“Shark” is not a species. A whaleshark is a species. A tigershark is a species. “Shark”, representing multiple species of shark, is a division, specifically the Selachii division.
The Selachii division is 200 million years old. One galactic year for Sol is 225 million years old. This means that sharks, as we know them, have not existed as a division for two galactic years, barely even for one! Horshoe crabs have been around for 250 million years nearly completely unchanged by evolution, so they have been around for one galactic year… But nobody ever seems to talk about them…
Officially, what came before sharks are classified as a different division with “shark-like morphology”, but they aren’t sharks.
Sharks have existed for longer than the North Star, though. So there’s that.
The oldest fossils known are stromatolite fossils from 3.48 billion years ago. There are living stromatolites today. They predate Earth having significant oxygen in its atmosphere, because the cyanobacteria that formed them created the oxygen gas through photosynthesis from carbon dioxide. They’ve orbited the galaxy over fifteen times.
CORRECTION!!
“Shark” is not a species. A whaleshark is a species. A tigershark is a species. “Shark”, representing multiple species of shark, is a division, specifically the Selachii division.
The Selachii division is 200 million years old. One galactic year for Sol is 225 million years old. This means that sharks, as we know them, have not existed as a division for two galactic years, barely even for one! Horshoe crabs have been around for 250 million years nearly completely unchanged by evolution, so they have been around for one galactic year… But nobody ever seems to talk about them…
Officially, what came before sharks are classified as a different division with “shark-like morphology”, but they aren’t sharks.
Sharks have existed for longer than the North Star, though. So there’s that.
The oldest fossils known are stromatolite fossils from 3.48 billion years ago. There are living stromatolites today. They predate Earth having significant oxygen in its atmosphere, because the cyanobacteria that formed them created the oxygen gas through photosynthesis from carbon dioxide. They’ve orbited the galaxy over fifteen times.