Sharks and Rays first evolved some 400 million years ago as a separate line in evolution from the bony fish which ultimately let to the land based amphibians. Sharks and rays have cartilaginous skeletons but still remain the top predators in the oceans today.
One of the earliest and most primitive sharks was Cladoselache. The main difference in its appearance to modern sharks is that the mouth was situated at the front of the head. Here it can be seen hunting for belmonites, mollusks that have a strikingly similar appearance to the squids of today.
Ironically as man has decimated shark populations over the last couple of decades, reducing the population levels of some species to just 1% of what they used to be, there has been a marked increase in the numbers of predatory squid, which seem to be filling the vacant hole at the top of the food chain. The first cases of swimmers being attacked by swarms of squid have also been reported of the coast of California. While sharks fin soup continues to be served to the ever expanding populations of East Asian countries and the utterly barbaric practice of 'shark finning' continues, the future for these ancient and magnificent creatures, who have been on the Eath for over 200 times as long as us humans, seems very bleak indeed.