Why Are There No More Dinosaurs?

CHLOE EFFRON / DINOSAURS: ISTOCK
CHLOE EFFRON / DINOSAURS: ISTOCK

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Actually, there are still dinosaurs: Birds! But let’s talk about that a little later. Scientists have found clues in rocks and fossils that tell us that by 65 million years ago, the climate (CLY-met), or usual weather, of the Earth had changed a lot, becoming cooler and drier. That was hard on the heat-loving dinosaurs. But that’s not why almost all of the dinosaurs became extinct, or disappeared forever. Scientists think a terrible event occurred that killed them off.

In 1991, scientists discovered a huge 110-mile-long crater, or hole, in the Gulf of Mexico. They think this crater was made by a giant, fiery, 6-mile-wide asteroid (AST-er-oyd) from space that smashed into the Earth about 65 million years ago. The impact was more powerful than any bomb we have ever known. Scientists believe this event killed most plant and animal life—including the dinosaurs. The asteroid probably caused shockwaves, earthquakes, fireballs, wildfires, and tidal, or really big, waves. It also sent huge amounts of dust and gas into the atmosphere, which is like a big blanket of air that surrounds the Earth. That was really bad for the planet.

The dust blocked sunlight, making the planet very cold and dark. Then, over time, the gases trapped heat, causing the Earth to get even hotter than it was before the asteroid hit. This change was deadly for most dinosaurs, and they became extinct. But birds survived. Many millions of years earlier, they had evolved (ee-VOL-ved), or changed slowly over time, from one group of dinosaurs. And when the dinosaurs disappeared, mammals diversified (die-VERSE-uh-fide), or changed, into many different kinds of animals—including us, many millions of years later. So the next time you see a bird swoop by, wave hello to the little flying dinosaur!    


Is There An International Standard Governing Scientific Naming Conventions?

iStock/Grafissimo
iStock/Grafissimo

Jelle Zijlstra:

There are lots of different systems of scientific names with different conventions or rules governing them: chemicals, genes, stars, archeological cultures, and so on. But the one I'm familiar with is the naming system for animals.

The modern naming system for animals derives from the works of the 18th-century Swedish naturalist Carl von Linné (Latinized to Carolus Linnaeus). Linnaeus introduced the system of binominal nomenclature, where animals have names composed of two parts, like Homo sapiens. Linnaeus wrote in Latin and most his names were of Latin origin, although a few were derived from Greek, like Rhinoceros for rhinos, or from other languages, like Sus babyrussa for the babirusa (from Malay).

Other people also started using Linnaeus's system, and a system of rules was developed and eventually codified into what is now called the International Code of Zoological Nomenclature (ICZN). In this case, therefore, there is indeed an international standard governing naming conventions. However, it does not put very strict requirements on the derivation of names: they are merely required to be in the Latin alphabet.

In practice a lot of well-known scientific names are derived from Greek. This is especially true for genus names: Tyrannosaurus, Macropus (kangaroos), Drosophila (fruit flies), Caenorhabditis (nematode worms), Peromyscus (deermice), and so on. Species names are more likely to be derived from Latin (e.g., T. rex, C. elegans, P. maniculatus, but Drosophila melanogaster is Greek again).

One interesting pattern I've noticed in mammals is that even when Linnaeus named the first genus in a group by a Latin name, usually most later names for related genera use Greek roots instead. For example, Linnaeus gave the name Mus to mice, and that is still the genus name for the house mouse, but most related genera use compounds of the Greek-derived root -mys (from μῦς), which also means "mouse." Similarly, bats for Linnaeus were Vespertilio, but there are many more compounds of the Greek root -nycteris (νυκτερίς); pigs are Sus, but compounds usually use Greek -choerus (χοῖρος) or -hys/-hyus (ὗς); weasels are Mustela but compounds usually use -gale or -galea (γαλέη); horses are Equus but compounds use -hippus (ἵππος).

This post originally appeared on Quora. Click here to view.

An Ice Age Wolf Head Was Found Perfectly Preserved in Siberian Permafrost

iStock/stevegeer
iStock/stevegeer

Don’t lose your head in Siberia, or it may be found preserved thousands of years later.

A group of mammoth tusk hunters in eastern Siberia recently found an Ice Age wolf’s head—minus its body—in the region’s permafrost. Almost perfectly preserved thanks to tens of thousands of years in ice, researchers dated the specimen to the Pleistocene Epoch—a period between 1.8 million and 11,700 years ago characterized by the Ice Age. The head measures just under 16 inches long, The Siberian Times reports, which is roughly the same size as a modern gray wolf’s.

Believed to be between 2 to 4 years old around the time of its death, the wolf was found with its fur, teeth, and soft tissue still intact. Scientists said the region’s permafrost, a layer of ground that remains permanently frozen, preserved the head like a steak in a freezer. Researchers have scanned the head with a CT scanner to reveal more of its anatomy for further study.

Tori Herridge, an evolutionary biologist at London’s Natural History Museum, witnessed the head’s discovery in August 2018. She performed carbon dating on the tissue and tweeted that it was about 32,000 years old.

The announcement of the discovery was made in early June to coincide with the opening of a new museum exhibit, "The Mammoth," at Tokyo’s Miraikan National Museum of Emerging Science and Innovation. The exhibit features more than 40 Pleistocene specimens—including a frozen horse and a mammoth's trunk—all in mint condition, thanks to the permafrost’s effects. (It's unclear if the wolf's head is included in the show.)

While it’s great to have a zoo’s worth of prehistoric beasts on display, scientists said the number of animals emerging from permafrost is increasing for all the wrong reasons. Albert Protopopov, director of the Academy of Sciences of the Republic of Sakha, told CNN that the warming climate is slowly but surely thawing the permafrost. The higher the temperature, the likelier that more prehistoric specimens will be found.

And with average temperatures rising around the world, we may find more long-extinct creatures rising from the ice.

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