| Project/Area Number |
12640460
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | NATURAL HISTORY MUSEUM AND INSTITUTE CHIBA |
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Principal Investigator |
MORITA Rihito NATURAL HISTORY MUSEUM AND INSTITUTE, CHIBA, 自然誌歴史研究部地学研究科, 上席研究員 (70200433)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2002: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥600,000 (Direct Cost: ¥600,000)
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| Keywords | Gastropoda / Coiling growth / Head-Foot Mass / Computer Modeling / サザエ / 付着物 / 巻き成長 / コンピュータモデリング / 異常巻き / 巻きシミュレーション / 迂回反応 / 足収縮筋の押し付け / C++プログラム / 発生的制約 / 付着物反応 / 飼育 |
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| Research Abstract |
Samples of Turbo cornutus were used to investigate how snail reacts to environmental disturbance like attachment of Oyster which blocks the normal course of the shell growth. In this project, silicon rubber balls were used as an obstacle. After one or two years, most of individuals succeeded in keeping their growth and the following patterns were induced as reaction to the attachment.
1. With the rubber ball attached in upper part (on abapical side) of aperture overlap zone on the previous whorl, the shell growth changes downward and then returns back to upward after passing by the obstacle.
2. With the rubber ball attached in lower part (on adapical side) of aperture overlap zone, the forward growth of the shell stops for a while the aperture expands outwards.
These two patterns of the reaction to the obstacle suggest a certain role of the head-foot contact on the aperture margin. In order to test the role of the contact on the shell morphogenesis, a computer simulation has been performed for the shell morphogenetic model involving the head-foot contact on the aperture margin. Results of computer simulation of this model are as follows.
1. Most popular model of coiling, regular and tight coiling, can be produced only by the head-foot contact on the aperture margin even if there is no intrinsic nature of coiled shell.
2. The head-foot/aperture contact mechanism can simulate the reaction of the natural snail to the-obstacle attached on the previous whorl.
All the experiments and computer simulations indicates that the head-foot contact mechanisms imposes the developmental constraints on the evolution of the shell coiling.
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