初期のホモの原始的な脳
Marcia S Ponce de León1, Thibault Bienvenu2, Assaf Marom3
1Department of Anthropology and Anthropological Museum, University of Zurich, CH-8052 Zurich, Switzerland. marcia@aim.uzh.ch zolli@aim.uzh.ch.
まとめ
人間の脳の進化は 前頭葉の組織が 思ったより遅れて変化したことを示しています 初期のホモは類人猿のような脳を持ち ホモはアフリカから散らばった後に人間のような組織が現れました
科学分野:
- 古人類学
- 進化生物学
- 神経科学
背景:
- 現代人の脳は 大きさと形状 そして皮質の組織で 類人猿の脳と大きく異なっています 特に前頭葉の領域です
- これらの前頭葉領域は 社会的認知,道具の使用,言語を含む複雑な認知機能に不可欠です
- これらの進化的脳の変化のタイミングは 科学的な議論の話題です
研究 の 目的:
- 人類の祖先における 前頭葉の進化の時間軸を調査する
- ヒトのような脳組織が ホモの系統で出現した時期を 判断するためです
主な方法:
- ヒトの頭蓋骨の化石を分析し,特に頭蓋骨の形状を分析した.
- アフリカと西アジア (Dmanisi) の初期のホモの化石と,南東アジアの後のアフリカ人のホモとホモエレクトスの前頭葉組織の比較分析.
主要な成果:
- ドマニシ (アフリカと西アジア) の初期のホモの化石には 類人猿のような原始的な前頭葉組織が表れています
- アフリカのホモの化石は150万年未満で 東南アジアのホモ・エレクタスの標本はすべてより派生した 人間のような前頭葉組織を示しています
- これは,前頭葉の重要な再編成が,これまで考えられていたよりも,人間の進化の後に起こったことを示しています.
結論:
- 人間のような前頭葉組織の進化は ホモの進化の比較的遅い出来事でした
- この再編成は ホモがアフリカから最初に分散してから 長い間続いたのです
- 前頭葉の再編成が アフリカの最古のホモの特徴であったという以前の仮定は これらの発見によって修正されています
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