デヴォン期末の大量絶滅後の脊椎動物の体格縮小

Lauren Sallan¹, Andrew K Galimberti²

¹Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104, USA. lsallan@sas.upenn.edu.

Science (New York, N.Y.)

|November 14, 2015

まとめ

脊椎動物はデボニアの絶滅後 3600万年にわたって気候ではなく生態学的要因によって縮小しました小さくて生殖が速い種が優勢で未来の生物多様性を形作りました

科学分野:

古生物学
進化生物学
生態系の動力学

背景:

デボニア期末の大量絶滅は脊椎動物に重大な影響を及ぼした.
絶滅後の回復期は進化の軌道を理解するのに極めて重要です
以前の研究では絶滅の現象は調べましたが長期にわたる体の大きさの傾向は調べられませんでした

研究の目的:

デヴォン期末の大量絶滅後の脊椎動物の体格の変化の要因と期間を調査する.
環境要因 (酸素,温度) や生態学的圧力が脊椎動物のサイズ縮小に影響を与えているかどうかを判断する.
絶滅後期の小型の脊椎動物と大型の脊椎動物の多様化パターンを分析する.

主な方法:

絶滅後3千6百万年の脊椎動物体の大きさのトレンドを追跡する化石記録の分析
身体のサイズ変化と環境パラメータ (酸素,温度) の関係を評価する相関分析
急速繁殖する小型の脊椎動物と,ゆっくり繁殖する大型の脊椎動物の多様化率の比較研究.

主要な成果:

脊椎動物は絶滅後少なくとも3600万年もの間体のサイズが減り続けていた.
全身の縮小は酸素濃度や体温の変化とは関係なかった.
小型の,急速に繁殖する線羽魚,サメ,四足動物 (1メートル未満) は,生態系を照射し支配し,大体の生存者は限られた多様性を示し,絶滅に直面した.

結論:

環境要因ではなく生態学的要因が,デボニアン絶滅後の脊椎動物体の大きさの傾向に主な影響を与えた.
絶滅後の回復間隔は,現代的な生態学的継承を反映し,サイズと生命の歴史の特徴を主体的に選択した.
脊椎動物や魚の生物群の破壊は一般的に長期にわたる広範な体サイズ減少につながり将来の生物多様性を根本的に構造化します

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