When did the dinosaurs roam Earth?

(THIS ARTICLE IS COURTESY OF TRIVIA GENIUS)

 

When did the dinosaurs roam Earth?

The age of the dinosaurs has fascinated the modern imagination for centuries. Often, we are tempted to think of the era as an ancient time when all our favorite dinosaurs squared off against one another in a battle of survival.

However, dinosaurs ruled Earth for a period spanning hundreds of millions of years, during which world-ending events occurred, and the planet changed in ways that are almost difficult to imagine. Here is a guide to the different time periods during which the dinosaurs roamed the planet.

Mesozoic Era

Illustration of dinosaurs during the Mesozoic Era
Credit: CoreyFord/ iStock

The overall time period in which the dinosaurs lived was known as the Mesozoic Era. The Mesozoic Era lasted 180 million years, from 248 million years ago to 65 million years ago. It was preceded by the Paleozoic era, during which life began to take shape, and was followed by the Cenozoic Era, in which we live.

The Mesozoic Era is divided into three distinct time periods:

  • The Triassic Period – 248 million to 206 million years ago
  • The Jurassic Period – 206 million to 146 million years ago
  • The Cretaceous Period – 146 million to 65 million years ago

During the Mesozoic Era, mountains rose, climates shifted, and life reshaped itself multiple times.

Triassic period

Fossil of a pterosaur
Credit: AKKHARAT JARUSILAWONG/ Shutterstock

The first period of the Mesozoic era was the Triassic period. During this time, all the continents were still connected in one giant super continent, known as Pangaea. Temperatures were warmer and there were no polar ice caps.

The oceans teemed with life during this period. Turtles and fish were common, and the corals developed alongside mollusks and ammonites. Large marine reptiles were present as well, such as the plesiosaurus and ichthyosaurus.

On land, early dinosaurs and mammals evolved, and the first flying reptiles, the pterosaurs, took to the skies. There were no flowering plants or grass present during the Triassic period, but cycads, ferns and ginkgoes grew near water sources such as rivers or streams. Small forests of conifers grew in some parts of Pangaea, but for the most part, inland areas were arid deserts with little or no plant or animal life.

Jurassic period

Illustration of Brachiosaurs
Credit: Orla/ iStock

The Triassic period came to an end with a mass extinction that wiped out over 90 percent of the species on Earth. The animals that survived this event began to repopulate the planet and usher in the Jurassic period.

The Jurassic period was marked by the slow break-up of Pangaea into two smaller landmasses known as Laurasia and Gondwana. When the supercontinent split, new mountains arose in the sea, pushing the sea level up and creating a much wetter, more humid environment.

Ferns and mosses covered much of the ground while the small coniferous forest of the Triassic period expanded to cover wide swaths of the two continents.

Giant dinosaurs ruled the land, the largest of which was the plant-eating Brachiosaurs, which scientists believe could grow to be 80 feet long and 50 feet tall. These large herbivores were hunted by massive carnivores such as the Allosaurus.

The Jurassic period also saw the first birds diverge from the reptile family, and the Archaeopteryx flew above these massive dinosaurs.

Cretaceous period

Skeleton of a Tyrannosaurus Rex
Credit: DavidHCoder/ iStock

During the Cretaceous period, the continents continued to drift apart and end in the locations that we know them today. The climate became both wetter and cooler, resulting in the emergence of the polar ice caps and setting the stage for the glaciers that covered large parts of North America, Europe, and Asia in the following era.

The drifting continents resulted in increased specialization and many new types of dinosaurs. Triceratops and Iguanodon traveled in herds, feasting on the ancestors of the flowers, herbs and broad-leaved trees that populate Earth today.

These massive plant-eating animals were hunted by the famous Tyrannosaurus Rex. Snakes first developed during this time period, as well as crocodiles and turtles. Insects and pterosaurs flew in the air, and the first mammals scurried across the ground.

Despite the proliferation of life during this period, another mass extinction followed a natural disaster at the end of the Cretaceous period. While both reptiles and mammals survived in small numbers, the age of the dinosaurs came to an end.

What’s next?

Earth as viewed from space
Credit: dem10/ iStock

In light of this vast history, do you ever wonder what lies ahead for both Earth and us?

When did the dinosaurs roam Earth?

(THIS ARTICLE IS COURTESY OF TRIVIA GENIUS)

 

Science

When did the dinosaurs roam Earth?

The age of the dinosaurs has fascinated the modern imagination for centuries. Often, we are tempted to think of the era as an ancient time when all our favorite dinosaurs squared off against one another in a battle of survival.

However, dinosaurs ruled Earth for a period spanning hundreds of millions of years, during which world-ending events occurred, and the planet changed in ways that are almost difficult to imagine. Here is a guide to the different time periods during which the dinosaurs roamed the planet.

Mesozoic Era

Illustration of dinosaurs during the Mesozoic Era
Credit: CoreyFord/ iStock

The overall time period in which the dinosaurs lived was known as the Mesozoic Era. The Mesozoic Era lasted 180 million years, from 248 million years ago to 65 million years ago. It was preceded by the Paleozoic era, during which life began to take shape, and was followed by the Cenozoic Era, in which we live.

The Mesozoic Era is divided into three distinct time periods:

  • The Triassic Period – 248 million to 206 million years ago
  • The Jurassic Period – 206 million to 146 million years ago
  • The Cretaceous Period – 146 million to 65 million years ago

During the Mesozoic Era, mountains rose, climates shifted, and life reshaped itself multiple times.

Triassic period

Fossil of a pterosaur
Credit: AKKHARAT JARUSILAWONG/ Shutterstock

The first period of the Mesozoic era was the Triassic period. During this time, all the continents were still connected in one giant super continent, known as Pangaea. Temperatures were warmer and there were no polar ice caps.

The oceans teemed with life during this period. Turtles and fish were common, and the corals developed alongside mollusks and ammonites. Large marine reptiles were present as well, such as the plesiosaurus and ichthyosaurus.

On land, early dinosaurs and mammals evolved, and the first flying reptiles, the pterosaurs, took to the skies. There were no flowering plants or grass present during the Triassic period, but cycads, ferns and ginkgoes grew near water sources such as rivers or streams. Small forests of conifers grew in some parts of Pangaea, but for the most part, inland areas were arid deserts with little or no plant or animal life.

Jurassic period

Illustration of Brachiosaurs
Credit: Orla/ iStock

The Triassic period came to an end with a mass extinction that wiped out over 90 percent of the species on Earth. The animals that survived this event began to repopulate the planet and usher in the Jurassic period.

The Jurassic period was marked by the slow break-up of Pangaea into two smaller landmasses known as Laurasia and Gondwana. When the supercontinent split, new mountains arose in the sea, pushing the sea level up and creating a much wetter, more humid environment.

Ferns and mosses covered much of the ground while the small coniferous forest of the Triassic period expanded to cover wide swaths of the two continents.

Giant dinosaurs ruled the land, the largest of which was the plant-eating Brachiosaurs, which scientists believe could grow to be 80 feet long and 50 feet tall. These large herbivores were hunted by massive carnivores such as the Allosaurus.

The Jurassic period also saw the first birds diverge from the reptile family, and the Archaeopteryx flew above these massive dinosaurs.

Cretaceous period

Skeleton of a Tyrannosaurus Rex
Credit: DavidHCoder/ iStock

During the Cretaceous period, the continents continued to drift apart and end in the locations that we know them today. The climate became both wetter and cooler, resulting in the emergence of the polar ice caps and setting the stage for the glaciers that covered large parts of North America, Europe, and Asia in the following era.

The drifting continents resulted in increased specialization and many new types of dinosaurs. Triceratops and Iguanodon traveled in herds, feasting on the ancestors of the flowers, herbs and broad-leaved trees that populate Earth today.

These massive plant-eating animals were hunted by the famous Tyrannosaurus Rex. Snakes first developed during this time period, as well as crocodiles and turtles. Insects and pterosaurs flew in the air, and the first mammals scurried across the ground.

Despite the proliferation of life during this period, another mass extinction followed a natural disaster at the end of the Cretaceous period. While both reptiles and mammals survived in small numbers, the age of the dinosaurs came to an end.

What’s next?

Earth as viewed from space
Credit: dem10/ iStock

In light of this vast history, do you ever wonder what lies ahead for both Earth and us?

Baby Snake That Lived Among Dinosaurs Found Preserved in Amber

(THIS ARTICLE IS COURTESY OF GIZMODO)

 

Baby Snake That Lived Among Dinosaurs Found Preserved in Amber

The baby snake encased in amber.
Image: Yi Liu

Scientists working in Myanmar have uncovered a nearly 100-million-year-old baby snake encased in amber. Dating back to the Late Cretaceous, it’s the oldest known baby snake in the fossil record, and the first snake known to have lived in a forested environment.

Over 2,900 species of snake exist in the world, and they can be found on every continent except Antarctica. These legless reptiles first emerged during the Cretaceous period, and they wasted little time, slithering to virtually every part of the planet by around 100 million years ago. The discovery of a baby snake fossilized in amber shows that early snakes had spread beyond swamps and sea shores, finding their way into forested environments. What’s more, these ancient snakes bore a startling resemblance to those living today—a classic case of evolution not having to fix something that ain’t broke. These findings were published today in Science Advances.

Artist’s conception of Xiaophis myanmarensis.
Image: Yi Liu

This remarkable fossil, along with a second fossilized snake specimen, were discovered at the Angbamo site in Myanmar’s Kachin Province. The second fossilized snake, also preserved in amber, only consisted of bits of scales and skin, but these remnants were clearly snake-like in appearance. Together, the fossils are offering fresh insights into the evolution of snakes and their global reach by the time of the Late Cretaceous.

Using uranium-lead dating, a research team led by Lida Xing from the China University of Geosciences and Michael Caldwell from the University of Alberta dated the fossils to about 99 million years old. A technique called synchrotron x-ray micro–computed tomographyallowed the researchers to get a close look at the tiny specimens inside the amber without having to break them apart.

The second fossil, dubbed DIP-V-15104, contains the discarded skin of a larger individual, featuring both dark and light patterns. This wasn’t enough for the researchers to identify the species.

Detailed x-ray view of the baby snake.
Image: Ming BAI, Chinese Academy of Sciences CAS

The baby snake, which was just a hatchling when it died, measured 47.55 mm (1.8 inches) in length, but it’s missing its head (for reasons unknown). The researchers were able to document nearly 100 vertebrae, along with bits of rib and other anatomy. It’s similar to other Cretaceous snakes, yet unique enough to warrant the designation of a new species, Xiaophis myanmarensis, where “Xiao” is the Chinese word for “dawn,” “ophis” meaning “snake” in Greek, and “myanmarensis” for Myanmar. Snakes have been found preserved in amber before, but this is the first time paleontologists have discovered a baby snake fossilized in this way.

Xiaophis myanmarensis is comparable in size and shape to some baby snakes observed today, like the Asian pipe snake. This fossil provides the earliest direct evidence showing that the growth patterns of snakes have remained unchanged for the past 100 million years. These two snakes are also the first Mesozoic snakes known to have lived in a forest environment, “indicating greater ecological diversity among early snakes than previously thought,” write the researchers in the study. Both fossils were found next to remnants of insects and fragments of plant materials associated with forest floors.

It’s not clear how this hatchling got stuck in a drop of tree sap, or how it lost its head, but its misfortune has turned into our scientific gain.

Scientists Say Dinosaur-Killing Asteroid Made Earth’s Surface Act Like Liquid

(THIS ARTICLE IS COURTESY OF THE NPR NEWS AGENCY)

Scientists Say Dinosaur-Killing Asteroid Made Earth’s Surface Act Like Liquid

A computer illustration of a large asteroid colliding with Earth. (Size may not be to scale.) Such an impact is believed to have led to the death of the dinosaurs some 66 million years ago.

Mark Garlick /Getty Images/Science Photo Library RM

When the asteroid believed to have killed off the dinosaurs smashed into Earth some 66 million years ago, its sheer force made the planet’s surface momentarily act like a liquid.

The asteroid ripped open a 60-mile-wide hole. From miles deep in that abyss, rock hurtled upward to a height twice that of Mount Everest and then collapsed outward to form a ring of mountains.

And it all happened within 5 minutes — 10 tops, as Sean Gulick, a geophysicist at the University of Texas, Austin, tells The Two-Way.

Gulick helped lead a team of researchers that drilled for samples of that mountain ring in the Chicxulub crater off the coast of Mexico earlier this year. Their initial findings were recently published in the journal Science.

He says these samples immediately settled a major debate about how a planet’s surface behaves during an asteroid impact — and how the mountain ring, known as a “peak ring,” is formed.

Some researchers have argued that the process is dominated by melting on the surface, which would mean that the ring is mainly formed from material moving from side-to-side. “So things collapse in from the sides, fairly shallow, and in that model this ring of peaks are created by shallow material kind of moving towards the center and being uplifted,” he says.

Others have suggested that it was a much more dramatic kind of movement, involving the fluid-like propelling of material from deep within the Earth’s crust. Gulick says there was a very clear moment during the expedition when the team knew this theory was correct.

“It was just so obvious, even on the drill floor when we’re out there, out in our hard hats and so on, looking at these cores coming up,” Gulick says. The researchers were seeing pink granite that is typically found deeper within the Earth — and not the limestone that would have been on the surface during the Cretaceous Period.

“And it was just plain as day,” he says, “and everybody staring at it went, ‘Wow, there’s the answer. It’s from deep.’ ”

Gulick likens the rapid process to what happens when you toss a rock into a pond:

“It makes a hole initially as the rock penetrates into the pond. And the sides will sort of collapse inward toward the hole while the center kind of rebounds up like a big water droplet rising up.

“If you picture all of this happening in a slightly slower-moving fluid than water would be, you can envision that the center that rebounds upwards and splashes upwards would kind of collapse outwards. So just as the sides are falling in, this rebounding center is sort of collapsing outwards to create … this ring of mountains, made from material that ultimately came from fairly deep.”

It’s worth noting that even though the rock behaved like liquid, Gulick says it remained solid. However, the materials were “either shocked or damaged so much that they’re able to temporarily lose their cohesion and move like a slow-moving fluid.” Big questions remain about how that physical process actually works, he says.

The pink granite that emerged from about 6 miles deep in the Earth might provide hints about how life came back to ground zero after the asteroid’s impact erased most of the species on the planet.

The rock is “completely shot through with fractures and faults,” and is much more porous and less dense than typical granite, Gulick says. Those nooks and crannies could have provided a habitat for microbial life. He says the “pore spaces and the hot fluids and the interesting chemistry that takes place in the wake of an impact” could be hospitable to these microscopic creatures.

Gulick’s team thinks the fluid-like movement “is probably the right way to think about impact processes” on the moon or on crater-dotted planets such as Mercury or Venus.

And he says that if we’re looking for evidence of life on other planets, these findings indicate that crater sites would be a good place to start.

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