Friday, September 08, 2006
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!
на 5:46 AM
Wednesday, August 16, 2006
Researchers from The barselon university compared the frequency of the occurrence of different cancerous diseases among the amateurs of fish dishes and patients, who completely ignore this form of food. Numbers proved to be impressive: in people, regularly "which practice" at least two fish days in the week, probability of the development of cancer of larynx and ovaries it proved to be to 30% less than in the "nelyubiteley" fish even that of more perceived was the difference in the frequency of the occurrence of cancer of the gullet, stomach, thick gut and of pancreas: the risk of the development of these illnesses in the adherents of fish dishes is reduced to 30-50% in comparison with the patients, who do not use fish dishes.
на 10:18 AM
Saturday, July 22, 2006
Ontogenesis (from the Greek. on, born case ontos - real and... genesis), the individual development of organism, the totality of the sequential morphological, physiological and biochemical conversions, undergone with organism from the moment of its origin to the end of the life. Ontogenesis includes increase, increase in the mass of body, its sizes, differentiation. Term "O." it is introduced by 3. Haeckel (1866) with the formulation to them biogenetical law. In animals and plants, which are multiplied through sex, the origin of new organism is achieved in the process of fertilization, and O. begins from the impregnated egg cell, or the zygote. In organisms, of which the characteristically sexless multiplication, O. begin from the formation of new organism by dividing of maternal body or specialized cell, via budding, and also from the rhizome, the tuber, the bulb and the like (see vegetative multiplication). In the course of O. each organism regularly passes sequential phases, stages or development periods, from which basic in the organisms, which are multiplied through sex, they be: embryonic (embryonic, or prenatal), poslezarodyshevyy (postembryonal, or post-natal) and the development period of adult organism. At the basis of ontogenesis lies the complex process of realization on the different stages of the development of the organism of the hereditary information, placed in each of its cells. The caused by heredity program O. is achieved under the effect of many factors (condition of environment, intercellular and intertissue interactions, humoral- hormonal and nervous regulations) and is evinced by the interconnected processes of multiplying of cells, their increase and differentiation. Laws governing the ontogenesis, causal mechanisms and factors of cellular, woven and organ differentiation are studied by complex science - biology of development, which uses, besides the traditional approaches of experimental embryology and morphology, the methods of molecular biology, cytology and genetics. Ontogenesis and the historical development of organisms - phylogenesis - the indissoluble and mutually caused sides of the united process of the development of living nature. The first attempt at the historical substantiation O. made i. f. of mekkel'. The problem of relationship O. and phylogenesis was set By ch. Darwin and was developed By f. Mueller, 3. Haeckel and all other connected with the change heredities, new in evolutionary sense signs appear in the O., but only those of them, which contribute to the best adaptation of organism to the condition for existences, they remain in the process of natural selection and are transferred to the subsequent generations, i.e. they are attached in the evolution. The knowledge of regularities, reasons and factors O. serves as scientific basis for finding the means of influence on the development of plants, animals and man, which has important significance for the practice of plant growing and stock raising, and also for medicine.
на 12:02 PM