0:01:05 > 0:01:09The planet on which we live is in a state of perpetual change.
0:01:10 > 0:01:15From cracks in its surface, molten rock is continually erupting.
0:01:33 > 0:01:37The forces that drive this lava to the surface also cause the continents
0:01:37 > 0:01:42to move round the globe, millimetre by millimetre, over thousands of years.
0:01:42 > 0:01:47When they collide, the buckling, contorted rocks are pushed up
0:01:47 > 0:01:50into great mountain ranges.
0:01:51 > 0:01:57But just as they rise, so are they cut down by the erosion of ice
0:01:57 > 0:01:59and snow and rushing water.
0:02:04 > 0:02:10At the poles, where the sun's rays strike the glob only obliquely, it's bitterly cold.
0:02:10 > 0:02:15Here glaciers grind their way across the land, gouge out deep valleys
0:02:15 > 0:02:17and flow down into the sea.
0:02:45 > 0:02:50At the equator, where the sun strikes the Earth four-square, the land is baked.
0:02:50 > 0:02:55Over centuries, the amount of rain falling on it has varied.
0:02:55 > 0:02:58As it diminishes, so the forests have dwindled and been
0:02:58 > 0:03:00replaced by grassland.
0:03:02 > 0:03:06And grassland, if it dries still further, turns to desert.
0:03:20 > 0:03:24Throughout all these changes, living creatures have evolved
0:03:24 > 0:03:28?with a speed that has matched that of the changing landscape.
0:03:34 > 0:03:39In the hot deserts, animals have evolved ways of living in oven-like temperatures
0:03:39 > 0:03:41without drinking any liquid whatsoever.
0:04:02 > 0:04:06In the cold deserts around the poles, other creatures, with the ability to
0:04:06 > 0:04:10generate their own internal heat, have grown insulating coats
0:04:10 > 0:04:14of fur and fat so that they are not frozen to death.
0:04:50 > 0:04:54Human beings, one of the last species of large animal to appear on the planet,
0:04:54 > 0:04:59have spread with extraordinary speed to all corners of the globe.
0:04:59 > 0:05:03They've be able to do so not so much because their bodies have changed to
0:05:03 > 0:05:07match different extremes but because they've used their skills
0:05:07 > 0:05:12and intelligence to exploit the adaptations of other living creatures.
0:05:12 > 0:05:16The Eskimos survive in the Arctic by keeping themselves warm
0:05:16 > 0:05:18with the skins of polar bears and seals.
0:05:21 > 0:05:25In the equatorial jungles of the Amazon, the Indians have learned where to find
0:05:25 > 0:05:30and how to collect everything they need to sustain themselves.
0:05:59 > 0:06:03Even though today they may cook in metal pots traded from the
0:06:03 > 0:06:07outside world, they still know how to make pottery from the clay.
0:06:13 > 0:06:17In the hot deserts of southern Africa, the Bushmen survive droughts
0:06:17 > 0:06:21by tapping the stores of liquid held in the bodies of animals
0:06:21 > 0:06:23and the roots and the stems of plants.
0:06:36 > 0:06:39Immediately after the rains, however, they can collect water
0:06:39 > 0:06:43from natural hollows, but even that takes knowledge and skill.
0:06:49 > 0:06:52Indeed, human beings, for nearly all the half-million year of their
0:06:52 > 0:06:57existence as a species, have lived simply by gathering wild plants
0:06:57 > 0:06:59and hunting wild animals.
0:06:59 > 0:07:02And 10,000 years ago, people were doing so here in the Middle East,
0:07:02 > 0:07:05just as they were everywhere else.
0:07:05 > 0:07:07In these forests, there's quite a lot to eat.
0:07:07 > 0:07:12There are pistachio nuts and wild almonds and acorns and juniper berries.
0:07:12 > 0:07:16And 10,000 years ago there were quite a lot of wild animals -
0:07:16 > 0:07:22wild goat, wild pig, wild horses, giant wild cattle and gazelle.
0:07:22 > 0:07:28Even so, there are hardships to be endured. There could be torrential rains.
0:07:28 > 0:07:31At night it can get crushingly cold and there could be snow.
0:07:31 > 0:07:34And during the day it gets bakingly hot.
0:07:34 > 0:07:40But about 9,000 years ago, man took a crucial step.
0:07:40 > 0:07:44Until then, the environment through evolution had shaped his body,
0:07:44 > 0:07:47as it had shaped the bodies of all animals.
0:07:47 > 0:07:51But now, uniquely, man turned that around.
0:07:51 > 0:07:55He began to change the environment to suit himself,
0:07:55 > 0:08:00and one of the places where he first did so is in that valley down there.
0:08:02 > 0:08:06This is Beidha in Jordan, and here were found the remains of one of
0:08:06 > 0:08:08mankind's earliest villages.
0:08:10 > 0:08:13This was no temporary encampment, but a permanent settlement
0:08:13 > 0:08:17with alleys and houses of stone built adjoining one another.
0:08:19 > 0:08:23They were half-dug into the ground, the floor and walls were covered with
0:08:23 > 0:08:25a plaster of mud and lime,
0:08:25 > 0:08:30and in the walls there were posts which supported a roof of thatch
0:08:30 > 0:08:34which probably just cleared the top of the wall so that light could get inside.
0:08:34 > 0:08:40So the people had created a snug home, protected from the rain and the sun,
0:08:40 > 0:08:45a place where mothers could bear their children in safety.
0:08:49 > 0:08:54There are lots of grinding stones, querns, here, in which the people
0:08:54 > 0:08:58ground the seeds of grass,
0:08:58 > 0:09:02a kind of wild barley that grows abundantly hereabouts.
0:09:02 > 0:09:05They'd long since discovered that you could take such grass seeds
0:09:05 > 0:09:08and scatter them on the ground and produce a crop.
0:09:08 > 0:09:11Indeed, they'd been doing just that with the seeds of another wild grass,
0:09:11 > 0:09:13wheat, for many centuries.
0:09:13 > 0:09:17And now they were settled, it was inconvenient to have to scour the
0:09:17 > 0:09:22countryside to look for places where the grass just happened to grow.
0:09:22 > 0:09:26Much better to throw it onto the ground nearby the village, where they
0:09:26 > 0:09:29could watch the growing crop, make sure that wild animals
0:09:29 > 0:09:32didn't plunder it, and where it was convenient to gather.
0:09:32 > 0:09:35So these people became farmers.
0:09:39 > 0:09:44The people were also meat-eaters, and in this one small chamber
0:09:44 > 0:09:50have been found great quantities of the bones of wild goat, like this.
0:09:50 > 0:09:53Domesticating animals must have been very much more difficult than
0:09:53 > 0:09:55domesticating plants.
0:09:55 > 0:09:58But in fact, the first steps towards doing so were probably taken
0:09:58 > 0:10:02many centuries earlier when the people were still nomads.
0:10:02 > 0:10:07A way in which that might have happened can be seen going on today
0:10:07 > 0:10:10amongst the Lapp peoples in Scandinavia.
0:10:14 > 0:10:17This is the most northerly living of all deer.
0:10:17 > 0:10:21It's found right round the Arctic wherever there is land.
0:10:21 > 0:10:25In America, it's called the caribou, in Europe, reindeer.
0:10:31 > 0:10:34In North America the caribou are completely wild,
0:10:34 > 0:10:39but here in northern Scandinavia they are, to some degree at least,
0:10:39 > 0:10:40domesticated.
0:10:40 > 0:10:46Man has managed to achieve that by becoming a nomad himself.
0:10:53 > 0:10:57The reindeer during the winter have to keep on the move in a continuous
0:10:57 > 0:11:01search for something to eat, and the Lapps, they want to keep an eye on
0:11:01 > 0:11:05their herd and maintain their possession to it, have to move with them.
0:11:09 > 0:11:13Traditionally, they do so on skis. Indeed, skis originated in this part
0:11:13 > 0:11:14of the world.
0:11:14 > 0:11:19But today the herdsmen are fully up to date with modern technology.
0:11:29 > 0:11:33The reindeer's winter food is a kind of lichen which they find
0:11:33 > 0:11:34growing beneath the snow.
0:11:37 > 0:11:41When the reindeer were completely wild, young stags as they mature
0:11:41 > 0:11:44would wander away from their parental group, taking a few
0:11:44 > 0:11:46young females with them.
0:11:46 > 0:11:50But the Lapps regarded the offspring of THEIR herd as their property.
0:11:50 > 0:11:55So to prevent them being lost, they castrated the young males.
0:11:55 > 0:11:58The few they left unmutilated in order to breed were those they
0:11:58 > 0:12:01thought most likely to remain unaggressive and disinclined
0:12:01 > 0:12:04to wander, even when adult.
0:12:05 > 0:12:09So, consciously or unconsciously, the Lapps over centuries have
0:12:09 > 0:12:13changed the reindeer from a nervous creature living in small family groups
0:12:13 > 0:12:18to one that is so docile it can be kept in herds thousands strong
0:12:18 > 0:12:22and can be moved from one snow slope to another simply by leading
0:12:22 > 0:12:24the way with a stag on a halter.
0:12:50 > 0:12:55It may well be that in some such way as this, the people who lived
0:12:55 > 0:12:599,000 years ago in the village of Beidha gradually turned the wild
0:12:59 > 0:13:04goats of the surrounding mountains into tamed domesticated ones.
0:13:06 > 0:13:09The techniques of domestication and maybe the domesticated
0:13:09 > 0:13:14animals themselves, slowly spread westwards across Europe.
0:13:15 > 0:13:207,000 years ago, the people living in France had their own herds.
0:13:20 > 0:13:23And around 6,000 years ago, the techniques and even perhaps
0:13:23 > 0:13:28the herdsmen with some of their stock crossed the channel into Britain.
0:13:50 > 0:13:54They must have landed somewhere in southern England,
0:13:54 > 0:13:57but the land they found didn't look like this.
0:13:57 > 0:14:00Like nearly all the rest of Britain, it was covered in trees.
0:14:00 > 0:14:05There were people already here living in the forests, gathering fruit and nuts
0:14:05 > 0:14:09and hunting the wild animals, deer and wild oxen.
0:14:09 > 0:14:12But they hadn't changed the woodlands of Britain
0:14:12 > 0:14:17any more than the Amazonian Indians have changed the jungle.
0:14:17 > 0:14:22But these new arrivals did. They began to clear the forests
0:14:22 > 0:14:25to make way for their farms.
0:14:25 > 0:14:31So this landscape of the South Downs is not natural. It's their creation.
0:14:34 > 0:14:38The people cut down the forests with stone axes.
0:14:38 > 0:14:41And then the teeth of their flocks kept the land open.
0:14:41 > 0:14:45Grazing sheep still prevent the seedlings of trees from growing
0:14:45 > 0:14:49and keep the pastures clear for cowslips and clover, orchids and
0:14:49 > 0:14:52buttercups, pipits and skylarks.
0:14:52 > 0:14:57This was the beginning of a process that was to transform Britain.
0:14:57 > 0:15:01Much of our apparently wild landscape is in fact man-made.
0:15:03 > 0:15:07The Norfolk Broads, that wilderness of shallow lakes, reed beds and
0:15:07 > 0:15:14winding waterways, are not natural basins but vast pits, dug by men
0:15:14 > 0:15:18collecting peat some 600 years ago, that have subsequently flooded.
0:15:29 > 0:15:32Many of the upland moors of northern England and southern Scotland
0:15:32 > 0:15:35were cleared of their forests thousands of years ago,
0:15:35 > 0:15:39but during the 19th century, men encouraged heather to grow there
0:15:39 > 0:15:42by setting light to the moors by regular intervals,
0:15:42 > 0:15:45for heather is the food of grouse,
0:15:45 > 0:15:48and men want flocks of grouse for their guns.
0:15:50 > 0:15:54Indeed, almost the only part of Britain that remains free of human influence
0:15:54 > 0:16:00is the land over 2,500 feet high that is of little practical use to people.
0:16:00 > 0:16:05It was scraped clean of soil by glaciers during the Ice Age 10,000 years ago
0:16:05 > 0:16:07and still remains stony and barren.
0:16:10 > 0:16:14As we transformed the landscape, of Britain, so we also rapidly
0:16:14 > 0:16:17altered the community of animals that lived here.
0:16:17 > 0:16:20Those that didn't suit us, we got rid of.
0:16:21 > 0:16:25Brown bears were once common, but they were regarded as dangerous
0:16:25 > 0:16:29and they could give good sport if they were baited with dogs
0:16:29 > 0:16:32The last British bear was killed in the 10th century.
0:16:34 > 0:16:38Wolves preyed on domesticated flocks and herds and even
0:16:38 > 0:16:40threatened people.
0:16:40 > 0:16:43The last English wolf had been killed by the year 1500
0:16:43 > 0:16:46and the last Scottish one by the middle of the 18th century.
0:16:53 > 0:16:56Beavers were hunted not so much because of the damage they did
0:16:56 > 0:16:59to the woodlands, but because their fur was so highly valued.
0:16:59 > 0:17:02They had all gone by the 13th century.
0:17:08 > 0:17:11Wild boar were once common in British woods,
0:17:11 > 0:17:15grubbing up roots and bulbs, munching acorns and beech nuts.
0:17:16 > 0:17:19But boars could be aggressive and dangerous, and the sows
0:17:19 > 0:17:22and particularly the piglets made good eating.
0:17:22 > 0:17:25By the 17th century, there were none of these left either.
0:17:29 > 0:17:33The elk, known in America as the moose, once lived here too,
0:17:33 > 0:17:37but it had been hunted into extinction even before the Romans arrived.
0:17:40 > 0:17:43Men also introduced animals to Britain.
0:17:43 > 0:17:45The Normans brought fallow deer from Europe.
0:17:47 > 0:17:48And rabbits.
0:17:48 > 0:17:51At first these creatures were carefully guarded in enclosures,
0:17:51 > 0:17:54for they were valued for their fur and meat.
0:17:54 > 0:17:58They only became really common in the countryside during the 19th century.
0:18:03 > 0:18:07Pheasants are Asian birds, and were brought here soon after
0:18:07 > 0:18:09the Norman Conquest.
0:18:09 > 0:18:14Other introductions, however, were unintentional and much less welcome.
0:18:15 > 0:18:18The house mouse from the Mediterranean may well have been
0:18:18 > 0:18:20the first animal of all to be brought to Britain by man,
0:18:20 > 0:18:25for the Romans found it living in British villages.
0:18:25 > 0:18:28And other, much bigger animals were living around the settlements
0:18:28 > 0:18:30of those early British tribes.
0:18:30 > 0:18:34Aurochs, the giant cattle whose images were painted on the walls of
0:18:34 > 0:18:39French caves during prehistory, also roamed in British forests.
0:18:39 > 0:18:42By Roman times, some had already been domesticated,
0:18:42 > 0:18:45and one of the early strains derived from them still survives
0:18:45 > 0:18:47in the Cheviot Hills.
0:19:02 > 0:19:07This herd at Chillingham was penned in a great park during the 13th century,
0:19:07 > 0:19:10and has lived here ever since, with scarcely any interference
0:19:10 > 0:19:12from human beings.
0:19:12 > 0:19:15The animals may well be very similar to those that wandered
0:19:15 > 0:19:18around the farms during Roman times.
0:19:18 > 0:19:20They're formidable animals, very different from the gentle
0:19:20 > 0:19:22Friesian of today.
0:19:35 > 0:19:39One great bull rules the herd. He mates with all the cows
0:19:39 > 0:19:42and fights every young male who challenges him.
0:19:49 > 0:19:51Eventually, after two or three years,
0:19:51 > 0:19:56he will lose and surrender his place to a younger, more vigorous animal.
0:20:14 > 0:20:17Having changed a wild animal into a relatively docile one by
0:20:17 > 0:20:21selective breeding, farmers now used the same techniques to modify
0:20:21 > 0:20:23the animal's body.
0:20:23 > 0:20:26They wanted meat, and soon they produced a very different-looking
0:20:26 > 0:20:28kind of beast.
0:20:28 > 0:20:32These portraits, commissioned by proud breeders 100 years ago,
0:20:32 > 0:20:35show clearly that the characteristics they valued in their cattle
0:20:35 > 0:20:38then are the same as those we prize today.
0:20:39 > 0:20:43Today's bulls have such stunted legs that they can't run fast
0:20:43 > 0:20:44to chase away a rival.
0:20:44 > 0:20:48Many don't even have horns with which to fight a courtship battle.
0:20:48 > 0:20:52But these won't be permitted to mate with a cow anyway.
0:20:52 > 0:20:55Their semen will be taken from them and injected into cows by syringe,
0:20:55 > 0:20:58so that each of them, without moving from his stall,
0:20:58 > 0:21:02may father thousands of offspring on the other side of the world.
0:21:04 > 0:21:09Under intensive feeding, such cattle can put on two pounds a day
0:21:09 > 0:21:13and grow so fast that they can be profitably slaughtered within a year.
0:21:14 > 0:21:18The new breeds of pig, direct descendants of the wild boars of the
0:21:18 > 0:21:23European forests, now grow five times faster than their wild cousins
0:21:23 > 0:21:26and are ready for slaughter within only six months.
0:21:39 > 0:21:43Turkeys are descended from wild birds that lived in Central America.
0:21:43 > 0:21:47They are produced entirely by artificial insemination and have
0:21:47 > 0:21:50been turned into creatures that will live not in small family groups
0:21:50 > 0:21:52but immense congregations.
0:21:57 > 0:22:01Chickens, originally birds of the Asian jungles, have been converted
0:22:01 > 0:22:05into egg-producing machines that can lay over 300 eggs a year.
0:22:08 > 0:22:12The same techniques of selective breeding produced our food plants,
0:22:12 > 0:22:15using species from all over the world.
0:22:15 > 0:22:19The potato came from the Andes, where it was grown by the Incas.
0:22:19 > 0:22:23The pea is a European plant first cultivated by the Italians
0:22:23 > 0:22:25in the 16th century.
0:22:25 > 0:22:31Beans came from Mexico, rhubarb from China, beetroot from Germany.
0:22:31 > 0:22:36And this plant was first cultivated in the 7th century in Afghanistan,
0:22:36 > 0:22:40taken from there to North Africa, then brought by the Moors into Europe,
0:22:40 > 0:22:47where it was cultivated by the Dutch to produce...this, a carrot.
0:22:47 > 0:22:51But wild plants from the family that is perhaps the most important
0:22:51 > 0:22:54to man for food don't grow in this allotment because they would be
0:22:54 > 0:22:57regarded as weeds - the grasses.
0:23:03 > 0:23:07The grass we call rice was domesticated in Asia some
0:23:07 > 0:23:107,000 years ago, at about the same time that people were learning
0:23:10 > 0:23:14to cultivate wheat in the lands around the Mediterranean.
0:23:16 > 0:23:20Over the centuries, the people of Asia have perfected the techniques
0:23:20 > 0:23:23of growing one kind of rice in flooded terraces.
0:23:23 > 0:23:28And they do so with such skill that the rice will flower and ripen
0:23:28 > 0:23:31and produce heads of swollen seeds several times a year.
0:23:33 > 0:23:38As mankind's population grew, so more and more of the land
0:23:38 > 0:23:40had to be taken into cultivation.
0:23:51 > 0:23:56Today, 11% of all the arable land on earth is devoted to growing
0:23:56 > 0:23:59just this one species of grass.
0:23:59 > 0:24:03Now more than 2,000 million people depend on it,
0:24:03 > 0:24:05half the population of the world.
0:24:16 > 0:24:20In the western world, people still prefer the kind of grass they first learned
0:24:20 > 0:24:24to eat during prehistory, but that too they have transformed.
0:24:26 > 0:24:31Today's wheat grows tall, uniform and dense, so it can be easily
0:24:31 > 0:24:33harvested by machines.
0:24:41 > 0:24:45Selective breeding techniques have greatly increased its yield.
0:24:45 > 0:24:49Even since the 1940s, its productivity has been doubled.
0:24:49 > 0:24:54Today it bears ten times the weight of seeds on each stem than does its
0:24:54 > 0:24:57wild ancestor that still grows in the parched lands of the Middle East.
0:25:03 > 0:25:08But this change has a price. Wheat like this can't even reproduce
0:25:08 > 0:25:11itself now without man's aid.
0:25:11 > 0:25:16It's true that it is largely immune to pests like moulds and rusts,
0:25:16 > 0:25:19but moulds and rusts also evolve very quickly,
0:25:19 > 0:25:24naturally, into forms which can attack the new strains.
0:25:24 > 0:25:28So farmers have to change the strain that they grow on average
0:25:28 > 0:25:31about every ten years.
0:25:31 > 0:25:37Today, in North America, over half the wheat comes from just four strains.
0:25:37 > 0:25:43Were plant breeders to fail to produce new varieties from wild species,
0:25:43 > 0:25:46then fields like this could be devastated and the western world
0:25:46 > 0:25:48would starve.
0:25:49 > 0:25:53To grow the vast quantity of grain needed by mankind's ever
0:25:53 > 0:25:57increasing population, huge areas of the most fertile lands on Earth
0:25:57 > 0:26:00have been turned over to its cultivation.
0:26:00 > 0:26:03Gone are the rich communities of grasses and other small plants,
0:26:03 > 0:26:06that once lived here together with hundreds different kinds
0:26:06 > 0:26:08of insects and small creatures.
0:26:08 > 0:26:13Now over thousands of square miles, all other plants and all other large animals,
0:26:13 > 0:26:17except human beings, are rigorously excluded.
0:26:17 > 0:26:19Intruders are poisoned or shot.
0:26:19 > 0:26:24So mankind has introduced to the earth a completely new type
0:26:24 > 0:26:27of environment, a monoculture, one which contains,
0:26:27 > 0:26:31to all intents and purposes, just one species.
0:26:35 > 0:26:39And this is another of mankind's virtual monocultures.
0:26:39 > 0:26:43The species that proliferates here and congregates of its own accord
0:26:43 > 0:26:48into dense swarms numbering millions is Homo sapiens himself.
0:26:48 > 0:26:54The tallest building he's constructed so far is in Chicago, the Sears Tower.
0:26:54 > 0:26:58It stands 1,454 feet high.
0:26:58 > 0:27:0312,000 people daily come to work in it, and they live in an
0:27:03 > 0:27:07artificial microclimate in which the temperature and humidity
0:27:07 > 0:27:09are controlled by computers.
0:27:09 > 0:27:14The whole structure is built of artificial man-made materials,
0:27:14 > 0:27:18a framework of steel, with black-skinned aluminium
0:27:18 > 0:27:24and bronze-faced glare-reducing glass forming a shell around it.
0:27:25 > 0:27:29In such an environment as this, you might suppose that animals
0:27:29 > 0:27:32and plants could have no place.
0:27:35 > 0:27:37But not so.
0:27:38 > 0:27:42Many human beings, it seems, don't wish to live totally out of
0:27:42 > 0:27:45contact with other living species.
0:27:48 > 0:27:52Once again, people have moulded their animals to match their particular
0:27:52 > 0:27:58whim and fancy, altering their size, their proportions, their fur.
0:27:58 > 0:28:01Even their smells.
0:28:09 > 0:28:13Dogs first associated with man when he was a nomadic hunter,
0:28:13 > 0:28:17accepting him as a leader in a chase, helping him to track and pull down
0:28:17 > 0:28:21his quarry, and taking a share in the spoils, but now
0:28:21 > 0:28:26that man no longer hunts, his dogs must play a very different role.
0:28:40 > 0:28:43Cats are not, in the wild, social animals like dog
0:28:43 > 0:28:47but solitary hunters with strong territorial instincts.
0:28:50 > 0:28:54They probably decided of their own accord to move into peoples houses
0:28:54 > 0:28:57and hunt rats and mice, and people accepted them because they
0:28:57 > 0:29:02performed this useful service, and because they're so endearing,
0:29:02 > 0:29:05but to this day they have remained independent operators,
0:29:05 > 0:29:09aloof and haughty, even when people have bred them to exaggerate
0:29:09 > 0:29:12the most cuddlesome of their characteristics.
0:29:16 > 0:29:19PA: 'Five tremendous cats, the best of their own varieties.
0:29:20 > 0:29:22'Our congratulations to the winners.'
0:29:22 > 0:29:27A few other living organisms have discovered that the city suits them.
0:29:27 > 0:29:32The well-drained sterility of a lava flow is not unlike that of a city street,
0:29:32 > 0:29:37and back in the 18th century a botanist found a yellow ragwort growing
0:29:37 > 0:29:39on the slopes of Mount Etna.
0:29:40 > 0:29:43He took it back to Oxford, where it was cultivated in the
0:29:43 > 0:29:45botanic gardens.
0:29:48 > 0:29:5160 years later, the ragwort was noticed growing on the stones
0:29:51 > 0:29:55of college walls, but for quite a time it spread no further.
0:29:57 > 0:30:03Then, in the 19th century, railways were built across Britain.
0:30:03 > 0:30:06The stone rubble on which the tracks were laid was exactly what
0:30:06 > 0:30:08the ragwort liked.
0:30:08 > 0:30:11And it spread along the railways to appear in all the cities along
0:30:11 > 0:30:15the main lines, where it still flourishes today.
0:30:21 > 0:30:24A few wild animals have also found what they need in the apparently
0:30:24 > 0:30:27hostile wildernesses that man has created.
0:30:27 > 0:30:31The sea otter swims happily in the waters of California's harbours.
0:30:33 > 0:30:36Prairie dogs, driven off the prairies by ranchers, and farmers,
0:30:36 > 0:30:39find new homes in urban playgrounds.
0:30:41 > 0:30:45English foxes have discovered a rich source of food in city litter bins
0:30:45 > 0:30:47and doze on suburban roofs.
0:30:51 > 0:30:55And in the south-west of the United States, acorn woodpeckers
0:30:55 > 0:30:59continue to store their acorns in the trunks of fir trees, even when
0:30:59 > 0:31:01they've been turned into telegraph poles.
0:31:11 > 0:31:15Ospreys habitually build their nests in the very tops of trees,
0:31:15 > 0:31:19and telegraph poles also give them the kind of isolation they need.
0:31:22 > 0:31:27Church towers, to kestrels, are just as good nesting sites as rocky crags.
0:31:35 > 0:31:40While kittiwakes apparently regard modern buildings as little more than
0:31:40 > 0:31:42particularly regular sea cliff.
0:31:49 > 0:31:53Swallows learned to tolerate man for the sake of the nest sites
0:31:53 > 0:31:57beneath his eaves, and now few nest anywhere else.
0:31:57 > 0:32:01But not all people's urban companions are so welcome.
0:32:03 > 0:32:06There are still plenty of creatures, mammals and insects,
0:32:06 > 0:32:09that manage to claim a share of mankind's food.
0:32:18 > 0:32:23Many insects eat cellulose, and find it in abundance in wood
0:32:23 > 0:32:25and in the paper with which people surround themselves.
0:32:34 > 0:32:38Grubs chew the sheep hair with which clothes are made.
0:32:39 > 0:32:43And this whole community of insects is in turn preyed upon
0:32:43 > 0:32:46by other unwelcome creatures: Spiders.
0:32:50 > 0:32:53So we wage war on the animals that have come to live with us.
0:33:04 > 0:33:08Brown rats originated somewhere in Asia and spread
0:33:08 > 0:33:10to Europe some 300 years ago.
0:33:10 > 0:33:14Today, rats are found in every large city in the world.
0:33:14 > 0:33:18They will eat almost anything, tackling meat with as much relish
0:33:18 > 0:33:20as grain and vegetables.
0:33:25 > 0:33:29They gnaw electric cables, causing short circuits, and even,
0:33:29 > 0:33:32in consequence, fires.
0:33:36 > 0:33:40They not only consume huge quantities of mankind food, but contaminate
0:33:40 > 0:33:44much of what they leave, and they spread disease.
0:33:45 > 0:33:50So if we're not to be overrun, we have to pursue them wherever they go.
0:33:50 > 0:33:53We created the city, and if it's to function properly
0:33:53 > 0:33:57and be neither oppressively sterile on the one hand nor infested with pests,
0:33:57 > 0:34:01on the other, we have to manage the living organisms that live in it,
0:34:01 > 0:34:05encouraging some, exterminating others.
0:34:05 > 0:34:09But our influence now spreads far wider than we often choose to recognise.
0:34:09 > 0:34:13Now we're changing the whole of the globe, and we must equally
0:34:13 > 0:34:16accept our responsibilities of managing that,
0:34:16 > 0:34:19but so far we are making a very poor job of it.
0:34:24 > 0:34:28We have to rid our cities of the vast quantity of rubbish we create.
0:34:31 > 0:34:36New York City produces 22,000 tonnes of refuse every single day.
0:34:37 > 0:34:40Half of that is taken by barge down the Hudson River
0:34:40 > 0:34:43and dumped on Staten Island.
0:34:57 > 0:35:03The rubbish is laid down in a layer several feet thick and 200 feet wide.
0:35:03 > 0:35:07Every day it advances 100 feet. When the land is covered,
0:35:07 > 0:35:10then another layer is dumped on top.
0:35:18 > 0:35:22But this is a very expensive way of getting rid of our rubbish.
0:35:22 > 0:35:26If there are cheaper ways of doing so, we unhesitating will take them,
0:35:26 > 0:35:30telling ourselves if it's out of sight, it doesn't matter what happens to it,
0:35:30 > 0:35:33assuming that somehow the world is so large
0:35:33 > 0:35:37that our poisons will simply be lost in its immensities.
0:35:39 > 0:35:43So we pour our waste chemicals and detergents into our rivers.
0:35:43 > 0:35:47Suds may or may not have been valuable in a kitchen sink.
0:35:47 > 0:35:51In a river they can be lethal, killing the plants and the fish.
0:35:57 > 0:36:01We spill oil into the sea, in spite of all the precautions,
0:36:01 > 0:36:05and set the waves aflame, and now there are patches of oil
0:36:05 > 0:36:08polluting even the remotest parts of the widest oceans.
0:36:20 > 0:36:23And we poison the very air we breathe.
0:36:25 > 0:36:29Fumes belched from our engines fill the atmosphere of the city.
0:36:39 > 0:36:44Steam rising from the cooling towers of power stations is relatively harmless,
0:36:44 > 0:36:49but the gases produced by burning coal and oil are certainly not.
0:36:49 > 0:36:52Our solution to this problem has been quite simple -
0:36:52 > 0:36:55to build chimneys even taller, so that the gases are blown
0:36:55 > 0:36:59farther away from our cities, but they don't disappear.
0:37:00 > 0:37:05They're carried by the prevailing winds to countries hundreds of miles away.
0:37:05 > 0:37:08The lakes of Scandinavia have, over the past few decades,
0:37:08 > 0:37:10become more and more acid
0:37:10 > 0:37:14until now fish and plants can no longer survive in many of them.
0:37:14 > 0:37:19In Norway alone, there are now 1,800 lakes without fish,
0:37:19 > 0:37:21and hundreds more that are dying,
0:37:21 > 0:37:25shameful monuments to our carelessness and lack of concern.
0:37:30 > 0:37:34In Germany, 10% of the forests are seriously damaged,
0:37:34 > 0:37:37almost certainly as a consequence of industrial pollution of the atmosphere
0:37:37 > 0:37:41and the collection of the poisons from it by rain.
0:37:44 > 0:37:48But we don't only despoil the natural world by accident.
0:37:48 > 0:37:50We do so quite deliberately.
0:37:51 > 0:37:55These islands, just off the coast of Peru, may seem, on the face of it,
0:37:55 > 0:38:01to be the very picture of fertility and ecological success
0:38:01 > 0:38:03They're the home of a great variety of seabirds -
0:38:03 > 0:38:09cormorants and pelicans, boobies, terns and gulls.
0:38:20 > 0:38:24But 30 years ago, another bird was also living here.
0:38:24 > 0:38:28These, a kind of cormorant called the guanay.
0:38:28 > 0:38:31When these pictures were taken in the 1950s,
0:38:31 > 0:38:36five and a half million of them were nesting on just one of these islands.
0:38:36 > 0:38:39The guanay lives exclusively on anchovies and, oddly,
0:38:39 > 0:38:45excretes an unusually high proportion of the fish it eats as droppings or guano.
0:38:45 > 0:38:48No rain ever falls here, so the guano wasn't washed away
0:38:48 > 0:38:50but accumulated on the rocks.
0:38:50 > 0:38:54A 100 years ago the world realised that this was a fertiliser
0:38:54 > 0:38:56of unparalleled richness
0:38:56 > 0:39:00It was collected and sold for such high prices that the guanay
0:39:00 > 0:39:05cormorant became known as the most valuable bird in the world.
0:39:06 > 0:39:11But then, in the 1950s, chemical fertilisers were developed in Europe,
0:39:11 > 0:39:15the price of guano began to drop and the people here started to harvest
0:39:15 > 0:39:20not the guanay's cormorant droppings, but its food, anchovies.
0:39:21 > 0:39:26In one year, 14 million tonnes of anchovies were taken out of these waters.
0:39:26 > 0:39:31They were sold not to feed people but cattle, and chickens and pets.
0:39:31 > 0:39:35The fishing was so intense that the anchovies were almost wiped out.
0:39:35 > 0:39:40That in turn brought about the collapse of the guanay cormorants' population.
0:39:40 > 0:39:45And now for every 50 cormorants that used to live here,
0:39:45 > 0:39:47you're lucky if you find one.
0:39:47 > 0:39:52And these walls that would be filled with guano to the top inside two years,
0:39:52 > 0:39:58now seldom accumulate more than an inch or so.
0:39:58 > 0:40:04But the cormorants shed their guano not only on the land but in the sea.
0:40:04 > 0:40:09Indeed, for every drop they put on land, they shed 20 into the sea.
0:40:09 > 0:40:13And there it fertilises water just as it fertilises the land,
0:40:13 > 0:40:18promoting the growth of floating plants, plankton, the food of the anchovy.
0:40:18 > 0:40:22So it's not only that if you get less anchovies you get less cormorants,
0:40:22 > 0:40:26and if you get less cormorants, you get less anchovies.
0:40:26 > 0:40:30Anchovies are food not just for cormorants but for sea fish
0:40:30 > 0:40:32like tuna and sea bass.
0:40:32 > 0:40:38So, with that one rash act of overfishing 30 years ago,
0:40:38 > 0:40:40Peru has lost anchovies,
0:40:40 > 0:40:47cormorants, guano and sea fish.
0:40:47 > 0:40:49It's a major blow to the nation's economy.
0:40:50 > 0:40:54Nor does it seem that we are learning from our mistakes.
0:40:54 > 0:40:57We're in the process of making similar catastrophic misjudgements,
0:40:57 > 0:41:02and on an even greater scale, in the world's tropical rainforests.
0:41:02 > 0:41:06This, the richest of all living communities, has been
0:41:06 > 0:41:08of enormous value to us.
0:41:08 > 0:41:12It's provided industry with rubber, craftsmen with hardwoods,
0:41:12 > 0:41:16and our larders with bananas, nuts, chewing gum and chocolate.
0:41:16 > 0:41:21Nearly a quarter of our drugs are based on animals and plants that live here.
0:41:21 > 0:41:25And still we have only investigated in detail the biochemistry of less
0:41:25 > 0:41:28than 1% of the rainforests' plants.
0:41:28 > 0:41:32And here, too, live some of the most beautiful and bizarre creatures
0:41:32 > 0:41:35to be found anywhere on the planet.
0:42:10 > 0:42:13These animals are the product of millions of years of evolution
0:42:13 > 0:42:15here, in these forests.
0:42:15 > 0:42:19They can't live anywhere else. The numbers of each different species
0:42:19 > 0:42:24within a given area remains remarkably stable, but over the past
0:42:24 > 0:42:28few centuries one species of animal outside the forest has suddenly
0:42:28 > 0:42:32started to increase in numbers in a way that is without parallel.
0:42:41 > 0:42:44In South-East Asia, as in South America and Africa,
0:42:44 > 0:42:46thousands of extra people every year
0:42:46 > 0:42:50are seeking land on which to grow food for themselves and their children.
0:42:50 > 0:42:54They take it from the forest. The labour is huge.
0:42:54 > 0:42:58After the trees have been felled and burnt, the people sow their crops,
0:42:58 > 0:43:00in this case, hill ruts.
0:43:02 > 0:43:07After a month, it's as tall as this, and in only five months it will be
0:43:07 > 0:43:08ready to be harvested,
0:43:08 > 0:43:14and it will have been sustained by this, the ash from the burnt forest.
0:43:14 > 0:43:19But there are only enough nutrient in this to sustain one crop.
0:43:19 > 0:43:25So next year the people plant not rice but this, cassava or tapioca,
0:43:25 > 0:43:26as it's called here.
0:43:26 > 0:43:30This is a different kind of crop, a root crop, which gets its nutrients
0:43:30 > 0:43:35from deeper in the soil, but even this can only produce for one year.
0:43:35 > 0:43:41After that, the seeds from the wild forest will come in and new plants will grow,
0:43:41 > 0:43:44producing a landscape like that.
0:43:44 > 0:43:50But they will have to grow for eight to ten years before they are big enough
0:43:50 > 0:43:56to be felled and produce enough ash and nutrients to refertilise the soil
0:43:56 > 0:43:58and allow the people to take a second crop.
0:43:59 > 0:44:03And the true forest, with all its original richness of animals and plants,
0:44:03 > 0:44:06will never be restored.
0:44:10 > 0:44:13It's not only the local people who cut down the forest.
0:44:13 > 0:44:17So, indirectly, do the people of the developed world.
0:44:35 > 0:44:37The huge trees are in perpetual demand
0:44:37 > 0:44:41to provide timber for furniture, for constructing buildings and crates
0:44:41 > 0:44:47and above all for the paper for which the world has an unquenchable appetite.
0:44:47 > 0:44:51So a tree that took 200 years to grow is now cut down by a
0:44:51 > 0:44:53chain saw in five minutes.
0:45:00 > 0:45:04The gigantic trunks, which once could only be shifted by elephants
0:45:04 > 0:45:08and only be extracted from forests growing on relatively flat country,
0:45:08 > 0:45:12are now handled with terrifying ease by modern machinery.
0:45:23 > 0:45:27Sometimes only the biggest trees are taken, leaving smaller ones standing,
0:45:27 > 0:45:32but the damage is such that the forest is largely beyond recovery.
0:45:32 > 0:45:36As the international price of timber increases, so more and more of the
0:45:36 > 0:45:38tropical forest is destroyed.
0:45:38 > 0:45:43In South-East Asia, it's been reduced to about a third of its original size,
0:45:43 > 0:45:46and, in the world at large, an area the size of Switzerland
0:45:46 > 0:45:49is being destroyed every year.
0:45:53 > 0:45:56But this may be a ray of hope.
0:45:56 > 0:46:00This is the fastest-growing tree in the world. It's called Albizia
0:46:00 > 0:46:05and comes from eastern Indonesia, and can be planted immediately
0:46:05 > 0:46:07after the felling of the jungle.
0:46:07 > 0:46:13In just one year it can grow to 10 or 11 metres tall, 35 feet.
0:46:13 > 0:46:17This one is some two years old and in only another six years
0:46:17 > 0:46:19it will be ready for logging.
0:46:21 > 0:46:25Albizia will grow well on the relatively poor land that once supported
0:46:25 > 0:46:29rainforest, and many sawmills actually prefer small, easily handled
0:46:29 > 0:46:31logs of uniform size.
0:46:33 > 0:46:37So if it were possible to produce this kind of timber on a really
0:46:37 > 0:46:42large scale, it might no longer be necessary to continue
0:46:42 > 0:46:47the extremely expensive and appallingly destructive business
0:46:47 > 0:46:50of felling the wild trees.
0:46:50 > 0:46:54And were that to happen, then, in some parts of the world,
0:46:54 > 0:46:57away from the coasts, away from the rivers, in remote and
0:46:57 > 0:47:02mountainous country, the tropical rainforest might still survive.
0:47:11 > 0:47:14The great rivers of the world can also yield riches to mankind,
0:47:14 > 0:47:17not simply food but power.
0:47:35 > 0:47:39We've known for almost a century how to turn the force of
0:47:39 > 0:47:42tumbling water into electric power.
0:47:42 > 0:47:45We've made mistakes in doing so. The dams we've built have filled up
0:47:45 > 0:47:49with silt and become useless within decades, and fields downriver,
0:47:49 > 0:47:53robbed of their annual supply of fertilising mud, have turned to desert.
0:47:56 > 0:48:01But we're getting better at it, and we're doing it on a greater scale.
0:48:01 > 0:48:05This dam, at Itaipu between Paraguay and Brazil,
0:48:05 > 0:48:09will harness the power of one of South America's greatest rivers, the Parana.
0:48:16 > 0:48:20I am walking across what was once the bed of that river.
0:48:20 > 0:48:25And above me rises the biggest dam ever built by man.
0:48:25 > 0:48:30It contains enough concrete to construct a whole city to house
0:48:30 > 0:48:32four million people.
0:48:32 > 0:48:38It will make a lake which will stretch upstream for 140 kilometres.
0:48:38 > 0:48:44And the power it will produce will be enough to supply the whole of Paraguay
0:48:44 > 0:48:49and the great cities of southern Brazil, Sao Paolo and Rio de Janeiro.
0:48:49 > 0:48:56And the astonishing thing is that it will have taken only seven years to build.
0:48:58 > 0:49:02There will, of course, be a heavy price to pay.
0:49:02 > 0:49:0844,000 people will have to be moved and their villages and fields submerged,
0:49:08 > 0:49:11fields that produce 200,000 tonnes of food a year,
0:49:11 > 0:49:15and that will create further demands on the rainforest.
0:49:21 > 0:49:24Even so, this major reshaping of the surface of the earth
0:49:24 > 0:49:28is likely to be one of the less damaging of those that mankind
0:49:28 > 0:49:30has inflicted on the planet.
0:49:30 > 0:49:33A million trees of 50 different forest species will be planted
0:49:33 > 0:49:37around the lake to prevent silt from washing down into it.
0:49:37 > 0:49:42The water will slowly clear and develop a population of fish.
0:49:42 > 0:49:45And the turbines in the dam, will produce power without poisoning
0:49:45 > 0:49:49the atmosphere or leaving behind radioactive waste.
0:49:49 > 0:49:54They will not deplete the Earth's irreplaceable reserves of fossil fuel,
0:49:54 > 0:49:57and the dam will continue to produce electricity, it's estimated,
0:49:57 > 0:50:00for the next 300 years.
0:50:05 > 0:50:08The scale of this immense construction is awe-inspiring
0:50:08 > 0:50:11evidence of the power that we now have in our hands
0:50:11 > 0:50:14with which to transform the face of the Earth.
0:50:19 > 0:50:22When, in prehistoric times, these stones were first put up
0:50:22 > 0:50:26to build this temple in the west of England at Avebury, they too
0:50:26 > 0:50:30must have been an astonishment to the local people, an amazing
0:50:30 > 0:50:35demonstration of how clever, how powerful, human beings had become.
0:50:35 > 0:50:40And yet that was less than 5,000 years ago, a mere moment
0:50:40 > 0:50:42in the history of life.
0:50:42 > 0:50:46And in the brief period since then, men have gone on to learn how to
0:50:46 > 0:50:52build dams like Itaipu, how to mould animals and plants to suit
0:50:52 > 0:50:57their needs or their fancies, how to transform whole landscapes.
0:50:57 > 0:51:00Immensely powerful though we are today,
0:51:00 > 0:51:05it's equally clear that we're going to be even more powerful tomorrow.
0:51:05 > 0:51:09And what's more, there will be greater compulsion to use our power
0:51:09 > 0:51:13as the number of human beings on Earth increases still further.
0:51:13 > 0:51:17Clearly, we could devastate the world.
0:51:17 > 0:51:20If we're not to do so, we must have a plan.
0:51:20 > 0:51:24And just such a plan has been formulated by environmental scientists.
0:51:24 > 0:51:27They called it the World Conservation Strategy
0:51:27 > 0:51:30and it rests on three very simple propositions.
0:51:30 > 0:51:36One - that we shouldn't so exploit natural resources that we destroy them.
0:51:36 > 0:51:40Common sense, you might think. And yet, look what we've done to the
0:51:40 > 0:51:42European herring, the South American anchovy,
0:51:42 > 0:51:45and are still doing to the whales.
0:51:45 > 0:51:50Two - that we shouldn't interfere with the basic processes of the Earth
0:51:50 > 0:51:54on which all life depends, in the sky, on the green surface
0:51:54 > 0:51:56of the Earth and in the sea.
0:51:56 > 0:52:00And yet we go on pouring poisons into the sky, cutting down
0:52:00 > 0:52:04the tropical rainforest, dumping our rubbish into the oceans.
0:52:04 > 0:52:10And third, that we should preserve the diversity of life.
0:52:10 > 0:52:15That's not just because we depend upon it for our food, though we do,
0:52:15 > 0:52:18nor because we still know so little about it that we won't know what
0:52:18 > 0:52:23we are losing, though that is the case as well, but it is surely that we
0:52:23 > 0:52:28have no moral right to destroy other living organisms
0:52:28 > 0:52:30with which we share the Earth.
0:52:30 > 0:52:34As far as we know, the Earth is the only place
0:52:34 > 0:52:37in the universe where there is life.
0:52:38 > 0:52:43Its continued survival now rests in our hands.
0:53:12 > 0:53:16Subtitles by Red Bee Media Ltd