付着生物の群集に見られる生態現象の解析I. : 組成種の消滅状態における顕著な2型
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概要
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(1) The present paper deals with a contrivance illustrating the extinction of species in a community os sessile organisms in the "analytical graph of ecological phenomera" which has already been published by the author (1944). (2) A series of concrete test-plates 30cm×30cm or 20cm×20cm were suspended in the sea about one metre below the surface. They were prepared one after another in every ten days and the organisms attached to them were scrutinized at regular intervals. As the result, two different types were found in the extinction of species. In certain species almost all the members were extinguished abruptly in a short duration of time (Type I), but in the other species individuals disappeared rather gradually (Type II). (3) In the "analytical graph" inserted here, a solid will be constructed by a series of growth curves of the organisms, z=f'(x), which start from the points on the curve indicating the increase of their number, y=f(x). The two types of extinction named above may be represented by two cut planes of this solid. The plane I perpendicular to the x-axis may represent the Type I, and the plane II, which is oblique and has undulated surface, the Type II. The line with which the latter cuts the xy-plane resembles the increase curve. (4) Type I will be found in the decay of a species caused by some environmental factors, but Type II in the death resulting from senility. Almost all the cases of species extinction in a community will be represented by one of the cut surfaces, the angle which it makes with the x-axis going between the ones made by the surfaces I and II.
- 社団法人日本動物学会の論文
- 1955-03-15