Download "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra"
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252Fv2o4QxW07sk%252Fmaxresdefault.jpg&w=1139&q=75)
Table of contents
Similar videos from our catalog
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252F8_OTEi-peO0%252Fhqdefault.jpg&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252FKATFZxwrQzg%252Fmaxresdefault.jpg&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252FO0RJO8FS3eY%252Fsddefault.jpg&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi_webp%252FV1vvq5gYwSk%252Fmaxresdefault.webp&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi_webp%252F_Loq6OnPWWU%252Fmaxresdefault.webp&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252FhYHf5UZxo2M%252Fmaxresdefault.jpg&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252Fq1sZzqEUzgI%252Fhqdefault.jpg&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252FsNE6gr4vhZs%252Fmaxresdefault.jpg&w=1139&q=75)
%3Aformat(webp)%2Fi.ytimg.com%252Fvi%252Fx_AdxKcWpu0%252Fsddefault.jpg&w=1139&q=75)
Video tags
Subtitles
Russian
00:00:00
life appeared on our planet00:00:04
more than 3.5 billion years ago00:00:08
the planet experienced periods in00:00:11
which ice extended to the00:00:13
equator as well as sweltering periods00:00:16
without ice at the poles00:00:18
the jungles of these geological eras00:00:21
have become the home of the reindeer00:00:23
today00:00:27
the sea level rose 200 meters00:00:30
above the current level00:00:32
turning the continents into00:00:34
archipelagos then fell 100 meters00:00:37
below the current level creating00:00:40
areas of land that are now00:00:42
submerged00:00:44
the continents moved closer and then00:00:48
further away00:00:49
600 million year old animals00:00:52
seem to be taken from a00:00:55
science fiction movie,00:00:56
although dinosaurs are the00:00:59
undisputed stars of the Mesozoic period, it is00:01:02
often forgotten that 400 million00:01:05
years before their existence, a multitude00:01:08
of animals preceded them00:01:11
in one way or another. The world changed as a00:01:15
result of climate change, the00:01:18
lack of food or the arrival of00:01:20
new predators. Most00:01:23
species failed to adapt and became00:01:27
extinct.00:01:28
However, they left their traces on00:01:31
Earth by lasting in the fossils, so00:01:34
these remains provide a00:01:36
detailed image of how What was life on00:01:39
earth before the dinosaurs,00:01:43
dear traveler Good morning, today we00:01:47
are going on a trip to the heart of the00:01:49
Proterozoic and Paleozoic Heras, that is,00:01:53
more than 400 million years ago before the00:01:56
reign of the dinosaurs,00:01:58
a trip to the past to discover00:02:01
surprising animals. and exciting00:02:04
journey in which you will discover our00:02:06
planet devastated by the worst00:02:08
episodes of extinction it has ever known00:02:11
but before leaving for another00:02:13
incredible adventure Don't forget to like00:02:16
the video and subscribe to the Channel So as not to00:02:19
miss anything Thank you all and have a good00:02:22
trip00:02:28
let's go back in the time long long00:02:32
before the era of the dinosaurs00:02:33
when the earth was a huge00:02:36
snowball completely frozen covered00:02:40
by glaciers from the poles to the00:02:43
tropics00:02:45
when volcanic eruptions00:02:47
produced CO2 in large quantities00:02:50
a greenhouse effect was created that allowed00:02:52
the warming of the planet00:02:54
the ice melted and different00:02:58
land masses joined together to form a00:03:00
supercontinent called rondinia00:03:04
it is surrounded by a single ocean called00:03:07
mirovia00:03:09
scientists use the appearance and00:03:12
disappearance of animals to divide00:03:14
the historical periods of the evolution00:03:16
of the earth00:03:18
these periods are divided In turn,00:03:20
epochs00:03:21
together constitute four epochs00:03:25
that cover the last00:03:27
635 million years.00:03:30
Let's begin our journey in the00:03:33
Edicardian period between 635 and 54200:03:38
million years ago,00:03:41
this marks the end of the00:03:43
Late Proterozoic Era and the beginning of the00:03:45
history of the aquatic fauna at the00:03:48
bottom of mirobia bacteria and00:03:51
microbes brought by rain00:03:53
began to come to life00:03:59
in00:04:00
1946 the Australian geologist Rex Freak00:04:04
was having lunch in the00:04:06
Ediacara hills in Australia00:04:08
when he suddenly observed some strange00:04:12
jellyfish-shaped footprints on some rocks that00:04:14
they were 600 million years old00:04:17
had just made one of the00:04:19
most important fossil discoveries00:04:21
of all time dickinsonia00:04:28
paleontologists believe that the00:04:31
oldest animal that lived in the sea was00:04:33
found in Australia and Russia about00:04:36
560 million years ago00:04:38
diquinsonia an animal It had a00:04:41
soft body and was oval and was covered with00:04:44
grooves formed by the sections of its00:04:47
body. Although it could grow up to 1.4 meters00:04:51
long, it was as thick as a sheet of00:04:53
cigarette paper. It00:04:55
was only a few centimeters thick. It00:04:58
was an animal, a plant or a mushroom00:05:04
to answer this question we had to00:05:07
wait until 2018 for a team of00:05:09
paleontologists to detect00:05:12
specific fat molecules from00:05:13
multicellular animals in Australian fossils,00:05:18
however this discovery is not00:05:21
enough to certify that00:05:22
latinsonia belongs to the animal kingdom, it00:05:25
could also be related to00:05:28
jellyfish or Sea anemones or even00:05:31
being a giant flattened worm00:05:38
in 1957 three English schoolchildren00:05:43
found a leaf-shaped fossil00:05:45
in a forest in Leicester Shire which they00:05:47
took to a geologist from the local university00:05:51
called charnia looks like a fern the00:05:55
discovery of other fossils of00:05:57
Charnia in formerly submerged rocks00:06:00
indicates that it was not a member of the00:06:02
plant kingdom. This animal lived in00:06:05
deep waters where the lack of light did not00:06:07
allow the development of plants.00:06:11
Since its discovery,00:06:13
other specimens have been recovered in rocks in00:06:15
Canada, Russia and Australia.00:06:19
Charnia did not have Nicaraguan skeleton and00:06:22
its body was soft, most of the00:06:25
fossils measure about 20 centimeters,00:06:28
however, a species related to it,00:06:31
Charlie aguardi, which is00:06:33
known in Canada, was up to two00:06:36
meters long.00:06:40
It is assumed that it was anchored to the bottom of the00:06:42
sea with a disc or spike and grew like00:06:45
a leaf on its stem, as it had no mouth00:06:48
or intestine, it probably fed00:06:51
by filtering or absorbing nutrients from00:06:53
water as its modern relatives do,00:06:55
the crinoids.00:06:58
Another fossil from the helicaric period00:07:00
also comes from the hills of00:07:02
Idiacara,00:07:04
named kimberrella. This one The animal was00:07:07
up to 15 centimeters long, 500:07:10
centimeters wide and 4 centimeters00:07:12
high. It00:07:14
had a single wide and muscular foot to00:07:16
move around.00:07:17
A soft but robust shell was used00:07:20
to retract its soft body in00:07:23
case of threat.00:07:25
In some rocks, the traces of00:07:28
Kimberrella's passage. They show a dentition00:07:32
that could be the ancestor of the Snail. It has00:07:36
all the characteristics that00:07:37
we find today in this animal and it00:07:40
can be clearly stated that Kimberla00:07:42
is the oldest mollusk00:07:46
still in the Diacara hills.00:07:49
Paleontologists discovered other fossils,00:07:51
including the tri-brachirium.00:07:54
This animal lived in shallow waters00:07:56
with a diameter of 400:07:59
centimeters and buried itself at the bottom of the00:08:01
sea, leaving just a few millimeters of its00:08:04
hemispherical body. At00:08:06
the top, three grooves00:08:09
started from the center and curved towards00:08:11
the edges like the Breton Triskelion,00:08:14
these created vortices.00:08:24
The00:08:27
closest relatives of the tri-brachirium00:08:29
today could be anemones or00:08:31
starfish.00:08:34
The first animal with a shell was It00:08:36
was called claudina and seemed to be very00:08:38
widespread. Fossils have been found in00:08:41
limestone rocks in Africa, Asia,00:08:44
North and South America, Europe and Antarctica.00:08:48
Its shell consisted of a pile of00:08:51
open cones that formed a tube that00:08:53
corresponded to its habitat. The00:08:56
largest specimens measure 15 centimeters00:08:58
long and 6 mm wide00:09:02
How it fed,00:09:04
what was its way of life,00:09:06
did it land on the bottom of the sea or could it00:09:08
have buried itself? All this remains00:09:12
a mystery.00:09:14
In any case, the way00:09:16
these marine animals fed00:09:18
probably clarified the water and It00:09:20
enriched its oxygen content, which00:09:23
favored the appearance of more00:09:25
mobile and energetic animals, as well as the00:09:28
development of their eyes.00:09:30
The holes drilled in some of the00:09:32
shells of the cloudina suggest00:09:35
attempts at predation by one animal00:09:37
on another,00:09:39
so the stage is set for the00:09:41
great confrontation that It occurred between00:09:44
predators and prey in the Paleozoic Era00:09:48
at the end of the Proterozoic Era the00:09:51
rondiña the supercontinent of the time00:09:53
divided into several continents00:09:58
first around 56000:10:01
million years ago three continents00:10:04
separated laurentia Siberia and the immense00:10:07
wonderwan a Land00:10:10
laurentia includes present-day North America00:10:12
without New England or Newfoundland but00:10:15
with northern Ireland and Scotland00:10:18
Siberia corresponds to present-day Russia00:10:22
Gondwanaland includes Africa South America00:10:25
Antarctica India China Southeast00:10:28
Asia Australia and southern Europe00:10:33
520 million years ago a new00:10:36
continent called Baltica was created. separated from00:10:39
rondiña it was similar to northern Europe00:10:42
little by little the opening of a new00:10:45
ocean the petus separated laurentia from00:10:48
baltica I Gondwana00:10:50
begins the Cambrian period that marks00:10:54
the beginning of the Paleozoic Era and the00:10:56
appearance of a new life00:10:58
exclusively in Marina the The00:11:01
most famous fossil site of the00:11:03
Cambrian period is located in00:11:05
British Columbia, Canada. It is the00:11:09
Bourgeois shale discovered in 1909 by00:11:13
paleontologist Charles Walcott.00:11:17
This site has produced00:11:19
exceptionally well-preserved remains of a00:11:21
rich invertebrate fauna that lived in00:11:24
the Middle Cambrian period ago. 520 million00:11:27
years ago,00:11:28
if you had dived in the Cambrian in00:11:30
search of macroscopic fauna, you would have00:11:33
encountered Lucigenia.00:11:36
In 1977, a strange fossil caught the00:11:40
attention of British paleontologist00:11:42
Simon White. Morris was00:11:44
extremely thin, measuring only two00:11:47
centimeters in length, and00:11:49
had a soft, bristly trunk. of00:11:52
Thorns and supported itself on 10 pairs of00:11:54
high legs as if it were walking on00:11:56
stilts.00:11:58
The seven pairs of hind legs00:12:00
were equipped with claws that were to be00:12:03
used to advance.00:12:06
The three pairs of front legs, which00:12:08
are longer and thinner, seem to be00:12:11
covered with a kind of feathers were00:12:14
sensory organs or had the function00:12:17
of retaining food suspended in00:12:19
water and bringing it to the mouth surrounded00:12:21
by teeth.00:12:23
The second hypothesis seems plausible00:12:25
because the opening in the head is00:12:28
covered with spines. Furthermore, further back00:12:31
there is a set of teeth in the shape of a00:12:33
needle in the throat It is therefore assumed00:12:36
that food was chewed once00:12:39
and swallowed a second time in the00:12:41
throat00:12:43
thanks to the latest advances in00:12:45
electron microscopy the fossil of00:12:48
allucigenia also reveals a pair of00:12:50
dark spots on its head which may00:12:53
correspond to the eyes00:12:56
thanks to these scientific advances that00:12:58
allowed a more precise description00:13:01
of hallucigenia the scientists were00:13:03
related to the onychophorans a group00:13:06
represented by the peripatos00:13:08
vermiform animals that live in00:13:11
tropical forests are relatives of00:13:13
arthropods among which are00:13:15
crustaceans and insects00:13:20
other Unusual animal from the group of00:13:22
arthropods intrigues scientists.00:13:25
This is already00:13:29
the first fossilized specimens were00:13:31
found in the Bourgeois shale,00:13:33
but others have been recorded in China,00:13:35
Russia, Australia and the Czech Republic.00:13:40
Its ovoid body, 5 centimeters00:13:43
long, was covered by 8 rows of00:13:45
overlapping plates called sclerites,00:13:49
the sclerites acted as a shell00:13:52
to escape attacks from00:13:54
predators and were topped by two00:13:57
rows of spikes up to 5 centimeters00:13:59
high.00:14:01
In addition, the scales of this00:14:03
natural armor loaded with00:14:05
microscopic structures reflected light like the00:14:08
back. of a beetle00:14:10
This was enough to dazzle and00:14:13
dissuade attackers from approaching00:14:17
wewatxia was at least hospitable00:14:20
since examination of the fossils shows that00:14:22
shells similar to those of clams lived on its back,00:14:25
therefore it is00:14:28
assumed that hueoaxia simply landed00:14:30
on the seabed and never escaped.00:14:34
Its food consisted of bacteria00:14:36
found at the bottom of the ocean. In00:14:40
fact, specialists have a hard00:14:43
time agreeing on the place00:14:44
that wewaxia occupies in the tree of life.00:14:47
Some point to its close relatives00:14:50
among worms. modern mariners,00:14:52
others suggest that since its00:14:55
mouth organ is reminiscent of that of the Snail, it is its00:14:58
ancestor. There are also those who believe that it00:15:00
is neither a worm nor a mollusk but a00:15:03
representative of a different group that00:15:06
has already disappeared00:15:08
among the arthropods, the star of00:15:11
these eras. geological remains the00:15:13
tribolite00:15:15
were ubiquitous in the00:15:17
Cambrian seas and occupied all types of habitat00:15:20
from coral reefs to the00:15:22
ocean floor for more than 27000:15:26
million years00:15:27
to date more than 20,000 species have been recorded.00:15:33
There are tribolites of all types shapes and00:15:35
sizes from the size of a fingernail to00:15:38
70 centimeters most00:15:41
species measured between 3 and 10 centimeters00:15:45
its body was divided into three parts00:15:47
both lengthwise and widthwise it has00:15:50
a head with three lobes from which it00:15:52
takes its name a thorax and a tail00:15:57
the head consisted of a central part00:16:00
supported by two cheeks that housed00:16:02
the eyes composed of hundreds of00:16:05
facets similar to those of a dragonfly00:16:08
the body was divided into other00:16:11
segments each of which carried00:16:13
two attachments such as antennae00:16:16
mouth organs or legs00:16:18
this body pattern differs from one00:16:21
species to another some had spines00:16:23
that stretched and twisted into00:16:26
strange shapes while others had eyes00:16:28
perched on stalks on their bodies00:16:32
most roamed the seabed in00:16:34
search of food and their morphology00:16:37
gave them a great ability to live in its00:16:39
aquatic environment00:16:42
its diets were varied predators00:16:45
scavengers slime eaters or even00:16:47
filter feeders00:16:49
it is believed that its closest relatives00:16:51
are spiders it is believed that its00:16:54
closest relatives are spiders and00:16:56
scorpions a00:16:58
distant cousin of the trivolite the marella00:17:01
was Nicknamed lace crab by00:17:04
paleontologist Charles The Little Walcott,00:17:06
who discovered it in the Bourgeois shale, it was00:17:10
abundant in the waters of the Cambrian,00:17:12
with more than 25,000 specimens having been found. It00:17:16
measures up to 2.5 centimeters and has two00:17:20
long extensions on the top00:17:22
of its head that They go backwards, which00:17:24
gives it a horseshoe appearance.00:17:27
Below, two pairs of thin antennae00:17:30
in the mouth probably allow it00:17:32
to orient itself on the sandy bottom00:17:34
[Music]00:17:36
another pair of mobile appendages at the00:17:38
bottom of the head, more robust00:17:41
and hairy, there may be It had a00:17:43
propulsion function to help it00:17:45
move.00:17:47
The rest of the body is made up of00:17:49
between 17 and 26 segments.00:17:54
How the marela fed.00:17:58
Several hypotheses have been raised. It could have00:18:01
been a hunter and a scavenger or it00:18:03
filtered water through its multiple00:18:05
legs equipped with00:18:08
thread-shaped excrescences the mystery remains let's00:18:15
continue our discovery of00:18:18
strange marine creatures from the Cambrian00:18:20
with the cephalopod nectocharisteryx00:18:24
although very little is known about this00:18:26
animal the fossils collected in the00:18:28
bourgeois shale provide00:18:31
invaluable information about the00:18:33
anatomy and lifestyle of This00:18:35
primitive creature,00:18:37
its soft, flattened cylindrical body00:18:40
when viewed from above, measured between two and00:18:43
five centimeters,00:18:45
had two dorsolateral fins00:18:47
similar to a hybrid of a stingray and a squid.00:18:50
This probably allowed it to swim00:18:53
quickly and agilely through the water. It00:18:57
also had two long tentacles00:18:59
protruding from its rigid head00:19:01
[Music]00:19:02
the nectocaris is a peculiar creature00:19:05
as it has a pair of rod-shaped eyes00:19:08
from the base of its mouth a00:19:11
kind of flexible cone opens to an00:19:13
internal cavity that contains a pair of00:19:16
gills00:19:19
this chimney is reminiscent of the siphon a00:19:23
tubular organ of00:19:25
modern cephalopods that they use to swim backwards00:19:28
scientists assume that the00:19:31
nectocaris used it to propel themselves through00:19:33
the water00:19:35
probably fed on small00:19:37
organisms such as plankton and00:19:39
bacteria while living in shallow waters00:19:41
near the coast00:19:44
all These anatomical characteristics00:19:47
are consistent with the hypothesis that00:19:50
nectocharysterix is the ancestor of00:19:52
octopuses and squids.00:19:56
Here is one of the most00:19:58
fascinating animals of the Cambrian or Pavinia.00:20:02
Its anatomy is quite strange. Its00:20:06
soft, segmented body, 700:20:08
centimeters long, gives it an appearance00:20:10
of The shrimp00:20:12
had five eyes perched on small00:20:15
stems, two in front and three behind, as well00:20:18
as a flexible proboscis that00:20:20
ended in a kind of war that it00:20:22
probably used to put00:20:24
food into its mouth.00:20:26
In the absence of powerful jaws, it had to00:20:29
feed on soft food00:20:31
by extracting worms from the ground. it00:20:35
had no legs the 1500:20:38
body segments were bordered by00:20:40
articulated lobes that may have been00:20:42
used for crawling and swimming00:20:46
the fan-shaped caudal fin is00:20:48
somewhat reminiscent of the lobster this00:20:51
would have helped it move and00:20:52
navigate00:20:54
many scientists saw in opavinia a00:20:57
A unique specimen, however, the00:21:00
careful comparison of numerous00:21:02
living and fossil species has led00:21:04
researchers to relate it to00:21:06
other soft-bodied segmented animals00:21:08
and even from afar with00:21:11
arthropods00:21:12
[Music]00:21:14
let's now move on to the Cambrian sea monster00:21:18
anomalocaris,00:21:21
its body resembles that of a00:21:23
giant shrimp since it measures up to a meter in00:21:26
length,00:21:28
it was a formidable hunter, the largest00:21:30
aquatic predator of this time,00:21:33
armed with spikes, its mouth organs00:21:36
hang from the head, its round,00:21:39
flattened mouth formed by plates, it resembles00:21:43
the shutter of a camera,00:21:46
its favorite prey probably00:21:48
trivolites since paleontologists have00:21:52
observed bite marks on some00:21:54
specimens corresponding to its00:21:56
jaw00:21:57
however paleontologist James00:22:01
suggested that this Predator could not00:22:04
eat hard-shelled prey So00:22:07
anomalokaris may have fed on00:22:09
tribolites during the00:22:11
mutation period but It was certainly more of a00:22:14
threat to worms.00:22:18
From Greenland to Australia,00:22:21
several dozen specimens have been found00:22:23
in Cambrian rocks. As the shape of00:22:26
the mouth parts varies from one00:22:28
species to another, it is assumed that they differ in00:22:31
their diet.00:22:32
Some seem to have specialized in00:22:35
predation while others00:22:37
searched the seabed or00:22:39
filtered water to capture tiny creatures00:22:43
with a diameter of 2 centimeters. The00:22:46
rod-shaped compound eyes were00:22:48
as large as those of any00:22:50
insect and had up to 16,000 facets00:22:54
even after appearance Of the00:22:57
fish, the anomalokaris continued to be one00:23:00
of the largest marine creatures until00:23:02
the Ordovician period.00:23:10
The graciles picaya, which is00:23:13
approximately one inch in size, was not00:23:16
especially large since they did not measure00:23:18
more than 5 centimeters. It is one of the00:23:22
oldest known species of the00:23:23
group. of the chordates to which00:23:26
all vertebrates belong, including the human being,00:23:30
an eel appeared to have no00:23:34
skeleton but a rather fat,00:23:37
flexible cartilaginous structure that00:23:39
ran through its fusiform body like a00:23:42
spinal column,00:23:44
a hundred myomeres. Small00:23:47
muscle bundles separated by00:23:48
connective tissue allow the picaya swims00:23:51
undulating00:23:52
[Music]00:23:53
the viscera of some specimens00:23:55
contain fossilized mud, which indicates00:23:58
that it grazed the seabed,00:24:01
the presence of muscles, nerves and00:24:04
blood vessels suggests a distant relationship00:24:07
with reptile fish and other skeletal animals,00:24:11
however, some aspects of its00:24:14
morphology They remain enigmatic, for00:24:17
example the two long tentacles on the00:24:20
top of the head and the00:24:22
multiple pairs of small appendages00:24:24
just below the ventral part.00:24:32
Milokunmigia also belongs to the group00:24:34
of chordates, smaller than the00:24:37
picaya, its body is no larger than a00:24:39
clip Its fossils come from the00:24:43
Maotianson shale in southern China. It00:24:47
looks like a fish with fins, skull muscles00:24:51
and even gills.00:24:54
Many researchers consider it the00:24:57
first known vertebrate, although it does not00:24:59
have a bone structure but rather a00:25:01
soft cartilage skeleton. Thus, during the00:25:05
Cambrian, life took off from In an00:25:07
unprecedented way, this period was a00:25:10
springboard for the explosion of00:25:12
aquatic animal diversity that was00:25:14
observed during the Ordovician00:25:18
[Music]00:25:21
The Ordovician period spans 65 million00:25:25
years beginning 500 million00:25:28
years ago and00:25:29
is the period of greatest00:25:31
continental fragmentation of the Paleozoic.00:25:35
the beginning of the closure of the ocean the petus00:25:38
brings Laurentia closer to the Baltic then00:25:42
the Caledonian orogeny took place that00:25:45
created the ancient massifs of Europe and00:25:47
North America including the00:25:49
Appalachians00:25:51
the opening of the Rhaetian Ocean separates00:25:55
Wallonia from Gondwana abalonia named00:25:58
after the mythical Island of Avalon where00:26:00
Excalibur was forged King Arthur's Sword00:26:03
included England Wales Southeast00:26:06
Ireland Northern France Nova00:26:09
Scotia and New England00:26:13
The Sea of Torquins separates the Baltic Sea from00:26:15
Abalonia00:26:17
In this period there was a new00:26:20
explosion of animal diversity The00:26:23
record fossil shows an00:26:25
increasing number of deep-sea species00:26:27
planktonic animals that swam in the00:26:30
open sea and predators well equipped00:26:32
to capture them00:26:35
built by sponges and other00:26:37
creatures reefs grew and00:26:40
multiplied giving shelter to more00:26:42
animals00:26:45
at the same time some took their00:26:47
first steps on land in brief00:26:49
excursions out of the water leaving their00:26:52
footprints on the shore00:26:55
the vegetation of the time consisted00:26:57
mainly of mosses and lichens00:27:00
much of the primitive fauna lived00:27:03
in the shallow seas near00:27:05
the coast but for any animal that00:27:08
could swim far enough00:27:10
in the sea the open ocean offered a00:27:13
vast territory new00:27:15
food resources And perhaps fewer predators00:27:21
along with crustaceans and other00:27:23
arthropods the nautiloid is a mollusk00:27:26
cousin of the squid and the octopus the fossils00:27:29
found in00:27:32
470 million year old Ordovician rocks00:27:35
show that They were present throughout00:27:37
the world.00:27:40
They are animals that00:27:42
gradually adapted to life in deep waters.00:27:46
It is believed that the first nautiloids00:27:49
were plantivores that rose and fell in00:27:51
the water, filling the cavities of00:27:54
their shell with gas and then00:27:57
changing the concentration. chemistry00:27:59
of their body fluids00:28:02
the increase in concentration00:28:03
transfers water from the shell to the body00:28:06
This causes the shell to fill with00:28:09
gas when the amount of gas in the00:28:12
shell increases the animal also00:28:14
does so and vice versa00:28:17
the nautiloids They then became00:28:19
more mobile They moved by projecting00:28:23
a jet of water through a hole00:28:25
near the head and hunted with their00:28:28
tentacles that carried food to their00:28:30
hard beaks.00:28:32
Most had shells only00:28:35
about 10 centimeters long but others00:28:37
were enormous and could reach up to 600:28:40
meters in length. length00:28:43
at the time they were at the top of the00:28:46
aquatic food chain00:28:48
damaged fossil shells show that00:28:51
nautiloids probably00:28:53
attacked each other traces of color00:28:56
preserved in some fossils00:28:59
even suggest that some species00:29:01
actually practiced camouflage in the00:29:04
upper half of the shell The gray00:29:07
and brown stripes allow the animal00:29:09
to blend in with the dark waters.00:29:13
Imagine a giant tadpole and you will have00:29:16
a good idea of what the first00:29:18
vertebrates were like.00:29:20
Baspis yanbieri is one00:29:24
of the oldest and best known. It is00:29:27
often considered the pioneer of00:29:29
The animals with a complete skeleton00:29:33
with a maximum length of 2500:29:36
centimeters are especially00:29:38
striking because their head is equipped with00:29:41
bony shields on the top and bottom,00:29:44
probably protecting it from00:29:46
predators, especially00:29:48
large invertebrates. The rest of the00:29:51
body was covered with long scales. It00:29:55
had jaws and had to pick up00:29:57
or suck food from the bottom of the water and00:30:00
then crush it in its throat.00:30:03
The eyes were located between two00:30:06
small nostrils and the mouth was00:30:08
armed with very thin plates.00:30:12
The Sabambaspis lived in shallow waters00:30:15
near the shore.00:30:18
Fossils have scratches on their bellies00:30:20
made by scraping the seabed.00:30:23
Currently, the largest animals00:30:25
in the sea are vertebrates, that00:30:28
is, whales and sharks.00:30:30
Although some deep-sea squid00:30:33
compete closely with00:30:35
them,00:30:36
hundreds of millions of years ago,00:30:39
enormous specimens They dominated the seas,00:30:42
among them the terigotus angricus, its00:30:45
name means winged fish because the00:30:48
Swiss naturalist Luia Gasif, who00:30:51
described it for the first time in 1839, thought00:30:54
it was a large fish.00:30:57
In fact, it belongs to a group of00:30:59
extinct arthropods also known00:31:01
as sea scorpions00:31:03
[Music]00:31:04
With a body that could reach up to00:31:07
80 meters, it was related to the00:31:10
giant europterids. Other species,00:31:13
however, were smaller, only about 5000:31:16
centimeters.00:31:19
Most of them lived in shallow waters,00:31:22
but their appearance at the same time in00:31:25
parts of the planet separated by vast00:31:27
oceans demonstrates They were perfect00:31:29
swimmers,00:31:31
the wheat moved with four pairs00:31:34
of legs, a fifth pair looked more like00:31:37
fins.00:31:39
It was armed with two00:31:41
front limbs, two powerful claws,00:31:43
perfect for grabbing and killing its00:31:46
prey.00:31:47
Its eyesight must have been excellent because it00:31:49
had a pair of lateral eyes.00:31:51
gigantic in addition to a second pair of00:31:54
smaller eyes in the center of the00:31:56
head00:31:57
its body was built for swimming and its00:32:01
flat tail was probably used00:32:03
as fins to propel itself00:32:05
despite its large size and fearsome00:32:08
appearance the terogotus anglicus did not00:32:11
survive the catastrophic00:32:13
mass extinction that ended their aquatic reign00:32:19
thousand-foot aquatic ancestors00:32:22
eutiquinoids are arthropods with an00:32:25
external skeleton, a pointed tail and00:32:28
an articulated body with up to 28 pairs00:32:31
of legs00:32:32
the size of a large shrimp of about00:32:34
10 centimeters, they are more of a cross00:32:37
between a lobster and a cochineal00:32:41
the rocks containing the00:32:43
oldest known fossils of uticarcoids00:32:46
date back to the late Cambrian00:32:50
Scientists suggest they were the00:32:52
first animals to venture onto the00:32:55
mainland where the coast was full00:32:57
of microbes and bacteria a meal00:33:00
served in a tray if you could00:33:02
reach it at low tide. In addition,00:33:04
venturing out of the water00:33:07
offered an escape route from predator attacks.00:33:12
At the end of the Ordovian period, a00:33:15
great extinction occurred when 85% of00:33:19
the existing species disappeared. It00:33:21
affected both organisms that live in00:33:24
the bottom as tribolites echinoderms and00:33:27
brachiopods as pelagic forms such as00:33:30
nautiloids00:33:31
[Music]00:33:33
this mass extinction has been related00:33:35
to the glaciation that occurred at this00:33:37
time the South Pole was then00:33:40
located in present-day Niger and much00:33:43
of Gondwana was covered by a00:33:45
thick ice sheet twice as00:33:47
large as the current Antarctic ice sheet,00:33:57
as a result the sea level00:34:00
dropped 50 meters, drying out the00:34:03
shallow seas where life once thrived,00:34:07
plus an anoxic event, that is, an00:34:11
extreme decrease in00:34:12
oxygen levels. in sea water destabilized00:34:15
the ecosystem of Marine life,00:34:17
what was once an ocean teeming with00:34:21
life is now an ocean of desolation.00:34:25
This crisis lasted between one and two00:34:28
million years before giving way to the00:34:30
Silurian period 435 million years ago00:34:36
[ Music]00:34:40
At the beginning of this third00:34:42
Paleozoic period that began 444 million00:34:46
years ago and lasted more than 28 million00:34:49
years, the melting of the00:34:51
polar caps caused a general rise in the00:34:53
level of the oceans and the shallow seas00:34:56
that covered the continental shelves00:35:01
After the closure of the Turkish Ocean the00:35:03
Abalonia land mass joined the00:35:06
Laurentian and Baltic land masses00:35:09
thus forming the continent of the old00:35:12
red sandstone abbreviated cvgr which is now00:35:16
variously called Laura00:35:20
Europe Euro-America or Laurussia00:35:24
the huge continent of Gondwana It was00:35:27
separated from the CGR by the Rhaetian Ocean00:35:29
and the Paleotis.00:35:32
The Silurian marks the beginning of the era of00:35:35
fish with the development of00:35:37
agnatic vertebrates, that is, fish without00:35:40
jaws that have00:35:42
external bone armor called ostracoderms,00:35:46
however there are also vertebrates with00:35:49
jaws. known As some that00:35:52
appeared in the Ordovician period,00:35:55
it was in the Silurian period that the00:35:58
terrestrialization of invertebrates occurred,00:36:00
that is, oligochaetes, arthropods and00:36:03
gastropods. The00:36:08
oldest plant macrofossils00:36:11
date back to the Silurian period, but they are scarce00:36:14
after the mass extinctions at the end of00:36:17
the Ordovician period, life returned to00:36:19
proliferate and diversify00:36:21
coral reefs are numerous in00:36:24
the island arcs that border the00:36:26
pantalasa and the palao tetis as well as in00:36:29
the bottoms of the shallow seas00:36:32
the general warm climate allows them to00:36:35
extend far beyond the intertropical zone00:36:39
the corals are mainly00:36:42
tetracoraliarids also known as00:36:44
rough and tabulated corals00:36:47
[Music]00:36:48
the emblematic animals of the Silurian00:36:51
are the eurypterids already present in the00:36:54
Ordovician. Their history continued and they never00:36:57
diversified so much in shape and00:36:59
size.00:37:01
The most important event among00:37:03
vertebrates was the appearance of the00:37:05
jaw that was formed from the00:37:08
second branchial arch of the Nata. The00:37:11
first vertebrates with jaws or00:37:13
ornathostomes were the acanthoids with00:37:17
their spiny fins and the placoderms00:37:19
whose front part of the body was00:37:22
enclosed in a bony shell.00:37:26
The placoderm was the first vertebrate00:37:28
with jaws and mobile teeth00:37:30
appearing. In the Early Silurian it00:37:33
also introduced an even number of00:37:36
fins that later evolved00:37:38
into the limbs of00:37:41
terrestrial vertebrates.00:37:43
Specimens of a 38000:37:46
million year old species00:37:47
found in the Goyo Formation, a00:37:50
fossil site in Western Australia,00:37:52
contained fossilized embryos.00:37:56
placoderm is therefore one of the00:37:59
first known vertebrates to have00:38:01
produced fully00:38:02
developed offspring instead of laying eggs00:38:06
but the most striking and00:38:08
strange feature of the placoderm are the00:38:10
bony plates that cover the head and00:38:13
upper part of the body this armor00:38:15
demonstrates that the seas The Silurians were00:38:17
a ruthless environment in which00:38:20
fish ate each other, not to00:38:23
mention the threat of00:38:25
invertebrate predators such as nautiloids and00:38:28
sea scorpions.00:38:30
The placoderm awaited its prey by00:38:32
lurking on the seabed or hunting00:38:35
in the open sea.00:38:38
Dunkleosteus stands out. such as the00:38:41
largest placoderm, reaching 600:38:44
meters in length and with jaws00:38:46
capable of exerting a force of 50000:38:49
kilograms,00:38:51
other specimens, however,00:38:53
fed on marine plants, for00:38:56
example the titanitis, one of the most00:38:59
impressive with its 8 meters in00:39:01
length and Its weight of one ton, it00:39:03
lacked teeth, probably00:39:06
filtered plankton suspended in the00:39:09
water like the current whale shark.00:39:11
However, giant placoderms00:39:14
were rare and most of them measured00:39:17
between 30 centimeters and one meter.00:39:20
Placoderms are found throughout the00:39:22
world living in freshwater and in the sea,00:39:26
when they became extinct at the end of the00:39:28
deponic period, they left the oceans to00:39:31
two groups: fish with bony skeletons, to00:39:34
which most of00:39:36
today's fish belong and which include the00:39:38
ancestors of terrestrial vertebrates00:39:40
and sharks and rays. soft-shelled,00:39:45
according to acanthodon fossils,00:39:48
sharks along with their cousins, rays,00:39:50
are descendants of this group of00:39:52
natostean vertebrates that appeared00:39:55
about 400 million years ago,00:39:58
acanthodonts. They are characterized by having00:40:00
long bony spines in the00:40:03
front part of their pectoral fins but00:40:05
Also on the dorsal and anal surfaces,00:40:09
their bodies were covered with00:40:11
small quadrangular scales,00:40:13
just as sharks had a00:40:16
heterocercal tail, that is, with two00:40:19
unequal lobes.00:40:21
Some acanthoids were predators that00:40:24
used their large eyes to00:40:26
detect their prey. Others lacked00:40:29
teeth and were content By filtering water,00:40:33
these predators flourished throughout the00:40:36
world, colonizing seas and rivers until they became00:40:38
extinct in the Permian about00:40:41
250 million years before our00:40:43
era.00:40:45
The invasion of the continents continued00:40:48
with the appearance of the first00:40:49
terrestrial arthropods and larger plants.00:40:52
Since00:40:56
terrestrial life is limited to a00:40:58
narrow strip of wetlands around00:41:00
rivers and lagoons,00:41:03
the best candidates for the title of00:41:05
terrestrial animals Pioneers are the00:41:07
ancestors of today's millipedes and00:41:10
scolopendras the group of myriapods00:41:14
[Music]00:41:16
pneumodesmos neumani was a00:41:18
relatively small that measured just over00:41:21
two centimeters long, however00:41:23
its most striking feature was its00:41:26
large number of legs, it had up to 4000:41:29
pairs.00:41:31
The holes that run through its body00:41:33
allow it to breathe, providing oxygen00:41:36
to its cells. They also show that the00:41:39
animal lived on land,00:41:43
the parallelonus. It is one of the00:41:45
oldest known scorpions,00:41:47
although its exact size is unknown. It00:41:50
probably did not measure more than 800:41:53
centimeters.00:41:54
This small size may have been an00:41:57
adaptation to the lack of food00:41:58
available at that time.00:42:02
Its ovoid body was flat and its long00:42:04
tail had a stinger. In the extreme,00:42:08
the most striking feature of the00:42:11
Palaeophonus is its large claws. It is00:42:14
possible that they were used for00:42:16
capture and defense and could have00:42:18
posed a serious threat to00:42:20
smaller prey.00:42:24
In terms of vegetation, a00:42:27
type of primitive plant, the coxonia, appeared.00:42:31
The size of the coxonia varies from a00:42:34
few centimeters to a meter in00:42:36
height.00:42:37
Microscopic analysis reveals a00:42:40
functional vascular system. This00:42:43
allowed it to transport water and00:42:45
nutrients from the soil through the stem,00:42:47
thus ensuring a constant supply00:42:49
of water, therefore cooking.00:42:53
It could easily adapt to00:42:55
periods of heat and dryness and00:42:57
survive them.00:43:00
Stomata have also been found in00:43:03
coxonia fossils. They are small holes00:43:06
in the cuticle wall that allow00:43:08
gas exchange with the cells.00:43:10
Therefore, they are its respiratory system00:43:13
without the which could not have00:43:15
developed00:43:17
without roots leaves or flowers consists of00:43:21
thin and branched stems00:43:23
the stems end in a00:43:26
trumpet-shaped structure called sporangion00:43:28
that serves to spread the spores00:43:30
outside the plant to colonize the00:43:33
surroundings00:43:35
these small plants dominated the00:43:37
continents for 40 millions of years00:43:40
were an important step in the00:43:43
evolution of land plants,00:43:46
among their descendants are00:43:49
some of the best-known current plants00:43:51
such as ferns, mosses and00:43:54
flowering plants.00:43:57
In addition, by diffusing oxygen in the00:44:00
atmosphere and stabilizing the soils, they00:44:01
also contributed. With the arrival of00:44:03
terrestrial animals,00:44:06
the Devonian is located between the Silurian and00:44:08
the Carboniferous. This period extends00:44:11
from 418 to 359 million years00:44:16
ago.00:44:18
The Bonian period is marked by the00:44:21
disappearance of the Rhaetian Ocean, which00:44:24
allowed the supercontinent Gondwana00:44:26
to continue its slow drift. Towards Urrusia,00:44:30
in this period there was the transition00:44:33
from fish to tetrapod animals00:44:35
with four limbs and a neck, as00:44:38
well as the appearance of hexapods, which00:44:40
group insects and arthropods with00:44:43
three pairs of legs00:44:44
[Music]00:44:46
apart from pantalasa, most of them The00:44:49
paleo ocean inherited from the00:44:52
lower Paleozoic was closed during the Devonian,00:44:54
giving rise to a00:44:57
pre-Pangean paleogeographic configuration.00:45:00
The first forests were established in00:45:03
the equatorial regions of Laurussia,00:45:05
participating in the00:45:07
photosynthetic activity that allowed the development00:45:09
of the ozone layer00:45:11
[Music]00:45:13
all of these Events took00:45:15
place in a generally warm climate00:45:18
responsible for the development of00:45:21
oxidized siliclastic sediments, the old00:45:24
red sandstone and carbonate rocks in which00:45:26
reef formations proliferated.00:45:30
The uniformly warm climate of the00:45:32
early Devonian favored the00:45:34
development of reefs.00:45:37
The building animals are00:45:39
invertebrates that They live in colonies00:45:41
called stromatopores. The00:45:45
tabular corals and the inland corals00:45:47
of the Silurian period still cover the00:45:50
ocean floor.00:45:51
The placoderms continue to dominate the00:45:54
ecosystems.00:45:56
The Dunkleosteus, for example, are a00:46:00
formidable predator and a threat to00:46:02
the giant eurypterids,00:46:05
although they were already present at this00:46:07
time. Sharks were not yet the00:46:10
supreme predators of the seas.00:46:12
They were joined by several representatives00:46:14
of the finfish groups, namely00:46:17
the actinopterygians, the acanthoids and the00:46:21
sarcopterygians,00:46:24
the graptolites classified as algae,00:46:27
sponges and pieces, bryozoans and00:46:30
pterobranchs, disappeared at the end of00:46:32
the Lower Devonian. A family00:46:35
of benthic graptolites passed into the00:46:37
Carboniferous.00:46:39
The seabed is still dominated by00:46:42
branchiopods, of which only00:46:44
relics remain in our current seas.00:46:46
The vivalvo mollusks became00:46:50
diversified and abundant shellfish in00:46:52
the shallow waters of the coast,00:46:54
as is still the case today.00:46:58
the large nautiloid mollusks00:47:00
begin to decline but give rise to00:47:02
the ammonoids omnipresent in the Mesozoic seas00:47:06
[Music]00:47:08
the mainly00:47:10
crinoid echinoderms or sea lilies formed00:47:13
true beds of sea grasses locally00:47:17
the fishes of the Devonian can be divided00:47:20
into two main groups the agnaths00:47:23
jawless fish and the nathostomes or00:47:26
jaw-like fish00:47:30
of these two groups the agnathans were00:47:33
the ones that had the most difficulty00:47:35
surviving the great biological crisis of the00:47:37
late Devonian of the six00:47:40
known groups at this time four became00:47:43
extinct of those that survived00:47:45
today only There are a few species such as00:47:48
lampreys and hagfishes00:47:52
among the nathostomes and the fates00:47:55
were diverse. On the one hand, the last00:47:58
ones all disappeared after the00:48:01
Devonian, as did the last00:48:02
placoderms.00:48:04
On the other hand, sharks and rays00:48:07
have prospered to this day in the00:48:10
Devonian several subgroups of00:48:13
sarcopterygians appeared and one of them was the00:48:15
origin of the first tetrapods, a00:48:17
notable evolutionary success. With 29,00000:48:20
current species without counting all those00:48:23
that have become extinct today,00:48:25
only a dozen species of fish00:48:28
along with coelacanths and fish00:48:30
lungfish belong to the00:48:32
sarcopterygians,00:48:34
the actinopterygians, the fish with00:48:38
stingray fins are an undeniable evolutionary success.00:48:41
With nearly 29,000 species that00:48:44
currently roam the waters of the world,00:48:46
making them the largest group00:48:48
of vertebrates00:48:50
[Music]00:48:54
the eucenopteron was one of the00:48:57
sarcopterygians. that was able to00:48:59
conquer the Earth00:49:01
had a pair of pelvic fins and a pair00:49:03
of fleshy pectoral fins, each00:49:06
connected to the body by a single bone.00:49:09
These bones are analogous to the00:49:11
bony extremities of00:49:13
terrestrial tetrapods, amphibians, reptiles, birds and00:49:16
mammals00:49:19
in these fish. fleshy fins the00:49:21
swim bladder is modified to00:49:23
allow air breathing00:49:26
the bony limbs were used00:49:29
to row in the water but also to00:49:31
crawl along the shore00:49:33
everything indicates that the eucenopteron could00:49:36
have reached 1.8 meters in length00:49:39
however most of the00:49:41
Paleontologists agree that the tiktalic never00:49:43
came out of the water.00:49:48
Thanks to certain aspects00:49:51
of its anatomy, it appears to be close to00:49:53
terrestrial animals. It was discovered on the00:49:56
island of El Esmere in the00:49:58
Canadian Arctic archipelago. It00:50:01
measures up to 2.5 meters and has a00:50:04
flattened head. It can rotate thanks to a00:50:06
movable neck,00:50:08
the holes that could be compared to00:50:11
the nostrils would probably00:50:13
allow it to breathe on land,00:50:16
its fins equipped with strong bones and00:50:19
a joint comparable to that of a00:50:21
wrist could have helped it00:50:23
get up so equipped, it00:50:26
could probably move in water. shallow00:50:28
but also travel short distances00:50:31
along the coast00:50:33
just as the crocodile must have00:50:36
traveled through rivers and swamps using its00:50:38
powerful fins and mobile neck to00:50:40
hunt other fish that it ripped to pieces00:50:43
with its sharp teeth,00:50:46
it is assumed that tiktalic did not remain00:50:49
long time out of water based on00:50:52
impressions left in the rocks in00:50:54
which their fossils were found00:50:58
the transition from fish to00:51:00
tetrapods is one of the00:51:02
key events in the history of00:51:04
terrestrial life that led to the colonization00:51:06
of the Earth's surface by vertebrates,00:51:11
however, for this00:51:14
change to occur, two major problems had to be solved:00:51:16
being able to breathe out of water00:51:18
and move around by walking,00:51:22
acanthus estega and histia Ortega00:51:25
are among the00:51:27
oldest known vertebrates with legs,00:51:30
therefore they provide essential clues00:51:32
to this mystery00:51:34
[ Music]00:51:38
in the song stega is a bridge between00:51:40
the species of fish with robust00:51:42
fins in the form of limbs like those00:51:45
of tiktalic and the first animals00:51:47
capable of living on land00:51:50
the acanthus fossils tegan measure about00:51:53
60 centimeters00:51:54
had a flat head gills for00:51:57
breathing in the water and a large00:51:59
caudal fin ideal for swimming but it also00:52:02
had lungs that allowed it to breathe00:52:04
air at the surface00:52:07
judging by its morphology and by the00:52:10
fossilized aquatic plants in the00:52:12
Greenland sites where it was00:52:14
found it lived in shallow rivers and00:52:16
swamps it00:52:17
rowed. with its paws among the vegetation00:52:20
in search of small prey00:52:23
its webbed feet ended in eight00:52:26
fingers but the lack of joints00:52:28
means that the paws were probably00:52:31
struggling to support its weight on the00:52:33
ground00:52:36
as for lithium Ortega is characterized00:52:39
by being a large cousin of The cantostega,00:52:41
since it can exceed one meter,00:52:44
must also have lived mainly in00:52:47
water, as attested by its powerful tail fin00:52:49
and gills.00:52:54
However, it seems to be improved for00:52:57
life on land since its ribs and00:52:59
its seven-fingered limbs are more00:53:01
robust and therefore They can support00:53:03
weight better,00:53:04
however, they could not walk like00:53:07
current terrestrial vertebrates. They may00:53:10
have had to use their00:53:12
front legs to crawl like a00:53:14
seal. As for the hind legs, they00:53:17
probably served as additional support.00:53:22
This development of terrestrial and00:53:25
aquatic life was interrupted. By the00:53:27
third great biological crisis in the00:53:29
history of the Earth00:53:31
374 million years ago, a00:53:35
new mass extinction occurred in the transition00:53:37
between the Frasnian and the Famenian two00:53:40
stages of the Bonic period00:53:43
while the Ordovician mass extinction00:53:45
was a unique event and00:53:47
Sudden, the Devonian mass extinction00:53:50
was a series of events that00:53:52
spanned three million years.00:53:55
There was a climate warming in00:53:58
which the temperature reached 3000:54:00
degrees. In addition, numerous00:54:03
extraterrestrial impacts weakened the biosphere00:54:07
in the bowels of the earth beneath00:54:10
present-day Siberia. magma ocean00:54:12
about to explode00:54:14
a giant plume is forming that is00:54:17
released from the magma ready to00:54:19
explode through the00:54:21
earth's crust00:54:25
superheated gases are expelled00:54:28
from the depths of the earth00:54:30
water boils underwater earthquakes00:54:33
destroy reefs eruptions00:54:36
are Disproportionate thousands of tons00:54:38
of molten rock were dumped into the00:54:41
oceans00:54:44
at the end of the Frasnian. There was a00:54:47
shortage of oxygen around the world.00:54:49
This phenomenon was called the WhatsApp event.00:54:55
When molten lava comes into contact00:54:57
with sea water, it generates00:55:00
toxic substances such as metals silver gold chrome00:55:04
iron magnesium and others the ocean is00:55:08
polluted and marine life is00:55:10
devastated00:55:12
the gases are released into the atmosphere00:55:14
releasing massive amounts of00:55:17
carbon dioxide and little by little the air is00:55:19
loaded with greenhouse gases00:55:22
the temperatures rise and the00:55:25
ocean currents stop the water reaches00:55:28
more than 30 degrees at the equator it is00:55:31
desolation the aquatic environment is00:55:34
dying00:55:37
250,000 years after the first00:55:39
eruption the earth continues pouring magma00:55:43
with the atmosphere saturated with00:55:46
carbon dioxide the vegetation exploded and invaded00:55:49
the surface of On Earth,00:55:52
the leaves have been falling for thousands of years,00:55:55
rotting on the ground and forming the00:55:57
first layer of a mousse on the planet.00:56:00
This nutrient-rich soil is00:56:02
washed away by the rains and flows00:56:04
into the seas,00:56:06
absorbed by the algae, which grow without00:56:09
control, stealing all the oxygen and00:56:11
suffocating aquatic life the coasts00:56:14
are infested and saturated with plants00:56:21
these eruptions that until now00:56:23
occurred in the sea are beginning to00:56:26
occur on land the air is loaded with00:56:29
sulfur dioxide methane and carbon dioxide00:56:33
enormous eruptions are produced and are launched00:56:36
into the atmosphere gigantic00:56:38
ash clouds several kilometers high the00:56:41
planet empties itself of its bowels it is00:56:44
chaos on earth00:56:47
the sky darkens burning ash00:56:50
falls on the continents00:56:52
fires break out all over the world00:56:55
the sun no longer penetrates the atmosphere it is00:57:00
winter volcanic00:57:02
temperatures of around 3000:57:05
degrees drop 20 degrees and the00:57:07
plankton that constitutes the base of the00:57:10
food chain disappears the00:57:13
fish eggs are decimated00:57:16
it is a massacre00:57:19
salvation came from the00:57:21
oxygen-producing trees the00:57:24
temperatures ended up stabilizing00:57:26
The seasons reappeared and00:57:29
life diversified again.00:57:32
This extinction took between 50 and00:57:36
70% of the species00:57:42
at the beginning of the Carboniferous. The00:57:44
continents of Russia and Gondwana were00:57:46
re-formed into a single00:57:48
continent, the small Pangea00:57:52
to the east. The ocean that exchanged the00:57:54
small Pangea is called Protothetis. These00:57:58
continental masses are surrounded by00:58:01
the super ocean Panthalasa.00:58:04
This movement of the tectonic plates00:58:06
raises the level of the oceans,00:58:08
drowning a large number of plants00:58:11
in the seas. More and more fish00:58:15
with spines appear, however. In the oceans,00:58:18
echinoderms and00:58:21
crinoids predominate, swarming on the bottom00:58:25
in the immense and lush swamps.00:58:28
In addition to the arthropods that reigned,00:58:30
the tetrapods and amphibians evolved00:58:33
that appeared in the Bonic period,00:58:35
as well as the first reptiles00:58:38
on land, the Devonian ferns00:58:41
were giving way to00:58:43
bark and seed trees.00:58:47
During fires or floods00:58:49
these trees and plants that were00:58:52
buried then decompose, thus00:58:56
preserved under the growing organic matter,00:58:59
this plant matter00:59:01
buried deep and heated00:59:03
for millions of years is transformed00:59:06
into charcoal. This00:59:07
process is called carbonization.00:59:12
330 million years ago the00:59:15
conditions for the formation of coal00:59:17
were so favorable that the period was00:59:19
called Carboniferous.00:59:22
The masters of the Carboniferous jungles00:59:24
were a group of vascular plants, the00:59:27
most common of which is called the00:59:30
dendron. majestic plant that can00:59:33
climb up to 30 meters in height, it had00:59:36
a trunk one meter in diameter. The00:59:39
initial growth was00:59:41
rapid and without branches.00:59:45
When this single, enormous shoot reached00:59:48
the top, the tree opened into a beautiful00:59:50
crown of branches whose tips bore00:59:53
cones containing spores00:59:57
another land plant from the00:59:59
Carboniferous period glossopteris was found in01:00:03
the rocks of South America southern01:00:05
Africa Madagascar India and Australia01:00:09
although this plant is one of the01:00:12
main components of Coal01:00:14
little is known about it01:00:16
era a woody plant with a trunk01:00:19
80 centimeters in diameter therefore01:00:22
it is conceivable that opteris01:00:25
could also be up to 30 meters high01:00:29
the carboniferous was a time of giant insects01:00:34
dragonflies the size of large birds01:00:36
cockroaches as large as mice and01:00:39
scorpions of more 50 centimeters in01:00:42
length01:00:44
but the gold medal goes to01:00:46
arzopleura, the largest invertebrate of this01:00:49
era.01:00:52
Although no01:00:54
complete fossil has yet been found, scientists01:00:56
agree that based on the study01:00:59
of fossil fragments and traces it could have01:01:02
had up to two meters01:01:04
long and 50 centimeters wide01:01:07
This relative of the modern millipede was01:01:10
covered by a thick and heavy01:01:12
shell made of chitin plates, a01:01:15
hard substance found in the01:01:17
exoskeleton of insects. It01:01:21
lived in tropical swamps covered01:01:23
by forests of tree ferns and other01:01:25
primitive plants01:01:28
As fossil mouths have not yet been found,01:01:30
scientists assume that it was01:01:33
a herbivore since the fossil feces01:01:36
attributed to arzopleura contain01:01:38
plant spores01:01:41
[Music]01:01:44
valan herpeton Woody was found in the01:01:46
famous Scottish site of East kirton01:01:49
inside tree trunks hollow fossils01:01:52
It is conceivable that this was the last01:01:55
refuge that these small amphibians01:01:57
found to protect themselves from a01:01:59
fatal detachment01:02:02
the morphology of balane pardon is01:02:05
unusual with its rounded skull and its01:02:09
elongated body of about 20 centimeters it01:02:11
looks like a salamander01:02:15
its wrists and ankles well ossified and01:02:19
robust suggest terrestrial locomotion01:02:23
has a large tympanic opening at the01:02:26
back of the skull that forms a01:02:28
rounded window Useful for detecting01:02:31
sounds from the environment01:02:34
is one of the few fossil amphibians that01:02:37
has about 40 teeth in the01:02:39
upper jaw while only the lower jaw01:02:41
There are about 20, therefore their diet was01:02:45
carnivorous, even insectivorous,01:02:50
as for reptiles and lizards, the01:02:53
gnomus thread is the oldest specimen.01:02:58
The first discovery of fossils of the01:03:01
gnomus thread occurred more than 15001:03:03
years ago on the Canadian island of Nova01:03:06
Scotia, which in the carboniferous period01:03:08
was in the tropics01:03:10
these were buried inside a01:03:13
hollow tree trunk and fossilized these01:03:16
trees grew far from the water a sign01:03:19
that the nomus thread had evolved01:03:22
enough to spend its life on01:03:24
land01:03:26
it lived roaming the forests in search01:03:28
of insects and millipedes, their body measured01:03:31
approximately 25 centimeters long01:03:34
including the tail01:03:36
and the nomus reveals the dawn of01:03:39
reptiles and with them the appearance of the01:03:42
amniotic egg that allowed them01:03:44
to free themselves from the aquatic environment.01:03:47
The vertebrates were then able to01:03:49
colonize the land and the reptiles01:03:52
dominated it. For more than 200 million01:03:55
years,01:03:59
animal life in the Carboniferous01:04:01
was also characterized by the development of01:04:03
giant insects. The meganeura stands out01:04:07
as an ambassador of giant dragonflies.01:04:11
With its 30 centimeters in length and 7001:04:14
centimeters in wingspan, it could be01:04:16
compared to the size of a pigeon.01:04:18
modern01:04:20
flying over rivers and lakes it fed01:04:24
on small insects that it could detect01:04:26
with its sharp eyes. So01:04:28
what is the reason for the enormous size01:04:31
of the animals of the Carboniferous period,01:04:34
the question is still the subject of01:04:37
debate, however the most01:04:40
common explanation lies in the content of Oxygen01:04:42
in the air01:04:44
today is 21%, but in the01:04:48
Carboniferous period it reached 35%.01:04:51
This enormous supply of oxygen01:04:54
came from the lush vegetation of01:04:56
the forests,01:04:57
just as oxygen promotes growth,01:05:00
amphibian insects and other01:05:02
invertebrates benefit from it,01:05:06
solitary or colonial corals01:05:09
build important reefs in the01:05:11
warm waters of the paleothelium,01:05:16
brachiopods and echinoderms also developed. and the01:05:19
mollusks in this last group, the01:05:22
goniatites are of great stratigraphic interest01:05:27
while some of these gocephalans01:05:29
experienced the terrestrial environment, others01:05:32
evolved in an aquatic environment.01:05:34
This is the case of crassigius scoticus,01:05:40
this fossil of a giant tadpole was01:05:42
discovered in some ancient mines near01:05:45
Edinburgh. It was up to two meters01:05:48
long01:05:50
with its large skull and01:05:52
atrophied limbs. Crasigirius scotticus01:05:55
lived in shallow fresh waters01:05:57
like a snake. In addition, its01:06:01
poorly ossified pelvis and spine01:06:04
allowed it a certain flexibility. It was a01:06:06
carnivore with a tendency to eat fish.01:06:09
It had several fangs inside the mouth01:06:12
Even in the palate, in addition, its01:06:15
cranial kinematics comparable to that of01:06:17
snakes testify that the animal01:06:20
could open its jaws wide,01:06:23
thus swallowing prey much larger than it01:06:26
[Music]01:06:29
another crazy stegocephalian lived in the01:06:32
Carboniferous period This was01:06:35
spaticephalus virus its skull is01:06:39
Modest in size, about 20 centimeters01:06:41
long and flattened like a Frisbee, at the01:06:45
top of the skull there are01:06:47
strange bean-shaped eye sockets01:06:49
that are very questionable.01:06:51
These may house eyeballs,01:06:54
glands or electro-sensory organs01:06:56
to detect prey.01:07:00
Another characteristic of spaticephalus is01:07:03
its dentition, it has many01:07:06
small and fine teeth but it does not have fangs.01:07:09
Only the lower jaw bone01:07:11
has about 120 teeth.01:07:14
The tips of the teeth were01:07:17
provided with small valves, which01:07:19
indicates that it had to swallow large01:07:21
amounts of water or mud that it filtered.01:07:23
to extract small invertebrates or01:07:26
fish01:07:28
during the late Carboniferous the planet01:07:31
cooled again And although the01:07:33
continent of Laurussia experienced01:07:35
relatively mild temperatures The01:07:38
same did not happen in the south01:07:40
in fact the continent of Gondwana01:07:43
was partially covered by01:07:46
ice and this lasted for about 80 million of01:07:49
years until the beginning of the Permian01:07:54
the Permian began about 29501:07:57
million years ago lasted about 50 million01:08:01
years01:08:02
this period will close the Paleozoic Era01:08:05
in a very significant way01:08:07
the land mass of Siberia Kazakhstan01:08:10
collided with Gondwanaland this new01:08:13
collision led to the formation of01:08:15
Pangea01:08:17
450 million years after the01:08:20
breakup of Rondinia,01:08:22
some continental blocks remain outside Pangea, these are01:08:27
North and South China,01:08:30
the continental waltz tended to change the01:08:33
climate and as a result the earth01:08:35
acquired a new face,01:08:38
the once humid and swampy lands.01:08:42
Lush Carboniferous vegetation01:08:44
gave way to vast arid deserts and01:08:47
mountain ranges formed as a result of01:08:50
the collision of continental masses01:08:54
during the Permian. Global01:08:57
sea level continued to fall until it reached01:08:59
a level close to that of our current oceans. To the01:09:02
east of Pangea is the01:09:05
Tethys Ocean. To the west of this mega continent01:09:09
is the vast and unique pantalasa ocean01:09:14
in its center. The young continent of01:09:16
Pangea that extends almost from Pole to01:09:19
Pole is subject to01:09:21
extreme and highly variable climatic conditions.01:09:26
Temperatures can vary from 0 to 4001:09:30
degrees Celsius in On the same day, the01:09:33
South Pole has remained frozen since01:09:35
the glaciation that began at the end of the01:09:38
Carboniferous period. As for the rest01:09:41
of the continent, the climate is rather dry01:09:44
and arid.01:09:46
This reunification of all the01:09:49
continental masses made the01:09:51
terrestrial fauna quite uniform01:09:54
among the continental vertebrates,01:09:57
reptiles became01:09:59
predominant and gradually supplanted01:10:01
amphibians,01:10:03
the emergence of amniotes has been witnessed,01:10:10
although current amphibians are01:10:13
small, their ancestor eriops did not go01:10:15
unnoticed,01:10:18
their fossils were discovered in the01:10:20
lower Permian rocks of Texas and01:10:22
New Mexico. one of the main01:10:25
representatives of the temnos, a group of01:10:29
amphibians whose lifestyle was01:10:31
semi-aquatic and semi-terrestrial,01:10:35
the heliops can reach two meters01:10:38
in length,01:10:40
its short and powerful legs were01:10:42
composed of four fingers in the01:10:44
front and five in the back, and01:10:48
the tail. It was modest in size and represented a01:10:50
little more than a third of the01:10:52
total length of the animal.01:10:55
Its skull was enormously wide and flat. Its01:10:59
predatory mouth showed numerous01:11:01
sharp teeth. It01:11:04
probably divided its life between the01:11:06
swamps and the mainland, where it could01:11:09
feed on small fish and animals.01:11:11
terrestrials,01:11:14
however, they have a great01:11:16
predator, this is Dimetrodon.01:11:21
Dimetrodon may look like a01:11:23
dinosaur, but it is not its ancestor.01:11:26
Nitrodon belongs to the group of01:11:29
synapsids, which predates the01:11:31
dinosaurs.01:11:32
It is one of the oldest superpredators01:11:35
that lives at the top of the01:11:38
food chain01:11:39
[Music]01:11:41
its name encompasses a dozen species01:11:43
whose size ranges between 6001:11:45
centimeters and almost 5 meters. The01:11:48
most massive specimens could01:11:52
reach 300 kilograms or a weight01:11:54
greater than that of an adult brown bear.01:11:58
Their jaws have formidable01:12:00
crenellated teeth and sharp canines in01:12:03
the front, its bite must have been01:12:06
very effective in killing, chopping and devouring01:12:09
large amphibians and fish. It01:12:12
had a powerful tail and01:12:15
muscular, robust legs. Its back was01:12:18
made up of long, veil-shaped spines01:12:21
that rested on the vertebrae.01:12:23
Scientists have01:12:26
long wondered about the role of01:12:28
this dorsal sail01:12:31
some paleontologists have suggested that01:12:33
the sail could have served as01:12:35
camouflage among the long reeds as01:12:38
reinforcement of the spine or to01:12:40
regulate body temperature01:12:44
other scientists claim that the01:12:46
rear sail was a colorful decoration to01:12:48
attract mates or intimidate01:12:50
rivals01:12:52
the truth may be a mixture of several01:12:55
theories01:12:59
the spectacular permian crisis01:13:03
occurred 252 million years ago it was the01:13:07
largest ecological catastrophe in the01:13:09
history of the earth it01:13:12
was characterized by a drastic01:13:15
reduction of Marine life 96% of01:13:19
the species lost their lives in the01:13:21
process01:13:23
the reef formations are once again01:13:26
on the front line01:13:27
other animals that live near the bottom01:13:30
suffer a similar fate the01:13:33
brachiopods are losing their01:13:35
diversity as are the bryozoans and01:13:38
the echinoderms Especially01:13:40
crinoids,01:13:42
according to scientific estimates, 75% of01:13:47
the species of land animals and plants01:13:48
have become extinct, including01:13:51
almost all reptiles.01:13:54
The causes of this extinction continue to01:13:57
be the subject of debate.01:13:59
The most cited are the anoxia of the01:14:01
oceans, great volcanism in Siberia. A01:14:05
significant drop in sea level or01:14:07
a combination of all of them,01:14:10
however, the volcanic hypothesis predominates.01:14:13
The vast lava flows that01:14:16
extend over two million01:14:18
square kilometers would have01:14:21
profoundly changed the Earth's climate, as a01:14:24
result of which many areas became01:14:26
uninhabitable.01:14:28
[Music]01:14:32
plants appear to be the first to01:14:35
be affected in fact a study of01:14:39
fossilized pollen grains rocks and01:14:41
sediments in Australia showed high01:14:44
levels of nickel for the period in01:14:46
question01:14:48
according to researchers it originated in01:14:51
Siberia vaporized by01:14:53
volcanic eruptions spread across the atmosphere01:14:56
and was deposited in various geographical places,01:14:59
little by little, it poisoned plant life, which01:15:03
decreased01:15:05
the disappearance of plants. It01:15:07
then affected the entire food chain,01:15:10
first the herbivores and then the01:15:13
carnivores.01:15:15
Nickel also contaminated the oceans01:15:17
that were already suffering from global warming.01:15:21
Likewise, when01:15:23
the earth's temperature increased to 5001:15:25
degrees Celsius, methane evaporated01:15:28
from the oceans, a greenhouse gas01:15:30
that would have aggravated this01:15:32
natural warming of the planet by01:15:35
reducing the amount of oxygen in the01:15:37
atmosphere.01:15:41
The Permian Triassic crisis thus marked At01:15:45
the end of the Paleozoic and the beginning01:15:47
of the Mesozoic,01:15:49
several species survived this01:15:52
mass extinction. Specialists01:15:55
call them catastrophic fauna.01:15:58
Among them was the01:16:00
listrosaurus, a mammal reptile similar01:16:03
to a cross between a dog and a wild boar, a01:16:05
distant ancestor of the current01:16:07
mammals that spread. on the01:16:10
surface of Pangea01:16:12
as life continued01:16:14
to evolve. It didn't take long for01:16:16
new species to emerge, dinosaurs01:16:19
dominated the earth throughout the01:16:22
Mesozoic period01:16:24
[Music]Description:
La vida apareció en nuestro planeta hace más de 3.500 millones de años. El planeta experimentó períodos en los que el hielo se extendía hasta el ecuador, así como sofocantes períodos sin hielo en los polos. Las selvas de estas épocas geológicas se han convertido en el hogar de los renos en la actualidad. El nivel del mar subió 200 m por encima del nivel actual, convirtiendo los continentes en archipiélagos. Luego descendió 100 m por debajo del nivel actual, creando zonas de tierra que ahora están sumergidas. Los continentes se acercaron y luego se alejaron. Los animales, de 600 millones de años, parecen sacados de una película de ciencia ficción. Aunque los dinosaurios son las estrellas indiscutibles del periodo Mesozoico, a menudo se olvida que 400 millones de años antes de su existencia, una multitud de animales les precedieron. De un modo u otro, su mundo cambió, como consecuencia del cambio climático, la falta de alimentos o la llegada de nuevos depredadores. La mayoría de las especies no lograron adaptarse y se extinguieron. Sin embargo, dejaron sus huellas en la Tierra al perdurar en los fósiles. Así, estos restos proporcionan una imagen detallada de cómo era la vida en la Tierra antes de los dinosaurios. 🔥 Como recordatorio, los vídeos se publican los DOMINGOS a las 18:00. ------------------------- 💥 LA TIERRA ANTES DE LA ERA DE LOS DINOSAURIOS: - Retrocedamos en el tiempo, mucho, mucho antes de la era de los dinosaurios, cuando La Tierra era una enorme "bola de nieve": completamente congelada, cubierta de glaciares desde los polos hasta los trópicos. Cuando las erupciones volcánicas produjeron CO₂ en grandes cantidades, se creó un efecto invernadero que permitió el calentamiento del planeta. El hielo se derritió y diferentes masas de tierra se unieron para formar un supercontinente llamado Rondinia. Está rodeado por un único océano llamado Mirovia. Los científicos utilizan la aparición y desaparición de animales para dividir los períodos históricos de la evolución de la Tierra. Estos períodos se dividen a su vez en épocas. En conjunto, constituyen cuatro épocas que abarcan los últimos 635 millones de años. Comencemos nuestro viaje en el periodo edicardiano, hace entre 635 y 542 millones de años. Esto marca el final de la era Proterozoica tardía y el comienzo de la historia de la fauna acuática. En el fondo de Mirovia, las bacterias y los microbios, traídos por la lluvia, comienzan a cobrar vida. El primer animal que desarrolló un caparazón se llamaba Cloudina y parecía estar muy extendido. Se han encontrado fósiles en rocas calizas de África, Asia, América del Norte y del Sur, Europa y la Antártida. Al final de la era Proterozoica, Rondinia se dividió en varios continentes. En primer lugar, alrededor de 560 Ma, tres continentes se separaron y se separaron: Laurentia, Siberia y el inmenso Gondwanaland. Laurentia incluye la actual Norteamérica, sin Nueva Inglaterra ni Terranova, pero con el norte de Irlanda y Escocia. Siberia corresponde a la actual Rusia. Gondwana incluye África, América del Sur, la Antártida, India, China, el Sudeste Asiático, Australia y el sur de Europa. Alrededor de 520 Ma, un nuevo continente llamado Báltica se separó de Rondinia. Es similar al norte de Europa. ------------------------- 🎬 En el programa de hoy: - 00:00 - Introducción - 02:30 - Aparición de la fauna acuática primitiva durante el Proterozoico Tardío (periodo edicardiano): Dickinsonia, Charnia, Cloudina, Kimberella, Tribrachidium - 10:20 - La explosión del Cámbrico: el origen de los grupos animales actuales: Hallucigenia, Wiwaxia, Trilobites, Marella, Nectocaris, Opabinia, Anomalocaris, Pikaia, Myllokunmingia - 27:40 - El período Ordovícico: nueva explosión de diversidad de animales acuáticos: Nautiloides, Sacabambaspis, Pterygotus, Euthycarcinoides - 37:20 - El período Silúrico: la salida de las aguas: Placodermos, Acanthodians, Pneumodesmus, Palaeophonus, La Cooksonia - 47:38 - Período Devónico: desarrollo de la vida terrestre: Eusthenopteron, Tiktaalik, Acanthostega, Ichthyostega - 01:00:44 - El período Carbonífero: la era de los insectos y los reptiles gigantes: Lepidodendron, Glossopteris, Arthropleura, Balanerpeton woodi, Hylonomus , Meganeura, Crassigyrius scoticus, Spathicephalus mirus - 01:10:32 - Período Pérmico: desarrollo de los vertebrados: Eryops, Dimetrodon ------------------------- 🔔 Si te gusta lo que hago: ❤️ SUSCRIBIRSE 👍 GUSTAR 🤳 COMPARTIR ✍️ COMENTARIO Narrador: Angel Nacar (canal YT), anacar1001 (Fiverr app).
Preparing download options
* — If the video is playing in a new tab, go to it, then right-click on the video and select "Save video as..."
** — Link intended for online playback in specialized players
Questions about downloading video
How can I download "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra" video?
http://unidownloader.com/ website is the best way to download a video or a separate audio track if you want to do without installing programs and extensions.
The UDL Helper extension is a convenient button that is seamlessly integrated into YouTube, Instagram and OK.ru sites for fast content download.
UDL Client program (for Windows) is the most powerful solution that supports more than 900 websites, social networks and video hosting sites, as well as any video quality that is available in the source.
UDL Lite is a really convenient way to access a website from your mobile device. With its help, you can easily download videos directly to your smartphone.
Which format of "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra" video should I choose?
The best quality formats are FullHD (1080p), 2K (1440p), 4K (2160p) and 8K (4320p). The higher the resolution of your screen, the higher the video quality should be. However, there are other factors to consider: download speed, amount of free space, and device performance during playback.
Why does my computer freeze when loading a "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra" video?
The browser/computer should not freeze completely! If this happens, please report it with a link to the video. Sometimes videos cannot be downloaded directly in a suitable format, so we have added the ability to convert the file to the desired format. In some cases, this process may actively use computer resources.
How can I download "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra" video to my phone?
You can download a video to your smartphone using the website or the PWA application UDL Lite. It is also possible to send a download link via QR code using the UDL Helper extension.
How can I download an audio track (music) to MP3 "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra"?
The most convenient way is to use the UDL Client program, which supports converting video to MP3 format. In some cases, MP3 can also be downloaded through the UDL Helper extension.
How can I save a frame from a video "El Increíble Viaje al Mundo Antes de los Dinosaurios | Documental la Historia de la Tierra"?
This feature is available in the UDL Helper extension. Make sure that "Show the video snapshot button" is checked in the settings. A camera icon should appear in the lower right corner of the player to the left of the "Settings" icon. When you click on it, the current frame from the video will be saved to your computer in JPEG format.
What's the price of all this stuff?
It costs nothing. Our services are absolutely free for all users. There are no PRO subscriptions, no restrictions on the number or maximum length of downloaded videos.