Dinosaurs and Paleontology

Some Arctic Dinos Lived in Herds By Sid Perkins Just as interesting, however, is how this was discovered. Scientists didn’t look at a single fossil bone. Instead, they analyzed a large number of preserved footprints on a mountainside located toward the southern end of central Alaska. Anthony Fiorillo works at the Perot Museum of Nature and Science in Dallas, Texas. As a vertebrate paleontologist, he studies the fossils of creatures with backbones. In 2007, he was part of a research team exploring Denali National Park. “We rounded the corner and there they were,” he recalls. Thousands of footprints had been preserved in stone. “It was amazing.” Dinosaurs died out more than 65 million years ago (not counting birds, their modern-day relatives). So, it’s a bit surprising that scientists know so much about these ancient creatures. Now, a new study reveals that a certain type of duckbilled dinosaur lived in the Arctic year-round. These animals also traveled in herds that included many age groups, they find. The creatures even appear to have gone through a “teenage growth spurt.” Those tracks pepper a steep patch of exposed rock about twice as long as a football field and up to 60 meters (roughly 200 feet) wide. They sit at least 160 kilometers (100 miles) north of the Gulf of Alaska. Between 69 million and 72 million years ago, that now-rocky material was muddy sediment on a floodplain near a seacoast, Fiorillo explains. The hadrosaurs walked across the squishy mud. Later, the footprints they left turned to stone. Previous studies suggested adult duckbills took care of their young, says Fiorillo. The new evidence that these dinosaurs truly traveled in herds with multiple age groups confirms that parents cared for their young well beyond the time they left the nest, his team concludes. The researchers published their findings June 30 in Geology. © Science News for Students Thousands of tracks cover this rocky mountainside in Alaska’s Denali National Park. They provide a wealth of information about the size, age and lifestyle of certain dinosaurs. COURTESY OF PEROT MUSEUM OF NATURE AND SCIENCE EVIDENCE FOR HERDS O F DINOSAURS Small meat-eating dinosaurs called theropods had left behind a few of the tracks that Fiorillo’s team found in Denali. Birds had left some others. But the vast majority came from creatures called hadrosaurs. These large plant-eating duckbilled dinosaurs had been quite common during the Cretaceous Period. That helps explain one of their nicknames: “cattle of the Cretaceous.” For the new study, the researchers focused only on the hadrosaur tracks. More than half of the footprints were preserved so well that they had clear impressions of the skin on the dinosaurs’ feet. Most tracks had a similar level of preservation. That suggests all were probably left within a short period. Other fossils in the nearby rocks, including insect burrows, suggest these hadrosaurs had left their footprints during the summer. These are trace fossils — evidence of ancient life other than a preserved carcass or bone. At the time these dinosaurs lived, Fiorillio says, the average temperature in the warmest months was between 10° and 12° Celsius (50° and 54° Fahrenheit). That’s about what conditions are like today along the border between Canada and the lower 48 U.S. states, he notes. The team measured a large sample of the duckbills’ footprints. They fell into four distinct size ranges. The largest tracks, presumably made by adults, measured about 64 centimeters (25 inches) across. The smallest tracks, 8 centimeters (3 inches) wide, were likely left by young duckbills. They would have been no more than a year old. Tracks of two other size groups were probably made by juveniles and near-adults. These data suggest the community of hadrosaurs included four different age groups. © Science News for Students A hadrosaur footprint made roughly 70 million years ago. For scale, the long blue bar at right is 10 centimeters long; each small blue or white bar measures 1 centimeter. COURTESY OF PEROT MUSEUM OF NATURE AND SCIENCE © Science News for Students THESE DINOSAURS DIDN’T MIGRATE About 84 percent of the tracks sampled for the new study had been left by older hadrosaurs — adults or near-adults. Roughly 13 percent came from the youngest members of the herd. And a mere 3 percent came from herd members considered to be juveniles, says Fiorillo. The rarity of tracks by these tweens suggests that the young of this species had a rapid growth spurt. If true, they would have spent relatively little time at this vulnerable size — and therefore left very few tracks. “What’s really neat is how many small tracks there are,” notes Anthony Martin. An ichnologist — or expert in trace fossils — he works at Emory University in Atlanta, Ga. Other scientists had analyzed fossil bones from duckbills. These studies had hinted that the equivalent of adolescent hadrosaurs would have experienced growth spurts. But the new findings are “the best evidence that I’ve seen,” says Eric Snively. He’s a vertebrate paleontologist at the University of Wisconsin- La Crosse. “This is a great study,” he adds, “and further evidence that juvenile hadrosaurs grew up in an eye-blink.” Also previously, researchers had proposed that Arctic dinosaurs migrated farther south for the winter. That’s because even if the region was much warmer than it is today, nights in the high Arctic would have been 24 hours long. So, with no sunshine for several months, Alaska would have had long periods of very bleak, chilly weather. But finding juveniles in the herd strongly suggests that these dinosaurs remained in the Arctic all year. That’s because adolescents and preadolescents wouldn’t have had the strength or stamina to make those long treks, Fiorillo maintains. Field work is often harsh. Paleontologists studying the dinosaur footprints here on an Alaskan mountainside sometimes worked in cold and fog. COURTESY OF PEROT MUSEUM OF NATURE AND SCIENCE © Science News for Students The presence of very young dinosaurs might have been expected, he notes: If this were a nesting region, the babies would have hatched sometime just before summer. And remember, that’s when these tracks were left. But that wouldn’t explain the juveniles, he says. The team’s findings “suggest that these dinosaurs were overwintering in Alaska somehow,” says Snively. At the time, the average temperature in the region remained above freezing even during the winter, he notes. But, he adds, “this study raises interesting issues about how the dinosaurs could live in the region when it was pretty dark for several months at a time.”

Make a quiz about this text: Learning from Fossils. A fossil is a part of a plant or animal thathas been preserved in the Earth. Fossils, like bones, teeth, and footprints, help people learn important things about the past. Palaeontologists learned a lot about dinosaurs from their fossilized footprints. They determined whether some dinosaurs walked on two or four legs, and if a dinosaur traveled in groups or alone, by looking af the number of footprints. They learned that many dinosaurs walked with their tails in the air, because the footprints did not have any “drag marks” near them. By looking af how far apart some footprints were, palaeontologists discovered the fastest dinosaurs could run over 40 kilometers per hour. By examining fossilized shark teeth, scientists determined that sharks lived over 400 million years ago, before the dinosaurs. They learned that one prehistoric shark, called Squalicorax, had teeth with edges like a knife. Scientists discovered that the Squalicorax ate large fish and reptiles, because they found fossilized bones of these animals with Squalicorax teeth in them! People will continue fo learn even more about the past from fossils.

Why should mankind explore space? Why should money, time and effort be spent exploring, investigating and researching something with so few apparent benefits? Why should resources be spent on space rather than on conditions and people on Earth? These are questions that, understandably, are very often asked. Perhaps the best answer lies in our genetic makeup as human beings. What drove our distant ancestors to move from the trees into the plains, and on into all possible areas and environments? It appears that we are driven to ensure the success and continuation of not just our own genes, but of the species as a whole. The wider the distribution of a species, the better its chance of survival. Perhaps the best reason for exploring space is this genetic predisposition to expand wherever possible. Nearly every successful civilisation has explored, because by doing so, any dangers in surrounding areas can be identified and prepared for. These might be enemies in neighbouring cultures, physical features of the area, a change in the area which might affect food supplies, or any number of other factors. They all pose a real danger, and all can be made less threatening if certain preparations are made. Without knowledge, we may be completely destroyed by the danger. With knowledge, we can lessen its effects. Exploration also allows minerals and other potential resources to be located. Additional resources are always beneficial when used wisely, and can increase our chances of survival. Even if we have no immediate need of them, they will perhaps be useful later. Resources may be more than physical assets. Knowledge or techniques acquired through exploration, or preparing to explore, filter from the developers into society at large. The techniques may have medical applications which can improve the length or quality of our lives. Techniques may be social, allowing members of society better to understand those within or outside the culture. Better understanding may lead to more efficient use of resources, or a reduction in competition for resources. We have already benefited from other spin-offs, including improvements in earthquake prediction – which has saved many lives – in satellites used for weather forecasting and in communications systems. Even non-stick saucepans and mirrored sunglasses are by-products of technological developments in the space industry! While many resources are spent on what seems a small return, the exploration of space allows creative, brave and intelligent members of our species to focus on what may serve to save us. While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers. The chances of a large comet or asteroid hitting the Earth are small, but it could happen in time. Such strikes in the past may account for the extinction of dinosaurs and other species. Human technology is reaching the point where it might be able to detect the possibility of this happening, and enable us to minimise the damage, or prevent it completely, allowing us as a species to avoid extinction. The danger exists, but knowledge can help human beings to survive. Without the ability to reach out across space, the chance to save ourselves might not exist. In certain circumstances, life on Earth may become impossible: over-population or epidemics, for instance, might eventually force us to find other places to live. While Earth is the only planet known to sustain life, surely the adaptive ability of humans would allow us to inhabit other planets and moons. It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future. The more a culture expands, the less chance there is that it will become extinct. Space allows us to expand and succeed: for the sake of everyone on the Earth, now and in the future, space exploration is essential.

WHAT DOES THE WORLD GAIN WHEN WE PROTECT TIGERS? Tigers are one of the world’s most recognized animals. Throughout history they can be seen in cultural traditions across Asia, as well as in brand images and logos the world over. But while they might be omnipresent across our cultural landscape, their actual existence in the wild has been dramatically reduced to only a few pockets of their historical range. Wild tigers are now found in just 10 countries, their historical range shrunk by over 95%.er / WWF-US If tigers completely disappeared, we’d be losing so much more than an iconic species… Protecting water sources for millions of people Tiger habitats overlap nine of Asia’s most important watersheds which supply water to more than 800 million people. Protecting these tiger forests is the most cost-effective way to prevent droughts, reduce flooding, and limit the impacts of climate change. Protected Areas are proven to reduce deforestation and across Asia tigers are the driving force behind creating and effectively managing protected areas. For example, India recently declared its 51st Tiger Reserve, Srivilliputhur Megamalai, in southern India and this new protected area will safeguard more than 1,000km2 of key river habitat. Lose tigers, and lose entire forests Here in Cambodia, where I photographed the country’s last wild tiger in November 2007, tiger spirits were used by indigenous communities to help regulate the management of forests and wildlife. Harvesting of valuable plants was only permitted in certain times of the year and only after the tiger spirits had been appeased. Failure to adhere would result in wild tigers stalking you in the forest. However, with the extinction of the tiger the spirits have vanished, and the forests become an open free-for-all.aysia / Lau Ching Fong Protecting tigers also protects a multitude of other species Tiger-protected areas save much of Asia’s amazing wildlife. Take, for example, India’s Manas Tiger Reserve in Assam where tiger populations are increasing. In addition to tigers the grasslands and forests of Manas Tiger Reserve support the only viable global population of the world’s smallest, and rarest pig –pygmy hog – and, my personal favorite, the Bengal florican. This critically endangered gamebird, which I studied for my doctorate, finds a mate with an elaborate display involving males shooting themselves into the sky before plummeting down kicking their legs as if riding a bicycle. Without tigers, these and many more species would not be as well protected. A cultural and spiritual icon for millions There are plenty of examples of mythical animals, such as the unicorn, and extinct creatures, like the dodo and dinosaurs, which remain part of international consciousness. Tigers are a global phenomenon, but unless conservation is successful, they will only be known in zoos or in cultural media. A world without tigers would be economically and spiritually a much poorer place. Let us continue focusing our efforts towards doubling wild tigers and ensuring that this species does not become a vanished cultural icon.

Jack-o-Lanterns What Is a Jack-o'-Lantern? Carved pumpkins are called jack-o'- lanterns. Jack-o'-lanterns are used to decorate for Halloween. People started carving jack-o'-lanterns more than a hundred years ago. At first, people didn't carve pumpkins. They used other vegetables instead. An old fable from Ireland may tell how people began carving jack-o'-lanterns. The fable is about a man named Stingy Jack, who liked to play tricks on everyone. When he died, he was cursed to walk in darkness forever. He carved a turnip and put a light inside. His ghost was known as "Jack of the Lantern," and then "Jack-o'-lantern." Modern Jack-o'-Lanterns The Stingy Jack fable later became part of a night called All Hallows' Eve. In Europe, people lit fires and dressed up to keep away ghosts. In Ireland and England, people carved scary faces on vegetables and placed a light inside. All Hallows' Eve later became known as Halloween. When jack-o'-lantern carving was brought to the United States, people started using pumpkins. About 1.5 billion pounds (more than 680 million kg) of pumpkins are grown in the United States each year. Carving Jack-o'-Lanterns Carving pumpkins is fun for people of all ages. Smooth pumpkins work well for jack-o'-lanterns. Some people buy carving kits, while others carve without any help. First, with help from a parent, cut a hole in the top of the pumpkin to make a lid. Next, scoop out the inside flesh and seeds. Draw a design on the pumpkin, and then carve it carefully. After the pumpkin is carved, place a candle or other light inside. Finally, put the pumpkin lid back on toр. Jack-o'-Lantern Events Many cities have events to show off their carved pumpkins. In Hudson Valley, New York, jack-o'-lanterns make up a big display with spooky sounds and music. Pumpkins are used to make snakes, dinosaurs, and a dome carved with twinkling stars. A huge display in Los Angeles, California, has pumpkin cars and dinosaurs, and pumpkin carvings of famous people. The artists carve their pumpkins at the event while people watch. A town in New Hampshire broke a world record for the most lit jacko'-lanterns. The town had thirty thousand jack-o'-lanterns lit at once! The Tradition Continues. Carving pumpkins into jack-o'- lanterns is a fun holiday activity. However they are carved, jack-о'- lanterns are a sure sign that Halloween is around the corner.

Sam and Lucky 14: Dinosaurs! 문장

Sharks Introduction. Sharks have lived in the oceans since before dinosaurs walked on Earth. Hundreds of kinds of sharks can be found all over the world. Sharks are fish, but their skeletons are made of cartilage instead of bones. Cartilage is what gives human ears their shape. Unlike most fish, sharks have rough skin. Sharks have a good sense of smell. They also see well in the dark. Sharks can sense other animals moving in the water. Description. Great white shark come in many sizes. Some sharks are only a few inches long. The huge whale shark is the largest fish in the world. Many sharks are dark on the top and light on the bottom. This shading makes it harder for other animals to see them. Sharks swim by swinging their tails from side to side. Fins help sharks steer, turn, and keep their balance. Eating. Most sharks have many rows of teeth. When one tooth breaks off, another one moves up to take its place. Most sharks eat fish. Large sharks eat sea lions, dolphins, and other sharks. Some sharks eat shellfish. These sharks have flat teeth for crushing shells. The huge whale shark has tiny teeth but doesn't use them when eating. It swallows very small ocean plants and animals that float near the ocean's surface. Shark Attacks. Many people are afraid of sharks, but most sharks do not attack humans. Great white sharks are one of the few kinds of sharks that are dangerous to people. Shark Hunting. Shark fishing boats. People hunt sharks for their skin, oil, and teeth. Many people eat shark meat, and shark fins are used to make soup. Many kinds of sharks are now in danger of being completely killed off. Sharks are an important part of the balance of life in the world's oceans. They have as much right to live as any other animal.

🐣 What are oviparous animals? Oviparous animals are animals that are born from eggs. This means the baby does not grow inside the mother’s body, but instead grows inside an egg that the mother lays. 🥚 How does this process work? The mother lays one or more eggs. Inside the egg, the baby (called an embryo) begins to grow. The egg protects the baby and gives it food to grow. After some time, when the baby is ready, it breaks the eggshell and comes out. 🐔 Examples of oviparous animals: Birds (like chickens, penguins, and parrots) Reptiles (like turtles, crocodiles, and snakes) Fish, amphibians, and insects also lay eggs. 🦕 What about dinosaurs? Dinosaurs were oviparous too! The dinosaur moms laid eggs in nests. Inside each egg, a baby dinosaur grew safely. When the baby was ready, it broke the shell with its head or a special part of its mouth and came out. Some were born alone, and others hatched with many brothers and sisters—just like a dinosaur family!

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