Original subtitles

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Although ants are tiny insects,

they can be very harmful to plant life.

This enormous jungle tree is powerless

against a colony of ants.

Little light penetrates the thick foliage during the day.

An extraordinary sight unfolds in the Peruvian jungle floor.

A long procession of leafcutter ants transports

leaves to their nest.

Large worker ants use their powerful razor-sharp jaws to

cut a section of a leaf with unmatched precision.

A ravenous colony of ants can consume more leaves

than a group of elephants.

This tree will be completely defoliated in just a few days.

The worker ants carry leaves that are several times larger

than themselves to their nest.

Some ant processions can reach several hundreds of meters.

But what makes these ants special is the fact that they

are the first creatures on earth that grew their own food.

Smaller ants in the colony are tasked with growing fungus.

They take the leaves harvested by the larger worker ants and

break them down into smaller pieces,

which are added to the fungus garden.

The fungus cultivated by the ants is rich in

protein and fed to the larva.

This is how leafcutter ant colonies have lived

for over 50 million years.

Every year, one-fifth of all newly-grown leaves in the

rainforest will be harvested by leafcutters ants.

But is that how the story always ends for trees?

Plant and trees use intelligent and sometimes

cruel tactics to repel their enemies.

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In a rainforest in Borneo, there lives an impressive

insect-eating plant.

It's a pitcher plant called nepenthes.

Most plant species draw nutrients from the soil and

use energy from sunlight for photosynthesis.

But when the soil environment lacks enough minerals to

sustain plant life, some plants will devise new

ways to collect energy.

Like this pitcher plant which preys on insects.

The bud of nepenthes grows into a tube-shaped pitcher cup.

As the plant grows, it develops striped patterns and

reveals an opening with a lid.

It takes 15 days to a month for the

pitcher cup to develop fully.

The lid prevents rain from seeping into the pitcher.

Insects are lured with sweet nectar that lies at

the ribs of the peristome.

A lone ant is attracted to the eye-catching colors and scent

given off by the carnivorous plant.

Sweet nectar and nutrients on the

plant's lip entices the ant.

It will lead the ant to the deathtrap below.

The curved lip is slippery.

Once an insect falls into the pitcher,

it is impossible to crawl out of it because

the walls are slippery too.

In the course of several days, the plant will use digestive

agents to absorb the nutrients from the ant.

Only the ant's exoskeleton will remain.

Carnivorous plants use ingenious ways to hunt insects for food.

The bladderwort, an aquatic plant,

has the quickest reflexes in the world.

It drifts in the water instead of staying in one place.

Since there are fewer nutrients in water than in

soil, the bladderwort must forage for nutrients.

Small bladder-shaped traps on the branches catch insects.

Instead of using roots to absorb nutrients,

the bladderwort relies on these traps.

It mainly catches mosquito larvae and water fleas.

When a mosquito larva approaches,

it is sucked into the bladder.

Everything happens in a split second.

On closer inspection, the trap has trigger hairs.

When an insect brushes against a trigger hair,

the trap sucks it in and then closes.

Once caught inside, the larva dies from suffocation.

A high speed camera is used to capture the plant's

astonishing reaction speed.

The larva approaches.

The trap sucks in water along with the larva.

And the door closes in a split second.

Since when did plants develop such ingenious strategies?

4.5 billion years ago, there was no life on planet earth.

Greenhouse gases filled the atmosphere and the ocean was

too hot and salty to support life.

A billion years later, something miraculous happened.

The first life form emerged in earth's sea.

On the west coast of Australia.

Made from microorganisms, these stromatolites were

formed 3.5 billion years ago.

They produced oxygen through continuous photosynthesis.

Tiny microorganisms went on to evolve into moss,

which developed into plants.

During the Silurian period of the Paleozoic

era 400 million years ago...

The first plant that grew on land was the cooksonia.

This primitive plant had a simple stalk which split into

two branches in the middle.

Each branch had a spore structure on top.

It could only survive near water because it

needed constant moisture.

The plant also needed water in order to multiply.

So how did the early ancestors of land plants look like?

On the southern coast of Jeju Island...

The Skeleton Fork Fern is likely to have been the first

vascular plant on earth.

This fern plant lacks roots and leaves.

Its Y-shaped branches indicate that it is a primitive plant.

Without any leaves, it relies on its stalk to collect

sunlight for photosynthesis.

However, this is not efficient.

The fern's spores are used to seed new plants.

When the spores inside the sporocyst mature,

it will be swept away by the wind.

Once it lands on moist ground, it will take root and grow.

The first land plants had inherent disadvantages which

they overcame through ingenious survival techniques.

The earliest known tree in the world is Archaeopteris,

which appeared 370 million years ago.

It had a stout trunk and long branches.

Having feather-like shaped fronds,

the tree was named "Archaeopteris."

Archaeopteris grew as tall as eight meters and bore a

resemblance to modern conifers.

This primitive tree formed the earliest forests as it became

the dominant species in earth's vegetation.

Diamond-shaped patterns are pronounced in this

petrified lepidodendron.

Lepidodendron first appeared on earth 300 million years ago.

They grew as tall as a 10-story building.

Their towering height and cluster of large leaves

enabled them to have robust photosynthesis.

They proliferated in wetlands.

The earth's atmosphere had higher oxygen concentration

levels during the Carboniferous period when

giant insects were abundant.

Meganeura, the largest flying insect every known,

had a wingspan that exceeded 70 centimeters.

As plants became more numerous,

earth's ecosystem teemed with life.

In a rain forest in Costa Rica.

Daniel Janzen, a world-renown expert in rain forest,

is a biology professor at the University of Pennsylvania.

He has dedicated his life to studying plants and

insects in tropical climates.

As you can see there's one stinging me there.

Among his research work, he studies the symbiotic

relationship between the bullhorn acacia and ants.

This acacia tree features horn-like thorns in

which ants make their home.

The ants feed on the nectar secreted

from the acacia branches.

No matter how much nectar they eat,

the supply of nectar seems to be endless.

But the tree is not providing this for free.

The nectar is exchanged for the ant's services.

Brown protein-lipid nodules on the the leaves also provide

nourishment to the ants.

With plenty of food to eat, the Pseudomyrmex ants do not

need to prey on other insects.

And the ants dwell in the recesses of

the hollowed-out thorns.

The swollen thorns provide a safe home for the ants

where they can lay eggs.

In return for all of this, the ants fulfill an important role.

They aggressively defend the tree from

acacia leaf-eating insects.

This ladybug is under attack from the rushing ants.

Many herbivores and insects like eating the acacia's

tender leaves and sweet nectar.

So the ants defend the tree from harmful insects in

exchange for food and shelter.

The tree has changed - evolved.

And the ants have changed - evolved.

They've changed from being hunters to being policemen.

And all they do is protect the tree.

She (queen ant) lives about 15 to 20 years.

And when she dies, the colony dies.

And when the colony dies, the tree dies.

Without the ants, the acacia tree would

be unable to survive.

So it has evolved to accommodate the

ants to ensure its survival.

But a peaceful symbiotic relationship is not

always pursued by plants.

Some plants survive by relying on their killer instincts.

In a thick jungle, plants must compete for sunlight by

growing as tall as possible because little light

reaches below the canopy.

This enormous tropical fig tree is called the strangler fig.

Its branches weave around the trunk of a tree.

A strangler fig latches onto a host tree.

While most trees scatter their seeds on the ground,

the strangler fig grows in a different place.

A fig seed will grow when it is dropped on top

of a tree and falls into.

It will envelop the tree and suck its nutrients.

Meanwhile, it will grow its roots downward,

and "strangle" the tree to death.

Within five years, the strangler fig's roots will

reached the ground and take away water from the host.

The support tree will eventually die,

leaving behind a columnar tree with a hollow core.

After killing the host, the fig will grow

upwards towards the sunlight.

It will live on for several hundreds of years,

claiming its territory.

Many insects and birds eat the fruit

and seed of trees for food.

The red crossbill is no exception.

The bird pecks a pine cone to get to the seeds and eat them.

This sight is fairly common in nature.

But it is a scene that embodies a vital shift

in the history of plant life.

The appearance of seeds.

The gingko is called a living fossil.

They existed during the Jurassic period

when dinosaurs flourished.

A gingko is a gymnosperm that relies on pollination

between pollen cones and ovulate cones.

Pollination is the process in which plants

reproduce and bear seeds.

The motile sperm or pollen has to fertilize the egg

in the ovule of the gingko.

Firmly rooted to the ground, gingkos stand immobile.

So the gingko must rely on the wind to carry its

pollen to another gingko tree.

Carried aloft by the wind, Gingko

pollen fertilizes an egg.

When the pollination is successful,

the tree will produce seeds.

Although they are technically seeds,

people commonly call them fruit.

Using seeds to reproduce its species,

gingko trees spread far and wide.

After eating the fruit, dinosaurs and small mammals

spread the seeds in their droppings.

Save for one species, all gingkos were suddenly

wiped out in the Cenozoic era, 65 million years ago.

Around the time gingko trees vanished,

a new plant species evolved.

They were flowering plants.

Magnolias grow flower petals before they grow leaves and

retain the characteristics of primitive flowering plants.

Having both the stamen and gynoecium in a single flower

allowed the plant to reproduce more efficiently.

Archaefructus is the earliest known flowering plant.

This fossil is dated at 125 million years old.

It looks starkly different from modern plants.

Having no sepals or petals, Archaefructus has been

revealed as coming from the angiosperm family.

Although it was an aquatic plant,

it was able to bloom above water where insects and the

wind would carry its pollen.

The beautiful colors and enchanting floral scent of

flowers are tools to ensure the survival of its species.

An amazing flower grows deep in the Borneo rainforest.

It is the rafflesia, the world's largest single flower.

It is unmistakably a flowering plant

with its oversized petals.

The flower has a 1-meter diameter and weighs

as much as 10 kilograms.

It takes a week for it to fully extend its petals.

Rafflesia does not have any stems or leaves.

It is a parasitic plant that absorbs nutrients from vines.

When the flower blooms for three to seven days,

it must be pollinated during this short window of time.

Giving off a smell like rotten flesh,

rafflesia is called the "corpse flower."

It attracts flies with this scent.

The flies will pollinate the flower as it moves

from one rafflesia to another.

Without the help of flies, the world's largest

flower could not exist.

Plants cannot move once they take root in the soil.

However, they are able to spread their seeds for a

considerable distance.

This is made possible by their blooming flowers.

Flowering plants attract insects with their bright

colors and honey.

This honeybee will fly away with more than honey.

It will also transport pollen to other flowers.

Flowers have developed nectar guides to

help insects find the honey

Insects can detect ultraviolet rays that are

invisible to the human eye.

After using a filter that only passes ultraviolet rays,

hidden patterns appear on the flower.

The petals reflect ultraviolet rays,

making them brighter whereas the center of the flower

absorbs the rays, giving them a dark color.

Let's take a look at this lily.

A pattern of long lines lead to the flower's center.

Similar patterns are revealed in this flower as well.

The lines show the insects where the honey is located.

40% of a sample of 200 flowers shot under a

filter revealed these patterns.

And experts have found that honeybees will

stay within the black area.

The flower's strategy is tailored

to pollinating insects.

Flowers also use camouflage to attract insects like this

mountain hydrangea.

The larger florets are sterile but have a showy appearance.

They trick insects and butterflies into approaching.

In the center of the cluster lie the smaller fertile florets.

Without this camouflage tactic,

the mountain hydrangea would not be able to reproduce.

The harsh winter cold has arrived.

Though there are no signs of any flowers,

the plants are not dead.

They are in hibernation.

In early spring, the goldthread blooms after its

stem grows upwards.

It grows flower petals before its leaves.

This type of goldthread blooms once it matures in three years.

It does not reproduce in large numbers.

It possesses an outsized flower in relation to its small stem.

This is necessary to attract bees and butterflies.

As a monocarpic flower, the goldthread will die after it

is pollinated and produces seeds.

The flower bud is teeming with seeds.

In June or July, the seeds will be ready to scatter.

The goldthread relies on ants to spread its seeds.

The white substance on the surface of the goldthread

seed is called elaiosome.

Giving off a sweet scent to attract ants,

it is rich in lipids and proteins.

When an ant is carrying a goldthread seed,

it clambers around in a zigzag pattern.

Since the white substance cannot be separated from the

seed, the ants carry the whole seed to their nest.

After the ants eat the elaiosome,

they will discard the seed.

And the seed will grow in its new surroundings.

In tropical regions you can find the world's only tree

species that is viviparous.

It is the mangrove.

Mangrove seeds hang from the tree branches.

Living in coastal habitats which are harsh on plant life

due to the high salinity levels, mangroves

have evolved to ensure that their offspring survive.

When the tree produces a seed, it doesn't scatter it.

A mangrove seed will germinate while attached to the

parent tree for a long period.

They will hang from the branch until they

form a propagule (seedling).

When the seedlings fall to the ground,

they will stick out upright.

And they will take root instead of being

carried off by the river.

Living in coastal regions where freshwater and saltwater

meet, mangrove tress have developed ways to

increase their survival.

In tropical forests, some flowers depend more on birds

rather than insects to be pollinated.

Birds are also pollinators.

The hummingbird is very industrious.

They only inhabit America and have co-evolved

with flowering plants.

About the size of an adult's thumb finger, the hummingbird

can flap its wings as many as 80 times per second.

It hovers in mid-air to drink nectar.

It must hover because there is no place for it to perch on.

Due to their high metabolism, hummingbirds must constantly

drink nectar to survive.

Heliconia flowers feature bright colors and over 200

types exist in nature.

They are mainly pollinated by hummingbirds but specific

Heliconia species have specific hummingbirds to pollinate them.

This long curved bill is well-suited for reaching the

nectar inside the flower.

The hummingbird's bill is a perfect fit

with the heliconia flower.

Without hummingbirds, some heliconia species

cannot produce seeds.

When a hummingbird drinks the nectar,

pollen will attach to its beak to be spread to other flowers.

Heliconia and hummingbirds have evolved together

to be perfectly compatible.

Plants are intelligent in how they

adapt to their environment.

Like a living creature, this ivy climbs a tree.

Its aerial roots look like human hands.

But as the ivy climbs it searches for

sunlight and moisture.

It does not blindly climb up a tree in a straight line.

An ivy has a unique structure that makes it well

adapted for tree climbing.

The secret lies in its aerial roots.

The aerial roots are about 3 millimeters in length and each

one has several suction cups.

It uses these to affix itself to the tree bark.

It also secretes a sticky substance that has the

adhesive power of solid concrete.

Thus, the stem of an ivy can support 2 million times its

weight while attached to a wall.

Using this intelligent strategy,

an ivy can move where it wants and grow its stem according to

the height of a tree or wall.

A plant's rapid movement is as complex as the

reaction of living creature's nervous system.

Shaped like a clamshell, the leaves of a Flytrap have an

array of sensitive hairs.

Once an insect touches a hair, the the leaves will

close in less than a second.

Resistance is futile.

Once it catches a prey, the Flytrap will never let go no

matter how hard the insect tries to free itself.

The trap will seal itself and form a "stomach" where enzymes

are secreted by the plant.

It will take a week or two to digest the insect.

There is a way to override the flytrap's mechanism.

The leaves will close only when a second hair is contacted

within 30 seconds from which first contact was made.

When no prey is caught in its trap,

it will open its leaves a few hours later.

A trap that has been used three to four times to catch

and digest an insect will wither.

Even small frogs can be digested by the Flytrap.

It is a cruel way to kill prey but it is

vital for their survival.

These crafty and intelligent survival tactics have allowed

plants to spread throughout nature.

And nature reaps benefits from plant diversity.

At the Smithsonian Tropical Research Institute in Panama,

Dr. Edward Allen Herre conducts research on figs.

Fig trees are called the tree of life in these parts.

They bear fruit all year round,

providing nourishment to all kinds of animals.

Figs have entered a mutual relationship with wasps.

But only a specific species of wasp can

fertilize a specific fig.

Just a millimeter in length, the fig wasp will lay

eggs inside the fig fruit.

The wasp would crawl inside one of these things.

The scientific name is syconium

Enclosed in this structure, the fig fruit provides

adequate protection to the wasp eggs.

The eggs hatch inside the fruit and usually the male

wasps will hatch first.

The wingless male has a sperm pouch at the end of its body.

As soon as the male hatches, it will search for the eggs of

a female in order to mate.

The male can fertilize the female before it even hatches.

After finding an egg containing a female,

the male will penetrate it and mate with the female.

Once the female wasp hatches it has a dual mission.

First it must repay the fig tree for providing it with

food and shelter by pollinating it and at the same

time lay eggs to reproduce.

The winged female will scrape pollen together

and attach it to its body.

Now it is ready to leave the fig.

Like its ancestors, the wasp will carry out its duty as it

has done for millions of years.

The female will pollinate another fig tree.

This is the coevolutional relationship between

the fig wasp and figs.

It depends on the female to follow

through with pollination.

After the female lays its eggs,

it will die and the fig will consume its corpse.

These two species have evolved beautifully together for a

long period of time.

This is coevolution in the sense that for over

90 million years, 80 million years at least,

figs have used wasps to pollinate them and wasps have

used figs to reproduce.

And the characteristics of each one have become very

finely tuned to allow the other to exploit the system.

The fig fruit was made possible through cooperation

between the fig and wasp.

Through sacrifices and dedication,

trees have provided food to creatures,

supporting forests throughout the ages.

Many animals on earth depend on plant life to live.

Evolving and overcoming challenges posed by harsh

habitats, plants have supported most life on earth.

But if plants had not moved out of water onto the land,

we wouldn't have any terrestrial ecosystems today.

Plants are absolutely fundamental.

They are the energetic foundation on which all of our

terrestrial ecosystems are built.

Without plants, there would have been no insects.

Without plants, there would have been no land vertebrates.

Without land vertebrates, there would have been no us.

Do you still believe that smart humans are using plants?

Maybe it is the other way around where plants are using

humans to propagate their species through human farming.

Life on earth flourishes through such mutual relationships.

This is the eternal cycle of life.

Thus, animals and humans might be the supporting cast on a

platform supported by plants.

Hidden in plain sight, plants are the true

rulers of the planet.