1. "What were Dinosaurs?"
Coined by English paleontologist Richard Owen in 1842, the word 'dinosaur' is derived from the Greek and means “terrible lizard”; it refers to the awesome size of these reptiles rather than them necessarily having a scary appearance. Paleontology is the study of what fossils tell us about the ecologies of the past, about evolution, and about our place, as humans, in the world.
The “Age of the Dinosaurs” lasted over 160 million years, from the Triassic period around 230 million years ago through the Jurassic period and until the end of the Cretaceous period some 65 million years ago, during what is known as the Mesozoic Era. The first dinosaur to be formally named was the Megalosaurus, back in 1824.
Rather than being carnivores (meat eaters), the largest dinosaurs such as Brachiosaurus and Apatosaurus were actually herbivores (plant eaters). To help defend themselves against predators such as Allosaurus or Spinosaurus, many plant eaters evolved natural weapons. Examples of these include the spikes on the tail of the Stegosaurus and the three horns attached to the front of the Triceratops’s head shield.
Birds descended from the suborder of dinosaurs known as theropods.
2. "Who was the baddest of them all?"
Perhaps the most famous dinosaur of all is the big beast with the fearsome reputation: Tyrannosaurus rex. Every school kids’ favourite, this 12.3m-long theropod stalked the Earth some 67 to 66 million years ago during the upper Cretaceous period, inhabiting what is now western North America, which then was an island continent named Laramidia.
Debate continues over whether T. rex was an apex predator or a scavenger but current scientific consensus is that it was an opportunistic carnivore, behaving as both a predator and a scavenger. Some experts suggest that T. rex was also partly feathered and able to regulate its body temperature in a similar way to warm-blooded birds and mammals.
Weighing in at up to 6.8 tonnes, T. rex was one of the largest known land predators and also one of the last non-avian dinosaurs to exist before the dinosaurs died out.
3. "Why is Jurassic Park’s Velociraptor not quite what it seems?"
Thanks to the movie Jurassic Park, Velociraptor is one of the world's most famous dinosaurs but
the animal portrayed wasn’t actually Velociraptor at all; it was a larger predatory dinosaur known as Deinonychus. However, the makers of the movie rightly thought that its name didn’t sound so catchy.
In fact, Velociraptor was about the size of a turkey and relatively puny. Although it was a predator, it only weighed about 15kg and stood about a metre tall. Paleontologists also believe that Velociraptor sported feathers
Despite its name, Velociraptor wasn’t especially speedy either. There is no evidence that it hunted in packs and it’s thought that Velociraptor's main weapons were its single, 8cm-long hind claws that could have been used to slash and jab at prey.
It is possible that this dinosaur survived by stabbing its prey in the gut in sudden, surprise attacks and then withdrew a safe distance while its victim bled to death.
4. "How did the dinosaurs become extinct?"
Scientists suggest that dinosaurs died out as a result of what they refer to as the Cretaceous–Paleogene extinction event or K-Pg, which was previously known as the Cretaceous–Tertiary (K–T) extinction. This happened some 65 million years ago and caused the mass extinction of some three-quarters of plant and animal species on Earth. It delineates the end of the Cretaceous period and with it, the entire Mesozoic Era, opening the Cenozoic Era that continues today.
We are able to see this represented in the geologic record, whereby K–Pg is marked by a thin layer of sediment called the K–Pg boundary that can be found throughout the world in marine and terrestrial rocks. The boundary clay shows high levels of the metal iridium, which is rare in the Earth's crust but abundant in asteroids.
A team of scientists led by Luis Alvarez proposed that the mass extinction of many species on Earth was triggered by a massive comet/asteroid impact; this had catastrophic effects on the global environment, including a lingering impact winter that caused huge changes to the world’s climate as sunlight was blocked out. This hypothesis was bolstered by the discovery of the 180-kilometre-wide Chicxulub crater in the Gulf of Mexico in the early 1990s; it provided conclusive evidence that the K–Pg boundary clay represented debris from an asteroid impact. Some scientists also argue that the extinction was caused or exacerbated by other factors, such as volcanic eruptions.
The extinction of the dinosaurs created the ecological “space” for other groups, such as mammals and birds to flourish.
5. "Are dinosaurs still around today?"
Palaeontologists have long accepted that birds are descended from therapod dinosaurs and that
the humble chicken is pretty much a modern-day dinosaur.
Back in 2007, study of collagen from the fearsome T. rex by experts from Harvard Medical School and Beth Israel Deaconess Medical Center even confirmed a genetic link to chickens, after scientists extracted seven protein fragments from a 68 million-year-old fossilised thighbone. Chickens and T.rex also share a remarkably similar bone structure, albeit on a different scale.
A British paleontologist, Dr Angela Milner, from the National History Museum, was quoted at the time as saying: “This corroborates a huge body of evidence from the fossil record that demonstrates birds are made from meat-eating dinosaurs. The analysis shows that T. rex collagen make-up is almost identical to that of a modern chicken.”
All of which means that, despite the mass extinctions of 65 million years ago, dinosaurs are big winners genetically: chickens are the planet’s most numerous bird species, estimated to number some 50 billion individuals.