252 million years ago,
ancient life on Earth suffered a serious blow from a deadly combination of heat and low oxygen.
95% of all marine species perished, and two-thirds of terrestrial species vanished.
It was a cataclysm so severe that it looked like the end of all life on planet Earth.
But as the saying goes, life finds a way, and the
most well-known prehistoric creatures would rise on Earth - The Dinosaurs.
If you love dinosaurs, then get ready to see your favorites,
how they evolved, and how they would rule the Earth for millions of years.
[LOGO]
The extinction event of the Permian-Triassic era 252 million years ago marked the beginning
of the Mesozoic Era of the Triassic, Jurassic, and Cretaceous period,
which lasted 186 million years. The Great Dying, which lasted 200,000 years, marked
the beginning of the Mesozoic Era which included the Triassic, Jurassic, and Cretaceous periods.
During the Triassic era, there was one vast supercontinent called Pangaea, which was
mostly vast deserts with a hot and dry climate surrounded by a huge ocean called Panthalassa.
Dinosaurs would first begin to evolve during the mid to late Triassic period.
When we talk about dinosaurs, we immediately imagine towering and thundering animals,
like Tyrannosaurus rex. But, new research shows that the dinosaurs, and their pterosaur relatives,
evolved from extremely small ancestors. Proof of this theory was discovered in Madagascar when a
newly discovered reptile species was found. Named Kongonaphon kely or ‘tiny bug slayer’,
it lived some 237 million years ago and stood just 10 centimeters tall [4-inches]. It is
one of the first small animals found from the root of the Ornithodira family tree, and is an
important discovery. The ‘miniaturization event’ in which it lived served as a survival strategy
for early ornithodirans, and wear on its teeth showed the tiny creature preyed on insects.
This eliminated the need for them to compete with their relatives for meat. Furthermore, research of
this tiny dinosaur relative showed that feathers and other fuzzy skin coverings, found on the
later true dinosaurs and pterosaurs, likely originated to protect the tiny dino ancestors
from the extreme climate of the mid to late Triassic period when the first dinosaurs evolved.
The Triassic marked the rise of the reptiles, mainly the archosaurs or ‘ruling lizards’,
and therapsids or ‘mammal-like reptiles’. For reasons unknown,
the archosaurs had an evolutionary edge, muscling out their mammal-like cousins and evolving by
the mid to late Triassic into the first true dinosaurs, such as Eoraptor and Herrerasaurus.
Dinosaurs were divided into two main branches: saurischian, which means ‘lizard-hipped',
and ornithischian, or ‘bird-hipped’ dinosaurs. Eoraptor was at the root of the Saurischian family
tree. It was only 91 centimeters long [3-feet] and weighed about 11 kilograms [25 lbs]. It had long
legs that allowed it to run fast, and its front paws had sharp claws that helped it to grab prey.
Herrerasaurus was more advanced in evolution than the Eoraptor because it had a joint in its lower
jaw. It had a large skull, and its jaws were armed with the sharp teeth of a carnivore. It averaged
in length from 3 to 6 meters [10 to 20 feet] and had five fingers on each paw with blunt claws.
Staurikosaurus was another early true dinosaur that was about 2 meters long [6.5 feet] with a
large skull as long as its femur, and there were 13-14 sharp teeth in its upper and lower jaws.
It has short front paws with five fingers. It had long hind legs that allowed it to run
fast. Staurikosaurus was a predator that weighed about 30 kilograms [66-lbs] And although this
dinosaur was kind of small, it probably had no trouble dealing with larger prey.
Eoraptor, Herrerasaurus, and Staurikosaurus are prime examples of the rapid evolution
of predatory dinosaurs 225 million years ago.
But at the same time, the first plant eating [herbivorous] dinosaurs appeared in the fossil
record. Pisanosaurus was a 1 meter [3.3 feet] dinosaur that weighed 2 to
9 kilograms [5-20 lbs] and had closely spaced teeth forming a continuous edge for grinding
plant matter. By the late Triassic period, there were at least 15 different dinosaurs.
During the Jurassic period, Earth’s climate changed from hot and dry to a much more humid
and subtropical climate. Forests of ferns, cycads, and conifers began to cover the planet, and the
air was warm, moist, with tropical breezes. During the beginning of this period, the breakup of the
supercontinent Pangaea continued and accelerated. Laurasia, the northern half of the continent,
broke up into North America and Eurasia. The southern half called Gondwana began to break
up during the mid-Jurassic. The eastern parts; Antarctica, Madagascar, India, and Australia,
split off from the western half of Africa and South America. New oceans flooded the spaces
in between. Huge mountains rose on the seafloor and pushed sea levels higher onto the continents.
It was all this water that created the humid and subtropical climate. Deserts began to turn green,
palm tree-like cycads, and conifer trees such as the araucaria and pine were abundant.
The oceans became full of diverse and abundant life. And at the top of the ocean food chain
were the marine reptiles; the Plesiosaurs with their long necks and paddle finned flippers.
Among them were giant marine crocodiles, sharks, and rays. Ichthyosaurs, squid-like cephalopods,
coil-shelled ammonites, sponges, snails, and mollusks were abundant in the ancient
oceans. Coral reefs grew and expanded quickly in the warm waters, and microscopic plankton
increased rapidly to the point that they may have turned parts of the ocean red.
The earliest known bird, Archaeopteryx, took to the skies in the late Jurassic,
likely evolved from an early Coelurosaurian dinosaur. Archaeopteryx had to compete for
airspace with pterosaurs, flying reptiles that had been buzzing the skies since the
late Triassic. Meanwhile, insects such as leafhoppers and beetles were abundant,
and many of Earth's earliest mammals scurried around the feet of dinosaurs.
It was at this time that the dinosaurs began making their mark in a huge way…
literally. Small quadrupedal plant-eating dinosaurs gradually evolved into multi-ton
giants. The plant-eating sauropod named Brachiosaurus was 16 meters tall [52 feet] and
stretched out to around 26 meters [85 feet] long, and could weigh as much as 25 tons! Another
herbivorous sauropod giant named Diplodocus was 27 meters [90 feet] long and weighed between 30 to 50
tons. The sheer size of these dinosaur giants may have stopped the attacks of a bulky meat-eating
dinosaur that walked on two powerful legs who also lived during this time; the ominous Allosaurus.
This huge carnivore ranged in size from 7 to 12 meters long [25 - 40 feet], weighed nearly 2 tons,
and had 16 sharp teeth in its upper and lower jaw. And like many predatory dinosaurs of the
Mesozoic Era, Allosaurus constantly grew, shed, and replaced its three to four inch teeth.
And this dinosaur was fast. Models suggest that Allosaurus could run up to 34 kilometers per hour
[21 mph]. Fossil evidence shows that Allosaurus preyed on Stegosaurus, and the plant-eating
dinosaur fought back, punching holes right through Allosaurus’ bones with its spiky clubbed tail. It
could be why Stegosaurus had a pretty long run and survived all the way up to the late Cretaceous.
But there were new predators that would come along that were as equally terrifying as the Allosaurus.
The North American Tyrannosaurus rex measured could grow to 12.5 meters long [40 feet] and
weigh up to 8 to 10 tons, although now some say it might have weighed half of these estimates.
But the T-rex wasn’t alone in the meat-eating dinosaur category. In fact, it was either
outclassed or equal to two other sharp toothed monsters; the South American Giganotosaurus which
had the same type of build and weighed 9 tons, and the 10 ton northern African Spinosaurus. Still,
the T-rex was a mean and nasty predator, if not downright unhygienic. Experts believe that shards
of rotten, bacteria-laden meat was constantly lodged in its closely packed teeth, which gave the
animal a ‘septic bite’ that would eventually be fatal to its wounded prey. Of course, this process
would have taken at least several days or weeks, and another T-Rex would probably reap the rewards.
Scientists examining a T-rex skull determined it had the bite force of between 1,500 to 5,000
pounds per square inch, and could take bites of flesh in the 225 kilogram [500 pounds] range.
But Tyrannosaurus rex, like Allosaurus, had problems with prey itself.
It lived in the same region and time period as some armored plant-eating dinosaurs.
One of the most iconic dinosaurs next to T-Rex has to be Triceratops,
which means ‘three-horned face’. All Triceratops had three-horned skulls. Two massive horns were
above the eye sockets and one smaller horn was over the nose. Weighing around 6.5 to 13 tons,
the biggest Triceratops was 9 meters [30 feet] long from nose to tail.
The tips of their shoulders were 3 meters [9.8 feet] off the ground.
Triceratops had teeth arranged in ‘dental batteries’, and each individual tooth was stacked
in a vertical column of three to five teeth. These formed rows with 36 to 40 tooth-loaded columns.
This means that a single Triceratops could have 800 teeth at its disposal. It had a narrow beak,
and powerful jaws that allowed it to grind down tough vegetation and trees.
It is one of the last non-avian dinosaurs to evolve at the end of the Cretaceous.
Ankylosaurus is another of the most famous armored dinosaurs. It was the largest ankylosaurid,
and the last of its kind – it is thought to have lived right up to the end of the Cretaceous Period
The body of Ankylosaurus was covered in bony plates. It had a beak and teeth,
and four horns that projected backwards from its head. Its tail ended in a club, which provided
protection from predators. This would have been useful, since Ankylosaurus lived alongside
Tyrannosaurus rex and other meat eating predators. At some point during the middle of the Creataceous
period, dinosaurs from the Ornithopod family evolved into the popular Hadrosaur
or duck-billed dinosaurs. They were large, oddly shaped, low-slung vegetation eaters
with tough beaks on their snouts, which were used for shredding vegetation.
These dinosaurs are believed to have lived in herds and were capable of walking on two legs.
Sauropods became even bigger by the Late Cretaceous period. You may have thought
that Brachiosaurus and Diplodocus were big. But by the time the late Creatacous period rolled around,
there was another dinosaur that existed, which could possibly be the biggest land animal that
has ever walked the Earth; Argentinosaurus. This behemoth could be 30 to 40 meters in
length [100 to 130 feet] and weigh between 50 and 100 tons. It was a member of the Titanosauria, the
dominant group during the Creataceous period and was a herbivore like its earlier sauropod cousins.
There was also a strange new breed of dinosaur that lived 20 million years before they all went
extinct. They are called Pachycephalosaurus, or Bone-Headed Dinosaurs, and have a bizarre
looking skull with horns on the snout and around the base of the skull. These could have been used
to fight off the last of the big predators, or even to show dominance over their own species.
Of course, there are more than 700 different dinosaurs that have been found so far,
but not enough time to cover them all in one video.
There are some dinosaurs that lived in the colder regions when they were further south
and within the Antarctic Circle during the Cretaceous. During this time there could have been
some snow and ice and temperatures as low as -10c [14°F] during the three month long dark winters.
There were a variety of different dinosaurs living in this polar zone. In 2014, a skull
section and upper and lower jaw bones were found of a miniature T-rex called Nanuqsaurus
hoglundi. It is believed that many dinosaurs had feathers to protect them from the elements,
and this tiny T-rex cousin, which was about 6 meters long [20 feet] It is now believed
that all species of Tyrannosaurus rex had feathers to protect them from the elements,
and Nanuqsaurus was no different. Other dinosaurs like the horned and duck-billed dinosaurs,
along with other small feathery predators, parrot-like oviraptors,
and a small herbivore named Leaellynasaura lived in the polar region as well.
But their time would soon come to an end…
Everyone talks about how dramatically the dinosaurs went extinct, but judging by the
whopping 165 million years they survived, they just might be the most successful vertebrate
animals to ever exist on planet Earth. In fact, some dinosaur relatives are still around on the
planet today. Modern-day birds are, in fact, descendants of feathered dinosaurs. And you
might be surprised to learn that crocodiles are the closest living relatives to birds,
as they shared a common ancestor. The two groups are the only known survivors of the Archosaurs.
We all know what happened to the dinosaurs, and if you missed our video on The Day The
Dinosaurs Went Extinct, we’ll put a link in the description for you.
Please let us know in the comments what you thought about the video, and tell us
what you’d like to see next. Stay tuned for more cool videos, and thanks for watching!