The first man appeared on earth two and a half million years ago. And the first fish appeared 450 million years ago, in what is now called the Devonian period.
That was the time when four-ton sharks came ashore to turn into crocodiles in another two hundred million years. Or well, at least that's what researchers of prehistoric and even "pre-dinosaur" eras claim.
The first biologist we know of, of course, was Aristotle (384-322 BC), who adhered to the theory of the spontaneous origin of life. According to this hypothesis, certain "particles" of matter contain a certain "active ingredient" that, under the right conditions, can create a living organism. Already in the 17th century, the Belgian-Dutch chemist Jan Baptiste Helmont created mice in three weeks. It required a dirty shirt, a dark closet, and a handful of wheat. The experimenter considered human sweat to be the active ingredient in the process of mouse birth. Oddly enough, he ended his life in his bed, not at the stake of the Inquisition.
Darwin gave the world the theory of evolution based on four postulates - hereditary variability, struggle for existence, natural selection and isolation.
Finally, in 1973, Francis Crick and Leslie Orgel proposed another option - controlled panspermia, that is, the deliberate "infestation" of Earth with microorganisms delivered on unmanned spacecraft by an advanced alien civilization. The latter, in their opinion, was facing a global catastrophe or simply hoped to terraform other planets for future colonization. By the way, the oldest of the manuscripts on the origin of life is, of course, the epic of King Gigalmesh of Uruk. He was two-thirds god, one-third earthly primate. He owed his appearance on Earth to astronauts. Where did the latter come from, Sumerian cuneiform is silent.
However, creationism - the hypothesis of the divine origin of life - still dominates in the mass consciousness. According to it, all living organisms are created by God. They are initially expedient and are preserved in an unchanged form. Everyone knows that "ichthysis," in its original form looking like "ΊΧθΥΣ", is an ancient acronym that briefly defines the Savior's name and the original Christian belief formula. Each of its letters is nothing but the first literal of the Greek words -Ἰησοῦς Χριστός, Θεοῦ Υἱός, Σωτήρ, translated into Russian as Jesus Christ the Son of God the Savior.
But "ichthys" is none other than "fish," the chief symbol of Christianity. The most ancient organism, according to scientists.
One of the representatives of shovelnose fishes, which lived just at the end of the Devonian period on the territory of modern Scotland, is Holoptychius flemingi. Holoptychius are relatively large fish with rounded scales, which in life were active predators, as evidenced by additional fang-like teeth on the palatal bones and a characteristic streamlined body shape, which facilitated rapid movement while chasing prey.
In 1836, a bed of sandstone with the remains of hundreds of late Devonian fish, including Holoptychius flemingi, was discovered during quarrying at Dura Den, Scotland. The fish were trapped in the reservoir and buried under a layer of silt, allowing their remains to persist for hundreds of millions of years, to later appear before visitors to the Mining Museum.
