Dinosaurs first appeared on Earth 235 million years ago but were all wiped out suddenly 170 million years later, probably by a massive asteroid (rock from space), which hit the Earth. Dinosaurs are the ancestors of modern reptiles and birds, and included the largest land animals ever. Some close relatives of dinosaurs also lived in the sea and flew in the air.
Food
Contents
Some dinosaurs ate meat, and others ate plants. Plant-eaters had small, peglike teeth, and some had horny beaks. Meat-eaters had large, sharp teeth for slicing flesh. A Tyrannosaurus rex tooth could be up to 15cm long!
Fossils
Fossils are formed over millions of years, when a dead dinosaur”‘s bones are buried under mud or sand, and are slowly replaced with minerals from the surrounding rock.
Sails
The Spinosaurus had a large sail on its back. In hot weather, it could pump blood into the sail to cool itself down.
Defence
Many plant-eaters had horns to protect themselves from big meat-eaters. This Styracosaurus had one on his nose. Male horned dinosaurs may also have used their horns for fighting each other, just like male cattle and antelope do today.
Giant
Dinosaurs The biggest of all dinosaurs were plant-eating sauropods like this Apatosaurus. Sauropods all had small heads on long necks. The largest, such as the giant Seismosaurus, could sometimes weigh more than 100 tonnes.
Skeletons
Most dinosaur fossils are just a few scattered bones, but sometimes complete skeletons are found. They can then be pieced together on metal frames, to be displayed in museums.
Plates
Stegosaurs were plant-eaters with twin rows of plates along their backs. These probably worked in a similar way to a sail of a Spinosaurus, both for display and to help the dinosaurs cool down. The largest and most famous of the stegosaurs was the Stegosaurus. The Kentrosaurus was one of the smallest members of the stegosaur family. Snakes are reptiles, like tortoises, turtles and lizards.
GK Questions and Answers for Class 7
- What did Spinosaurus have on its back: wings or a sail?
Answer: A sail
- What’S’ was the largest stegosaur?
Answer: Stegosaurus
- Which dinosaur had plates on its back: Kentrosaurus or Tyrannosaurus rex?
Answer: Kentrosaurus
- Which had larger teeth: plant-eating or meat-eating dinosaurs?
Answer: Meat-eating dinosaurs
- Tyrannosaurus re teeth could be more than 10cm True or false?
Answer: True
- Do fossils take thousands or millions of years to form?
Answer: Millions of years
- Did sauropods have long necks or short necks?
Answer: They had long necks
- Did any dinosaurs have beaks?
Answer: Yes
- What did Styracosaurus have on its nose?
Answer: A horn
- What did male horned dinosaurs probably use their horns for, apart from defence?
Answer: To fight each other
- Which are more common: scattered fossil bones or entire fossil skeletons?
Answer: Scattered fossil bones
- What type of dinosaur was Kentrosaurus?
Answer: A stegosaur
- How did a Spinosaurus cool down?
Answer: By pumping blood into its sail
- Where can you see dinosaur bones on display?
Answer: At a museum
- What did Tyrannosaurus rex eat?
Answer: Meat
- Which was bigger: Seismosaurus or Stegosaurus?
Answer: Seismosaurus
- Are fossils made of bone or of minerals from rock?
Answer: Minerals from rock
- Synecosaurus ate True or false?
Answer: False
- Is an Apatosaurus more closely related to a Seismosaurus or a Styracosaurus?
Answer: Apatosaurus and Seismosaurus are related
- How many tows of plates did most stegosaurs have?
Answer: Two