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Darwin was loath to admit his evolutionary view. | 0:00:36 | 0:00:39 | |
He began breeding pigeons and joined fanciers clubs. | 0:00:39 | 0:00:44 | |
He wanted to know how they created their extraordinary strangely feathered birds. | 0:00:44 | 0:00:50 | |
Darwin bought and kept every known breed in England and many of the types he kept survive today. | 0:00:50 | 0:00:57 | |
These were the sorts of fancy breeds that existed in Darwin's day. | 0:01:01 | 0:01:06 | |
Here we have the English pouter, the biggest and tallest of the pouters. This big yellow one. | 0:01:06 | 0:01:11 | |
He knew if these birds were wild they would have been classed as distinct species. | 0:01:11 | 0:01:16 | |
Miniature, where it gets its name from. The pygmy. | 0:01:16 | 0:01:19 | |
And the Jacobin, which is the exotic feathering... | 0:01:19 | 0:01:22 | |
But all the fancy breeds were of one species. | 0:01:22 | 0:01:25 | |
He crossed his tumblers and fantails to prove it. | 0:01:25 | 0:01:29 | |
Different from the common garden fantails you see. | 0:01:29 | 0:01:32 | |
And the runt... | 0:01:32 | 0:01:34 | |
All had been bred over generations from one ancestral type. | 0:01:34 | 0:01:39 | |
The breeders' craft was a mysterious business. More art than science. | 0:01:39 | 0:01:43 | |
But Darwin knew that within it lay their secrets of selection. | 0:01:43 | 0:01:47 | |
We're just waiting for... the markings are all right. | 0:01:47 | 0:01:51 | |
We can already see at this stage how much better it is in length of leg. | 0:01:51 | 0:01:57 | |
These minute differences are what we're looking for all the time. | 0:01:57 | 0:02:00 | |
-So that's the champion? -Hopefully, if everything carries on developing, yes. | 0:02:00 | 0:02:05 | |
-At what age can you first spot the difference? -As early as day one. | 0:02:05 | 0:02:08 | |
We have two babies here one day old and you can see the difference. | 0:02:08 | 0:02:12 | |
-From the same nest? -Yeah. | 0:02:12 | 0:02:14 | |
From day one you can see the difference in the beak. | 0:02:14 | 0:02:18 | |
He found what he'd expected. The individual birds were composed | 0:02:18 | 0:02:21 | |
of a myriad tiny variations, invisible to all but experienced fanciers. | 0:02:21 | 0:02:27 | |
The selecting hand was artificial, but all nature must be like this. | 0:02:27 | 0:02:33 | |
Nature was a supreme selector picking out those with an edge, discarding and killing the rest. | 0:02:33 | 0:02:41 | |
Pigeon breeding gave Darwin the most graphic example of how new species originate. | 0:02:43 | 0:02:48 | |
In Victorian times, the collecting of butterflies that showed any slight variation | 0:02:56 | 0:03:01 | |
from the normal pattern was fashionable. | 0:03:01 | 0:03:03 | |
It was popularly thought that such varieties were unimportant, they just died off. | 0:03:03 | 0:03:09 | |
Darwin didn't think that at all. | 0:03:09 | 0:03:12 | |
"These individual differences are of the highest importance for they're often inherited." | 0:03:12 | 0:03:19 | |
And as the variation is inherited, Darwin thought wild animals, | 0:03:19 | 0:03:23 | |
just like our domestic animals, had the potential to change, too. | 0:03:23 | 0:03:28 | |
"According to my view, varieties are species in the process of formation." | 0:03:28 | 0:03:34 | |
This was a startling idea. | 0:03:34 | 0:03:36 | |
Although it was accepted that new species could appear and old ones disappear, | 0:03:36 | 0:03:41 | |
these changes were commonly believed to be due to divine acts of creation or destruction. | 0:03:41 | 0:03:48 | |
But Darwin believed he'd discovered a natural process by which | 0:03:48 | 0:03:52 | |
a variety could evolve into a brand new species. | 0:03:52 | 0:03:56 | |
He was supplanting God's work by a natural process. | 0:03:56 | 0:04:00 | |
It was a dangerous idea. | 0:04:00 | 0:04:02 | |
How exactly did Darwin think new species came into being? | 0:04:04 | 0:04:10 | |
Before answering that, he had to propose a view of nature that went against a romanticised, | 0:04:10 | 0:04:16 | |
Victorian ideal of how the natural world worked. | 0:04:16 | 0:04:19 | |
"We behold the face of nature bright with gladness, | 0:04:21 | 0:04:25 | |
"we forget that the birds idly singing around us mostly | 0:04:25 | 0:04:29 | |
"live on insects or seeds and are thus constantly destroying life. | 0:04:29 | 0:04:34 | |
"Or we forget how their eggs or nestlings are destroyed by birds or beasts of prey." | 0:04:34 | 0:04:40 | |
He was suggesting that the tranquil beauty around us is largely an illusion. | 0:04:40 | 0:04:47 | |
In the natural world, life is often a struggle just to survive, let alone breed. | 0:04:47 | 0:04:52 | |
Of all the arguments raised against his ideas, | 0:05:02 | 0:05:05 | |
nothing troubled Darwin more than that about the origin of the eye. | 0:05:05 | 0:05:10 | |
"The belief that an organ so perfect as the eye could have been | 0:05:10 | 0:05:14 | |
"formed by natural selection is enough to stagger anyone." | 0:05:14 | 0:05:18 | |
It certainly staggered his critics. | 0:05:19 | 0:05:23 | |
"It's only here or there that a second rate naturalist would | 0:05:23 | 0:05:28 | |
"sympathise at all with such dreamy views." | 0:05:28 | 0:05:32 | |
They simply couldn't believe that such an intricate mechanism could arise by any natural process. | 0:05:32 | 0:05:38 | |
Darwin thought it could. | 0:05:38 | 0:05:42 | |
"If numerous gradations from a simple eye to one complex and perfect can be shown to exist, | 0:05:42 | 0:05:47 | |
"each grade useful to its possessor, then the difficulty of believing a complex eye could be formed | 0:05:47 | 0:05:53 | |
"by natural selection shouldn't be considered as subversive of the theory." | 0:05:53 | 0:05:58 | |
The earthworm has a layer of light, sensitive cells in its skin that can detect light from dark. | 0:05:59 | 0:06:05 | |
It's the simplest eye possible and all that an earthworm needs. | 0:06:08 | 0:06:13 | |
If a random variation should cause these cells to be set back in a pit, | 0:06:16 | 0:06:21 | |
then the animal can detect the direction of light just as the limpet can. | 0:06:21 | 0:06:25 | |
The snail has an additional refinement. | 0:06:30 | 0:06:33 | |
A blob of mucus in the pit acts as a simple lens. | 0:06:33 | 0:06:39 | |
The snail can seek a roughly focused image. | 0:06:39 | 0:06:44 | |
If the lens then hardens, the vision becomes better. | 0:06:44 | 0:06:48 | |
The conch has this kind of eye. | 0:06:48 | 0:06:50 | |
Darwin argued that there were no limits to what such a process might ultimately produce. | 0:06:53 | 0:06:58 | |
"A structure even as perfect as an eagle's eye might thus be formed." | 0:06:58 | 0:07:03 | |
The eagle's vision is said to be | 0:07:03 | 0:07:05 | |
eight times more acute than our own. | 0:07:05 | 0:07:08 | |
It can spot prey at distances over which we would spot nothing. | 0:07:08 | 0:07:13 | |
Darwin believed his theory could explain the entire variety of life on Earth. | 0:07:17 | 0:07:23 | |
Through the adding up of tiny variations, fish would have evolved into amphibians. | 0:07:36 | 0:07:41 | |
At every stage, the new form would be better adapted to an amphibious life than the last. | 0:07:41 | 0:07:48 | |
In the struggle for life, the new kind would out compete the old and drive it to extinction. | 0:07:48 | 0:07:55 | |
In the end result is a world today with fish and amphibians, but nothing in between. | 0:07:55 | 0:08:02 | |
But don't the missing links turn up as fossils? | 0:08:02 | 0:08:06 | |
"It's been asserted over and over again that geology yields no linking forms." | 0:08:06 | 0:08:13 | |
Darwin's critics maintained he couldn't point to a single | 0:08:13 | 0:08:18 | |
fossil intermediate between two different groups of living animals. | 0:08:18 | 0:08:21 | |
He replied that few animals have ever become preserved as fossils. | 0:08:23 | 0:08:27 | |
The fossil record was like an incomplete book. | 0:08:27 | 0:08:31 | |
"Only here and there a short chapter has been preserved | 0:08:31 | 0:08:35 | |
"and of each page only here and there a few lines." | 0:08:35 | 0:08:38 | |
Yet he was sure that in time | 0:08:38 | 0:08:41 | |
intermediate forms would come to light. | 0:08:41 | 0:08:45 | |
One year after The Origin Of Species was published, | 0:08:45 | 0:08:49 | |
an extraordinary fossil was found in Germany. | 0:08:49 | 0:08:52 | |
It had a mouthful of teeth like a reptile and feathers like a bird. | 0:08:52 | 0:08:57 | |
This is Archaeopteryx. | 0:09:02 | 0:09:04 | |
It's an animal intermediate between two living animal groups. | 0:09:04 | 0:09:09 | |
Darwin felt this natural process would hinge on which animals | 0:09:20 | 0:09:25 | |
survived the struggle for life to breed and which do not. | 0:09:25 | 0:09:30 | |
"Individuals having any advantage, however slight, over others would | 0:09:30 | 0:09:34 | |
have the best chance of surviving and procreating their kind." | 0:09:34 | 0:09:38 | |
This gazelle may be just that bit fast or stronger than the rest. | 0:09:41 | 0:09:46 | |
"The preservation of favourable individual differences and the destruction | 0:09:53 | 0:09:59 | |
"of those which are injurious I've called natural selection or survival of the fittest." | 0:09:59 | 0:10:06 | |
So here is the crux of Darwin's great theory. | 0:10:14 | 0:10:17 | |
A natural law, survival of the fittest, | 0:10:17 | 0:10:19 | |
determines which animals will live long enough to have offspring. | 0:10:19 | 0:10:24 | |
If this natural selection were to go on constantly | 0:10:24 | 0:10:28 | |
perhaps those tiny individual differences could add up, then wild species might change. | 0:10:28 | 0:10:35 | |
"Natural selection is daily and hourly scrutinising | 0:10:35 | 0:10:40 | |
"the slightest variations, rejecting those that are bad, | 0:10:40 | 0:10:44 | |
"preserving and adding up all those that are good." | 0:10:44 | 0:10:49 | |
This scrutiny may be constant, but the resulting change would be slow. | 0:10:50 | 0:10:56 | |
The variation between individuals of a species | 0:10:56 | 0:10:59 | |
are usually very slight | 0:10:59 | 0:11:00 | |
yet the differences between one species and another | 0:11:00 | 0:11:03 | |
may be very great, a lot of adding up of tiny differences | 0:11:03 | 0:11:07 | |
would be needed to produce a new and different species. | 0:11:07 | 0:11:11 | |
If he's looking a little smug, it may be with good reason. | 0:11:21 | 0:11:25 | |
Joshua is the very first of a new kind of cat. | 0:11:25 | 0:11:28 | |
You can stroke him all day long without risk of red eyes, sneezing or skin rash. | 0:11:28 | 0:11:34 | |
In the UK alone, 8 million cats are kept as household pets, | 0:11:34 | 0:11:39 | |
but many end up being given away because their presence | 0:11:39 | 0:11:42 | |
can bring out an allergic reaction in their owners. | 0:11:42 | 0:11:45 | |
It's the cat saliva which is responsible, or rather a protein within it called Fel d 1. | 0:11:45 | 0:11:51 | |
The American scientists isolated two cats which were low in Fel d 1 | 0:11:51 | 0:11:55 | |
and bred them over several generations until the protein had virtually been eliminated. | 0:11:55 | 0:12:02 | |
In doing so, they created cats which don't bring out allergies. | 0:12:02 | 0:12:05 | |
The RSPCA has criticised the development saying selective | 0:12:05 | 0:12:09 | |
breeding undermines the value of animal life. | 0:12:09 | 0:12:12 | |
The company responsible is emphasising the benefits to people. | 0:12:12 | 0:12:16 | |
I know how pet owners really are and in times of need and passion, | 0:12:16 | 0:12:21 | |
whether it's depression or something traumatic, nothing | 0:12:21 | 0:12:26 | |
substitutes the love of a pet. | 0:12:26 | 0:12:28 | |
You can't put a price and it. | 0:12:28 | 0:12:31 | |
But in fact they have. A moggy like this will set you back more than £2,000. | 0:12:31 | 0:12:35 | |
There's already a long waiting list. | 0:12:35 | 0:12:38 | |
Some living animals are so bizarre they seemed hard to explain by Darwin's theory. | 0:12:46 | 0:12:51 | |
How can a tail like this evolve when it seems sure to slow its owners escape from predators? | 0:12:53 | 0:12:59 | |
And wouldn't the same apply to the great cumbersome jaws of this stag beetle? | 0:13:01 | 0:13:06 | |
Surely these are exactly the sort of things | 0:13:06 | 0:13:08 | |
that would be weeded out in the struggle for life. | 0:13:08 | 0:13:11 | |
Darwin said these kind of exaggerated features evolved by what he called sexual selection. | 0:13:19 | 0:13:26 | |
"This form of selection depends on a struggle between the individuals | 0:13:26 | 0:13:31 | |
"of one sex, generally the males, for the possession of the other sex. | 0:13:31 | 0:13:36 | |
"The result isn't death, but few or no offspring." | 0:13:36 | 0:13:41 | |
The struggle isn't violent. | 0:13:41 | 0:13:44 | |
The males gather to show off their tails and the females choose which males to mate with. | 0:13:44 | 0:13:50 | |
If, even with such long tail feathers, a male peacock is still strong enough | 0:13:50 | 0:13:55 | |
to escape from predators then such feathers are a sure sign of a healthy male. | 0:13:55 | 0:14:00 | |
From an ancestral form of peacock with short tail feathers, | 0:14:00 | 0:14:05 | |
the females of each generation would have chosen the longest feathered males to mate with. | 0:14:05 | 0:14:11 | |
In time, the feature would have become exaggerated | 0:14:11 | 0:14:14 | |
to produce today's peacocks with their spectacular tails. | 0:14:14 | 0:14:18 | |
Such a process would also explain the famous displays of male birds of paradise. | 0:14:18 | 0:14:25 | |
But sexual selection isn't just about show. | 0:14:28 | 0:14:32 | |
"In many cases victory depends on having a special weapons." | 0:14:32 | 0:14:38 | |
Male stag beetles actually fight other males. | 0:14:40 | 0:14:43 | |
The winner gets the female. | 0:14:43 | 0:14:45 | |
So the biggest jawed males of each generation beat their rivals and have big-jawed offspring. | 0:14:45 | 0:14:52 | |
The adding up of tiny advantages leads to animals superbly adapted to their own way of living. | 0:15:00 | 0:15:08 | |
Given the number of offspring every living thing is able to produce, | 0:15:17 | 0:15:21 | |
it's actually a good thing life is a struggle. | 0:15:21 | 0:15:25 | |
"There's no exception to the rule that every organic being naturally increases at so high a rate | 0:15:26 | 0:15:32 | |
"that if not destroyed the earth would soon be covered by the progeny of a single pair." | 0:15:32 | 0:15:39 | |
The result of just a few successive generations, in which all offspring | 0:15:41 | 0:15:46 | |
from one original pair survive to breed, would be dramatic. | 0:15:46 | 0:15:50 | |
Temporary outbreaks of mice in Australia when food is abundant | 0:15:56 | 0:16:00 | |
and predators scarce are living proof of that. | 0:16:00 | 0:16:05 | |
The hard times will return, then the struggle will begin again | 0:16:23 | 0:16:27 | |
and many animals will die before they can breed. | 0:16:27 | 0:16:31 | |
The first challenge to overcome is the intense and unrelenting heat. | 0:16:50 | 0:16:54 | |
Red kangaroos deal with the worst of this by finding shade | 0:16:54 | 0:16:59 | |
and digging to find cooler earth below the sun-baked ground. | 0:16:59 | 0:17:03 | |
Another trick is to conserve as much water as possible. | 0:17:03 | 0:17:06 | |
When resting, they don't sweat. | 0:17:06 | 0:17:10 | |
Instead, they lick their forearms so that saliva cools blood vessels close to the surface. | 0:17:10 | 0:17:17 | |
Emus also cool down using surface blood vessels, | 0:17:18 | 0:17:22 | |
increasing the flow to their long necks, long legs and big feet. | 0:17:22 | 0:17:26 | |
Their flightless wings have unique double quilled feathers that | 0:17:26 | 0:17:32 | |
protect them from the burning heat so they can brave the midday sun without shade. | 0:17:32 | 0:17:38 | |
The second problem desert dwellers face here, | 0:17:38 | 0:17:42 | |
unlike their rainforest past, is finding water. | 0:17:42 | 0:17:46 | |
Emus are often forced to walk huge distances to find water | 0:17:50 | 0:17:54 | |
as they need to drink every day. | 0:17:54 | 0:17:56 | |
Red kangaroos can memorise pools they visited before, | 0:18:01 | 0:18:05 | |
but they're better adapted to cope without a drink. | 0:18:05 | 0:18:08 | |
They store more water in their bodies, in the muscles and their guts, than other mammals. | 0:18:08 | 0:18:15 | |
And can withstand water loss that would easily kill a human. | 0:18:15 | 0:18:20 | |
If there are plenty of green plants, the kangaroos' sole diet, they don't need to drink at all. | 0:18:20 | 0:18:27 | |
But they can't always count on that. | 0:18:27 | 0:18:29 | |
Red kangaroos have evolved broad padded feet designed not to damage new shoots, | 0:18:32 | 0:18:36 | |
but still their biggest problem is finding enough to eat. | 0:18:36 | 0:18:41 | |
They're experts in saving energy. | 0:18:45 | 0:18:47 | |
They can survive on the bare minimum of food. | 0:18:47 | 0:18:50 | |
Kangaroos, and all of Australia's marsupials, | 0:18:50 | 0:18:54 | |
have a much lower metabolism than mammals in other parts of the world. | 0:18:54 | 0:18:58 | |
This means they use less energy, whether resting or on the move, | 0:18:58 | 0:19:02 | |
so they can live on less food than other mammals of their size. | 0:19:02 | 0:19:06 | |
A vital adaptation to desert life. | 0:19:08 | 0:19:10 | |
Today, they number 10 million. | 0:19:12 | 0:19:14 | |
But the kangaroos' ability to scrimp and save is nothing | 0:19:16 | 0:19:20 | |
compared to their neighbours. | 0:19:20 | 0:19:23 | |
In nearby creeks and billabongs, freshwater crocodiles have barely | 0:19:23 | 0:19:27 | |
changed since their rainforest days 50 million years ago. | 0:19:27 | 0:19:32 | |
They feed on fish, insects, crustaceans and the occasional unwary bird. | 0:19:32 | 0:19:39 | |
When times are good, they lay down fat in special stores along their tails. | 0:19:40 | 0:19:46 | |
This, combined with an exceptionally low metabolism, | 0:19:46 | 0:19:49 | |
far lower than the kangaroos', allows them to survive up to two years without a single meal. | 0:19:49 | 0:19:55 | |
Among the towering cliffs, peaks and ridges of Ethiopia's Semien highlands, | 0:20:07 | 0:20:13 | |
the so-called roof of Africa, | 0:20:13 | 0:20:15 | |
Walia Ibex - Ethiopia's national symbol. | 0:20:15 | 0:20:19 | |
They can exist in these precarious places and they do. | 0:20:25 | 0:20:29 | |
But that's mainly because they have to. | 0:20:29 | 0:20:31 | |
The cliffs are something like a kilometre high | 0:20:36 | 0:20:39 | |
and they're almost sheer. | 0:20:39 | 0:20:40 | |
That's where the Walia Ibex live | 0:20:40 | 0:20:42 | |
and to see them in this enormous distance | 0:20:42 | 0:20:46 | |
on these sheer cliffs is truly spectacular. | 0:20:46 | 0:20:49 | |
I tried to film them years and years ago for another series and they proved too difficult. | 0:20:51 | 0:20:55 | |
The Walia Ibex were much wider spread at one time throughout the mountains of Ethiopia | 0:20:57 | 0:21:02 | |
and are related to the Ibexes of Europe. | 0:21:02 | 0:21:05 | |
But as humans have spread through Ethiopia | 0:21:05 | 0:21:09 | |
and the environment has dried out, the Walia Ibex has | 0:21:09 | 0:21:13 | |
been pushed into the most marginal habitats it can find and some | 0:21:13 | 0:21:19 | |
of the last remaining places humans can't get to | 0:21:19 | 0:21:22 | |
are these incredible sheer cliffs | 0:21:22 | 0:21:24 | |
and it's only just been with a lot of warfare | 0:21:24 | 0:21:28 | |
in the last century in Ethiopia, the Italian invasion | 0:21:28 | 0:21:33 | |
and then a big civil war, that the Walia Ibex became favourite food for soldiers. | 0:21:33 | 0:21:39 | |
The Semien mountains saw a huge amount of fighting | 0:21:39 | 0:21:43 | |
through the 1970s and 1980s and in that period | 0:21:43 | 0:21:47 | |
the easiest food for a very cold soldier would have been to take a shot at one of the Walia Ibex. | 0:21:47 | 0:21:53 | |
We saw the numbers decimated. | 0:21:53 | 0:21:56 | |
The one thing the Walia has going for it is the habitat it lives in. | 0:21:56 | 0:22:01 | |
These sheer, sheer cliffs. | 0:22:01 | 0:22:02 | |
There are very few animals in the world that could live on precipices like the Walia. | 0:22:02 | 0:22:09 | |
It has a little niche it can cling to, | 0:22:09 | 0:22:13 | |
but it's such a fragile situation. | 0:22:13 | 0:22:17 | |
600 animals for a large mammal is nothing. | 0:22:17 | 0:22:21 | |
When you've no other habitats to spread in to, no other populations to interbreed with, | 0:22:21 | 0:22:26 | |
no Walia Ibex in captivity, | 0:22:26 | 0:22:28 | |
you'd better be sure you can protect that one last piece of cliff they have. | 0:22:28 | 0:22:33 | |
Aborigines survive by their exceptional knowledge of the land | 0:22:44 | 0:22:47 | |
and its secret sources of food and water. | 0:22:47 | 0:22:51 | |
This priceless knowledge is inherited through storytelling. | 0:22:51 | 0:22:56 | |
Stories that relate to the magical dream time are passed from generation to generation. | 0:22:56 | 0:23:03 | |
They retrace the journeys of the ancestral beings as they wandered | 0:23:03 | 0:23:06 | |
over the empty continent creating the world. | 0:23:06 | 0:23:10 | |
In doing so, every feature of the land and its invaluable resources | 0:23:10 | 0:23:15 | |
are recounted to enable future generations to survive here, too. | 0:23:15 | 0:23:20 | |
But even if you know what food you're looking for, | 0:23:20 | 0:23:23 | |
how do you find enough? | 0:23:23 | 0:23:25 | |
The best strategy is to keep on the move and eat | 0:23:25 | 0:23:28 | |
from a wide variety of sources - to avoid any becoming depleted. | 0:23:28 | 0:23:34 | |
And an intimate knowledge of wildlife is essential. | 0:23:34 | 0:23:38 | |
Eggs from the freshwater crocodile are usually laid in the holes within ten metres of water. | 0:23:38 | 0:23:45 | |
After laying, the female leaves them unguarded, only returning when the baby has hatched. | 0:23:45 | 0:23:51 | |
So with the right knowledge, it's safe to raid her nest. | 0:23:51 | 0:23:55 | |
By breaking open the roots of certain bushes and trees, witchety grubs can be found. | 0:23:59 | 0:24:04 | |
These plump white insects are larvae of the ghost moth - | 0:24:04 | 0:24:08 | |
an important source of protein, said to taste like almonds. | 0:24:08 | 0:24:12 | |
They're usually cooked in ashes but can easily be eaten raw. | 0:24:12 | 0:24:17 | |
The trail of a certain ant leads to a sweeter delicacy. | 0:24:20 | 0:24:26 | |
Digging a hole as deep as herself, | 0:24:27 | 0:24:30 | |
this Aboriginal woman can access the underground nest of the honey ant. | 0:24:30 | 0:24:35 | |
Some of the worker ants are fed on nectar by other members of the colony | 0:24:35 | 0:24:40 | |
until their abdomens are so swollen they can barely move. | 0:24:40 | 0:24:44 | |
They become living storage vessels, tucked away deep in the nest where | 0:24:44 | 0:24:49 | |
other ants can feed on them in times of drought. | 0:24:49 | 0:24:52 | |
By easing them gently out with a stick, others can feed on this sugar sauce too. | 0:24:54 | 0:25:00 | |
As women are traditionally gatherers, it's their task | 0:25:02 | 0:25:06 | |
to collect plant food which makes up half of their diet. | 0:25:06 | 0:25:10 | |
They have a special technique to help it grow. | 0:25:11 | 0:25:15 | |
Firestick farming, as it's called, works in two ways. | 0:25:17 | 0:25:20 | |
First, it burns off the tall, dominant grasses | 0:25:23 | 0:25:26 | |
allowing a range of edible plants to grow in their place. | 0:25:26 | 0:25:30 | |
So there is not only in more food to eat, but it's easier to find. | 0:25:30 | 0:25:36 | |
The Aborigines rely on their detailed knowledge of the land to see them through. | 0:25:40 | 0:25:45 | |
Just like their predecessors 40,000 years ago, they know | 0:25:45 | 0:25:49 | |
how to find water underground when their usual water holes dry up. | 0:25:49 | 0:25:54 | |
The desert sand protects this water from evaporating and the grass acts as a filter. | 0:25:56 | 0:26:03 | |
So, digging in the right place can produce a life-saving drink. | 0:26:03 | 0:26:07 | |
And in desperate times, every drop of water helps. | 0:26:10 | 0:26:15 | |
Burrowing frogs can shut down body systems and live dormant underground for seven years. | 0:26:15 | 0:26:23 | |
Even in the hottest months, they don't dry out because layers of dead skin act like cocoon. | 0:26:23 | 0:26:29 | |
They stay alive this long by using water stored in their bladders after previous rains. | 0:26:32 | 0:26:37 | |
And Aborigines know how to access this in an emergency. | 0:26:41 | 0:26:44 | |
As temperatures in Australia rose, most of the rainforest trees died out, | 0:27:01 | 0:27:07 | |
but one, the eucalyptus, adapted well to the new dry conditions | 0:27:07 | 0:27:12 | |
and seized its chance to spread. | 0:27:12 | 0:27:14 | |
There are now over 700 species of eucalypts in Australia's dry, dusty earth. | 0:27:14 | 0:27:20 | |
To save precious nutrients, they grow fibrous leaves full of poisons | 0:27:20 | 0:27:26 | |
so that like the Spinifex grass, nothing can eat them. | 0:27:26 | 0:27:29 | |
But one animal has broken through its defences... | 0:27:31 | 0:27:34 | |
..the Koala. | 0:27:36 | 0:27:38 | |
In fact, it eats nothing else. | 0:27:38 | 0:27:42 | |
Koalas have very long digestive tracts, | 0:27:42 | 0:27:45 | |
full of specialised bacteria, | 0:27:45 | 0:27:48 | |
which must be passed on to their young through their faeces. | 0:27:48 | 0:27:51 | |
They carefully select leaves with the fewest tannins and the highest oil content. | 0:27:54 | 0:28:00 | |
But despite munching through a kilo a day, | 0:28:00 | 0:28:03 | |
they still gain very little energy. | 0:28:03 | 0:28:07 | |
The price they pay for this poor diet is to sleep | 0:28:07 | 0:28:11 | |
an epic 19 hours a day. | 0:28:11 | 0:28:13 | |
Since they spend five hours feeding, | 0:28:15 | 0:28:17 | |
there is little time for anything else. | 0:28:17 | 0:28:20 | |
Koalas have another way to save energy. | 0:28:20 | 0:28:24 | |
They are bears of very little brain. | 0:28:24 | 0:28:28 | |
The brain consumes more energy than any other organ, | 0:28:29 | 0:28:32 | |
so if all you do is eat and sleep, a small brain probably makes sense. | 0:28:32 | 0:28:38 | |
But there is an upside to this poor diet. | 0:28:39 | 0:28:42 | |
The chemicals in the pungent leaves means koala flesh is not popular to eat. | 0:28:42 | 0:28:49 | |
So despite their sluggish way of life, | 0:28:49 | 0:28:52 | |
koalas can still sleep away their days in relative peace. | 0:28:52 | 0:28:57 | |
In the High Arctic, the Planet Earth team saw | 0:29:04 | 0:29:10 | |
polar bears behaving in ways they'd | 0:29:10 | 0:29:13 | |
never seen before. | 0:29:13 | 0:29:15 | |
Get your eye behind the viewfinder, the adrenalin starts rushing. | 0:29:55 | 0:29:59 | |
You know you're recording something so unusual, something so amazing | 0:29:59 | 0:30:03 | |
that very few people have ever seen before. | 0:30:03 | 0:30:06 | |
But you have to focus. | 0:30:06 | 0:30:09 | |
It is very rare to see a bear go after walruses | 0:30:09 | 0:30:12 | |
and to actually physically | 0:30:12 | 0:30:14 | |
jump on them and attack them, stalk them, hunt them. | 0:30:14 | 0:30:18 | |
Ten years ago, at the same time of year and at the same latitude, | 0:31:03 | 0:31:08 | |
this, as filmed in a BBC Wildlife Special | 0:31:08 | 0:31:12 | |
was what polar bears were doing. | 0:31:12 | 0:31:14 | |
The sea was frozen and the bears were hunting | 0:31:17 | 0:31:21 | |
less intimidating prey. | 0:31:21 | 0:31:23 | |
Not enormous walruses in defensive herds on dry land, | 0:31:27 | 0:31:32 | |
but small ring seals out on the ice. | 0:31:32 | 0:31:36 | |
We are rapidly losing ice cover. | 0:31:52 | 0:31:55 | |
It's happening as we speak. | 0:31:55 | 0:31:57 | |
The ice cap is getting thinner and in its extent, is greatly reduced, | 0:31:57 | 0:32:01 | |
and that icecap is the home of the polar bear. | 0:32:01 | 0:32:04 | |
So, they're finding the places they're accustomed to breeding and hunting are disappearing. | 0:32:05 | 0:32:12 | |
There's no doubt, people can see the ice breaking up, | 0:32:12 | 0:32:16 | |
they can see the glaciers retreating. | 0:32:16 | 0:32:19 | |
That's a real problem for the polar bears. | 0:32:19 | 0:32:22 | |
Polar bears are in deep trouble and there's lots of research to show that. | 0:32:24 | 0:32:29 | |
There are two possibilities, one, they go extinct | 0:32:29 | 0:32:32 | |
as they try desperately to find ice. | 0:32:32 | 0:32:35 | |
Or, they may go further south and come on to firm land. | 0:32:35 | 0:32:39 | |
Of course, their habits will have to change greatly. | 0:32:39 | 0:32:43 | |
Maybe they will evolve to do that? | 0:32:43 | 0:32:46 | |
It's got a very short time in which to do this, | 0:32:46 | 0:32:48 | |
if the projection is that | 0:32:48 | 0:32:50 | |
the polar icecap will have disappeared within 50 years, | 0:32:50 | 0:32:53 | |
we are expecting an awful lot | 0:32:53 | 0:32:55 | |
in the way of habitat change, annual movement change, | 0:32:55 | 0:32:59 | |
feeding habits, hunting techniques of a bear. | 0:32:59 | 0:33:03 | |
I think it's going to be very interesting to see if it can do that. | 0:33:03 | 0:33:06 | |
The estimates we have is that we might lose 35% of them over the next 50 years. | 0:33:08 | 0:33:15 | |
As that population starts to go down and their prey species move out, | 0:33:15 | 0:33:19 | |
it's going to be a tough adaptation for the polar bear. | 0:33:19 | 0:33:24 | |
No part of the Earth is more hostile to life than the frozen wastes around the Poles. | 0:33:35 | 0:33:42 | |
850 miles north of the Arctic Circle, this is Ellesmere Island. | 0:33:42 | 0:33:48 | |
No animal can live permanently on these ice fields. | 0:33:48 | 0:33:51 | |
And even plants face almost insuperable problems, | 0:33:51 | 0:33:55 | |
for the four things they must have are in cripplingly short supply. | 0:33:55 | 0:34:00 | |
Water, it's true there is a lot of frozen water all around me, | 0:34:00 | 0:34:04 | |
but water has to be liquid for plants to make any use of it. | 0:34:04 | 0:34:09 | |
Nutrients, there's virtually none in this frost-shattered rock. | 0:34:09 | 0:34:14 | |
Warmth and light, | 0:34:14 | 0:34:15 | |
for six months of the year it's dark, | 0:34:15 | 0:34:18 | |
and in the brief summer as now, | 0:34:18 | 0:34:20 | |
the sun doesn't rise high in the sky and devastating winds | 0:34:20 | 0:34:24 | |
can carry away what little warmth it brings. | 0:34:24 | 0:34:27 | |
And yet, there are plants here. | 0:34:27 | 0:34:30 | |
Some live... | 0:34:30 | 0:34:32 | |
actually inside the rock. | 0:34:32 | 0:34:35 | |
This thin green line is made by algae, microscopic plants. | 0:34:40 | 0:34:46 | |
They're so small they can live actually between the grains of the sandstone. | 0:34:46 | 0:34:52 | |
And there at least, they're out of this desiccating wind. | 0:34:52 | 0:34:57 | |
On the surface of the rocks there are lichens. | 0:34:57 | 0:35:00 | |
They grow incredibly slowly and may take 50 years to cover a square centimetre. | 0:35:00 | 0:35:05 | |
But they can survive even if there are only two days in the year when it's warm enough for them to grow. | 0:35:05 | 0:35:12 | |
In spite of these bleak conditions, there are in fact flowers to be found here. | 0:35:12 | 0:35:17 | |
But you have to look hard to find them. | 0:35:17 | 0:35:20 | |
Here's one. | 0:35:22 | 0:35:24 | |
It's a kind of mustard, | 0:35:24 | 0:35:26 | |
but it's much smaller than its more southerly relatives. | 0:35:26 | 0:35:30 | |
But by being so small, it manages to keep out of the crippling wind. | 0:35:30 | 0:35:35 | |
In mid-summer, for a few weeks, enough water melts from the glaciers | 0:35:35 | 0:35:39 | |
for streams to flow, then, miniature gardens burst into bloom. | 0:35:39 | 0:35:46 | |
The searing wind compels them all to keep close to the ground. | 0:35:56 | 0:36:01 | |
None keeps closer than this. | 0:36:09 | 0:36:12 | |
It is in fact a tree, a willow. | 0:36:12 | 0:36:14 | |
These are its catkins. | 0:36:14 | 0:36:17 | |
But the trunk grows horizontally instead of vertically | 0:36:17 | 0:36:21 | |
and it can stretch almost as far along the ground | 0:36:21 | 0:36:23 | |
as its more southerly relatives stand up above it. | 0:36:23 | 0:36:27 | |
Even so, it still produces enough leaves to sustain a few grazers - | 0:36:27 | 0:36:34 | |
musk ox. | 0:36:34 | 0:36:36 | |
The Arctic poppy, like all plants needs warmth to grow, | 0:36:40 | 0:36:44 | |
but it's unusually efficient at collecting it. | 0:36:44 | 0:36:48 | |
As the mid-summer sun skims round the horizon, all 360 degrees | 0:36:48 | 0:36:53 | |
in 24 hours without setting, | 0:36:53 | 0:36:55 | |
the poppy turns its flowers to track it. | 0:36:55 | 0:36:58 | |
The slanting sun may not be strong, | 0:37:06 | 0:37:09 | |
but it is at least continuous during the few weeks of high summer. | 0:37:09 | 0:37:13 | |
The heat of the poppy gathers by staring continuously at the sun enables it to develop the seeds | 0:37:18 | 0:37:23 | |
in the centre of each flower before summer comes to an end | 0:37:23 | 0:37:27 | |
and the sun disappears below the horizon for months. | 0:37:27 | 0:37:31 | |
On the high peaks of the Alps, | 0:37:46 | 0:37:48 | |
spring brings a greater benefit than it does in the Arctic. | 0:37:48 | 0:37:52 | |
The sun rises higher in the sky and is warm enough to melt all but the highest snowfields. | 0:37:52 | 0:37:58 | |
As it melts, it reveals the snow bell, already in flower. | 0:37:59 | 0:38:04 | |
The plant formed its flower buds last autumn, | 0:38:07 | 0:38:10 | |
before the increasing cold shut down all its activities for the winter. | 0:38:10 | 0:38:15 | |
The buds remained dormant until the spring sunshine filtering down through the snow triggered | 0:38:15 | 0:38:21 | |
them into action and they opened even before | 0:38:21 | 0:38:25 | |
the snowy blanket above them had melted. | 0:38:25 | 0:38:28 | |
In summer, the high meadows, | 0:38:35 | 0:38:37 | |
newly freed from snow, fill with flowers. | 0:38:37 | 0:38:41 | |
Because for so much of the time it's so cold, | 0:38:42 | 0:38:44 | |
the vegetation here decays only very slowly. | 0:38:44 | 0:38:48 | |
So a peaty soil forms, but it's only a thin layer over solid rock | 0:38:48 | 0:38:53 | |
and boulders and trees find it difficult to get root. | 0:38:53 | 0:38:57 | |
Not only that, but avalanches regularly sweep these slopes, | 0:38:57 | 0:39:02 | |
carrying away saplings before they can get firmly established. | 0:39:02 | 0:39:07 | |
So, shallow-rooted plants have these parts of the mountains | 0:39:07 | 0:39:11 | |
largely to themselves, and in summer they bring a rich display of colour. | 0:39:11 | 0:39:16 | |
But, for every 1000 ft you climb, | 0:39:16 | 0:39:19 | |
the average temperature drops by about three degrees. | 0:39:19 | 0:39:23 | |
Plants living in the high mountains | 0:39:23 | 0:39:26 | |
have to be able to survive extreme cold. | 0:39:26 | 0:39:29 | |
It's very important to keep out of the worst of the chilling winds, | 0:39:29 | 0:39:33 | |
and many plants here form small, rounded humps | 0:39:33 | 0:39:36 | |
and that brings them a number of advantages. | 0:39:36 | 0:39:40 | |
Growing into the shape of a cushion | 0:39:44 | 0:39:46 | |
is an excellent way of conserving heat. | 0:39:46 | 0:39:49 | |
And no plants do it more spectacularly than these growing | 0:39:49 | 0:39:52 | |
high in the mountains of Tasmania. | 0:39:52 | 0:39:55 | |
These are the largest cushion plants in the world. | 0:39:55 | 0:39:58 | |
They grow to over 12 ft across. | 0:39:58 | 0:40:00 | |
Any one square yard contains over 100,000 shoots. | 0:40:00 | 0:40:04 | |
So I guess this one cushion around me contains several million. | 0:40:04 | 0:40:09 | |
This rounded shape does more than just reduce wind chill. | 0:40:10 | 0:40:15 | |
The air temperature around me here at about 3,500 ft high | 0:40:15 | 0:40:20 | |
is only a degree or so above freezing. | 0:40:20 | 0:40:22 | |
But if I take this temperature probe, put it on the surface of this cushion, | 0:40:22 | 0:40:26 | |
I can see that there, it is several degrees warmer. | 0:40:26 | 0:40:30 | |
The cushion in fact acts as a solar panel, | 0:40:30 | 0:40:32 | |
absorbing heat directly from the sun. | 0:40:32 | 0:40:35 | |
So that even on very cold days, providing it's not covered with snow | 0:40:35 | 0:40:39 | |
and is exposed to direct sunshine, it can photosynthesise and grow. | 0:40:39 | 0:40:44 | |
The plants that form these spectacular cushions | 0:40:44 | 0:40:47 | |
come from several different families. | 0:40:47 | 0:40:50 | |
Sedges and rushes, daisies and dandelions. | 0:40:50 | 0:40:53 | |
One cushion may contain several species tightly packed together | 0:40:53 | 0:40:58 | |
and growing to exactly the same height. | 0:40:58 | 0:41:00 | |
For one kind to grow higher than those around it would be suicidal. | 0:41:00 | 0:41:05 | |
In the New Zealand Alps, one of these cushion-forming species | 0:41:06 | 0:41:10 | |
also protects itself by developing a blanket of hair. | 0:41:10 | 0:41:15 | |
This tall pillar growing on Mount Kenya | 0:41:15 | 0:41:18 | |
also covers itself in a blanket. | 0:41:18 | 0:41:21 | |
It's a giant lobelia. | 0:41:21 | 0:41:23 | |
Its long leaves are fringed with dense hairs. | 0:41:24 | 0:41:27 | |
Its flowers are hidden away from the frost beneath this downy covering. | 0:41:27 | 0:41:33 | |
There's no point in having bright petals if they can't be seen, and these are just simple tubes. | 0:41:33 | 0:41:38 | |
But the lobelia's pollinator, a sunbird, knows where they are | 0:41:38 | 0:41:43 | |
and how to reach them. | 0:41:43 | 0:41:44 | |
During the day, it can get quite warm. | 0:41:45 | 0:41:48 | |
For Mount Kenya stands almost exactly on the equator. | 0:41:48 | 0:41:51 | |
But up here, at 14,000 ft, once the sun goes down it gets bitterly cold, | 0:41:51 | 0:41:57 | |
and then the lobelia will have real need of its hairy blanket. | 0:41:57 | 0:42:01 | |
There are other giants here, too. | 0:42:02 | 0:42:04 | |
Tree groundsels, relatives of the little yellow weed that grows in European gardens. | 0:42:04 | 0:42:10 | |
They have a different way of dealing with the cold nights. | 0:42:10 | 0:42:14 | |
Their dead leaves remain attached | 0:42:14 | 0:42:16 | |
to the stem so that they act like lagging and prevent the liquids | 0:42:16 | 0:42:20 | |
in the pipes running up inside the trunk from freezing solid. | 0:42:20 | 0:42:24 | |
Conditions here can change with extraordinary speed. | 0:42:24 | 0:42:28 | |
One moment the equatorial sun is blazing down from a cloudless sky, | 0:42:28 | 0:42:33 | |
the next, a chilling wind begins to blow and the great mountain | 0:42:33 | 0:42:37 | |
collects a cloud cover. | 0:42:37 | 0:42:39 | |
As well as the tree groundsel, there's another member of the family | 0:42:43 | 0:42:47 | |
that grows close to the ground like a cabbage. | 0:42:47 | 0:42:51 | |
As night falls, | 0:42:51 | 0:42:52 | |
it makes its own preparations for surviving the bitter cold. | 0:42:52 | 0:42:57 | |
The most precious and vulnerable part of the plant is the bud | 0:42:59 | 0:43:03 | |
in its centre, from which all growth comes. | 0:43:03 | 0:43:06 | |
That must be protected at all costs and folding the thick leaves over it does the trick. | 0:43:06 | 0:43:11 | |
The birdcage plant lives in California. | 0:43:21 | 0:43:24 | |
But the desert dunes are always moving and a sheltered site | 0:43:24 | 0:43:27 | |
can suddenly become intolerably exposed - | 0:43:27 | 0:43:30 | |
so the plant must find a new place. | 0:43:30 | 0:43:33 | |
This plant is now dead. | 0:43:51 | 0:43:53 | |
But within it, there is still life. | 0:43:53 | 0:43:57 | |
These tiny particles are the next generation. | 0:43:59 | 0:44:02 | |
Each is a miracle of packaging because each, after all, contains | 0:44:02 | 0:44:07 | |
complete genetic instructions for rebuilding an adult plant like this. | 0:44:07 | 0:44:13 | |
And it's precisely because these grains are so small | 0:44:13 | 0:44:16 | |
that it is in this form that most plants do most of their travelling. | 0:44:16 | 0:44:21 | |
Some of these genetic particles, in fact, are microscopic. | 0:44:21 | 0:44:24 | |
The smallest of all belong to fungi. | 0:44:26 | 0:44:29 | |
Fungi are not, to be accurate, plants at all. They belong to a kingdom all their own. | 0:44:29 | 0:44:34 | |
But the particles they produce, called spores, are in many ways similar to seeds. | 0:44:34 | 0:44:41 | |
A single puffball produces so many that someone has calculated that if, | 0:44:45 | 0:44:49 | |
for two generations, every spore | 0:44:49 | 0:44:51 | |
grew into an adult, the resultant mass of puffballs would be 800 times | 0:44:51 | 0:44:57 | |
the volume of the Earth. | 0:44:57 | 0:44:58 | |
Like the birdcage plant, a puffball can be carried along by the wind. | 0:45:01 | 0:45:05 | |
But the real long-distance travelling is done by the spores | 0:45:05 | 0:45:09 | |
that are knocked from it in clouds, like smoke. | 0:45:09 | 0:45:12 | |
In autumn, other, smaller fungi appear on the woodland floor. | 0:45:23 | 0:45:29 | |
Earth stars. | 0:45:31 | 0:45:33 | |
Their appearance, just after they have emerged above ground, | 0:45:36 | 0:45:39 | |
gives little hint of how complex they will become. | 0:45:39 | 0:45:42 | |
As the damp autumn airs blow through the leafless woods, | 0:45:42 | 0:45:46 | |
the earth stars begin to transform themselves. | 0:45:46 | 0:45:50 | |
They open at this time of year to take advantage of the falling rain. | 0:46:23 | 0:46:28 | |
A drip gives them all the energy they need | 0:46:36 | 0:46:38 | |
to propel their spores into the air. | 0:46:38 | 0:46:41 | |
A snow leopard, the rarest of Himalayan animals. | 0:47:05 | 0:47:10 | |
The Planet Earth team spent months | 0:47:11 | 0:47:14 | |
just trying to glimpse a snow leopard, and more months to film one. | 0:47:14 | 0:47:20 | |
How do you conserve a creature that you're lucky even to see? | 0:47:23 | 0:47:27 | |
How do these scientists, or how do these conservationists know | 0:47:29 | 0:47:34 | |
where this animal is, how many there are, and what their behaviour is? | 0:47:34 | 0:47:39 | |
Someone told me that there were 3000 between China and Afghanistan. | 0:47:39 | 0:47:44 | |
Now, I mean, we've had a very tough time identifying three. | 0:47:44 | 0:47:49 | |
There is a threat to its existence, | 0:47:51 | 0:47:53 | |
simply because not enough is known about it. | 0:47:53 | 0:47:57 | |
We really don't know where it thrives. | 0:47:57 | 0:48:01 | |
Because it's isolated, you expect that a lot of wildlife is there. | 0:48:02 | 0:48:06 | |
How much of it and what are the elements affecting it are unknown. | 0:48:06 | 0:48:10 | |
In the distant reaches of Outer Mongolia, | 0:49:03 | 0:49:06 | |
one of the planet's great migrations is underway. | 0:49:06 | 0:49:10 | |
Few people ever see this extraordinary annual event. | 0:49:11 | 0:49:16 | |
Mongolian gazelle. 2 million are thought to live here. | 0:49:19 | 0:49:22 | |
But what will happen to the gazelle in 15 years? | 0:49:25 | 0:49:29 | |
And if they go the way of the saiga, will it matter? | 0:49:29 | 0:49:32 | |
Should we concentrate only on the most important species? | 0:49:32 | 0:49:36 | |
If so, which ones are the most important? | 0:49:37 | 0:49:41 | |
We need every species. | 0:49:42 | 0:49:45 | |
We need a great diversity of species. | 0:49:45 | 0:49:48 | |
We need every species | 0:49:50 | 0:49:53 | |
because... | 0:49:53 | 0:49:54 | |
when you start decreasing the numbers of species, | 0:49:54 | 0:49:58 | |
especially in an environment | 0:49:58 | 0:50:00 | |
which has adapted to a high level of diversity, | 0:50:00 | 0:50:03 | |
you'll start reducing the stability of the area. | 0:50:03 | 0:50:08 | |
I think any extinction that is before its time matters. | 0:50:09 | 0:50:14 | |
If one was to pick two groups, it's at the very top and the very bottom. | 0:50:14 | 0:50:18 | |
You know, the creatures that keep the planet going | 0:50:18 | 0:50:21 | |
and the big organisms that keep our souls and imaginations on fire. | 0:50:21 | 0:50:27 | |
The tiger, probably the best known poem in the English language, | 0:50:27 | 0:50:31 | |
Blake's Tiger Tiger, which | 0:50:31 | 0:50:32 | |
every child can recite and every child understands what it means. | 0:50:32 | 0:50:36 | |
"Tiger Tiger, burning bright, In the forests of the night." | 0:50:36 | 0:50:40 | |
They know that it's not just dark forest. | 0:50:40 | 0:50:42 | |
It's to do with the pulse of life. | 0:50:42 | 0:50:45 | |
If we lose these majestic creatures, | 0:50:45 | 0:50:48 | |
with their sense of power and ancestry and their possibility | 0:50:48 | 0:50:54 | |
of power over us sometimes, then I think | 0:50:54 | 0:50:57 | |
we are diminished by that, as well as the ecosystem. | 0:50:57 | 0:51:03 | |
If you go to a village in India | 0:51:03 | 0:51:05 | |
and you start talking to them about saving the tiger, | 0:51:05 | 0:51:08 | |
people will say to you, "How can you talk about saving the tiger when | 0:51:08 | 0:51:13 | |
"we've got starving people here?" | 0:51:13 | 0:51:15 | |
I think the way conservation was developed over the last 50 years, | 0:51:15 | 0:51:21 | |
we have focused our energy into trying to convince people | 0:51:22 | 0:51:26 | |
that things like tigers are inherently important. | 0:51:26 | 0:51:29 | |
Ultimately, if our movement is not relevant to the lives of real people | 0:51:29 | 0:51:34 | |
dealing with real issues, we're just going to be preaching to the choir. | 0:51:34 | 0:51:38 | |
My concern is the great indifference that most people have toward | 0:51:38 | 0:51:43 | |
the species of lesser creatures | 0:51:43 | 0:51:45 | |
that they'd never noticed or dismissed as bugs and weeds. | 0:51:45 | 0:51:48 | |
That's where the bulk of life on Earth exists. | 0:51:48 | 0:51:52 | |
When you magnify one of these organisms | 0:51:52 | 0:51:57 | |
to human size and approach it as an independent, | 0:51:57 | 0:52:02 | |
highly-complicated entity on Earth, | 0:52:02 | 0:52:05 | |
then you see it as the equal of a large mammal. | 0:52:05 | 0:52:10 | |
The organisms that matter, perhaps most of all, are the plants. | 0:52:13 | 0:52:18 | |
Many of them very unglamorous, hard-working, fantastically common. | 0:52:18 | 0:52:23 | |
Of course, without which, | 0:52:23 | 0:52:24 | |
there would be no way in which the energy of the sun | 0:52:24 | 0:52:27 | |
was translated into available energy for all other organisms. | 0:52:27 | 0:52:33 | |
Each of these creatures plays a role in its ecosystem. | 0:52:33 | 0:52:36 | |
Some of those roles quite important. | 0:52:36 | 0:52:38 | |
If you think in terms of a brick wall, | 0:52:38 | 0:52:40 | |
we are systematically knocking out bricks. | 0:52:40 | 0:52:42 | |
Sooner or later the wall collapses. | 0:52:42 | 0:52:45 | |
This is biodiversity. | 0:53:35 | 0:53:38 | |
The planet's full wide range of life-forms. | 0:53:38 | 0:53:41 | |
And it benefits every single species, including the human one. | 0:53:41 | 0:53:46 | |
How? | 0:53:46 | 0:53:47 | |
The whole planet Earth is a system | 0:53:47 | 0:53:50 | |
and we, human species, | 0:53:50 | 0:53:53 | |
are only a very small part of the system. | 0:53:53 | 0:53:57 | |
There are literally millions of species out there. | 0:53:57 | 0:53:59 | |
We may not know them. | 0:53:59 | 0:54:01 | |
We may not know their value. | 0:54:01 | 0:54:03 | |
But we want to conserve them. | 0:54:03 | 0:54:06 | |
There are a very wide range of practical reasons | 0:54:08 | 0:54:11 | |
as to why we need to conserve this planet's biodiversity. | 0:54:11 | 0:54:14 | |
For a start, all our food ultimately derives from biological systems. | 0:54:14 | 0:54:18 | |
So do a lot of our medicines. | 0:54:18 | 0:54:19 | |
A lot of our industrial products are based upon chemicals | 0:54:19 | 0:54:23 | |
we've taken from nature, for example. | 0:54:23 | 0:54:25 | |
Biodiversity is very much part, therefore, of the global economy. | 0:54:25 | 0:54:29 | |
Very much part of our wellbeing. | 0:54:29 | 0:54:31 | |
I don't think there's a single compelling | 0:54:31 | 0:54:34 | |
reason of an economic kind | 0:54:34 | 0:54:38 | |
that compels us to preserve biological diversity. | 0:54:38 | 0:54:42 | |
Insofar as there are reasons, one says, we want to preserve all this | 0:54:42 | 0:54:47 | |
gene pool because maybe we can use it. | 0:54:47 | 0:54:50 | |
Very human-centred. | 0:54:50 | 0:54:51 | |
Maybe we can be clever enough to just understand the molecules ourselves. | 0:54:51 | 0:54:56 | |
The second says, we depend on the services ecosystems give - pollinating, | 0:54:56 | 0:55:02 | |
cleaning water... | 0:55:02 | 0:55:05 | |
and as we reduce the number of species, we can't be sure they will continue to deliver those services. | 0:55:05 | 0:55:11 | |
Maybe we could be clever enough to live in an impoverished world. | 0:55:12 | 0:55:16 | |
The third reason is a straight ethical reason that says we have a responsibility of stewardship. | 0:55:16 | 0:55:22 | |
And how strong that is depends on the luxury you have to enjoy it. | 0:55:24 | 0:55:28 | |
The head count of the Amur leopard is disturbing. | 0:55:41 | 0:55:45 | |
Because of habitat loss and poaching, | 0:55:45 | 0:55:49 | |
there are just 30 left in the wild. | 0:55:49 | 0:55:52 | |
With extinction so close, conservation becomes desperate. | 0:55:56 | 0:56:01 | |
Here in New Orleans, the Audubon zoo, we have a pair of the Amur leopards. | 0:56:08 | 0:56:12 | |
Our long-term strategy with them is to work with what we call | 0:56:12 | 0:56:16 | |
the species survival plan. | 0:56:16 | 0:56:18 | |
The Amur leopard is one of the high-priority animals. | 0:56:18 | 0:56:22 | |
What's happened recently, and some of the work we're doing involving cloning, has allowed | 0:56:27 | 0:56:33 | |
us to now not necessarily take eggs and sperm but we're able | 0:56:33 | 0:56:38 | |
to take tissue samples from these animals. | 0:56:38 | 0:56:41 | |
Put this tissue sample in a culture and where it was once maybe 100 cells, | 0:56:41 | 0:56:44 | |
we can now grow thousands of cells. | 0:56:44 | 0:56:46 | |
Each one of those cells contains the complete copy of DNA of this animal. | 0:56:46 | 0:56:53 | |
So we can freeze these cells. | 0:56:53 | 0:56:56 | |
Let's say 50 years from now, scientists go into those liquid nitrogen containers and they | 0:56:56 | 0:57:02 | |
pull out the DNA from tigers, Amur leopards, rhinos. | 0:57:02 | 0:57:07 | |
That DNA is alive and it's able to be used to produce | 0:57:07 | 0:57:12 | |
embryos that then could result in babies - in offspring. | 0:57:12 | 0:57:16 | |
So, what I'm hoping we leave in our lifetime is this living library for the future. | 0:57:16 | 0:57:21 | |
50 years from now, the scientists can say, "Oh my gosh, we're about to lose | 0:57:21 | 0:57:27 | |
"this little rusty-spotted cat from Sri Lanka or the Amur leopard, but do you know what? We have the DNA. | 0:57:27 | 0:57:33 | |
"We have the science to at least be able to bring the numbers up of the species so they won't go extinct." | 0:57:33 | 0:57:40 | |
We have to be careful about producing | 0:57:40 | 0:57:42 | |
something which is a facsimile of a wild animal, | 0:57:42 | 0:57:46 | |
from something which is able to exist in the wild. | 0:57:46 | 0:57:49 | |
One of the problems of keeping animals in conventional zoos, the | 0:57:50 | 0:57:54 | |
selective pressures are very great | 0:57:54 | 0:57:56 | |
and you're actually moving that animal towards domestication. | 0:57:56 | 0:58:01 | |
It may look the same, but it may not have the skills | 0:58:01 | 0:58:04 | |
or the behavioural attributes or physiology to survive in the wild. | 0:58:04 | 0:58:08 | |
You know it's funny when people say, we may be playing God, we may be | 0:58:08 | 0:58:11 | |
controlling and taking charge of kind of these species' destinies. | 0:58:11 | 0:58:17 | |
But you know, man played God a long time ago. | 0:58:17 | 0:58:20 | |
I think, and I believe, God gave us stewardship over these animals. | 0:58:21 | 0:58:25 | |
What we're doing is using the capabilities that we have | 0:58:25 | 0:58:30 | |
as humans to not destroy animals any longer but to try to protect them, | 0:58:30 | 0:58:33 | |
to preserve them and bring them back. | 0:58:33 | 0:58:36 | |
Subtitles by Red Bee Media Ltd | 0:58:44 | 0:58:47 | |
E-mail [email protected] | 0:58:47 | 0:58:50 |