At Science Explorers, we teach a Dynamite Dinosaur class to pre-school aged children. Just this week in fact, I was assisting in a dinosaur class. The children were learning about the different types of eaters: carnivores, herbivores, and omnivores. In response to the question, “Name an animal is an herbivore,” one boy responded, “Brachiosaurus!” In response to the question, “Name an animal that is an omnivore!” another responded “Gorilla!” And finally, in response to the question, “Name an animal that is a carnivore,” another boy replied matter of factly, “A teacher!”
With the recent popularity of the movie Jurassic World, it is fun to revisit what life might have been like for the creatures that existed so many years ago. Scientists posit based on fossil records that animals like the dinosaurs lived in the Mesozoic Era. During this era was the Jurassic period which took place roughly between 200 and 150 million years ago. The big names of the Jurassic period include creatures like the tyrannosaurus rex, the brachiosaurus, the triceratops, and the pterodactyl. As tempting as it may be to gather other creatures of that era and place them into one category – the dinosaur category – this would not be accurate. In fact, even a pterodactyl is not truly a dinosaur. While dinosaurs may have been dominant in their time, there were a myriad of other creatures that, though similar in habitat and appearance, are actually not as related to the dinosaurs as most would think.
The word “dinosaur” was first coined in 1841, by biologist and paleontologist Sir Richard Owen. It is derived from two words: dienos – meaning “terrible, powerful, and wondrous” and saurus – meaning ”lizard”. Put them together, and a dinosaur is a terrible, powerful and wondrous lizard! It’s no wonder with this name that we tend to label so many of the Jurassic creatures as dinosaurs.
Scientists today use special category of science called cladistics to determine which animals are the most related to one another. For living animals, this task is easy. Scientists can take use the building blocks of an animal, housed within something called DNA. For animals that are extinct, like dinosaurs and other Jurassic creatures, the task is more difficult. Scientists rely on evidence found when comparing the fossil remains of these creatures.
For example, pretend that all birds were extinct. If, as a scientist, you had never seen a living bird, you would rely on fossil remains to categorize them. When you discovered that there was a group of animals that all have feathers in their fossil remains, you might place them into one category and call them birds on this basis.
So, what links all the dinosaurs together? It’s probably not what you might think. All dinosaurs were reptiles – cold blooded, egg laying creatures. Some walked on two legs. Others walked on four legs. Some were very large. Others were quite small. Some ate leaves. Others preyed on other dinosaurs. What all dinosaurs had in common was actually their hips! At the place where a dinosaur’s thighbone (or femur) connects to its pelvis, there is a hole. Dinosaurs have open hip sockets!
For example, pretend that all birds were extinct. If, as a scientist, you had never seen a living bird, you would rely on fossil remains to categorize them. When you discovered that there was a group of animals that all have feathers in their fossil remains, you might place them into one category and call them birds on this basis.
So, what links all the dinosaurs together? It’s probably not what you might think. All dinosaurs were reptiles – cold blooded, egg laying creatures. Some walked on two legs. Others walked on four legs. Some were very large. Others were quite small. Some ate leaves. Others preyed on other dinosaurs. What all dinosaurs had in common was actually their hips! At the place where a dinosaur’s thighbone (or femur) connects to its pelvis, there is a hole. Dinosaurs have open hip sockets!
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