Written by “What came first?” is a great science question, and it opens up lots of opportunities for competitive chat around the dinner table, in the classroom, or on a family walk. Whether you’re debating evolutionary timelines or quirky biological twists, these baffling head-scratchers will make you rethink everything you thought you knew about the natural world.
Get ready to test your knowledge and challenge your friends as you find out what actually came first!
What Came First?
The Chicken or the Egg
We had to start with this one! The egg came first. Amniotic eggs existed long before birds, and birds gradually evolved from reptiles. The first true chicken hatched from an egg laid by a bird-like ancestor that had a small genetic mutation. Slowly, birds evolved into what we think of as a bird today!
Did you know?
Modern birds, including chickens, are the closest living relatives to Tyrannosaurus Rex!
Tyrannosaurus or Stegosaurus?
The Stegosaurus was alive a whopping 80+ million years before Tyrannosaurus! If you put this on a timeline that includes humans, Tyrannosaurus is actually closer in time to humans than Stegosaurus.
Stegosaurus lived about 150 million years ago during the Late Jurassic Period and went extinct long before Tyrannosaurus arrived. Tyrannosaurus lived in the Cretaceous period, around 68 million years ago.
Did you know?
A Stegosaurus’s brain was only the size of a walnut or small lemon, even though its body could be 9 meters long! Meanwhile, Tyrannosaurus had a massive head up to 1.5 meters long!
Blue Whales or Woolly Mammoths
The blue whale came first! Blue whales first appeared, looking like they do today, around 1.5 million years ago! Woolly mammoths evolved as their own species around 0.8 million years ago and went extinct 4000 years ago.
Did you know?
Most woolly mammoths went extinct 10,000 years ago due to climate change (the Earth warmed up after the Ice Age) and human hunting.
The last known woolly mammoths lived on Wrangel Island off the coast of Siberia and went extinct due to natural events.
Flushing Toilets or Toilet Paper?
Flushing toilets might seem like a modern luxury, but the Minoans built the world’s first flushing toilet around 3500 years ago. They poured water into the toilet to flush waste through a network of pipes that carried it to the sea or a river.
The first toilet paper was created in 1391 for the Chinese emperor and his family! So the flushing toilet came first.
Did you know?
People have used all kinds of things to wipe their bottoms after going to the toilet, including dried-up corncobs and sponges on sticks!
Sir John Harington invented the first mechanical toilet in 1596 for Queen Elizabeth I. This had an overhead tank, and pulling a valve released water from a cistern, flushing waste away from the toilet.
The rolls of toilet paper we used today were patented in the USA in 1857.
Wheels or Boats
Boats and wheels are pretty old, but which is the oldest?
The oldest boat is thought to be a 10,000 year old Dutch Pesse canoe, but it’s thought that humans used simple boats up to 60,000 years ago!
Wheels are thought to have been invented around 5000 to 6000 years ago. The oldest complete wooden wheel with an axle was found in the Ljubljana Marshes in Slovenia and is around 5,200 years old.
Did you know?
Building a wheel isn’t just about the wheel. It also needs a strong axle that can support weight and move without too much friction.
Potters actually invented the earliest wheels to make clay ceramics.
Earth or Saturn’s Rings
Earth came first!
Earth, Saturn and the other planets formed around 4.6 billion years ago. Saturn’s rings actually came much later!
The rings are thought to have formed from ice and dust around 100 million years ago. No one really knows how they formed, but some scientists think Saturn’s moons may have crashed into each other and broken up into bits that became the rings.
Did you know?
Saturn’s rings are mostly made of pure water ice, ranging from tiny grains to chunks as large as mountains!
Sharks or Trees?
Sharks came first!
Sharks are ancient oceanic survivors. The earliest fossilised shark teeth and scales date back about 450 million years!
Trees, on the other hand, didn’t appear on land until around 350 to 380 million years ago! That means sharks swam through Earth’s oceans for nearly 100 million years before a single tree ever grew on land.
Did you know?
Sharks are so old that they have survived all five major mass extinction events on Earth. They are older than trees, older than dinosaurs, and even older than Saturn’s rings!
The next time you get into a friendly discussion with friends, you’ll have the ultimate science trivia up your sleeve to prove what really came first.
Last Updated on November 7, 2026 by Emma Vanstone
The post What Came First? appeared first on Science Experiments for Kids.
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