367
00:38:44,920 --> 00:38:46,960
if you're all alone?

368
00:38:51,000 --> 00:38:55,720
The methods British trees might use
won't work here.

369
00:38:57,320 --> 00:38:59,800
Below the canopy,
there's virtually no wind.

370
00:39:01,000 --> 00:39:05,080
And relying on a general pollinator,
such as a honeybee,

371
00:39:05,080 --> 00:39:07,880
is a bit like posting a letter
without an address.

372
00:39:07,880 --> 00:39:10,760
It might have collected YOUR pollen,

373
00:39:10,760 --> 00:39:14,800
but it's just as likely to deposit it
on the wrong flowers.

374
00:39:16,800 --> 00:39:20,720
No, what's required in the rainforest
is special delivery.

375
00:39:24,320 --> 00:39:29,080
The nectar in these long flowers
is out of the reach of most animals.

376
00:39:31,400 --> 00:39:34,320
Because these petals have evolved
in harmony with

377
00:39:34,320 --> 00:39:36,000
a very specific pollinator...

378
00:39:38,120 --> 00:39:39,520
..a sunbird.

379
00:39:46,160 --> 00:39:50,160
With his long bill, he can reach
the nectar deep within the flower.

380
00:39:51,280 --> 00:39:53,320
And he needs to get this nectar

381
00:39:53,320 --> 00:39:56,280
because he's evolved to feed on
little else.

382
00:40:11,560 --> 00:40:14,760
And critically,
when he's had his fill here,

383
00:40:14,760 --> 00:40:20,400
he'll have to find another tree
with the same type of flowers.

384
00:40:20,400 --> 00:40:24,480
If you're a tree in a rainforest,
this relationship is ideal.

385
00:40:29,680 --> 00:40:34,320
For plants, specialist pollinators
act as a form of insurance policy.

386
00:40:36,080 --> 00:40:39,920
You see, these animals have evolved
to feed on your flowers

387
00:40:39,920 --> 00:40:41,840
and only your flowers.

388
00:40:41,840 --> 00:40:43,600
So once they've visited you,

389
00:40:43,600 --> 00:40:46,640
no matter how far away
your nearest neighbour is,

390
00:40:46,640 --> 00:40:50,480
they'll get there
and effect pollination.

391
00:40:50,480 --> 00:40:52,560
And this is typical.

392
00:40:52,560 --> 00:40:57,800
Many of the trees and plants out here
will have specialist pollinators.

393
00:40:57,800 --> 00:41:00,080
And because
there are thousands of species,

394
00:41:00,080 --> 00:41:05,600
this in turn means that there are a
vast array of these types of animal.

395
00:41:20,880 --> 00:41:25,080
The final leg of my journey
takes me to Amazonian Peru.

396
00:41:43,920 --> 00:41:48,000
Now we know why jungles
are so productive,

397
00:41:48,000 --> 00:41:49,200
so diverse,

398
00:41:49,200 --> 00:41:54,440
I want to see how the whole ecosystem
fits together.

399
00:42:13,880 --> 00:42:18,440
There's one series
of remarkable relationships

400
00:42:18,440 --> 00:42:22,320
that even in this distant rainforest
involves me and you.

401
00:42:28,120 --> 00:42:31,880
Now, you may not know what this is.

402
00:42:31,880 --> 00:42:34,080
But I'm certain
you know what this is.

403
00:42:34,080 --> 00:42:37,120
This is a brazil nut.

404
00:42:37,120 --> 00:42:39,120
And this is a brazil nut pod.

405
00:42:39,120 --> 00:42:43,240
So inside here are about 20 of these.

406
00:42:43,240 --> 00:42:44,520
Come down here.

407
00:42:45,880 --> 00:42:49,800
Because quite naturally,
this has come from a brazil nut tree.

408
00:42:52,360 --> 00:42:56,040
And here is that tree.

409
00:42:56,040 --> 00:42:57,240
What a thing!

410
00:42:57,240 --> 00:42:58,440
It's magnificent.

411
00:43:17,400 --> 00:43:21,840
Each huge seed pod
takes 12 months to grow.

412
00:43:25,880 --> 00:43:30,360
And this mighty tree
owes its entire existence

413
00:43:30,360 --> 00:43:34,360
to connections that have taken
science years to uncover.

414
00:43:40,080 --> 00:43:46,760
One of the most intricate
relationships takes place up there.

415
00:43:53,160 --> 00:43:54,560
I think I've got it.

416
00:43:54,560 --> 00:43:57,160
It's difficult to say,
it's so high up.

417
00:44:00,600 --> 00:44:03,360
Now, that is it, that's it.

418
00:44:04,600 --> 00:44:05,920
Yeah.

419
00:44:32,520 --> 00:44:37,400
Well, after a bit of a climb, here's
the plant that I was looking for,

420
00:44:37,400 --> 00:44:40,840
and saw from all the way down there
on the ground.

421
00:44:40,840 --> 00:44:42,640
It's an orchid.

422
00:44:43,880 --> 00:44:47,560
This little orchid is absolutely
essential to the brazil nut.

423
00:44:47,560 --> 00:44:51,280
In fact, if you've ever eaten one
yourself,

424
00:44:51,280 --> 00:44:54,640
then you owe a debt of gratitude
to these flowers.

425
00:44:56,320 --> 00:45:02,040
The story of why the brazil nut
needs the orchid is extraordinary.

426
00:45:02,040 --> 00:45:05,880
It's so wonderful,
it's almost beyond belief.

427
00:45:05,880 --> 00:45:08,200
And through unravelling that story,

428
00:45:08,200 --> 00:45:10,880
we can understand
some astonishing things.

429
00:45:12,440 --> 00:45:14,160
SAWING

430
00:45:15,960 --> 00:45:19,040
It starts with those
amazing-looking seed pods.

431
00:45:23,280 --> 00:45:25,800
How on Earth do they get dispersed?

432
00:45:28,120 --> 00:45:32,200
They're not only very heavy,
they're unbelievably tough.

433
00:45:41,880 --> 00:45:44,800
I want to try a little experiment
to find out.

434
00:45:49,280 --> 00:45:53,560
All I need is some fishing line
and some little pink flags.

435
00:45:59,840 --> 00:46:02,800
I know this might seem a bit odd,
but trust me,

436
00:46:02,800 --> 00:46:04,920
this is cutting-edge ecology.

437
00:46:15,280 --> 00:46:17,760
It's all primed and ready for action,

438
00:46:17,760 --> 00:46:20,560
but there are none of the animals
around at the moment.

439
00:46:20,560 --> 00:46:23,000
So I'm going to put this down here,

440
00:46:23,000 --> 00:46:25,320
wait for them to sniff it out,
and be patient.

441
00:46:34,600 --> 00:46:38,440
Given their size,
you might expect something large.

442
00:46:40,040 --> 00:46:43,920
But the animal that can handle it
is actually rather small.

443
00:46:50,440 --> 00:46:53,080
It's a rodent called an agouti.

444
00:47:03,440 --> 00:47:05,600
She may look insignificant,

445
00:47:05,600 --> 00:47:08,760
but her actions
have a very significant impact

446
00:47:08,760 --> 00:47:10,120
on this rainforest.

447
00:47:14,760 --> 00:47:18,920
She specialises in eating
tough seeds and nuts.

448
00:47:18,920 --> 00:47:21,920
Thanks to her teeth,
which work like chisels.

449
00:47:34,760 --> 00:47:37,760
So this is how
they're meant to be opened!

450
00:47:45,880 --> 00:47:50,360
That nut is packed full
of energy and nutrients.

451
00:47:50,360 --> 00:47:53,360
After all, it contains
everything you need

452
00:47:53,360 --> 00:47:55,440
to start growing a brazil nut tree.

453
00:48:08,000 --> 00:48:12,080
And what happens next is the bit
that I'm really interested in.

454
00:48:13,520 --> 00:48:16,360
Because there are so many nuts
in the pod,

455
00:48:16,360 --> 00:48:18,720
she can't eat all of them in one go.

456
00:48:21,040 --> 00:48:23,120
She's saving the rest for later.

457
00:48:33,120 --> 00:48:36,880
The question is,
where is she going to put them?

458
00:49:06,120 --> 00:49:07,800
And look at that.

459
00:49:07,800 --> 00:49:12,200
She's even putting every leaf back
exactly where she found it.

460
00:49:26,480 --> 00:49:31,080
Each nut is being carefully carried
away to a different hiding place.

461
00:49:40,600 --> 00:49:44,920
As far as she is concerned,
this is the ideal place for a larder.

462
00:49:50,560 --> 00:49:54,680
And by complete coincidence,
as far as the tree is concerned,

463
00:49:54,680 --> 00:49:58,120
this is the ideal place
for its seed to germinate.

464
00:50:07,680 --> 00:50:11,080
Here is one of our marked nuts.

465
00:50:11,080 --> 00:50:15,920
And the mother tree
is hundreds of metres through there.

466
00:50:15,920 --> 00:50:20,880
So the tree, a plant, has managed to
get a mammal to bury its seeds

467
00:50:20,880 --> 00:50:24,640
with just as much care
as a really good gardener.

468
00:50:24,640 --> 00:50:28,160
It's one of those magical
rainforest relationships.

469
00:50:34,960 --> 00:50:40,360
And the best thing about it is that
she has no idea how important she is.

470
00:50:44,440 --> 00:50:47,080
The agouti is the only animal

471
00:50:47,080 --> 00:50:51,560
that can disperse the seeds
of the brazil nut tree,

472
00:50:51,560 --> 00:50:56,840
so the brazil nut tree
is completely reliant on the agouti.

473
00:50:56,840 --> 00:51:01,480
It's a case of what we call
species specific dependency.

474
00:51:01,480 --> 00:51:04,560
Off it goes to bury one of the nuts.

475
00:51:04,560 --> 00:51:05,560
And you know,

476
00:51:05,560 --> 00:51:10,360
I can guarantee that every brazil nut
that you've ever cracked open

477
00:51:10,360 --> 00:51:14,640
has come from a tree that was
planted by one of these animals.

478
00:51:15,760 --> 00:51:17,760
That's fantastic.

479
00:51:17,760 --> 00:51:20,840
You've got to admit,
ecology is fantastic.

480
00:51:33,080 --> 00:51:36,880
It's clear why the brazil nut tree
needs an agouti.

481
00:51:36,880 --> 00:51:41,120
But how does the orchid that I found
fit into our story?

482
00:51:44,360 --> 00:51:49,280
Like many flowers,
it uses pollinating insects, bees.

483
00:51:50,440 --> 00:51:51,480
In fact, these orchids

484
00:51:51,480 --> 00:51:55,160
use a very special group of bees
called Euglossine,

485
00:51:55,160 --> 00:51:56,560
or orchid bees.

486
00:51:59,600 --> 00:52:03,240
And more specifically,
they have to be males.

487
00:52:07,480 --> 00:52:10,560
Unlike most bees,
which are after nectar,

488
00:52:10,560 --> 00:52:13,640
this one is after something
quite different.

489
00:52:13,640 --> 00:52:15,280
He's after perfume.

490
00:52:18,080 --> 00:52:23,560
He collects a waxy secretion by
rubbing his legs all over the flower.

491
00:52:23,560 --> 00:52:27,000
And in doing so,
pollinates that flower.

492
00:52:36,760 --> 00:52:41,440
Collecting this perfume is so
important to a male orchid bee

493
00:52:41,440 --> 00:52:45,800
that it may fly miles all over
the forest in search of it.

494
00:52:48,480 --> 00:52:50,600
The reason that he's collecting scent

495
00:52:50,600 --> 00:52:53,840
is that the males compete with
one another using smell.

496
00:52:53,840 --> 00:52:56,040
They have a sort of a scent-off.

497
00:52:56,040 --> 00:52:58,480
The one with
the best bouquet of perfumes

498
00:52:58,480 --> 00:53:00,920
gets the right to mate with
the females.

499
00:53:06,120 --> 00:53:10,680
But what has all of this got to do
with our story of brazil nut trees

500
00:53:10,680 --> 00:53:11,800
and agoutis?

501
00:53:13,760 --> 00:53:17,160
Only the male orchid bees
pollinate the orchids.

502
00:53:17,160 --> 00:53:19,840
To reduce competition
between the sexes,

503
00:53:19,840 --> 00:53:23,000
the males and females
have evolved different niches.

504
00:53:23,000 --> 00:53:26,320
It's another example
of the extreme diversification

505
00:53:26,320 --> 00:53:28,600
that takes place
here in the rainforest.

506
00:53:28,600 --> 00:53:33,240
So the females pollinate
a completely different species.

507
00:53:33,240 --> 00:53:35,240
A very, very much larger one.

508
00:53:36,680 --> 00:53:38,320
The one that I'm sat on.

509
00:53:38,320 --> 00:53:39,520
The brazil nut tree.

510
00:53:41,800 --> 00:53:46,120
Once a year, the tips of
the brazil nut tree branches

511
00:53:46,120 --> 00:53:48,640
are adorned with large white flowers.

512
00:53:51,200 --> 00:53:54,240
They attract insects
from all over the forest.

513
00:53:55,760 --> 00:54:00,040
Including the much larger
female orchid bees.

514
00:54:04,600 --> 00:54:07,560
The nectar is hidden beneath
a special petal.

515
00:54:11,840 --> 00:54:13,840
And the female orchid bees

516
00:54:13,840 --> 00:54:17,280
are one of the few insects
that are big enough

517
00:54:17,280 --> 00:54:19,920
and strong enough
to open the flowers.

518
00:54:23,400 --> 00:54:25,640
This smaller bee, on the other hand,

519
00:54:25,640 --> 00:54:28,280
simply doesn't have the strength
to open it.

520
00:54:31,120 --> 00:54:32,480
This selective door policy

521
00:54:32,480 --> 00:54:37,440
is the tree's way of ensuring
that it will only be used

522
00:54:37,440 --> 00:54:43,560
by insects which are guaranteed to
visit other brazil nut tree blooms

523
00:54:43,560 --> 00:54:46,760
and then pollinate them.

524
00:54:49,800 --> 00:54:55,280
The intricate relationship between
the male orchid bee and the flowers

525
00:54:55,280 --> 00:54:59,400
is the reason that brazil nut trees
like this one

526
00:54:59,400 --> 00:55:04,280
can only grow
in intact rainforest ecosystems.

527
00:55:04,280 --> 00:55:08,840
Now, the brazil nut tree
needs the agouti,

528
00:55:08,840 --> 00:55:12,280
way down there,
to disperse the seeds.

529
00:55:12,280 --> 00:55:18,040
The agouti needs the female orchid
bee up here to pollinate the flowers

530
00:55:18,040 --> 00:55:20,400
so those seeds are produced
in the first place.

531
00:55:20,400 --> 00:55:23,800
The female orchid bee needs the male,

532
00:55:23,800 --> 00:55:27,800
which in turn
needs those orchid flowers.

533
00:55:27,800 --> 00:55:33,000
That's why the brazil nut
needs the orchid.

534
00:55:33,000 --> 00:55:35,320
You just couldn't make it up,
could you?

535
00:55:42,600 --> 00:55:46,680
This wonderfully complex web
of connections has all come about

536
00:55:46,680 --> 00:55:49,920
due to the sheer biodiversity
of rainforests.

537
00:55:51,560 --> 00:55:53,120
And understanding it

538
00:55:53,120 --> 00:55:56,840
reveals the natural world
in a very different light.

539
00:56:00,880 --> 00:56:04,360
Animals don't simply live in forests.

540
00:56:04,360 --> 00:56:05,840
They are the forests.

541
00:56:07,200 --> 00:56:12,720
And forests without orang-utans
and elephants are broken ecosystems.

542
00:56:14,840 --> 00:56:18,400
We might want to save rainforests
for the elephants,

543
00:56:18,400 --> 00:56:23,040
when, really, we should be saving
the elephants for the forest.

544
00:56:23,040 --> 00:56:28,320
We've been motivated
by what an orang-utan looks like.

545
00:56:28,320 --> 00:56:31,160
We should be motivated by
what it does.

546
00:56:36,520 --> 00:56:41,280
Stretched out around me is the most
complex ecosystem on our planet,

547
00:56:41,280 --> 00:56:44,800
home to millions
of different species.

548
00:56:44,800 --> 00:56:48,640
And whilst there's wonder in
the detail of their individual lives,

549
00:56:48,640 --> 00:56:53,320
nothing competes with the sheer
beauty of the bigger picture.

550
00:56:53,320 --> 00:56:58,320
The dynamic, functional,
living, breathing rainforest.

551
00:56:58,320 --> 00:57:04,080
For me, science is the art
of understanding truth and beauty.

552
00:57:04,080 --> 00:57:06,800
Well, here's the beauty.

553
00:57:08,080 --> 00:57:10,360
And we've seen
just a little of its truth.

554
00:57:42,840 --> 00:57:44,400
If you'd like to know more

555
00:57:44,400 --> 00:57:47,720
about the fascinating web of links
between species,

556
00:57:47,720 --> 00:57:50,920
the Open University
has produced some material

557
00:57:50,920 --> 00:57:53,040
both to inform and inspire you.

558
00:57:53,040 --> 00:57:54,520
For your free copy,

559
00:57:54,520 --> 00:57:58,120
or to find out more about Open
University programmes, ring...

560
00:58:02,960 --> 00:58:04,800
Or go to the website...

561
00:58:08,440 --> 00:58:10,680
And then follow the links
to Open University.

562
00:58:11,720 --> 00:58:12,960
And join me next time,

563
00:58:12,960 --> 00:58:17,600
when I'll be travelling to some
of the world's greatest grasslands.

564
00:58:30,400 --> 00:58:33,440
Subtitles by Red Bee Media Ltd.