絶滅の機構と過程について-南西諸島における陸産貝類をモデルケースとして

论灭绝机制与过程——以南西群岛陆生螺为例

• 批准号: 06740402
• 负责人: 千葉 聡
• 金额: $ 0.58万
• 依托单位: Shizuoka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Encouragement of Young Scientists (A)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06740402/
• 关键词: 陸貝; 絶滅; 面積種数関係; 形態進化; 琉球列島

本研究では,奄美大島,喜界島,北大東島において化石陸貝および現生陸貝の採取を行い,その分類,形態解析,遺伝的解析をおこなった.化石は海岸や段丘上の砂丘や石灰岩の割れ目,鍾乳洞の堆積物から産出した.炭素同位体法によって,各サンプルごとに時代決定を行った結果,これらの化石は更新世末期(2〜3万年前)から完新世(1万年以降)にかけてのものであることが明らかになった.島ごとに時代別の陸貝の種数,絶滅率,移入率をもとめたところ,特に喜界島で更新世終末期に著しい種の絶滅(63%)が認められた.また島から絶滅した種の現在の分布域を調べたところ.この絶滅種は多くが現在琉球列島よりも寒冷な地域(九州以北)に分布していることがわかった.従って完新世以降の温暖化がこの絶滅の要因のひとつと考えられた.また琉球列島の各島に分布する現生の陸貝の種数と島の面積に,べき乗の関係が認められ,かつ最終氷期の海面温度から推定された当時の面積と当時の種数が,この関係によく対応したことから,この絶滅には海面上昇に伴う島の面積の減少も大きくかかわっていたと考えられる.次に,殻の10形質の計測値と,主成分分析に基づく形態解析の結果,喜界島における3種,北大東島における1種の陸貝で,最終氷期以降の体サイズの減少および幼形進化が,共通して認められた.遺伝的な解析の結果から,これらの種は各島ごとに隔離されており,島の中でそれぞれ独自の進化を遂げたものと考えられた.このように本研究により最終氷期以降の気候変化が,群集組成や表現型の著しい変化をもたらしたことが推定された.

The purpose of this study is to study the nature of the study, Amami, Xijie, Peking University, Peking University, Beijing University, Peking University, Peking University, Beijing University, Beijing University, Peking University, Beijing University. Fossil "coastal" dunes on the dunes, limestone "cut" eyes, "milk cave" accumulating active material to cut out. The carbon isotope method was used to determine the results of the experiment, and the results were determined by the carbon isotope method. The end of the Pleistocene (20,000 ~ 30,000 years ago) and the end of the Pleistocene (10,000 years ago). In recent years, the number of subscribers, the turnover rate, and the migration rate have increased significantly. We are particularly happy to see the number of subscribers at the end of the renewal period (63%). Please tell me that the distribution domain is currently located. Several kinds of typhoons are now distributed in the cold areas of the Ryukyu train (north of Kyushu). Since the end of the Pliocene, there has been an increase in temperature and temperature in the region. In the Ryukyu train, the number of weather stations is very high. The number of weather stations in the Ryukyu train is much higher than that in the Ryukyu train. In the Ryukyu train, it is estimated that the maximum temperature of the sea surface temperature (SST) is the number of days in which the weather is due. In the second phase, the results of principal component analysis are as follows: the results of principal component analysis are as follows: the results of principal component analysis, the results of principal component analysis and the results of principal component analysis. in the second phase, the results of principal component analysis and principal component analysis show that there are 3 kinds of drugs in the world and 1 in Peking University. The results of the analysis of the results show that each person is quarantined from each other, and that in the middle of the test, it is necessary to improve the performance on its own. In this study, in order to reduce the climate change, the cluster is organized into a table model, which is related to the presumption of climate change.