関連する実験動画
Updated: Aug 9, 2026

08:14
Who is Who? Non-invasive Methods to Individually Sex and Mark Altricial Chicks
Published on: May 24, 2014
クレタセウス-第3期境界を越えて鳥の大量生存:分子証拠
1School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand. alan.cooper@bioanth.ox.ac.uk
まとめ
クレータ紀・第三期の絶滅イベントでは,22以上の鳥類の系統を含む多くの陸上の脊椎動物が限られた絶滅を経験しました. 証拠は,大量絶滅の出来事ではなく,徐々に多様化することを示唆しています.
科学分野:
- パレオントロジー・パレオントロジー
- 進化生物学の進化生物学について
- 脊椎動物学 脊椎動物学
背景:
- クレータ紀・三次紀 (K-Pg) 絶滅イベントが陸上の脊椎動物に与える影響は議論されており,大量絶滅から選択的集団損失までの理論が論じられている.
- K-Pgの絶滅を理解することは,脊椎動物の進化史を再構築するために非常に重要です.
研究 の 目的:
- 白亜紀の終わりに地上の脊椎動物が絶滅した範囲を調査する.
- K-Pgイベントが大量絶滅,またはより限られた絶滅を代表したかどうかを明確にするために.
主な方法:
- 分子および古生物学的データの分析.
- 鳥類の系統と他の陸上の脊椎動物群の調査,白亜紀と地表の境界を越えて.
主要な成果:
- 現代の鳥類の順序は白亜紀初期に相違し始め,少なくとも22の鳥類の系統がK-Pg境界線から生き残った.
- 他の地上の脊椎動物集団からのデータは,同様の生存パターンを示唆しています.
- 発見は,クレタセオスの間における漸進的な変化と多様化を,初期の第三期における突然の放射線に裏付けるものである.
結論:
- クレータ紀・三次紀の絶滅イベントは,大惨事的な大量絶滅ではなく,より漸進的な変化と多様化,特に鳥類と哺乳類を伴う可能性が高い.
- 重要な数の鳥類の系統がK-Pg境界を越えて存続し,回復力を示した.
- この研究は,陸上の脊椎動物にとって,白期を通しての漸進的な進化的変化のモデルに好意を示している.
関連する概念動画
Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
Conservation of Declining Populations
Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent populations from going extinct.
Genetics of Speciation
Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.The genetics of speciation involves the different traits or isolating mechanisms preventing gene exchange, leading to reproductive isolation. Reproductive isolation can be due to reproductive barriers that have effects either before or after the formation of a zygote. Pre-zygotic mechanisms prevent fertilization from occurring, and post-zygotic mechanisms...
The Evidence for Evolution
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.The collection of fossils within sedimentary rocks give a record of common ancestry and often depicts the history of evolution.
The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
Convergent Evolution
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.The structures that arise from convergent evolution are called analogous structures. They are similar in function even if they are dissimilar in structure. Further, structures can be analogous while also...

