Des scientifiques ont découvert un monde préhistorique inconnu sur Terre

Sympa

Vous n'allez pas croire ce que les scientifiques viennent de découvrir - un monde préhistorique caché ici même sur Terre ! Imaginez découvrir des créatures et des paysages anciens tout droit sortis d'un film à succès. Ces découvertes sont en train de réécrire les livres d'histoire et nous offrent un aperçu d'une époque bien avant que les humains ne peuplent la planète. C'est comme pénétrer dans une machine à remonter le temps et assister de première main à l'incroyable évolution de la Terre. Qui sait quels autres secrets ce monde mystérieux pourrait renfermer ? Restez à l'écoute pendant que les chercheurs plongent plus profondément dans ce fascinant voyage à travers le temps !  Animation créée par Sympa. ---------------------------------------------------------------------------------------- Musique par Epidemic Sound https://www.epidemicsound.com   Pour ne rien perdre de Sympa, abonnez-vous!: https://goo.gl/6E4Xna​ ---------------------------------------------------------------------------------------- Nos réseaux sociaux : Facebook: https://www.facebook.com/sympasympacom/ Instagram: https://www.instagram.com/sympa.officiel/  Stock de fichiers (photos, vidéos et autres): https://www.depositphotos.com https://www.shutterstock.com https://www.eastnews.ru ----------------------------------------------------------------------------------------  Si tu en veux encore plus, fais un tour ici:  http://sympa-sympa.com

Transcript

00:00 There are whole communities of unusual organisms

00:04 that live in the lagoons of Patagonia.

00:06 And they are among the first forms of life ever existing.

00:09 Nobody knew them until two scientists, Brian and Maria,

00:14 went to explore some areas in Patagonia.

00:17 Patagonia occupies almost half of Argentina,

00:20 and few people live there.

00:21 Only a few farmers and sheep farmers

00:24 who mainly stay near the rivers

00:26 and grow things like apples, pears and alfalfa.

00:30 A long time ago, it was a wild and remote place

00:33 where Indian tribes lived,

00:35 for example the Tehuelch.

00:37 But this time, we will follow the traces of life

00:40 that appeared long before humans

00:42 and take a closer look at these interesting microorganisms

00:45 that Brian and Maria found.

00:47 These two had to drive for nine hours

00:50 on difficult roads to reach their destination.

00:53 They stayed in a small village,

00:55 only 35 people live there.

00:57 Six genes depend on a single source

01:00 because it almost never rains there.

01:02 On the last night in the village,

01:04 Brian realized that the satellite images he had taken

01:07 showed a set of lagoons,

01:09 which were only 16 km away.

01:11 The next day, the small team jumped in a car

01:14 and went up the road as far as they could,

01:17 until it became too difficult to drive.

01:20 They continued to hike the rest of the way.

01:23 It was difficult because they had to carry water

01:26 to face the intense sun.

01:28 In some places, they ended up sinking

01:31 to the knees in a salt bath.

01:33 Up there, there were 12 lagoons with perfectly clear waters.

01:36 The place itself did not offer much

01:38 apart from very acidic and salty water

01:40 and a direct and intense sun.

01:42 But it was a bit like a time travel,

01:45 because these conditions looked like what the Earth looked like

01:48 many, many years ago.

01:51 When Brian examined the lagoons,

01:53 he was surprised to see many unusual microorganisms there.

01:57 We call them.

01:59 And they are so small that we can't even see them without a microscope.

02:02 But they come together and form large communities.

02:06 In the past, many unusual species lived this way,

02:10 for example cyanobacteria.

02:13 They were important at the time because they produced oxygen.

02:17 The Earth, at its beginning, did not have much of this gas in its atmosphere.

02:23 The first stromatolites could have been formed by different types of bacteria

02:27 which did not necessarily produce oxygen,

02:30 but simply lived their peaceful lives there.

02:33 They formed layers, stacking on top of each other,

02:36 so that at least some of them could receive a little sunlight.

02:40 They used sand and glue liquids to stay close to each other.

02:45 Brian was also incredibly surprised

02:48 because it was in his head that the largest living stromatolites he had ever seen.

02:53 Living stromatolites usually grow up to more than one meter high,

02:57 but those that had just been discovered were 5 meters wide and a few feet high,

03:02 which is gigantic compared to those living in other places.

03:06 And the fossils were even bigger.

03:09 A long time ago, they could have grown bigger than today

03:12 because there were not many other species that could eat or harm them.

03:16 In addition, there are many other organisms today that can develop faster

03:21 and more massively than them and take their place.

03:24 This is why stromatolites can only survive in rare places

03:29 where almost nothing else can live,

03:31 such as in these salt lagoons located at high altitudes,

03:35 more than 3,650 meters, in the Apuna of Atacama.

03:39 The stromatolites found there are the most famous

03:42 because they could be among the best examples of the first forms of life on our planet.

03:47 However, they are not really the first form of life on Earth.

03:51 The oldest of their fossils are 3.5 billion years old,

03:55 while other evidence we have tells us that life on our planet

03:59 appeared about 4.1 billion years ago.

04:03 Maybe some stromatolites also lived at that time.

04:06 But the Earth has changed a lot since then,

04:09 and the places where they could have lived have not survived.

04:12 All this may not seem like much at first glance,

04:15 because no one has yet found an exotic and strange beast

04:18 that our world has never seen before.

04:21 But these are notable examples of what life search elsewhere in the universe could look like.

04:26 Scientists interested in the study of Mars

04:29 often come to this place because it could look like what the red planet looked like a long time ago.

04:35 If fossils were hidden in ancient rocks on Mars,

04:38 they could look like these stromatolites.

04:41 Another distant country has revealed some of its secrets.

04:44 It is Antarctica with an ancient "lost world" found under its ice.

04:48 Antarctica has not always been this isolated and icy land of snow and ice.

04:53 In the past, it was part of the supercontinent Gondwana,

04:57 with those which is now South America, Africa, Australia, the Arabian Peninsula and the Indian subcontinent.

05:03 But at one point, it separated and began to build a life apart.

05:08 It formed when other terrestrial masses began to move,

05:12 which formed its coast.

05:14 But Antarctica was also different in many ways at that time.

05:18 It was a land covered with magnificent forests and rivers full of life.

05:22 Scientists used radars and satellites to explore a mysterious world hidden under the ice there.

05:28 This ancient land, which is close to the Indian Ocean, is as large as the American state of Maryland or Belgium.

05:34 It is more than 14 million years old.

05:36 Some studies say that this area was formed more than 34 million years ago,

05:40 long before Antarctica fell into its great ice.

05:43 At first, the temperatures were higher there,

05:46 perhaps like the weather in Patagonia or the cold-tempered rain forests of Tasmania, New Zealand,

05:52 or perhaps even more tropical than that.

05:55 But as the climate became cooler, small glaciers began to form on the hills near the rivers.

06:01 The valleys sank further because of all this ice covering them.

06:06 And then, the temperatures dropped again.

06:09 And a huge layer of ice covered the entire continent, hiding these ancient glaciers.

06:14 Rivers shaped this lost world a long time ago,

06:17 long before they ended up being covered with ice almost 3.2 km thick in some places.

06:23 Scientific studies in this region have shown that these landscapes were filled with highlands and mountains.

06:29 The ice that had formed on Antarctica made the entire region very cold,

06:33 so that the landscape could no longer erode.

06:36 This means that everything remained essentially the same and intact under the ice for millions and millions of years.

06:43 What is interesting is that we know less about this hidden land under the ice than on the surface of Mars.

06:49 One way to explore it further would be to forest ice caps to check for sediment samples below.

06:56 They could tell us more about the flora and fauna frozen below.

07:01 This is not a new method.

07:03 A similar method has been used to collect samples from 2 million years ago in Greenland.

07:08 Australia also has its own secret world.

07:11 Ancient organisms have been found hidden in rocks from the north of the continent,

07:15 dating back to about 1.6 billion years ago.

07:19 These microscopic things are part of a family called the Eukaryotes.

07:23 The members of this family that exist today include plants,

07:27 mushrooms, animals, and even these tiny organisms have a single cell, such as amoebas.

07:34 All living beings with nuclei in their cells, including us,

07:38 can trace their genealogical tree to one of the oldest members of this family.

07:43 This is called the last common ancestor, Eukaryote,

07:47 and it lived more than 1.2 billion years ago.

07:51 These ancient organisms were more complex and larger than bacteria.

07:56 Perhaps they were the first predators on Earth, hunting bacteria.

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