Dinosaurs
Millions of years ago, gigantic reptiles ruled the Earth. Today, all we have left are their fossilised remains hidden in the rocks. Let us dig into how we know these incredible creatures existed and what exactly happened to them!
Digging Up the Past!
No, never! Dinosaurs and humans never lived at the same time. As Bill Nye the Science Guy explains, we missed them by about 64 million years.
The rocks tell the story. We know they lived because palaeontologists continue to dig up their fossilised bones and discover their ancient footprints preserved in stone.
Put Your Instincts to the Test
Think about what you already know about ancient Earth. Pick an answer for each question, then see if your instincts were right.
65 million years ago. That is right! The giant non-avian dinosaurs went extinct long before the first ancient humans ever walked the Earth.
Less than an inch from the final goal line. Bill Nye the Science Guy demonstrates that humans have only been around for a tiny, microscopic fraction of Earth's total history.
Iridium. This heavy metal is rare on Earth's surface but common in space rocks. Scientists found a layer of it all over the globe right at the 65-million-year mark, suggesting a massive meteorite impact!
Understanding the Science
To understand how these ancient creatures lived, scientists have to look closely at the clues left behind in the earth. Tap each card to reveal the explanation.
Key Concepts
Fossil
Tap to learn moreA fossil is the preserved remains or impressions of prehistoric organisms. The word comes from Latin, meaning "something that has been dug up." Fossils are the primary way we know dinosaurs existed.
Permineralisation
Tap to learn morePermineralisation is the process where water rich in minerals seeps into the tiny spaces inside buried bones. Over time, the water evaporates and the minerals harden, literally turning the bone into solid stone.
Palaeontologist
Tap to learn moreA palaeontologist is a scientist who studies ancient life and fossils. They act like detectives, piecing together clues from rock layers to reconstruct past environments and ecosystems.
Iridium
Tap to learn moreIridium is a rare metal on Earth's surface that is found abundantly in meteorites. Finding a global layer of iridium in the rock record provides a major piece of evidence for the meteorite impact that caused the dinosaurs' extinction.
Radioactive Decay
Tap to learn moreRadioactive decay is the process by which an unstable element (like Potassium) slowly changes into another element (like Argon) at a predictable rate. Scientists use this exact natural clock to measure the age of volcanic ash layers near fossils.
Ecosystem
Tap to learn moreAn ecosystem is a biological community of interacting organisms and their physical environment. By studying different types of fossils found together, palaeontologists can reconstruct entire ancient ecosystems.
Try It: Radiometric Dating Simulator
Scientists date the rock layers above and below a fossil to find out when the dinosaur lived. They often look for Potassium-40, an unstable element found in volcanic ash, because it slowly decays into Argon gas at a steady, predictable rate. Drag the slider to advance time and watch the parent Potassium isotopes (orange) decay into daughter Argon isotopes (blue).
Apply Your Knowledge
Palaeontologists rely on different types of evidence to piece together the history of the dinosaurs.
Match the Concepts
Click an object to select it, then click the matching description to place it.
Real-World Challenge
Imagine you are a palaeontologist who just discovered a new set of fossilised footprints in the mud. What specific clues would you look for to decide if the dinosaur walked on two legs or four, and whether it was walking slowly or running?
What Has Changed Since This Episode Aired
This episode first aired in 1993. While the core science remains incredibly accurate, our understanding of dinosaurs has expanded significantly.
Updated: It is no longer a joke! Modern palaeontology officially classifies birds (including chickens) as actual, living avian dinosaurs. The giant non-avian dinosaurs died out, but the feathered ones survived and evolved into the birds we see today. They didn't completely disappear; they just took flight!
Updated: Thanks to incredible new fossil discoveries since the 1990s, we now know that many, many dinosaur species were actually covered in feathers! They likely looked much more like massive, brightly coloured ground birds than the green scaly lizards depicted in older movies and books.
Test Your Understanding
Answer these questions and get instant feedback. How many can you get right?
Results
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Reflection
If you could discover a brand new species of dinosaur, what would you name it and what special features or adaptations would it have to survive in its ancient environment?
Episode Discussion
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