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00:30a life has expired most species that ever existed on the earth maybe even 99% of them are extinct
00:42this kangaroo is no longer of this earth
00:47oftentimes death comes at the most
00:59unexpected hour of course it does remove sometimes whole groups but it is also a
01:08creative force five mass extinctions have occurred during the four billion year
01:17history of life on earth species died off because they were weak or because they
01:24could not adapt to changes in the environment some succumb to sudden
01:27disasters which had never before occurred
01:39but the extinction of one species was an opportunity for another this is the
01:45story of the destruction and creation brought on by mass extinctions
01:52we are on our way in search of Earth's first animals
01:54we are on our way in search of Earth's first animals
01:59we are on our way in search of Earth's first animals
02:09we are on our way in search of Earth's first animals
02:21this is the Flinders ranges a mountain range in southern Australia
02:31there is no human presence here instead the area is populated by wild animals
02:43Dr. Jim Gelling hangs precariously from a cliff looking for something
02:55he is a paleontologist from South Australian Museum who has been researching the fossils found here for the past 30 years
03:05he finally discover something
03:12this is the fossil of a creature belonging to the Ediacra biota
03:20before the time of the Ediacaran fossils we only had microscopic fossils for 3 billion years
03:27nothing that you could see with the naked eye and then very rapidly we see these strange creatures appear in the fossil record
03:46these creatures which look like leaves might have been rooted to the ocean floor
03:50they swayed in the current while subsisting on the nutrients floating in the water
03:59although some had heads and tails many of the creatures seem to have no means of locomotion
04:09Dickinsonia is the most common species amongst the Ediacra biota
04:17they were flat creased creatures which had neither a mouth nor muscles
04:26the smallest were as tiny as a grain of rice while the largest creatures grew as large as a cushion
04:35none of them so much as resembles the creatures living on Earth today
04:39so what was the environment they lived in like?
04:47they lived in the sea 600 million years ago
04:50species of the Ediacra biota lived in all the oceans of the world
04:54most of the biota lived stationary lives secured to the ocean floor
04:59and they subsisted on the plankton floating around in the water
05:03while there was a diverse array of these creatures
05:06they were completely different from the creatures living on Earth today
05:10within the Ediacra biota we have some truly weird creatures
05:17and we see nothing like that today
05:20so we assume that these things did not survive into the Cambrian period
05:26they were only known in the Ediacran period
05:29although they were the first animals to inhabit the ocean some 600 million years ago
05:35they all became extinct before the Cambrian period arrived
05:42next we set out for a place where clues to their mass extinction can be found
05:50this is another area of the Flinders ranges where fossils from the Ediacra biota have been found
05:57these slanting geological strata record the history of life on Earth
06:04these sandstone rocks are like pages in the geological history of the evolution of life
06:14on my right we have the sandstones of the Ediacran period
06:19with the soft bodied fossils of the Ediacra biota and here I stand on a boundary
06:26we move across a most important boundary
06:29the base of the Cambrian and the beginning of the Cambrian explosion of life
06:36this is a geological stratum from the Cambrian period
06:40although they merely look like fissures in the rock
06:44the cracks are evidence that a new page had been turned
06:48in the history of evolution
06:59this is a fossil from the Ediacran period
07:03they are trails left by a creature that crawled around on the ocean floor
07:08they are noticeably different from the trace fossils from the Cambrian period
07:19this difference reflects the end of one period and the beginning of another
07:24once animals evolved that could eat other soft bodied animals
07:29then the only animals that could survive could either swim fast
07:33make a protective cover or a shell
07:37or if they had neither of those abilities
07:40they had the muscles to dig into the sea floor and hide there
07:46as it turns out the fissures in the rock are actually fossilized holes
07:52that creatures dug into the sand in order to hide from predators
08:03here in the Flinders ranges there is a borderline between the Ediacran and Cambrian periods
08:08there is another Cambrian fossil on this rock that Dr. Gelling is kneeling on
08:19this creature had a hard covering around its body
08:21in this way life evolved in order to adjust to the changing environment
08:26500 million years ago
08:33Earth's oceans were teeming with creatures in a wide array of shapes and sizes
08:38but something changed in the relationship between the creatures
08:43suddenly they realized that there was food to be had besides the plankton floating in the water
08:48they could prey on each other
08:51in this way animals began to prey and be preyed upon
08:56and it was around this time that hard protective shells and mussels appeared
09:02so what effect did such a change have on the creatures of the Ediacra biota?
09:09this is a fossil of two Dickinsonia
09:12they are spaced apart as if uninterested in each other
09:16animals from the Ediacra biota did not prey on other animals
09:26instead they subsisted on nutrients floating in the sea
09:31but the change in the environment proved to be fatal to them
09:40an animal which was soft bodied like Dickinsonia
09:44a big sheet of meat lying on the sea floor
09:47it's dinner waiting for an animal that could eat it
09:57in the end the Ediacra biota became extinct
10:01while these once microscopic creatures managed to grow significantly in size
10:05they could not adjust to the appearance of predators
10:07that's why they are called a failed experiment
10:23this rocky and barren terrain
10:28was once the stage for the rise and fall of Earth's first animals
10:32they are testament to the transient nature of life
10:33they are testament to the transient nature of life
10:37they are testament to the transient nature of life
10:40they are testament to the transient nature of life
10:44so were the species that adjusted more actively to this change
10:45able to avoid extinction?
10:46so were the species that adjusted more actively to this change
10:47able to avoid extinction?
10:48so were the species that adjusted more actively to this change
10:51able to avoid extinction?
10:55so were the species that adjusted more actively to this change
11:09able to avoid extinction?
11:12the trilobite which first appeared during the Cambrian period
11:18and survived for 300 million years could be called a witness of evolution
11:24these creatures were able to survive and flourish through two mass extinctions
11:26thanks to their quick and varied adaptations to changes in the Earth's environment
11:47trilobites were capable of very rapid evolution
11:50and this applied even towards the end of their history
11:57some of the trilobites that went out at the end of the Ordovician
12:01had been around in the ocean since the Cambrian period
12:06so one could say that they were themselves already tremendous survivors
12:12trilobite fossils are extremely common
12:15when one takes into account that the average species last for 5 million years
12:18before it goes extinct
12:21the trilobite's 300 million years of survival is an amazing feat
12:25as their name indicates trilobites can be divided into three sections
12:32they were a hard shell over their backs for protection from hungry predators
12:37also they were equipped with jointed appendages which allowed them to move very quickly
12:42even the earliest of their species had well developed eyes
12:48and they came in a wide variety of sizes
12:52with the smallest the size of a fingernail and the largest the size of a cushion
12:57these creatures were most likely heavily preyed on in the seas
13:02some fossilized trilobites have chunks bitten out of them
13:05so how did they protect themselves?
13:07many of the trilobites that survived the end Ordovician extinction event were capable of rolling up
13:16this shows you how beautifully adapted they are
13:19the head and the tail actually lock together in some of these forms
13:23so that if you are like that you are protected from the action of an attacking predator
13:33its soft underbelly was the most vulnerable to attack
13:41but by rolling up in this manner the trilobite could keep safe from predators
13:46this was the first feature the trilobite evolved in order to survive in the predatory waters of the ancient seas
13:54but that wasn't all
13:58this is the head of the trilobite as seen from above
14:02the trilobite has a pair of compound eyes
14:05it probably saw the world through thousands of tiny hexagonal window panes
14:16the waters they lived in were full of predators hungry for a meal
14:20so it was advantageous to be able to detect the movements of potential predators and prey
14:24they had really quite sophisticated visual systems even the early ones
14:31but some of the later ones evolved really sophisticated
14:37under a microscope the eyes of the trilobite are as intricate and beautiful as a finely carved sculpture
14:44the eyes were so advanced that they could focus on objects
14:47this was another adjustment necessary for survival
14:51but the evolution of the trilobite did not stop here
14:57it protected itself using fearsome spines and hard armor
15:02sometimes the unusual spines were uniquely adapted for their environment
15:09so were these heavily armored creatures the last to survive?
15:14Professor Suzuki Yutaro of Shizuoka University offers an unexpected answer
15:26the trilobite that managed to survive as its more elaborately armed kin slowly died off
15:31was in fact quite ordinary
15:32I remember what they lived here in the last few years
15:36the trilobite that saved the trilobite were to survive as a model
15:42the shape of the trilobite are normal
15:45the parts of the trilobite are normal
15:47the trilobite are normal
15:49the ändern that has become a small body
15:52the trilobite has become a small body
15:54in the past few years
15:55and the trilobite has become a small body
15:57so when the outside of the area was used to have the species or other species,
16:06then it started to change the species too.
16:11It had to change and it didn't happen.
16:23This tiny 4cm long trilobite was the last to remain
16:27until the species died off completely.
16:33Instead of specifically adapting itself to various conditions around it,
16:37the trilobite proliferated quickly thanks to its small size
16:40and was able to survive longer than its more elaborately designed cousins.
16:49Earth changed constantly during the 300 million years of the trilobite's existence,
16:54but the creature was able to adapt to these changes and survive.
17:00Nevertheless, there were some changes that were all but impossible to prepare for.
17:06It's just bad luck if you're in the wrong place at the wrong time.
17:10And certainly at the end of the Permian, as much as 90% of species went extinct,
17:16so this is almost all of life,
17:18and it's probably more sensible to think about the 10% who survived as just being lucky.
17:28Next, let us investigate an incident that occurred at the end of the Permian period 250 million years ago.
17:36This is a geological stratum from the Permian period located in Meishan, Zhejiang province, China.
17:43This band of dark rock indicates the passage from one geological period to another.
17:48The slanted layers of rock are marked with letters and numbers.
17:53They indicate the era, when the layer formed.
17:57It is here that traces of Earth's most devastating mass extinction can be found.
18:02In the second, a large green plant is she was discovered.
18:05This plant was died through the second,
18:07comes from the first to the third of the year,
18:09in the first of the world.
18:11When it was left,
18:13there was a leaflet plant on Earth's most devastating mass extinction.
18:15This is a tree that was created through soil.
18:18This is a tree that was created through a form of water.
18:20This plant is a tree that is a tree that is created through ground.
18:25And this eternal meat.
18:26This is a tree that corresponds to grow as an entold,
18:28and this tree temeth mass extinction of earth,
18:31which was the greatest of the world.
18:33This was to prove that after the death of the death,
18:35we received another one that was on the main level.
18:38This was also to prove that the death of the death of the death of the death of the death of the death.
18:47These rocky mountains harbor clues of a chilling past.
18:51So what exactly happened on earth 250 million years ago?
19:01Around the end of the Permian period, great cascades of lava began to gush out of a volcano near what is modern-day Siberia.
19:12The lava flow covered the Ural Mountains and Lake Baikal and reached all the way to Kazakhstan in the south.
19:19This endless river of lava solidified to create a layer 20 meters thick.
19:25The lava from this greatest volcanic eruption in Earth's history covered an area roughly equal to the American continent.
19:35Creatures were helpless in front of this massive disaster, whose scale was unprecedented.
19:54This disaster triggered even more disasters.
20:00The smoke and ash that gushed out with a lava filled Earth's atmosphere.
20:07The planet's temperature rose by 6 degrees Celsius due to the greenhouse effect brought on by carbon dioxide.
20:13Sulfur dioxide and chlorine mixed with the air, causing acid rain to drench the Earth and make its soil uninhabitable to any form of plant life.
20:21Also, with the balance of the atmosphere broken, the solid methane in the oceans began to melt, causing Earth's ecosystem to spiral into chaos.
20:36This was the greatest mass extinction in the history of life, with 97% of aquatic animals succumbing to extinction, and 70% of terrestrial vertebrates dying off.
20:47When natural disaster rears its ugly head, no creature can withstand it.
21:04But it is only a matter of time before life takes root once more, and flourishes.
21:18This was not so with a mass extinction that occurred at the end of the Permian period.
21:23What was the reason that this extinction event was so much more devastating than similar events in the past?
21:28Professor David Jablonski of the University of Chicago is an internationally renowned expert on mass extinctions.
21:43We asked him what factor played the biggest role in determining whether a species would survive a global disaster.
21:49So there's a real difference in being widespread, having your evolutionary eggs in more than one basket, as opposed to being concentrated in just one small area.
21:59Even if those lineages are very well adapted to the conditions before the mass extinction, unless they're widespread, they're in serious trouble.
22:05Earth's plates shift endlessly, moving the continents with it.
22:14Sometimes, the continents become clustered together, just like at the end of the Permian period.
22:22In other words, animals were clustered together as well, leading to a disastrous result.
22:27Broad geographic ranges of entire evolutionary lineages, whether they're found on multiple continents,
22:35seems to control the survival of major evolutionary lineages, and other features that used to matter go away.
22:41So that means that these short, sharp extinction events have a disproportionate effect on the evolutionary process.
22:51So how did life resurface after the demise of most of Earth's creatures?
22:57First, a single seed must have been carried on to shore by the waves.
23:08Full of vitality, such seeds became vast plains of grass and lush forests, creating an environment hospitable to life.
23:16This newly created ecology opened the doorway for new species, attracting animals such as small reptiles, that fed on plants.
23:33Also, birds flittered in to feed on the berries and fruits, spreading their seeds even farther.
23:38Sometimes, during the endless evolutionary cycle of life and death, the fate of life on Earth takes an unexpected turn.
23:49This is Gubbio, a town located in northeastern Italy.
24:00People stroll leisurely amongst medieval buildings.
24:04Past and present coexist in peaceful harmony here.
24:07But in the mountains on the fringes of the town, there are vestiges of a mass extinction event that took place 65 million years ago.
24:23This is part of the Apennine Mountains, which were once the seabed until they rose up around the time the Mediterranean appeared.
24:29There is a geological stratum from the end of the Cretaceous period, located on the roadside in the Potaccioni Valley.
24:45These slanted geological strata bear the traces of scientific research.
24:50The strata harbor the secrets of a truly horrific event.
24:53Called the KT boundary,
25:23the K and T stand for the Cretaceous and Tertiary periods, respectively.
25:31This ordinary-looking layer of rock drew scientific interest due to the presence of a rare metal.
25:38The KT boundary contained ten times the iridium found in other geological strata.
25:44Meteorites, which fall from the sky, often contain metals that are extremely rare on Earth.
25:46The meteorites, which fall from the sky, often contain metals that are extremely rare on Earth.
26:02Iridium is one such metal.
26:04Some scientists even claim that all the iridium on Earth is the result of collisions with asteroids and meteorites.
26:09The iridium concentrations found in Potaccioni Valley are also traces of an asteroid impact, which occurs on Earth.
26:15The iridium concentrations found in Potaccioni Valley are also traces of an asteroid impact, which occurs on Earth.
26:16Iridium is one such metal.
26:19Some scientists even claim that all the Iridium on Earth is the result of collisions with asteroids and meteorites.
26:33The Iridium concentrations found in Butaccioni Valley are also traces of an asteroid impact which occurred 65 million years ago and had a devastating effect on life on Earth.
26:46Let us find out more about this incident.
27:04After the mass extinction that occurred at the end of the Permian period, the new masters of the Earth were giant reptiles.
27:11They ruled supreme over land, air and sea and were Earth's dominant predators for nearly 200 million years.
27:19Although the predator's large size was an advantage when hunting prey, it left them vulnerable to sudden changes in the environment.
27:33Moreover, there was no way that they could prepare for a catastrophe caused by an extraterrestrial event.
27:43This is a crater 1.6 kilometers in diameter and 170 meters deep located in the middle of the Arizonan desert.
27:58It's the impact site of a meteor that collided with Earth around 50,000 years ago.
28:05The vertical geological strata are testament to the awesome power of the impact.
28:16Scientists estimate the crater was made by a meteor 50 meters in diameter, traveling at over 10 kilometers per second.
28:23What would happen if an asteroid 200 times larger than that collided with the Earth?
28:37Some 65 million years ago, that is exactly what happened.
28:42The asteroid fell in what is known as Mexico today.
28:49At the time, North and South America were divided by a sea.
28:58Scientists say the impact was similar to having Mount Everest collide with Earth, traveling at the speed of a bullet.
29:04Countless dinosaurs were killed by the great ball of fire that fell from the sky.
29:13None could prepare for such a cataclysmic disaster.
29:21But the initial impact was just the beginning of an extended tragedy.
29:24Great plumes of black ash rose up into the sky, causing acid rain to fall, and clouds of sulfur dioxide hid the sunlight, causing the temperature to plummet.
29:39The plants were the first to succumb to the sudden change.
29:42They were quickly followed by plant-eating dinosaurs and the predators that fed on them.
29:45With a sudden scarcity of food, the large size of the dinosaurs proved to be a tragic weakness.
29:53But this most recent mass extinction was a blessing in disguise for one species.
30:03It was also an important event for humankind.
30:06People might tend to think of extinction as a disaster.
30:13Well, it is a disaster for a short time for the organisms that exist prior to the extinction.
30:22And, of course, it does remove, sometimes, whole groups.
30:26But it is also a creative force, because after the extinction, ecological opportunities are open.
30:36Niches are vacant for new organisms to move into, for new adaptations to occur.
30:4565 million years ago, an asteroid which was 10 kilometers in diameter collided with the Earth.
30:57While the dinosaurs were powerless to avoid the resulting chaos, Aeoma, the tiny mammal, sought shelter.
31:06Even before the disaster, these tiny creatures only came out at night in order to avoid the much larger dinosaurs.
31:13They were at the bottom of the food chain.
31:21Years passed by.
31:22And around the time when the effects of the most recent disaster began to fade,
31:27this mammal was preparing to open a new chapter in the history of life.
31:33Unlike dinosaurs whose large size proved to be a fatal shortcoming,
31:37the tiny, warm-blooded mammals were able to survive the mass extinction.
31:41Ironically, the tiny size of the creatures, which was a weakness in the past,
31:46was the factor which allowed it to survive.
31:48And when the predatory dinosaurs became extinct, it was these mammals that began their dominance of Earth.
31:57The mass extinction turned out to be a gift for these small and frail creatures.
32:01After the demise of the dinosaurs, the mammals began to spread at breakneck speed.
32:18Their warm blood helped them adapt to the increasingly seasonal climate of the Earth.
32:24The mammals took on a diverse array of sizes and shapes, and each species developed characteristics which helped it to adapt to its new environment.
32:36Mammals whose defining characteristic was the fact that they gave birth to live young and reared them continued to evolve.
32:49Until finally man, the crowning achievement of mammalian evolution appeared.
32:54So, what affected man would this hyper-developed brain have on the natural environment?
33:04This is Narcourt Caves National Park in southern Australia, which has been designated as a UNESCO World Heritage.
33:23Professor Gavin Perdue of Flinders University passes a dark and narrow passageway and climbs down into a cave.
33:36This is Victoria Fossil Cave.
33:39Thought to be a giant sinkhole in the past, the floor of this cave is strewn with countless animal bones.
33:44The fossilized remains of some 45,000 animals are preserved in this cave alone.
33:51One can ascertain from the large size of the bones that the animals themselves were quite large.
33:56There are remains of a kangaroo that was over 2 meters in height, as well as bones of a 6 meter long lizard.
34:03So, how did these animals meet their death on this cave floor 50 meters below the surface of the Earth?
34:08After the animals fall in, they can't escape and they either die on impact or they die of thirst or starvation or injuries.
34:22Their remains get incorporated into the sediments and they sort of slide down through water and just gravity
34:32and mixed up also from other animals trampling on top.
34:37And that is how we excavate them.
34:40Australia possesses a fascinating ecosystem.
34:44It was originally part of a massive supercontinent called Kondwana, located in the southern hemisphere.
34:50This continent also included Africa, Antarctica, South America and India.
34:54But 35 million years ago, Australia became separated from this continent and became home to a unique ecosystem.
35:03There are many species in Australia that cannot be found anywhere else.
35:11This is a result of millions of years of isolation.
35:15This is also the case with the animals fossilized in Victoria Fossil Cave.
35:26For some reason, placental mammals could not take root in Australia.
35:31Instead, a wide array of marsupials, mammals with pouches, proliferated on the continent.
35:36Such animals include a kangaroo with a much shorter face than the kangaroos of today.
35:48Telecoliocarnifex, the marsupial lion which was the apex predator of the Australian continent.
35:55And a protodon, the giant wombat whose massive size can be gleaned by the size of its enormous jaw bones.
36:06So how were these animals able to grow so large?
36:15A hundred thousand years ago, Earth's climate became increasingly cold and dry.
36:20And the only plants able to survive in this environment were nutrient poor.
36:25In other words, herbivores had to eat large amounts of food in order to gain the necessary nutrients.
36:31And this resulted in their growing larger in size.
36:33The predators that fed on these herbivores also had to grow larger in size.
36:42The marsupial lion, which was the apex predator in the Australian ecosystem, weighed more than 150 kilograms.
36:49It would hide in the bushes and pounce on prey, slashing the victim's neck with its large saber teeth.
36:58The largest kangaroo in Earth's history grew over two meters in height.
37:04It fed by picking and feeding on leaves using its front legs.
37:12The protodon and herbivore, which weighed three tons, usually lived in herds by the water.
37:18The large size of these animals was the result of adapting to an environment which was becoming increasingly barren.
37:31But this adaptation alone proved to be insufficient.
37:34This was because of a new species which hunted and lived in an entirely different manner.
37:47What was the species which caused the downfall of these large animals?
37:52One is that they were hunted to extinction by people when they first arrived in Australia.
38:00People arrived 60,000, 50,000 years ago.
38:02The megafauna became extinct soon after that.
38:05One of the other explanations is that it was the lighting of fires by people that changed the nature of the vegetation,
38:13wiped out the food plants that the megafauna were adapted to eating,
38:17and then they became extinct and then their predators became extinct.
38:23Even the marsupial lion, which once ruled supreme, was no match for this new species,
38:28which was armed with sharp spears.
38:33To man, these giant mammals were merely a rich source of fat and protein.
38:40The fire that early man used to hunt would spread uncontrollably,
38:44destroying the habitats of these animals.
38:46To make matters worse, the climate changed drastically.
38:50Man coexisted with these giant animals for 20,000 years.
38:54But in the end, the animals fell victim to man's fire and spears.
39:06Unlike other animals, humans stood and walked upright,
39:09so their hands were free to make the fire and tools with which to overcome their weaknesses.
39:14Although man's only advantage was his highly developed brain,
39:19he used it to make the tools necessary to hunt and kill animals much stronger than him.
39:25Man was not an especially vicious or violent animal.
39:31He merely did what he needed in order to survive.
39:33And this brought about the unfortunate demise of other species.
39:39So was this an unavoidable course in evolutionary history?
39:42humans will use different devices to encourage its own species to increase.
39:54And if this has an impact on totally unrelated species, then so be it.
40:00The whole process of evolution is an all-encompassing complex panorama
40:13that takes advantage of every conceivable niche and opportunity.
40:19It's the most opportunistic and selfish system that you can possibly imagine.
40:24Man's tools have become far more advanced.
40:31But even now, he is in constant struggle with the nature around him.
40:36It is all but impossible to draw the boundary between the destruction that is necessary for man's survival
40:41and the destruction wrought by man's unnecessary greed.
40:52All we can be sure of is that if this destruction continues, man's days on Earth will be limited.
40:58Whether man exists or not, life on this planet will go on as it has even through the five mass extinctions that have come and gone.
41:28We are now back in the Flinders Ranges, where Earth's first life-forms were born.
41:40Dr. Jim Gelling is investigating something.
41:45It is a trace fossil, a petrified trail that was left by some unknown creature.
41:50There is no way to know what the creature was doing or where it was headed.
41:53Was it on its way to find food?
41:56It could have been looking for a mate or running away from a hungry predator.
42:00There is no way to tell.
42:03All we know is that this creature is now extinct.
42:11Maybe 9 out of every 10 of these species went extinct.
42:16But the 10 percent, 1 in 10, are enough to take the genetic material into the future.
42:26These may be the ancestors of all modern animals.
42:35The life-form which was born 600 million years ago grew in size, proliferated and diversified,
42:41only to disappear once more, leaving all but a few traces.
42:46And with its disappearance, it made room for a new generation of life to take root and flourish.
42:52In this way, the history of life has been an endless cycle of birth and death, creation and destruction.
43:00Extinction is an end, but it is also a beginning of everything.
43:05Extinction is an end, but it is also a beginning of everything.
43:35Extinction is an end with everything.
43:38Extinction is one of those.
43:40Ancient only is the outerny tetions, as a world of vomiting.
43:44Extinction is a Automata.
43:46Extinction is one of those.
43:48It is educational for the dinosaurs the class as they're not in at work.
43:53They're in a time so it fails.
43:54But not everyone can perform any action.
43:57Nós'avisa are一個 where we are the Methodists.
44:00Coaches are able to purchase additional,
44:03Expectantrund인데요.