A plate of fish and chips provides hearty sustenance for not only the body, but also for enquiring minds.
Poke around in a seafood platter and you can find stark evidence that fish – and all vertebrates, including humans – are descended from segmented worm-like ancestors.
Fish, like frogs, lizards, birds and humans, are segmented, too.
The flakes of meat that separate when you prod a fish fillet with a fork are blocks of muscle, called myotomes, that correspond to the body segments of invertebrate forebears.
It is the contraction of these muscles in sequence that produces a fish’s characteristic undulating swimming motion.
Humans have myotomes, too. It’s just that our individual segments have become increasingly specialised over the course of evolutionary history, so are no longer as obvious as they are in fish, let alone earthworms.
They can, though, be seen clearly during our early embryonic development before they take on their specialised functions.
The repeating vertebrae of the spinal column are also echoes of our segmented past, as are our ribs.
Each myotome is associated with its own nerve supply sprouting from a specific point along the spinal cord.
By testing the strength of muscles formed from different myotomes, doctors are able to identify precisely the position of spinal injuries.
Main image: Raw salmon meat shows the segmental myotomes. © Tetra Images/Getty