アビオティックがケノゾーイクにおけるプランクトンの進化を促した
Daniela N Schmidt1, Hans R Thierstein, Jörg Bollmann
1Department of Earth Sciences, Eidgenössische Technische Hochschule (ETH) Zürich, and University of Zürich, ETH-Zentrum, CH-8092 Zürich, Switzerland. d.schmidt@gl.rhul.ac.uk
まとめ
プランクトンフォラミニフェラの試験サイズはケノゾーイク時代に増加し,より強い海洋層分化に適応した. この地球温暖化傾向はプランクトンの進化と海洋生態系に影響を与えた.
科学分野:
- パレオセアノグラフィー
- マイクロパレオンタロジーとは
- 進化生物学の進化生物学について
背景:
- プランクトンフォラミニフェラは,化石化可能な殻 (テスト) を有する重要な海洋プランクトンです.
- 彼らの進化の歴史は,過去の海洋状態についての洞察を提供します.
- 彼らのマクロ進化を駆動する要因を理解することは,古気候の再構築にとって極めて重要です.
研究 の 目的:
- プレンクティック・フォラミニフェラの進化的放射をケノゾーイクを通して特徴づける.
- プランクトンフォラミニフェラの試験サイズと環境パラメータとの関係を調査する.
- パレオセアノグラフィの変化に対応して試験サイズを増やすことの適応的意義を決定する.
主な方法:
- 500以上のケノゾイク期の海洋堆積物サンプルから採取した試験サイズ分布の分析.
- 100万以上の個別のフォラミニフェラ菌の検査を調査した.
- ホロセンのサイズパターンを環境データで校正し,ケノゾーイク時代のパレオプロキシ記録と比較.
主要な成果:
- プランクトンフォラミニフェラの試験サイズと地表水層化の強度の間には一貫した正の相関が認められた.
- プランクトンのフォラミニフェラは,ケノゾーイク全体で試料の大きさを増加させるマクロ進化の傾向を示した.
- この大きさの増加は,極地の冷却によって引き起こされる,低緯度の地表水層分化の強化と相関していた.
結論:
- 観測されたプランクトンフォラミニフェラの試験サイズの増加は,海洋層分化の強化に対する適応的反応を表しています.
- 地球規模の極地冷却に関連した層分化の強化は,プランクトンのフォラミニフェラの進化に重要な役割を果たしました.
- プランクトンのフォラミニフェラにおけるテストサイズの進化は,過去の地表水条件と気候の動態のプロキシとして機能します.
関連する概念動画
Formation of Species
Speciation describes the formation of one or more new species from one or sometimes multiple original species. The resulting species are discrete from the parent species, and barriers to reproduction will typically exist. There are two primary mechanisms, speciation with and without geographic isolation—allopatric and sympatric speciation, respectively.Allopatric SpeciationIn allopatric speciation, gene flow between two populations of the same species is prevented by a geographic barrier, like...
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.
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...
Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
Diversity of Protists IV
Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...
Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...


