Friday, September 08, 2006

Repeats the phylogenesis

In THE XIX century the scientists, who studied the intrauterine development of human embryo, noted that in the first months of life it possesses striking similarity to other vertebrates. For example, at the monthly age in human embryo in the region of neck are noticeable slots, in every respect similar to the rudimentary gills. Late embryo has a similarity to the amphibious, then with the birds and finally - with others mammals. It is thought that the ontogenesis of the living being (development of individual) repeats the way of the phylogenesis (development of the type, class or form - see classification system Of linneya). Thus, human embryo is first similar to the embryo of fish, then reptile and so on - until its belonging with the kind of people appears. Is such one of these ideas - clear, beautiful, reasonable -, also, in the root of incorrect. In reality the human embryo never has the gills or any other appendages, which it it should be in accordance with this concept had at one or other stage or another of development. The being appeared zhabropodobnye slots are called the second branchiate arc. In fishes these formations actually are developed into the gills, but in man they serve as the predecessors of the parts of the head and neck. Exactly as the theory of evolution assumes not that the fact that man occurred from the primates, but that that he has with them general ancestor, so also embryology it asserts not that the fact that the human embryo in its development passes all steps of evolution, but simply that that in it are developed other organs from the same embryonic cells. It is sometimes useful to relate skeptically to the obvious things!