化石の双valveの地理的な範囲を越えて進化のパターンの変動
Melissa Grey1, James W Haggart, Paul L Smith
1Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada. mgrey@eos.ubc.ca
Science (New York, N.Y.)
|October 25, 2008
まとめ
ブキアの貝殻を調査すると,ランダムな散歩や静止のような形態学的進化パターンが,地理的に変化していたことが明らかになる. 海の深さや古緯度などの環境要因は,これらの進化の形態と速度に影響を与えた.
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
- マリン・バイオロジー マリン・バイオロジー
背景:
- 化石記録は,長期的な形態学的変化のパターンと速度を理解するために極めて重要です.
- マクロ進化の過程を理解するには,これらのパターンが分類体内でどのように変化するかを知る必要があります.
- 進化の様式と速度の変動を誘発する要因は,依然としてほとんど解決されていない.
研究 の 目的:
- メソゾイク期の海洋双valve Buchia属における形態学的変化のパターンを調査する.
- ブキアの地理的・時間的な範囲において,進化の様式と速度がどのように変化しているかを調査する.
- これらの進化パターンに対する環境要因の影響を決定する.
主な方法:
- ビバルバ属ブキア (Buchia) の化石記録の分析
- 地理的および時間的な分布における貝殻形態の検討.
- モード (例えば,ランダムな散歩,静止) と形態学的変化の速度を特定するための統計分析.
主要な成果:
- ブキアの形態学的変化の観察されたほとんどのモードは,ランダムな散歩または静止のいずれかに適合した.
- 進化の様式と速度の両方とも,異なる場所の間で大きな変動を示した.
- 静止は,より深い海洋環境でより一般的であり,ランダムな散歩は,より高い古緯度でより一般的であった.
結論:
- 環境要因は,進化のパターンを形成する上で重要な役割を果たします.
- 地理的な位置と関連する環境条件は,形態学的変化の形態と速度に影響を与えます.
- この研究は,マクロ進化の研究における環境文脈の重要性を強調している.
関連する概念動画
02:55The 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.
01:07Speciation 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.
02:05Gene Evolution - Fast or Slow?
The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...
In contrast, regions which code...
02:05Gene Evolution - Fast or Slow?
The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain crucial regulatory sequences, the vast majority of this DNA serves no known function. Typically, these regions of the genome are the ones in which the fastest change, in evolutionary terms, is observed, because there is typically little to no selection pressure acting on these regions to preserve their sequences.
In contrast, regions which code...
In contrast, regions which code...
02:16Genetics 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...
02:56The 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...