The impressive wealth of forms of living organisms, thanks to the efforts of many generations of scientists, has been included in a system based on the principle of structural similarities adopted by Carl Linnaeus..
This classification, the essence of which is to rank closely related species into superior groups, called systematic units, not only brings order to the confusing image of the diversity of the animal world, but it also allows an insight into the course of its differentiation throughout history and evolutionary development. However, as knowledge progresses, numerous modifications are introduced to the already existing system, or new proposals for solving particular problems are presented. Hence comes also a certain change in the treatment of a group of fish, to which the pike belongs. Earlier taxonomic systems distinguish them into a separate row of pike-like species (Esociformes, synonym - Haplomi), later (after Berg, 1940) belong to the order of the herring-like (Clupeiformes). Second variant, taken over by the Bertin and Arambourg classification that is commonly used today (Grasse, 1958), determines the systematic position of the pike as follows:
|Type||strunowce — Chordata|
|Subtype||kręgowce — Vertebrata|
|Overhead||szczękowce — Gnathostomata|
|Gromada||ryby — fish|
|Podgromada||kostnoszkieletowe — Osteichthyes|
|Niadirząd||kościste — Teleostomi|
|Government||śledziokształtne — Clupeiformes|
|In a row||szczupakowce — Esocoidei|
|Family||szczupakowate — Esocidae|
|Type||szczupak — Esox Linnaeus, 1758|
|Type||szczupak — Esox lucius Linnaeus, 1758|
Comparison of pike and herring fish, although seemingly surprising, found justification in the analysis of anatomical details. Many features considered primary - for example, the connection of the swim bladder to the digestive tract, cycloid scale, soft and segmented fin rays, structure of some bone elements - indicates the common origin of both groups. It is believed, that the pike group separated from the main trunk of herring fish at the end of the Mesozoic era, about a hundred million years ago, through forms similar to today's gummed ones (Osmeridae), with which it is most closely related. Further evolution proceeded in three directions, leading to the creation of three modern families of the suborder Esocoidei.