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?

Hamas Controlled Zoo: Cramped Gaza Zoo Reopens, Only Months After Closure

(THIS ARTICLE IS COURTESY OF THE SAUDI NEWS AGENCY ASHARQ AL-AWSAT)

 

Cramped Gaza Zoo Reopens, Only Months After Closure

Sunday, 22 September, 2019 – 11:30
Two lions and three cubs are penned in cages only a few square metres in size at a zoo in the Gaza Strip VIA AFP
Asharq Al-Awsat
A lioness is beaten with sticks while her cubs are dragged away — a Gazan zoo closed after a long campaign has reopened, with conditions seemingly as bad as ever.

The Rafah Zoo in the southern Gaza Strip was known for its emaciated animals, with the owners saying they struggled to find enough money to feed them.

In April, international animal rights charity Four Paws took all the animals to sanctuaries, receiving a pledge the zoo would close forever, AFP reported.

But last month it reopened with two lions and three new cubs, penned in cages only a few square meters in size.

Critics say the owners want to bully Four Paws or other animal welfare organizations into giving them thousands of dollars to free the animals into their care.

Four Paws paid the zoo’s owners more than $50,000 in the year before its closure for medical treatments, food and caretakers.

The zoo’s owner insists the reopening is solely for the enjoyment of local residents.

Meanwhile, when AFP visited the zoo recently, the badly stuffed corpse of a lion was displayed near the entrance. An ostrich in a three-meter-square pen pecked endlessly at the cage’s bars, while two monkeys sat chewing on litter.

At the far end the lion and lioness were kept in separate cages, each only a few square meters.

The owners were seeking to remove the cubs from their mother to play with visiting children.

To do so they hit the lioness with sticks and banged on the cage to confuse her, with staff later taunting her when the cubs had been taken out.

“A lion needs 1,000 square meters to play in. Here they have seven square meters,” Mohammed Aweda, a prominent animal enthusiast in Gaza, told AFP.

“The zoo won’t survive during the winter, because they are lacking in daily goods which cost a lot. For you or I or anyone who owns a zoo (in Gaza), the economy is very tough.”

The newly reopened zoo’s manager Ashraf Jumaa, from the same family that owned the old one, said they brought the new lions through tunnels from Egypt. However others suggested they were bought from another animal centre in northern Gaza.

He denied they wanted to blackmail Four Paws.

“The first goal is entertainment, not trade. The main reason we reopened the zoo was people in the area that supported us,” he said.

He said it would be less expensive because there were fewer animals, but admitted they would struggle to afford enough food once the cubs were fully grown.

“Every day they will need between 22 and 30 kilos of meat costing between 100 and 150 shekels (between $28 and $43),” he said.

They currently receive around 50 visitors a day, he said, with tickets on average costing two shekels (around $0.50).

Four Paws said footage it saw from the zoo was “very concerning”.

“The animals are not kept in species-appropriate conditions. They seem to be in bad conditions and urgently need medical attention and proper food,” it said

An official from the Gaza agriculture ministry, speaking on condition of anonymity, said there had been no coordination regarding the zoo’s reopening.

According to AFP, he said Gaza needed a large park meeting international standards.

What If There Were No Sharks?

(THIS ARTICLE IS COURTESY OF LIVE SCIENCE)

 

What If There Were No Sharks?

A school of scalloped hammerhead sharks (Sphyrna lewini) swims in the Galapagos.

A school of scalloped hammerhead sharks (Sphyrna lewini) swims in the Galapagos. In the Galapagos Marine Reserve, these sharks gather in groups of up to several hundred individuals.
(Image: © Shutterstock)

Sharks are magnificent predators that represent an impressive evolutionary success story. They’ve swum the oceans for more than 400 million years, diversifying over time to inhabit rivers and lakes as well. About 500 known species are alive today, and there are likely even more yet to be discovered.

Sharks can be huge, like the massive whale shark (Rhincodon typus); or human-hand-size, like the pocket shark (Mollisquama parini). However, it’s the great white shark (Carcharodon carcharias) that typically commands the public’s imagination. These sharks have a reputation for aggressiveness toward people, shaped by decades of terrifying portrayals in movies. In fact, these fearful pop-culture portraits of great whites are so pervasive that they might lead some people to wonder if the world would be better off with no sharks at all.

But what might the oceans look like if all of the sharks disappeared?

Related: 7 Unanswered Questions About Sharks

Sharks make their homes in ecosystems around the world, including shallow mangrove habitats, tropical coral reefs, frigid Arctic waters and the vastness of the open ocean. Regardless of where sharks live or how big they are, all of them are predators and, therefore, are vitally important to the health of their habitats, said Jenny Bortoluzzi, a doctoral candidate in the Department of Zoology at Trinity College Dublin in Ireland.

Fish-hunting sharks weed out weak and sick individuals, ensuring that the fish population remains healthy and at a size that the habitat’s resources can support. These fearsome predators can even help to preserve their ecosystems through their presence alone, Bortoluzzi told Live Science in an email. For example, tiger sharks (Galeocerdo cuvier) that live in seagrass meadows scare away turtles and keep them from overgrazing the vegetation, she explained.

Sharks also play a role in regulating oxygen production in the ocean, by feeding on fish that devour oxygen-generating plankton, Victoria Vásquez, a doctoral candidate with Moss Landing Marine Laboratories in California, told Live Science in an email.

Lemon sharks (Negaprion brevirostris) live primarily in shallow coastal habitats such as mangroves, bays and coral reefs.

Lemon sharks (Negaprion brevirostris) live primarily in shallow coastal habitats such as mangroves, bays and coral reefs.

(Image credit: Shutterstock)

Coral reef environments are another good example of sharks’ importance for overall biodiversity and ecosystem health, said Toby Daly-Engel, an assistant professor in the marine science department and director of the Shark Conservation Lab at Florida Tech.

“If the sharks disappear, the little fish explode in population, because nothing’s eating them,” Daly-Engel told Live Science. “Pretty soon, their food — plankton, microorganisms, little shrimps — all of that is gone, so all the little fish ultimately starve.”

When that happens, algae and bacteria move into the reef, covering the coral so that it can’t photosynthesize. “The coral will die, leaving just its skeleton behind, which eventually turns into limestone,” Daly-Engel said. “Then, in come the animals like starfishes and sea urchins; we call those grazers. So instead of a bunch of different species — sharks, bony fishes, invertebrates and mollusks — you end up with a reef with four to five species in it, tops. That’s a dead reef.”

Sharks serve another important role in ocean food webs: They are food for marine carnivores. Dead great white sharks that washed up on South African beaches without their livers were thought to have been victims of orca attacks. And video footage recently showed a dogfish shark (Squalus clarkae) feeding frenzy on the bottom of the Atlantic that ended with a grouper swallowing one of the sharks whole. Even octopuses are known to feed on sharks, as demonstrated in a video that National Geographic posted to YouTube in 2009.

Migrating sharks, such as the gray reef shark (Carcharhinus amblyrhynchos), also provide nourishment for organisms in multiple locations in the ocean, by leaving behind generous helpings of their nitrogen-rich poo, marine biologist Melissa Cristina Márquez wrote in Forbes earlier this year. Márquez is the founder of The Fins United Initiative, which provides educational resources about sharks and their close relatives skates and rays.

In fact, gray reef shark forays between coastal waters and the deep sea in the Pacific Ocean’s Palmyra Atoll bring the reef more than 200 lbs. (95 kilograms) of nutritious nitrogen per day, Márquez wrote.

A murky future

Approximately 25% of all shark, skate and ray species are currently threatened with extinction, according to the Smithsonian Institution’s Ocean Portal. Because sharks have few babies and are slow to mature, their numbers aren’t replenishing quickly enough to keep up with losses from commercial fishing, Daly-Engel said.

In recent decades, some shark populations have declined by up to 90%, reflecting an unsustainable trend of overexploitation in ocean habitats, according to Bortoluzzi.

“Many species also face the loss of habitats, with refuge areas such as mangroves being destroyed to accommodate our growing human population, and habitats such as seabeds and reefs being damaged by destructive fishing methods such as trawling,” Bortolozzi said.

Related: On the Brink: A Gallery of Wild Sharks

What does the future hold for sharks? Federal legislation and international treaties such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora can help to protect vulnerable populations. But many shark species are poorly understood, which can hinder conservation efforts, said Michael Scholl, CEO of the nonprofit Save Our Seas Foundation.

“Government institutions must have validated information to support significant decline in populations, for example,” Scholl told Live Science in an email. To that end, Save Our Seas works alongside marine researchers to gather shark data that can inform much-needed protective measures; the nonprofit also works to raise public awareness of shark diversity and its importance to their marine ecosystems, Scholl said.

But sharks may be running out of time. And if they were to disappear, the repercussions on ocean food webs would ultimately affect humans, too.

“Fisheries may collapse, with artisanal fishers being the likely most affected, and popular tourism destinations which rely on sharks to attract tourists will also suffer greatly,” Bortoluzzi said.

“It’s important to understand that as much as our oceans need sharks, so do we,” she added.

Editor’s note: The article was updated on Sept. 9 to correct the species of dogfish shark that was swallowed by a grouper in a YouTube video: Squalus clarkae, not Squalus acanthias.

(Alpha Wolf/Poem) Within My Gaze

Within My Gaze

(FIRST PUBLISHED 11-8-16)

What is it that your feeble mind thinks I am

I can see my picture as I walk your yard

Upon your T-Shirts, paintings and plates

Displayed proudly upon your walls

 

You think me to be cuddly

Domesticated easily like a lap dog hound

Yet it is only to the giant bear

Have I have ever backed down

 

You come to my home

To sleep, laugh, and play

When was the last time that you ever

Seen me strolling into your home

 

More ignorant than the lamb I had this morning

My belly is grumbling as the dark is setting in

Now do you think I am so cute and cuddly

As I back you down

Your eyes glued, within my gaze