"(ANIMALS CALL)" "We live in extraordinary times." "We are surrounded by more species of animals and plants than there's probably ever existed, at any one time, in the history of the earth." "For nearly fifty years, I've been lucky enough to spend my time travelling around the earth documenting those animals and those plants." "It's now increasingly apparent that one species, our own, has developed the unique ability of so altering its surroundings that it can destroy whole species, indeed whole environments." "How great is the damage we're actually doing to the world?" "Why is it that what we do has such a destructive effect?" "How can we change what we do, in order to ensure that our children and grandchildren inherit as wonderful and as varied a world as we were lucky enough to do?" "I'll be putting those questions to some of the world's leading scientists, in order to discover the very important answers." "I will be looking for clues all over the world." "Some can be found on the savannahs of Africa." "Others are to be sought under the sea." "We will visit our own past and consider our future." "Scientists will talk about their own most recent research, in order to help us understand the truth about the current state of our planet." "First, we have to establish the facts about the scale of the damage we have done to the earth so far." "Forty years ago, our curiosity about the worlds beyond our planet led to one of the most stupendous achievements in human history." "(GROUND CONTROL) We have ignition sequence start." "Five... four... three... two... one... zero..." " We have contact..." " Lift off..." "(ATTENBOROUGH) Paradoxically, sending a rocket towards the moon made us aware in a radically new way of the true nature of the world it left behind." "For most of human history, our world had seemed vast and its resources infinite." "But those men in space saw something different." "(ASTRONAUT) It is a most beautiful sight." "What a view!" "It's absolutely unreal!" "I have never seen..." "All I can say is it's spectacular!" "(ATTENBOROUGH) The astronauts' view made us realise more vividly than ever before that the earth is limited in both its space and its resources." "From that, it follows that there must also be a limit on the amount of life our planet can hold." "Living creatures on this planet have always had to endure natural catastrophe and change." "Yet now there is a greater variety of life on earth than there has ever been." "So change and damage are not necessarily destructive to life as a whole, and the view from space showed us why." "It's because such damage, even when on a scale that seems disastrous to those of us in the midst of it, is usually local in extent." "We now realise that such change is the spur which has created life's richness by presenting new opportunities and challenges to which animals and plants have responded." "Life, in fact, can recover from or adapt to even very great local damage." "But today the damage inflicted by humanity is global and it's taking place at a speed that is without precedent in the whole three and a half billion years of its history." "To understand the scale of our impact on the rest of life, we have to discover just how great the diversity of life on earth really is." "For the past 500 years, scientists and explorers have travelled the world cataloguing its natural wonders." "We can still see the biggest creature that has ever lived, the blue whale, and the simplest, microscopic bacteria." "0n land, in the air and under the sea, we have discovered an astonishing variety of life-forms." "That work is still going on, giving us an ever better understanding of this astonishing variety of life, this biodiversity." "So, how many different kinds of living things are there?" "Biologist Sir Robert May has made a special study of this question." "Amazingly, we don't actually know how many distinct species have been named and recorded." "For the major groups, like birds and mammals, the furries and the featheries, we really do know that for most groups, they're on scattered records in different museums, not yet coordinated into one big computer base." "Best guess would be about one and a half million different plants, animals, fungi, algae..." "This listing and cataloguing of the natural world has occupied the lives of many experts and still does." "A total as great as one and a half million species might seem to suggest that we have discovered the majority of life-forms on the planet." "But that is not so." "Again and again, new discoveries suddenly make us aware of just how limited our knowledge still is." "Nowhere demonstrates this better than the savannah grasslands of East Africa." "In this environment, as in many others, it's the big mammals that capture our attention." "They've become so famous through books, television programmes and safari holidays, that you might well think that they represent the majority of the animals here." "The scale of biodiversity on the African grasslands is a bit deceptive." "If you go out during the day, you're probably looking for spectacular animals like elephants." "You'll also see a few smaller things like butterflies and beetles and bugs, but the overwhelming impression you have, in terms of sheer mass of life, is of herds of just a few kinds of big animals." "The truth, as research has recently shown, is quite different." "For evidence of that, just look in the grass." "This is a column of driver ants." "Their ferocity is so great and their appetite so huge that they've given rise to all kinds of legends." "Stories about human beings or horses stumbling into their path and being stripped to skeletons within minutes are perhaps a little exaggerated, but the appetite of these ants is so huge that they will attack anything that can't get out of their way." "They prey mainly on other small animals and move across the grasslands in columns that may contain twenty million individuals." "So many ants need vast quantities of prey, so their abundance is living proof that the savannahs teem with smaller life." "When scientists recently began to study these smaller creatures, they found that 50% of the insects they were seeing were new to science." "Simple calculations suggest that driver ants alone consume more animal matter per year on the grasslands than all the famous big predators put together." "The reason why it's difficult to appreciate the full scale of biodiversity on the savannahs is that many creatures that live here are both nocturnal and very, very small." "You get some impression of what they are if you come out at night with a lamp like this." "To get an idea of the full range of those creatures, you have to use a light of a very special kind, like this one..." "The bulb that's illuminating this sheet produces a high proportion of ultraviolet light, and many night flying insects find that absolutely irresistible." "There are moths... small ones, big ones, here's a kind of silk moth." "Beetles... more moths." "A mantis... a great fat sausage fly." "An ant lion." "Lots of tiny little insects, I can hardly see what they are." "0h, and mosquitoes!" "Recent work has shown that there's a far greater variety of insect life on the savannahs than was previously thought." "There may not be as many species as are found in the tropical rainforest, but in terms of sheer quantity, the savannahs are their equal." "It was in the famously rich rainforests of South America that research first revealed the scale of our ignorance." "If you walk slowly and look carefully in a rainforest like this one in Ecuador, you can find all kinds of small, interesting creatures." "And that's how the first explorers and naturalists worked." "It's still possible to find new species that way." "I picked up this little stick insect from over there." "In order to discover whether it's a new species or not," "I'd have to show it to an expert in stick insects, and if he couldn't match it exactly, then he'll describe it, give it a new name and I'll have discovered a new species." "However, I can only search the area from the ground up to a couple of feet above my head, but the trees here grow to over a hundred feet tall." "What might be up there?" "Well, birds and monkeys I know because I can see them from down here, but what else might there be?" "Until very recently, that was a matter of pure speculation." "But then professor Terry Erwin invented a way of finding out." "He decided that in order to discover what actually lived high in the canopy of a single tree, or even a single branch, he had to use a machine known as an insecticide fogger." "This was originally designed for mosquito control, but it can be used to sample other insects equally well." "(ERWIN) When we first started fogging in Peru, the results were just absolutely fantastic." "We never imagined we were going to get so much." "(ATTENBOROUGH) The fog, harmless to anything but insects, drifts up into the canopy and the insects drop down." "The results of Terry Erwin's early work dramatically altered our estimates of how many different kinds of animals there might be on this planet." "This might seem a rather drastic way of discovering what lives in the trees." "However, as well as providing information that's important for conservation, this work has also shown that insects reproduce so fast here that within four months of a tree being fogged insects living in it return to their previous numbers." "From all of the studies I've made over these past 25 years, and the little bit that we've been able to analyse in the laboratory, it seems like at least 80% of the species we're getting out of the canopy" "are new species, new to science - and the reason that's true is that the average size, for example of a beetle, is only three millimetres long." "And so, just the small stuff hasn't been studied." "(ATTENBOROUGH) It's not just small things in rainforests that are still being discovered." "We're still finding things even among the primates." "Among the mammals, our closest relatives, there are about half a dozen new species of primate that have turned up this decade... small marmoset things..." "really underlines what we don't know." "Most of those small primates were found in the Amazon rainforests." "Until very recently, European explorers could only penetrate any distance into these vast forests by travelling up the rivers." "Now, however, using powerful machinery, roads have been cut through the forests that enable scientists to reach even the least known areas in their search for biological gold - new species." "It's here that they discovered new marmosets." "One way of enticing a primate to show itself is to play back the calls of a closely related species." "This can trick it into thinking its territory has been invaded by rivals, so it may emerge from the forest to investigate." "In 1992, this technique revealed a new species of marmoset in this area of southern Brazil." "Since that discovery, no one has been back again to look for it, and until now it has never been filmed." "This kind of waiting game can go on for weeks or months, usually without success." " (HIGH-PITCHED SCREECH)" " There it is, the call of a new species." "This is the black-faced marmoset." "We have no idea how this animal lives or what kind of social interactions take place in its groups." "It has yet to be studied." "As quickly as they appeared, the black-faced marmosets melt back again into the forest." "It's not only on land that the scale of recent discoveries has amazed scientists." "The oceans too have been found to contain a far greater diversity of life than was previously thought." "The sea covers two-thirds of the planet." "In some parts it's filled with a huge range of species." "The famous coral reefs, which occupy just a tiny fraction of the oceans, are probably its best known, most closely studied habitat." "Would it be fair to suggest that here at least, we have discovered most of the inhabitants?" "Sylvia Earle is an expert in marine biology." "Just as with what we have begun to understand about rainforests, is that there are thousands, perhaps millions of species that have yet to be discovered, described, even named." "So it is with coral reef systems that are enormously complex and diverse, but diverse on a scale that exceeds even that in rainforests." "(ATTENBOROUGH) If so much remains to be discovered even about coral reefs, which occupy the most shallow and accessible parts of the sea, what about the rest of it?" "The average depth is two and a half miles, the depth where the Titanic rests." "The maximum depth is seven miles, and we're still nibbling around the surface." "Scuba divers go to a hundred, a hundred and fifty feet, fifty metres or so." "We have a few submersibles that can go down to half the ocean's depth and one has been to full ocean depth once, but most of the ocean remains a mystery." "(ATTENBOROUGH) What does this tell us about the scale of discoveries still to be made in the sea?" "(EARLE) The greatest area of discovery has just begun." "The oceans, less than 5% have really been looked at." "Mapping has been done, we know where the valleys are, the mountains and plains, etc, but who lives in the sea?" "What do we really know of how the natural systems actually function?" "We are just beginning to understand the magnitude of our ignorance." "(ATTENBOROUGH) How little we know has been brought home to us by research in the deep ocean, where conditions are so severe that it was once thought that no life of any kind could possibly exist." "In fact, there are great numbers of creatures in these ocean depths." "Some recently discovered are so strange that it can be difficult to see any relationship to organisms that live in shallower water." "Even in the best-known environments, there are still discoveries to be made." "Surprisingly, the greatest may come from underground." "The topmost layer of land in many places is of course soil." "This is crucial because, quite simply, it's what most plants grow on, and it's vital to us because we plant our crops in it." "We might think that it's just dead matter with a few worms in it, but actually it's full of the most extraordinary creatures." "Beneath the surface of the soil, the abundance of life is breathtaking." "In this small patch, there could well be 2,000 different species and a quarter of a million individuals." "Most of them of course are very small." "Some are microscopic." "But on their own scale, the drama of their world is just as great as you can find on the plains of East Africa or the rainforests of South America." "Here, there are predators and prey, just a few millimetres long, with their own complex systems of attack and defence." "This world lies directly beneath our feet but we know little more about it than we do about the deepest depths of the ocean." "Nematode worms, so small they can only properly be seen under the microscope, are armed with piercing weaponry and protected with elaborate armour." "What is the significance of all the small forms of life that are being constantly discovered these days?" "Biologist Edward Wilson is an expert in biodiversity." "What's important about bugs and weeds is not just that they have most of the biodiversity around the world, but that they are the foundation of the ecosystem." "If you were to remove all of the biggest animals - humanity is in the process of doing that - there would be important changes in the forests and grasslands and the other major habitats, but they would survive, they would go on." "If you remove all of the insects, probably the entire thing would collapse." "It's the little things that make the world work." "(ATTENBOROUGH) Bacteria are among them." "They're also probably the most abundant, yet they remain among the least understood of all forms of life." "If a visitor from another planet were to analyse all the cells that make up my body, he or she would come to the conclusion that I am only 10% human." "That is because 90% of the living cells in my body are bacteria." "Bacteria are the most numerous living organisms on earth." "They're also among the smallest." "To understand just how small they are, let me take a perfectly clean... pin and put it in this scanning electron microscope." "At low magnifications the pin seems perfectly clean." "It's only when we zoom in and magnify it to ten thousand times that the size of the bacteria becomes clear." "Every living thing on the planet depends on bacteria, in one way or another." "But we still have no accurate idea of how many kinds there are." "Recently, extraordinary discoveries deep below ground have shown that all our previous estimates were far too low." "These pumps in California are pulling up oil from a thousand feet below the surface." "They bring up evidence that there is life down there as well." "Mostly in the form of bacteria." "Indeed, other evidence suggests that such microscopic forms of life may exist two miles, three and a half kilometres below the surface." "Such bacteria may grow so slowly that an individual bacterium may only reproduce once every 500 years." "Among the most extraordinary claims made for this new and unexpected wealth of life is that if one were able to gather it all together it would weigh more than all forms of life, animal and plant, that live on the surface." "The discoveries are so new that we can't yet be sure." "As for how many different kinds of life there is down there, we simply have no idea." "All of which goes to show we still have a lot to learn about the planet on which we live." "So what might be the final total of all the different kinds of living organisms that presently exist on earth?" "(WILSON) Different specialists in the field, using different methods, have produced estimates of the number of species out there." "Plants, animals, bacteria and other micro-organisms that fall anywhere from... shall we say... five million up to as high as 100 million." "(ATTENBOROUGH) Now that we appreciate, if only roughly, how great life's diversity really is, we can begin to judge the scale of threat it faces from human activities." "The sad truth is that even though we have only identified a minority of the earth's species, even some of those we've named have already become extinct, some so recently that we have their images on film," "including the Tasmanian tiger and the golden toad." "Many more are now so rare that there is real danger that they too will be lost before long." "To access the rate at which species are now disappearing, we need to know a little more about the ways such losses happen." "What does extinction actually mean?" "Nothing could illustrate it more dramatically than the sad and infamous case of the dodo." "This is a kind of giant, ground-living pigeon that was discovered by Portuguese sailors at the beginning of the sixteenth century living on the island of Mauritius." "They didn't think much of it;" "apparently they called it fat and lazy and stupid." "But that didn't stop them clubbing it over the head in vast numbers and eating its flesh." "And they introduced pigs and monkeys which ate its eggs." "By the mid-sixteen hundreds, the dodo was teetering on the brink of extinction." "(ANIMAL CRIES 0UT)" "(THWACK)" "(GRUNTING)" "A few dodos were captured and shipped back to Europe as curiosities." "Most of them died on the way." "How long the last dodo survived alone on its island, we don't know." "It could have been hours, days or even years, but eventually that last one also died." "And at that point the dodo, as a species, was extinct." "The dodo was particularly prone to extinction because it lived only on the relatively small island of Mauritius." "But the process of extinction becomes more difficult to chart when a species has a wider distribution." "In May 1980, Mount St Helen's, on the Pacific northwest coast of the United States, erupted." "A huge area of the landscape was virtually scoured clean of life." "In the hours after the eruption, rocks and mudflows swept almost every living thing off the mountain slopes." "But within weeks, life began slowly to return to the devastated landscape." "The scale of damage was astonishing." "Within minutes of the eruption beginning, a superheated blast of gas, travelling at 500 miles an hour, had flattened 250 square miles of virgin forest." "No species was exterminated because none was restricted solely to Mount St Helen's." "Even though the blanket of ash looked so sterile, some plants were able to grow in it, and soon the landscape was repopulated from the surrounding areas." "Some environmental losses, however, though they may look less dramatic, are more permanent." "In recent times, virtually the whole of southern England was covered by woodland." "A small patch of which survives behind me." "It was home to a great range of species." "Plants, insects, birds, mammals." "Now, however, most of that woodland has been felled in favour of agriculture." "Fields like these are totally unsuitable for those woodland species, so they disappeared." "When a species disappears over a small part of its range, it's known as a local extinction." "If you have too many local extinctions, the population level will fall dangerously low, and then that species may be on the road to total extinction." "(WILSON) There comes a time in the life of a species when... it has been reduced to the point that it can't be recovered..." "even by strenuous efforts." "A lot of species are in that condition and ecologists call them the living dead." "An animal that nearly became one of the living dead still lives near the city of Rio de Janeiro in Brazil." "In this area, 90% of the forest that once spread hundreds of miles along the coast has been lost." "The remains have been split up into small patches." "One of the most famous inhabitants of this forest is the beautiful golden lion tamarind." "It was in imminent danger of disappearing because it had lost most of its home." "At the last moment, a major captive breeding project was started and strict controls introduced to conserve the last remnants of its habitat." "So the species may have been pulled back from the brink of extinction." "But most living dead species do not receive this kind of intensive help." "One of the difficulties of measuring the current rates of extinction is that animals classed as living dead may be doomed, yet they can hang on in slow decline for many years." "John Lawton is a biologist who specialised in the study of animal populations." "(LAWTON) Some extinction is instantaneous, some will happen over a 20- or 30-year time period, when the population suddenly gets hit by a rare, extreme event, and some may take over a hundred years to happen" "as the last adults of a non-reproducing species finally dies out." "These estimates of extinction are bedevilled by the fact that it's very hard to be sure that something's really gone." "Several species which were thought for many years to have been lost have reappeared." "An example occurred recently in Australia." "Brisbane Museum holds the preserved remains of many Australian mammals, including three dried skins of a small marsupial known as the mahogany glider." "They were collected by a clergyman in 1886 at a place called Mount Echu in Queensland." "But they were never recorded again." "Was this animal extinct?" "That seemed very likely." "But then, in 1989, some unidentified mammal skins, collected fifteen years earlier, were by chance re-examined and one was recognised as a mahogany glider." "The skins came from Barrett's Lagoon, near the Queensland town of Tully." "But even as the specimens were being collected, their environment was being destroyed." "Surely the mahogany glider must now be extinct?" "Then this stuffed animal was noticed in a house near Barrett's Lagoon." "The farmer who had collected it thought it was a squirrel, so he had had it mounted with a nut in its hand." "But it was a mahogany glider." "The trail was obviously still warm." "Eventually, on 5th December, 1989, 103 years since it was last recorded, the mahogany glider was rediscovered alive at Barrett's Lagoon." "Today, it's been provided with nest boxes but it remains critically rare." "Although mostly nocturnal, individuals do appear during the day and put on a splendid display of aerobatics, gliding between the trees." "There was great excitement, and not only among scientists, that this beautiful creature was still around." "This was a narrow escape, but is it something about which we should be greatly concerned?" "Haven't such losses always been happening?" "Extinction is a natural event." "These drawers and racks in the Natural History Museum in London are full of the fossilised remains of creatures called ammonites." "They first appeared about 250 million years ago." "Over the millennia, some species died out, other ones appeared." "But 65 million years ago, all the ammonites disappeared, and with them went a great number of other species of animals and plants." "Such mass extinctions have happened five times in the history of our planet." "The question arises, are we ourselves, at this moment, on the verge of such an event?" "In some groups, such as the birds, all recent extinctions have been recorded." "So we can estimate the rate at which extinctions are happening and compare it with the past." "There's absolutely no doubt in my mind and of all my professional biological colleagues that the Earth is facing a massive extinction crisis." "The extinction rate is of crisis proportions." "Perhaps a hundred to a thousand times higher than before humanity came along." "That's the kind of acceleration in extinction rates, a hundred- to a thousand-fold, that characterises the lead-in to the five great waves of mass extinction in the fossil records." "The last of those five mass extinctions took place 65 million years ago, when the dinosaurs disappeared." "Studying that event reveals the scale of loss that a mass extinction can inflict on life's diversity." "Palaeontologist Peter Ward has made a study of these events." "What we've got here on a beach in France is evidence of one of the world's greatest mass extinctions." "We had a global catastrophe, and that catastrophe is written in the rocks with this very thin layer through here." "This is the end of the age of the dinosaurs, this is the start of the age of mammals, and that differentiation is deposited as this very thin band of strata." "In that band of strata we have evidence of a meteor impact." "We have pieces of Mexico which have been thrown into space, come down, deposited on the deep sea bottom in France." "Ancient dinosaur creatures are found in the strata, right up to this point, and they suddenly go extinct." "This mass extinction was sudden, it was catastrophic, it wiped out over 60 to 70% of all species on earth." "(ATTENBOROUGH) Can we define such an event?" "Mass extinctions are very short intervals of time when huge numbers of species go extinct." "They are over thousands of years, maybe tens of thousands of years, when more than half of the biodiversity then on earth goes extinct." "(ATTENBOROUGH) Now, due to the spread of the human species over the earth, it seems we are on the verge of an even more dramatic one." "The difference between the last five great mass extinctions and the sixth, which some scientists think we're on the verge of, is one of speed." "Each of the last took place over many thousands of years." "The next, according to some predictions, could happen within a hundred." "It will take a great deal of willpower and economic strength if we're to significantly reduce the damage we're doing to biodiversity." "In order to decide whether that's worthwhile, we must ask," ""Does the disappearance of a species really matter?"" "In a very few cases the species that go extinct... are likely to prove to be what we call keystone species." "That is, like the keystone of an arch but pulled out, a lot of the remaining structure changes, and usually not for the good." "It's often extremely difficult to know beforehand which species will be keystone species." "(ATTENBOROUGH) Sea otters are a clear example." "They live off the Pacific coast of North America." "In the southern part of their range, a huge seaweed, the giant kelp, grows up from the sea floor and creates a kind of underwater forest." "Many different animals depend on these kelp forests." "They're the spawning ground for fish." "Seals live here as well, and many smaller creatures such as clams, snails and urchins." "Sea otters feed on these clams and urchins." "They bring them to the surface and open them by smashing them on stones balanced on their stomachs." "During the eighteenth and nineteenth centuries, sea otters were intensively hunted for their skins and exterminated over huge areas." "Their disappearance led to dramatic changes in the environment." "The sea urchins, with no sea otters to keep their numbers down, increased explosively." "Urchins eat kelp, and their vast numbers soon began to destroy the underwater forests." "As the kelp disappeared, so did all the animals that depended on it." "What was left was a bare seabed carpeted with sea urchins." "Species do not exist in isolation." "They're linked to one another in complex ways, and when those links are cut a crisis may result." "Eventually, hunting the otters was banned." "They spread back into this area from further afield and the kelp forests slowly recovered." "Clearly many of the species that are on the verge of extinction, when they were taken out, their loss is not going to cause the collapse of an ecosystem." "We should lament their passing for other reasons." "But there are many that might cause serious repercussions, and until we understand the whole process better, we're rolling the dice, we're taking chances whenever we let a species go extinct." "So how would the loss of species and environments affect us?" "First of all, if you want to be completely practical, there is the matter of wild species being an almost bottomless source of new antibiotics and other pharmaceuticals, yet to be discovered and developed." "New crops, new fibres and other new natural products." "We're just getting underway the whole effort to make use of biodiversity in this way." "(ATTENBOROUGH) An example of a useful product from a surprising source comes from Cape Cod in the United States." "Horseshoe crabs are collected here daily from the seabed, for their blood contains a substance that can save human lives." "The crabs are taken to a laboratory and, in what looks like a scene from a sci-fi film, they're restrained in racks and some of their blue blood is extracted from them." "One of the substances it contains is used in many parts of the world to test whether batches of inoculants are healthy or contaminated with lethal bacteria." "The crabs are then released unharmed in a part of the sea that will not be harvested again for a year." "Clearly, many individual wild species can be of great use to us, but are there benefits to be gained from conserving natural environments?" "The whole matter of ecosystem services, an ecosystem like the one we're sitting in here, is doing a tremendous amount for humanity." "It's creating soil, it's cleansing water, it's creating the very air we breathe." "The important thing is it's doing it all for free." "(ATTENBOROUGH) Many reasons for preserving biodiversity are selfish, to do with our health and comfort." "Is there any other reason for us to be concerned about the loss of species?" "There is a care, an ethical argument, an argument of stewardship." "An argument of handing on a world as rich as the one we inherited." "That's an argument we in the First World have the luxury to consider." "But we'd have a different perspective if we were struggling to get the next meal." "It is an extraordinary gift that our generation received as natural heritage, and to destroy a large part of it just fundamentally seems wrong, especially when you think of what we're doing to future generations." "(ATTENBOROUGH) Scientists have a word for environments which have lost a number of their animals and plants - they call them "impoverished"." "Some may have lost almost all their species, as happened recently on many coral reefs." "Other environments may appear to be largely intact, even though many of their original inhabitants have become critically rare, or even lost altogether." "Future losses will include many smaller kinds of life yet to be discovered, as well as some of the best-known animals on the planet." "There is a spiritual value, an aesthetic value, a psychological benefit for having a large diversity of life on earth;" "we should not be removing it." "I believe it could conceivably be possible that in a few hundred years time we reduce that dependence and we lived in an almost wholly science-fictiony, artificial world, the world of a cult movie, "Blade Runner"." "The question you have to ask is, "Do you want to live in that world?"" "(ASTRONAUT) That is the most beautiful sight." " What a view!" " It's absolutely unreal." "(ATTENBOROUGH) The view the astronauts gave us when they looked back at earth enabled us to see more vividly than ever before just how limited space is on this small planet for life." "We now know that we are seriously damaging biodiversity, and there's the risk that the world that we hand on to our next generation will be less rich, poorer in variety, than the one we inherited." "Why is it that the activities of our one species, aimed at no more than living in reasonable comfort and avoiding hunger, should cause such devastation on the rest of the natural world?" "That is the question we'll look at in the next programme." "We will see what the extinction of the dinosaurs can show us about events today." "A remarkable story from our own past will provide vital clues." "I'll look for evidence from the bed of the North Sea." "And we will unravel some surprising stories from remote islands."