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  • 5/12/2025

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00:00The
00:30There is a wild island in Indonesia.
00:49Early in the morning, when the rays of the sun spread to the foot of the mountain, a monster stirs from its sleep.
01:00This is an island full of danger. Predators are lurking in every shadow.
01:10Finally, the monster begins to move.
01:24This vicious and ill-tempered predator is the Komodo dragon.
01:28The creature spies its target.
01:54It rushes towards its prey at full speed.
02:00The monster rarely fails in its hunting attempts.
02:14It swallows both flesh and bone, with its gaping jaws.
02:28Wherever this monster goes, death follows close on its heels.
02:35Designated by UNESCO as a World Heritage, Komodo National Park is a Komodo dragon reserve.
02:46This giant lizard can grow up to 3 meters in length and reach 70 kilograms in weight.
02:53It is a fearsome predator and natural-born killing machine.
03:00It can easily detect the movement of prey with its sharp eyes.
03:06It tracks down its victims using a highly sensitive tongue.
03:13It can even sense prey as far as 4 kilometers away.
03:16It can even sense prey as far as 4 kilometers away.
03:20It is also armed with a tail powerful enough to fell a wild bird.
03:23It can easily detect the movement of prey with its sharp eyes.
03:26It tracks down its victims using a highly sensitive tongue.
03:28It can even sense prey as far as 4 kilometers away.
03:32It is also armed with a tail powerful enough to fell a wild boar with a single stroke.
03:49And its saliva is a cocktail of toxic bacteria, so a single bite can cause its victim to die.
04:01This animal was born to kill, and will whenever it gets the chance.
04:10Komodo dragons rush towards a freshly killed animal, fighting for an extra morsel of flesh.
04:15Such feasts also afford the dragons with another opportunity.
04:21The Komodo dragons are solitary animals, so they don't gather together very often.
04:27When you have a dead animal, a carrion, and then you have different animals, different Komodo dragons that come and feed on dead animals,
04:46then you will have a mixture of maids and females.
04:49So there will be an opportunity for Komodo dragons actually to meet at the same place.
04:56The Komodo dragon is a solitary animal.
04:58But from May to August, which is mating season, it begins to search for its other half.
05:04But this mating instinct is often the cause of fierce battles.
05:23Only the strongest of the species can earn the right to mate.
05:26The males engage in fierce battles which often prove to be fatal for the loser.
05:42This is a sight that can only be seen during mating season.
05:45When a male Komodo concedes defeat, it may never get the chance to mate again.
06:00And to the victor goes the spoils, which in this case is a female.
06:07Rubbing a female on the cheek is an act of courtship.
06:10And if the female acquiesces, mating can commence in earnest.
06:35Love seems to be a basic instinct to even these vicious and cruel creatures.
06:53And it's this basic instinct that makes them more aggressive than any prey could.
06:57What is it about mating that makes the Komodo dragon risk its life for the privilege?
07:10We have millions of species.
07:14We've had millions of species that have gone extinct in the past.
07:18And I think that without sex, we would live in a much simpler, less interesting world.
07:28Under the sea, a pair of mandarin fish engage in an elegant courtship dance.
07:34The tiny ladybug holds marathon mating sessions that last a mind-boggling nine hours.
07:39Early in the autumn, a pair of leaf-colored crickets enjoy making love.
07:57This is a once-in-a-year occurrence for them.
07:58Earthworms, which possess both male and female reproductive organs, release sperm into each other's spermatheca.
08:09In this way, mating is a wonderful and oftentimes dangerous endeavor to undertake.
08:16Countless creatures, big and small, mate all over the world in order to produce offspring.
08:29So, when did genders and sex first come into existence?
08:33The answer to this riddle can be found in Chlamydomonas, a kind of green algae.
08:48This tiny single-celled life-form is invisible to the naked eye and it has no gender.
08:53It copies its DNA in order to propagate.
09:023.5 billion years ago, Earth was home to such microorganisms.
09:07For single-celled organisms, self-replication is the fastest and most efficient way to propagate.
09:14But as nutrients in the oceans began to dwindle due to environmental change,
09:19they were pushed to the brink of extinction.
09:22And they were forced to look for another strategy for reproduction.
09:29We moved Chlamydomonas to an environment devoid of nutrients.
09:39This caused pairs of Chlamydomonas to quiver and collide with each other.
09:43Soon thereafter, the two organisms fuse into one.
09:52In order to survive in a nutrient-poor environment, the two organisms decided to pool their resources.
10:00A significant change occurs when the two single-celled organisms come together.
10:07The new organism retains the DNA of both single-celled organisms.
10:15When it undergoes mitosis, a completely new species with a new genetic sequence results.
10:21And when this process is repeated, it results in the creation of male and female, or gender.
10:28The two forms are stopped by living.
10:30A significant change in the future.
10:31ذا, we are supposed to live.
10:33This is the point of birth in a new species.
10:36We are used to live, and we have to live, and live together to be a new species!
10:40The second factor from the pattern is a new species.
10:46And the second factor of the species is actually more.
10:49So we have trodative material in the body.
10:50This is a different species.
10:52We can't become one-celled species to live,
10:56you can think of it as shuffling the deck in a game of cards that is if you don't mix things up
11:06when you prepare to play cards so that all the cards are reassorted you'll end up getting the
11:12same cards over and over again in in the process and the reason why you want to mix things up is
11:20to take advantage of increasing the diversity of what you might get dealt this is a tropical
11:34rainforest in Peru South America somewhere in this forest lives an insect prize for its rarity and
11:40beauty each year countless insect collectors venture into this forest in order to find this
11:47precious species we find this rare insect amidst a patch of leaves glistening in the sunlight
12:05it is an augerous butterfly the jewel of the forest
12:09the butterfly spreads its wings revealing its beautiful vivid colors each butterfly of the
12:35species is marked with a different pattern on its wings the butterfly is testament to the diversity
12:41that arises from sexual reproduction such diversity is not merely an external phenomenon it also affects
12:52such important matters as the ability to survive and adjust to various environments sex is is very
13:00good at enabling you your offspring to quickly find new combinations to changing circumstances whether
13:08it's the introduction of an antibiotic or a different temperature or some change in the environment
13:24through sexual reproduction which brings together male and female and allows for a combination of
13:29their genes to be passed down to later generations creatures big and small were able to evolve a
13:36diverse array of characteristics to help them adapt to Earth's endlessly changing environment
13:44also males and females each took on specialized roles males provided the sperm which fertilized the eggs of females
13:51they were able to move on to the animals but somehow it seems that females became trapped in an unfair arrangement where they must carry their offspring and give birth all alone this arrangement has given specialized roles to the males and females
14:09the males
14:16males must court females for a chance to reproduce while females are able to pick and choose their mates
14:27this is a tide land home to countless species of fauna from may to august during the low tide when the water recedes a unique courtship ritual takes place here
14:46It is the courtship ritual of the Fiddler Crab.
15:02A male crab waves its large claws in the air in a threatening manner.
15:08This is actually a serenade of sorts.
15:13It is courting females through this behavior.
15:21The Tideland serve as a ballroom where Fiddler Crab perform their mating dance.
15:25The males court the females ardently and persistently.
15:31They even engage in fierce battles for the affections of the females.
15:35Such violent altercations are a chance for males to prove their physical strength and
15:39prowess.
15:45While the loser often meets with a tragic end, the victor is able to court the female unimpeded.
15:57It enters its home, waiting for the female to follow suit.
16:16But the female does not seem at all interested.
16:21The male has no choice but to resume his courtship.
16:28Courting a female can be a trying and frustrating task.
16:32But the male must not give up.
16:38The male is the sex that must seduce, while the female is the sex that can pick and choose
16:42whichever partner she pleases.
16:45This is a rule decreed by Mother Nature herself.
16:54When mating season arrives, male Fiddler Crabs in the Tidelands began courting females.
17:13Female Fiddlers tend to be finicky and capricious.
17:23They will break off a relationship even as they are mating if something displeases them.
17:28Finally, the male finds a willing partner and begins to mate.
17:43What is the true significance of the courtship ritual of the Fiddler Crab?
17:51Why must males struggle so hard to find a female to mate with?
17:58The female is the one who automatically makes a big investment by having an egg and being
18:03pregnant.
18:05The female has more to lose than the male who makes many cheap sperm in a mating event.
18:13So automatically, those basic differences between the male and the female where they exist ought
18:20to make the female the more selective sex.
18:23They have the most to lose so they are under more selective pressure to make a good choice.
18:2915 days later, the female undergoes a physical change.
18:42It is carrying eggs.
18:49When a male fails to seduce a female, this means that the male will fail to produce offspring.
19:03While it is the common arrangement for males to court and females to choose, there is a
19:07species that has adopted an entirely different reproductive strategy.
19:15The Okinawa Banehas is a transparent fish with an orange hue.
19:22These tiny 2cm long fish live in homes as narrow as pipes.
19:29The male stays in its home.
19:31Then, when a female appears, it approaches it and begins its courtship.
19:40It circles the female in the hopes that it will accept its overture.
19:49The female seems hesitant at first, then it follows the male inside its home.
19:56This is a sign that it has accepted the male's courtship.
20:01Now, after the female lays its eggs, the male sprays its sperm to fertilize them.
20:19This mating behavior seems typical of other animal species.
20:26But when the Banehas is faced with a dearth of partners, it adopts an entirely different
20:30strategy for producing offspring.
20:34There are two females living with a male in this tank.
20:41But when the scientist removes the male that inhabits the pipe, only the two females remain.
20:46We observe the situation to see what would happen.
20:5316 minutes later, a female enters the pipe previously occupied by the male.
21:03After about 30 minutes, the female inside the pipe swims outside in search of the other female.
21:08It is behaving like a male.
21:13Two days later, the female has transformed into a male.
21:18The female had undergone a sexual transformation.
21:22This is the reproductive strategy of the species.
21:24Senator.
21:25Oh, thank you.
21:26Senator.
21:27Oh, you're trzy.
21:28There are three ships, right?
21:29One, two, three.
21:30Do you think that a small horse will be a child for a child?
21:35It is probably difficult.
21:37In such a small time, the body will be a child for a child,
21:44and when it is enough, it will be a child for a child.
21:49So it will be a child for a child for a child.
21:54Sometimes, the opposite occurs.
22:06We tried adding a new male to a tank occupied by the lone Benihaz male.
22:12A moment later, a tussle occurs between the two males.
22:16They are fighting to determine the stronger of the two fish.
22:33The victor occupies the much-coveted pipe.
22:36The male Benihaz which lost the fight changes its sex and becomes a female.
22:41It employs this strategy in order to hand down its genes to the next generation.
22:51Male becomes female and female becomes male.
22:55The shifting of genders is a strategy adopted to preserve the species in situations where
22:59sexual reproduction seems all but impossible.
23:18In 2006, an amazing phenomenon occurred in London Zoo which overturned commonly held beliefs
23:24about mating.
23:26At the center of this phenomenon was none other than the Komodo dragon.
23:40A female Komodo which had been isolated from males for years suddenly gave birth to a nest
23:45of eggs.
23:49A DNA analysis of the Komodo's offspring revealed that the mother Komodo had no contact with
23:59any male.
24:04So, basically, this is a parthenogenetic event which is common in some species of reptiles.
24:15It's particular because that was the first time that was described on a large charismatic
24:24reptile like the Komodo dragon.
24:27It is commonly thought that sexual reproduction is much more advantageous than asexual modes
24:34of reproduction.
24:38Under normal circumstances, the Komodo dragon mates through the union of male and female.
24:48In other words, it was thought that a female that had no contact with males could not lay eggs.
24:54But in this instance, the female chose parthenogenesis in order to reproduce.
25:06In this way, animals often adopt outdated methods of reproduction in order to preserve their species.
25:133.5 billion years ago, the first life appeared on Earth.
25:25This simple single-celled life form gave rise to male and female through its struggle to survive.
25:34Afterwards, life on Earth became increasingly diverse and each species adopted its own unique
25:39strategy for propagation.
25:44But it was an entirely different challenge to successfully birth and raise the offspring,
25:48which had been created through mating.
25:51This also required new and innovative strategies.
25:58The traces of one such strategy can be found in the fossil of a primitive fish,
26:03which is housed in the Museum of Natural History in London.
26:07It is the fossil of a placoderm, which lived 380 million years ago.
26:16There is an important clue in the fossil.
26:19It is the petrified images of fry which were found inside the mother's body.
26:23The incisor scutum specimen in the British Museum was very exciting, very important,
26:30because it showed that the largest group of placoderm fishes, the arthrodias, such as these ones here,
26:36were actually giving birth to live young, and therefore they were reproducing by having copulation.
26:43380 million years ago.
26:52Some of the seas of the world were home to fish that gave birth to live young.
26:56And the fossil of incisor scutum is proof of this.
27:02Why did the species choose to reproduce through internal fertilization,
27:14instead of external fertilization like modern fish?
27:21To switch from laying lots of eggs in the water, where they could be easily eaten by prey,
27:26to giving birth to just a few live young inside, gave a definite advantage to this group,
27:32because they could nurture their young to a point where they were able to be born
27:36and then fend for themselves, and be more able to survive.
27:43This is Selingen Island in Malaysia.
27:46But the beautiful oceans surrounding the island are as perilous as they were 380 million years ago.
27:58This is because they are full of vicious predators that prey on the creatures of the sea.
28:03Nevertheless, there is an animal which braves this dangerous sea every August.
28:08It is the sea turtle which swims thousands of kilometers in order to reach this island.
28:14The turtle returns to this island every year in order to lay its eggs.
28:28When night falls, the sea turtle climbs up onto the beach.
28:33It looks for an appropriate spot to lay its eggs, and begins to dig a hole.
28:53While the eggs of the sea turtle are soft, they are covered by an outer shell which keeps the eggs from drying,
28:58even when they are buried deep in the sand.
29:09It is thanks to the shell that the eggs are able to hatch successfully.
29:13Once you've got a shelled egg, you can lay it on land, conditions in which amphibian eggs wouldn't survive,
29:23where it's much drier.
29:25So you can begin to inhabit a greater area of the land surface than if you're tied to water the whole time.
29:35Shells were adopted by creatures eons ago after they left the sea for the land.
29:44The shells protect eggs and keep them from drying up, even on the land where they are not surrounded by water.
29:50Thus, the eggs can be hatched successfully as long as they are kept hidden from the prying eyes of predators.
29:55Two months have passed since the mother turtle returned to the sea.
30:11The hatchlings, which have just come out of their shell, crawl towards the water.
30:15They must crawl as quickly as they can in order to avoid hungry seagulls.
30:25Even if they reach the water successfully, most of the hatchlings will be devoured by fish and seagulls,
30:30and only 5% will survive to see adulthood.
30:37It will take years until these fragile turtles grow big enough to fend off the attacks of predators.
30:42It's the end of August, and the forests are becoming dense with the foliage of summer.
30:55It is legaying season here in Indonesia's Komodo National Park.
31:04This bird, which is digging up dirt using its red legs, is the megapode.
31:08Using the earth it digs up, it builds a nest that is reminiscent of a grave.
31:15But there is a creature lurking in the shadows and watching the bird as it digs its nest.
31:23It is a Komodo dragon.
31:26This bird lay the eggs in this nest, but also the Komodo dragons use this nest to lay their own eggs.
31:36During egg-laying season, you can see Komodo dragons digging holes in the ground everywhere in Komodo National Park.
31:47These Komodos are all carrying eggs.
31:53This is a decoy nest.
31:56Komodos hide their eggs inside the nest of the megapode and dig multiple holes which serve as decoys to trick hungry predators.
32:06This increases the chance of the egg survival.
32:08When they use this nest, yes, they kind of excavate different holes and they will choose only one hole to lay their eggs.
32:17The other holes are just fake.
32:18It is the end of March, and the rainy season which has lasted for half a year is coming to an end.
32:26Thanks to the constant precipitation, the environment is pristine and the food abundant.
32:41Around this time, one will find that there are baby Komodos living high up in the trees.
32:46Females, they lay their eggs from the end of August to the beginning of October.
33:00Then you have a period of incubation of the eggs that will hatch at the end of the rain season,
33:08where the environment is greener, where there are more preys in terms of little lizards, geckos,
33:20or little species that the hatchlings, that are very small, about 40 centimeters in length, can feed on.
33:33The Komodo dragon is one of the largest predators on Earth.
33:36Nevertheless, hatchlings are exposed to many dangers because of their size.
33:49They are easy prey for hungry predators and must take refuge high up in the trees.
33:53They live in the trees, subsisting on insects until they are large enough to survive on the ground.
34:10When they have just been hatched, even these fearsome predators are too weak to protect themselves.
34:20Meanwhile, mammals adopted the strategy of giving birth to live young and raising them.
34:34The Australian kangaroo gives birth to live young and raises them inside its pouch.
34:48In the pouch, the baby kangaroo feels its mother's warmth and listens to her heartbeat, and this accelerates the growth of the baby.
35:06The baby kangaroo stays inside its mother's pouch for a year and feeds on her milk.
35:24The baby kangaroo suckles its mother and receives her protection inside her pouch until it grows big enough to fend for herself.
35:35Although the pouch provides the baby with protection, it is an uncomfortable and dangerous burden for the mother.
35:42So why did kangaroos adopt a strategy for rearing their young?
35:49So I think the move towards, you know, live birth and a lot of development really reflects ecological and evolutionary conditions that select for fewer, more competitive, fully equipped offspring.
36:07So I think it's a good thing.
36:13Chibaki, the chimpanzee, is about to give birth.
36:17She thrashes around, unable to bear the pangs of labor.
36:22Chimpanzees can go through up to seven hours of labor.
36:25In an act of desperation, the chimp grabs onto her trainer's legs.
36:42In chimps as in humans, labor seems to be a painful ordeal.
36:45Yeah!
36:48It has a kiss!
36:49Oh, it this is their head!
36:50The mental mondo is good?
36:51No!
36:52Yeah, yeah, yeah!
36:54What about it?
36:55How about it?
36:56Sure, how about it?
36:57It's my baby.
36:58It's our baby?
36:59How about it?
37:00How about it?
37:01There's a body.
37:02The demi-bye child.
37:05Yeah, it's all over it.
37:07Natsumi, the newborn champ is so physically developed, that it is able to embrace its mother as soon as it's born.
37:14Yes, yes, yes.
37:17It's okay, it's okay, it's okay.
37:22Okay, it's okay.
37:25Six years have passed since Natsumi the chimp was born here,
37:29in the Great Ape Research Institute.
37:35This playful chimp running across the field with its mouth full of food is Natsumi.
37:44Her mother, Chubaki, also seems to be in good health.
37:53During the past six years, Chubaki also gave birth to Hatsuka.
38:04Three-year-old Hatsuka is still young and needs her mother to look after her.
38:09Natsumi also grew up under the protection of her mother.
38:15Like humans, chimps also live in clans and societies.
38:22Usually they spend their day picking each other's fur.
38:33Chimps have a strictly hierarchical society.
38:35This is Roy, the head of the Chimp Society here.
38:46In the Society of Chimps, the alpha male always has the first choice,
38:50whether it be food or mates.
38:53The alpha male's anger is stoked when a lower-ranked male steals a male.
38:54The alpha male's anger is stoked when a lower-ranked male steals a male.
38:56its food or mate.
38:57The alpha male's anger is stoked when a lower-ranked male steals its food or mate.
38:59The alpha male's anger is stoked when a lower-ranked male steals its food or mate.
39:06The alpha male's anger is stoked when a lower-ranked male steals its food or mate.
39:19Roy has been angered by Namba, the second-ranked male in this society.
39:20As a result, Namba has been brutally assaulted and injured by the stronger alpha male.
39:25Male chimpanzees often get into violent confrontations over females.
39:28As a result, Namba has been brutally assaulted and injured by the stronger alpha male.
39:37Male chimpanzees often get into violent confrontations over females.
39:42In chimp society, males are able to mate with multiple females.
39:55Also, the female may choose any male to mate with.
40:01The female may choose any male to mate with.
40:06Because of this, female chimpanzees often goad the males to fight over them.
40:25It shows that the male has to fight over the too, and that it will Dogs are likely to fight over themselves.
40:36The strongest female is likely to fight over the.
40:40When they make the male who will be attacked over the only, I would say to kill a male.
40:46It will be stronger than a female in the same way.
40:48Thanks to their mother's efforts to burr the strongest possible young and protect them through childhood,
40:54Natsumi and Hatsuka are healthy and strong.
41:01And someday, they will find appropriate meals to mate with
41:04in order to give birth to a new generation of chimpanzees.
41:10This is because it is the basic instinct of all living things
41:14to birth offspring and preserve their species.
41:20A planet where sex hadn't evolved would be very boring.
41:24We have very few life forms, and within those life forms
41:29there would not be the elaborate beauty that we think that exists in the world.
41:36In fact, you might not even be able to detect beauty if you didn't have sex
41:40because beauty itself, the ability of humans and other things
41:45to see things as beautiful or not beautiful, is the result of sex.
41:54However, one of the troubled things that doesn' change across waste is
41:59I would actually tell you something result of life.
42:01I want to tell you something important looks like
42:06さんの色は、こう変わらず今は今まで gestעった限り