Sharks have been around for a really long time – more than 450 million years! Back then, there were these fish without jaws called ostracoderms, which had a bony skeleton and bone scales. Eventually, some fish evolved jaws and became placoderms, which had actual bones in their heads and trunks.
The History of Sharks
Around 420 million years ago, the first true sharks appeared. They were called Cladoselachida and had long, streamlined bodies, powerful tails, and sharp, jagged teeth. They were great hunters and could be found all over the world.
As time went on, different types of sharks emerged. Some liked to swim near the surface of the water, while others preferred the deep, dark depths of the sea. Some grew really big, while others stayed small and nimble.
Today, there are over 500 different kinds of sharks. Some, like the pygmy shark, are tiny, while others, like the whale shark, are really big and can grow up to 40 feet long! Despite being so old, sharks are still really important to our oceans. They help keep things balanced and healthy by eating other animals, and they play a big part in the food chain.
So, sharks have been around for a really, really long time. The first true shark appeared about 420 million years ago, and since then, they’ve changed a lot. But one thing that hasn’t changed is how important they are to our oceans.