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00:00Our planet is alive, from the shores of Antarctica to the plains of Africa.
00:25It's a world of great beauty and stunning diversity.
00:43But there is also a dark side.
00:47Life is a war, filled with predation, rivalry, and brutality.
01:03But what created this great drama called life, with its beauty and its violence?
01:13Breakthroughs in our understanding of evolution can now explain how animal life arose,
01:21how it fought to survive in the ancient past, and still struggles today.
01:34We now know how behavior has been shaped by conflict, in battles for mates, by predators chasing prey,
01:48through the tensions in family life, and by mind games of intelligence.
01:56We share the earth with fellow veterans of life's four billion year war for survival.
02:02The astounding variety of winners in this ancient struggle is the triumph of life.
02:26The present world has been created.
02:38The present world has been created.
02:43A tropical shore, 65 million years ago.
03:09Life has already existed for more than 3 billion years.
03:13The struggle to survive continues.
03:18Trudontid dinosaurs scavenge the beaches.
03:30Primitive seabirds return from a hard day's fishing.
03:35Below the waves, turtles navigate dangerous waters.
03:44Pliosaurs, huge predatory reptiles, patrol the coast.
03:53The fastest and most alert survive.
04:02Like all living things, they fight to continue their line and are compelled to nest despite the dangers.
04:15In the ancient battle for survival, there have been many years of survival.
04:20There have always been winners and losers.
04:21In the ancient battle for survival, there have always been winners and losers.
04:29Those that live and those that die.
04:38In the ancient battle for survival, there have always been winners and losers.
04:47Those that live and those that die.
04:52But dinosaurs, not turtles, were doomed.
05:08Today, only fossil bones testify to the dinosaur's ancient rule.
05:33But life itself survived.
05:49Turtles still hatch on tropical beaches.
05:52The world has changed in 65 million years.
05:55But the fight to survive remains the same.
06:02Many set out, but not all will reach the sea.
06:09Today's predators are waiting.
06:11But they must run the gauntlet.
06:18The race of their lives is on.
06:25Life's path is full of obstacles.
06:28The journey, always a struggle.
06:36Survival odds are not random.
06:38Each individual is a unique product of its parents.
06:42And some have the edge on others.
06:49Moving swiftly in company is safest.
06:52Getting left behind or lost can be fatal.
07:08While the weak succumb, the strong struggle on.
07:28Vultures take a heavy toll on both.
07:30Frigate birds now launch aerial attacks.
07:33Frigate birds now launch aerial attacks.
07:37Stragglers fall prey to forest mammals.
07:58Coates and coyotes.
08:00Frigate birds.
08:01Frigate birds.
08:07While the race for the sea continues.
08:09One hatchling heads inland.
08:14But this is no place for a sea turtle.
08:21For other creatures, the land has long provided huge opportunities.
08:24Myriad animals have escaped the sea and now carve out a living here.
08:35Crocodiles have barely changed since the age of dinosaurs.
08:40While birds have taken many forms.
08:45Mammals have also diversified in body and behavior.
08:48All living things are triumphant veterans of the four billion year war.
09:04Called evolution.
09:06Which has raged since life first appeared.
09:11Survival skills stay sharp.
09:13As they are tested anew.
09:15Every moment of every day.
09:18The cast of life's drama is never fixed.
09:22And changes over time.
09:24As the victorious prevail.
09:28The rules of the war are harsh.
09:31Some individuals fail.
09:32Others triumph.
09:33Only winners emerging from the battleground of life.
09:34Carry their family line forward through time.
09:35The cast of life's drama is never fixed.
09:37The cast of life's drama is never fixed.
09:38And changes over time.
09:39As the victorious prevail.
09:41The rules of the war are harsh.
09:42The rules of the war.
09:43The rolling heat.
09:44The sword of the war win.
09:46Brutal
10:12Despite the losses, some youngsters do make it through the ranks of predators,
10:18which have gorged until they can eat no more.
10:35They now face life's continuing challenge.
10:42Those fittest for the riggers ahead may one day return to breed themselves.
11:00As the secrets of each generation's success are passed on, life evolves.
11:06But clues to life's shared ancestry remain hidden within every animal.
11:14Skeletons reveal remarkable similarities.
11:19Bony fingers, limbs and backbones, though subtly changed, are recognizable in very different vertebrates.
11:27Birds, whales and turtles are far more alike than they appear on the surface.
11:43Each living form began the journey that shaped it way back in the past.
11:53A turtle, about to hatch, is clearly a turtle, with an obvious shell and flippers.
12:11A week or so earlier, these features are less distinct.
12:23A young embryo could be almost any vertebrate, with spine, eyes and four stubby limbs.
12:40Beyond that, it's more fish-like.
12:43Then, just a mass of dividing cells.
12:46Finally, it's a single cell, but one containing the complete blueprint for a turtle.
12:57At the heart of the cell, lie the chromosomes.
13:01And within them, lies the key to life itself.
13:06The most incredible substance on Earth.
13:08A unique molecule in the shape of a double helix.
13:13DNA.
13:17Evolution is driven by the way DNA copies itself with near-perfect accuracy.
13:22And the information it contains.
13:25Its genes shapes life's varied patterns.
13:28African hunting dogs are distinct from other kinds of dog.
13:43And individuals differ from each other in many ways,
13:47including the unique markings on each dog's coat.
13:49They get their looks from their parents, through their genes.
14:02But they also inherit much more.
14:08Even the urge to hunt, vital to their survival, is built into them from birth.
14:19Only good hunters live to breed.
14:22A pack has just one breeding male.
14:25And his distinctive white tail is mirrored in some of his pups back at the den.
14:28Not only good hunters, but also good hunters.
14:32A pack has just one breeding male.
14:35And his distinctive white tail is mirrored in some of his pups back at the den.
14:41A pack has just one breeding male.
14:47And his distinctive white tail is mirrored in some of his pups back at the den.
14:54Not all look the same, since half their genes come from their darker mother.
15:06With a mix of genes from two successful parents,
15:09they've a chance to grow up strong and to continue their family line.
15:24Genes shape every detail of animal form.
15:37Some have brought recent innovations,
15:40but many originated way back in time
15:43and have flowed through countless generations of triumphant life.
15:47I'm a person here.
15:48How is that a species?
15:49Why are theyismo finding people living with
15:50this kind of human brain murderer?
15:57Why are they trading these names?
15:59In Vangust me.
16:12Feel free to drive this refuge.
16:13But how did life begin?
16:25What kinds of creatures were the ancestors of those alive today?
16:30And how did the first genes, the original threads of life, arise?
16:43HE SINGS
17:13Primeval Earth, four billion years ago, the toxic air was devoid of oxygen.
17:22Molten lava spewed into a noxious sea, and yet these were the perfect conditions for the building blocks of life to form.
17:34Such foul waters may have been the crucibles of creation.
17:39Chemicals reigned in, and ultraviolet radiation and lightning bombarded them.
17:47An organic soup gradually formed.
17:51All was chaos, but order and complexity somehow emerged.
18:00A very special molecule with an elegant spiral shape arose.
18:05It alone copied itself faster than it was destroyed and multiplied.
18:13This renewal was the origin of life.
18:18And once it found protection inside cell walls, life was set to transform the planet.
18:24When cells first trapped the sun's energy three and a half billion years ago, life began to blossom.
18:36The oceans teemed with simple plants, and mats of them, layered with sediment, built the world's first living monuments.
18:50Stromatolites.
18:51Stromatolites.
18:54For over a billion years, these three-foot-high mounds were the pinnacles of life's progress.
19:01But the Earth would be transformed by their waste.
19:06Oxygen.
19:07This new gas, at first toxic to all life, gave rise to the ozone layer.
19:20Shielded for the first time from the sun's damaging ultraviolet rays, life now made huge advances.
19:26Plants, which had produced oxygen in the first place, now came under threat from primitive animals that thrived on oxygen and consumed them.
19:39Amoeba engulfed plants.
19:54Ciliates wafted them inside.
19:57Two billion years ago, single-celled animals first did what grazing mammals do now.
20:02They used oxygen to burn up plant food.
20:09But how did the spectacle of today arise from such simple origins?
20:18Progress came when identical cells teamed up to form cooperative bodies.
20:28Then, life really moved on as cells specialized.
20:33In jellyfish, some gave propulsion, others caught food.
20:39Multi-celled life was now taking shape.
20:48The advance was driven by genes deep within.
20:53A recent breakthrough in understanding how genes organize bodies has shed new light on the evolution of complex animals.
21:05As embryos develop, some genes control which cells do what.
21:11It was the emergence of these special genes which organized bodies into segments, with head ends and tail ends, that allowed life to take off like never before.
21:26Five hundred and fifty million years ago, life exploded into a multitude of new complex forms.
21:40Many of those classic designs survive today.
21:45Segmented worms marched over the seabed.
21:49Life began to move in more elaborate ways.
21:54Life began to move in more elaborate ways.
21:58Life began to move in more elaborate ways.
22:00Life began to move in more elaborate ways.
22:01Life was when possible, life began to move in half an hour.
22:03Life began to move as high as runnerså·¥.
22:04Life began to move in longer point.
22:06New, strangely shaped animals appeared, encased in tough skeletons with flexible joints.
22:33The ancestors of sea spiders and crustaceans were on the move.
23:02Genes that built better eyes and successful body shapes survived.
23:18The pace of life increased and new, dynamic breeds of animal preyed on one another.
23:34Defense became vital, and armor plating and spines proliferated.
23:45Predatory worms could be defeated by tough shells and escape maneuvers.
23:53With genes shaping life like never before, all the basic animal groups alive today emerged in just 50 million years.
24:01The previous three billion had led to nothing more complex than jellyfish.
24:11Life was also threatened by the first large predator.
24:18More than three feet long, Anomalikaris was the scourge of the ancient seas.
24:39But the big predator's days were numbered, for a little creature had evolved whose line would take over the world.
24:54Pikaia gently filtered food from water, as lancelets still do today.
25:04What made Pikaia special, and ancestral to our own vertebrate line, was its spine of cartilage supporting its muscles.
25:14This light, strong design allowed speedy escapes.
25:23But the ancient seas were still dominated by invertebrates.
25:33Their heavily armed hordes were the top predators and scavengers for another hundred million years.
25:42Today's crustaceans reflect that ancient armored world.
25:46But the invertebrates are not the force they once were.
25:54Alongside these hardened battlers, the vertebrates survived, and one line evolved into fish.
26:02They had no jaws, like today's lampreys, but compared to most invertebrates, they had better eyesight and sharper brains.
26:16When it came to alertness and reaction speed, the invertebrates were beaten.
26:31Fish became faster and sleeker, and far more numerous.
26:41They developed a bony spine, and crucially, toothy jaws.
26:46The sea became a much more dangerous place.
27:01in the background
27:05with earth paws, you know they didn't grab a muscle, though.
27:06Anybody can get a few Можно appear to be okay if you join the
27:14procedentiining and other species of earth.
27:16While the ocean is on top of the ocean,
27:21the ocean is on top of the ocean.
27:24of the sea and the sea.
27:46While the oceans were full of life,
27:48the virgin land beyond the sea lay empty.
27:54But 450 million years ago, things were about to change.
28:20Life invaded from the sea.
28:23The sea was invaded from the sea.
28:53These strange creatures are horseshoe crabs, ancient relatives of spiders.
29:06To this day, they emerge on just a few tides a year, as their ancestors have done for hundreds of millions of years.
29:23They come to mate at the edge of the sea.
29:33Females burrow into the sand and lay their eggs beyond the reach of the ocean's hungry hordes.
29:43Once, they had the beaches to themselves, but today, flocks of birds descend.
29:53Gulls gorge on eggs exposed by the waves.
30:00And vast numbers of shorebirds join this annual feast.
30:12Ancient life and modern life now converge as horseshoe crabs and birds fight the ongoing battle for survival.
30:23Flipped over by waves, some crabs are stranded. They soon die as their gills dry out.
30:34But most live on. Horseshoe crabs have barely changed in hundreds of millions of years and continue a successful way of life.
30:48Strong skeletons allow them to venture briefly onto land, but they remain creatures of the sea.
30:55But such pioneers were just the first wave of life to reach the land.
31:06By 400 million years ago, much of the earth was cloaked in green.
31:11Plants had colonized fresh waters and spread onto land.
31:18Once they were established, animals soon followed.
31:25Centipedes were among the first land creatures.
31:36They developed simple lungs and skin that kept vital water in.
31:39Scorpions, cousins of the horseshoe crabs, also made an early move onto land.
31:50Their line of eight-legged predators has spread far and wide since then.
31:55The invertebrates were the first animals ashore, but others were not far behind.
32:17Fish penetrated weed-choked lagoons.
32:31Using bony fins, they forced their way through the tangles to stalk prey.
32:47As competition increased, fish sought new pastures to hunt in.
33:07Fins became more and more like legs.
33:10The vertebrates were on the verge of a breakthrough.
33:17The first amphibians emerged from the swamp some 370 million years ago.
33:40Their soft, moist skins absorbed some oxygen,
33:44and simple lungs allowed them to breathe air.
33:56The exertion of hauling themselves over land required plenty of fuel.
34:01But the land was now crawling with life.
34:11The first flightless insects made easy prey.
34:17The first flightless insects made easy prey.
34:20The first flightless insects began to survive.
34:23The first flightless insects began to survive.
34:24The first flightless insects was more than one of the most.
34:29Despite delicate skin, many amphibians came to live on land,
34:34as the feeding was so good.
34:35But they were confined to damp places.
34:36land as the feeding was so good, but they were confined to damp places.
34:47The insects went much further. 320 million years ago, some forms underwent a remarkable change.
34:55Under the control of new genes, they transformed into very different creatures.
35:15They grew wings.
35:25Life was about to conquer the air, as well as the land.
35:47The power of flight gave insects a huge advantage.
35:51They now number more than half of all kinds of animal on Earth today, and they've reached
35:58almost every corner of the planet.
36:21They have invaded some of the driest places on Earth.
36:37Ants are by far the most numerous insects of all, and their social habits have helped them
36:43to succeed around the world. But here, they are not alone.
36:51Reptiles, evolved from amphibians but with a tougher, waterproof skin,
37:14ventured where amphibians could not go.
37:27The skin of horned lizards can even resist attack by ants,
37:34at least most of the time.
37:35Reptiles also pioneered another survival strategy. Waterproof eggs allowed them to breed in dry places.
37:51Developing young were now bathed in a miniature ocean within the eggs.
37:55The reptiles were on the verge of global domination.
38:07One thing held them back. With their skin now water and air tight, breathing became a problem.
38:13Lizards breathe as their chests expand and contract. But because of how they walk, they often have to hold their breath.
38:32Their sprawling gait, inherited from ancestral fish, forces their chests to flex as they walk.
38:38Their lungs can't expand to draw in air, and lizards easily become breathless.
38:52The ancestors of the crocodiles, though, developed far more stamina.
38:56By standing up on their legs, the crocodile line began to walk tall.
39:12No longer swaying from side to side,
39:14these high-stepping reptiles breathed easily as they strode relentlessly over the land.
39:26And more than just walking, these reptiles could sprint.
39:56the crocodile line began to walk tall.
40:09Today, the crocodiles have returned to the water and only rarely trek overland.
40:15But 200 million years ago, the small steps their ancestors took led to a giant leap forward.
40:26An athletic line of dinosaurs came to tyrannize the world.
40:42But the future belonged to mammals living quietly in the shadow of the dinosaurs.
40:4865 million years ago, the world suffered a massive upheaval.
41:05All the great dinosaurs disappeared.
41:08But many creatures survived, including the mammals.
41:21The earliest were small and furry, quite like today's tree shrews.
41:25They had evolved from reptiles whose scales became modified into hair.
41:30Unlike the dinosaurs, they survived a cooling of the climate.
41:34And dinosaur doom led to mammalian triumph.
41:44The mammals also had great strength in their family life.
41:52Mothers reared their young by providing milk.
41:54In the void left by the dinosaurs, the mammals stepped into a world of new opportunities.
42:16Many teamed up for survival and came to live in ever bigger families.
42:20In a dazzling range of forms around the world, the mammals have followed in the dinosaur's footsteps.
42:43They have taken over the roles of powerful predators, resourceful scavengers, and grazers.
43:03And they ventured into the world's harshest regions.
43:13They still share an ancient need.
43:26Water, where life itself was born.
43:33A waterhole is a meeting place for many mammals.
43:43A waterhole is a meeting place for many mammals.
43:44Their varied forms reflect both their different ways of life,
43:49and the long evolutionary war their forebearers fought to survive.
44:13The battle to live has molded mammals into a huge variety of shapes and sizes.
44:37Some now need to be wary of others.
44:43Mammals have taken center stage.
44:56But have the dinosaurs all disappeared?
45:05Perhaps not entirely.
45:13Birds are really feathered dinosaurs.
45:21One line of small, fast-moving, and most likely warm-blooded dinosaurs evolved into birds.
45:35Birds have become great successes thanks to their feathers.
45:38As well as insulating them from heat and cold, feathers gave birds a further power.
45:53A power that made life much harder for their predators.
45:56Birds have conquered the air, just as mammals have mastered the land.
46:16The vertebrates have come a long way since their lowly origins in the sea.
46:20Birds have come a long way since they are in the sea.
46:29Evolution's products might seem perfect, but the process never ceases.
46:36Where opportunities arise, further change can always occur.
46:40On the Galapagos Islands, a variety of creatures have returned to the cradle of their ancestors.
46:52The sea.
46:58Marine iguanas evolved from land lizards that found the best feeding on the seashore.
47:03Many would have been washed in.
47:13Those that swam survived drowning.
47:16And today, their descendants dive in to reach the rewards below.
47:33These bizarre reptiles, remolded in form and action by evolution, swim daily out to sea.
47:50Here, by harvesting the choicest seaweed, they have carved out a unique way of life.
47:56The sea.
48:00Fish have lured other animals to the sea.
48:04Galapagos cormorants evolved from flying birds.
48:08But their wings have been shrinking into feeble vestiges.
48:14They're now grounded, but the sea provides their living.
48:20Penguins also gave up flight further back in time.
48:24And now have flippers where their ancestors had wings.
48:30Sea lions, too, evolved from land creatures.
48:33And like all sea mammals, they must still breathe air.
48:37Even when asleep in a rock pool.
48:39All these creatures have returned to the water and have once more mastered the ocean.
49:09Of course.
49:25If you have kubatus and they can be exposed to the sea.
49:27In parts of the sea.
49:30Pets in peace.
49:32These mammals and birds have developed the speed and skills to hunt the sea's abundant
49:48fish. In the battle for survival, evolution constantly reshapes life to seize opportunities,
50:09wherever they arise. Today a sleek swimming mammal competes for fish with a supreme aerial
50:25master, sea lion and frigate bird. Winning designs evolved from reptiles and born of the battle
50:33for life. Even at the ends of the earth, life has found a way to triumph.
51:03Wherever animals are found, they are molded for survival by the rigors they confront.
51:33King penguins struggle ashore from Antarctic waters. Conditions here are harsh, but vibrant
51:52life carpets the frozen land.
52:05Despite all adversities, countless new lives continue the battle for survival. The young
52:15carry the genes of successful parents forward through time. Their lives and their genes will
52:25be tested to the limits. Our world is filled with triumphant survivors of evolution's four
52:35billion-year war. Life's struggle continues to shape everything that lives.
52:48To learn more about what you've seen on this nature program, then
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