Morphological and ecological complexity in early eukaryotic ecosystems

  title={Morphological and ecological complexity in early eukaryotic ecosystems},
  author={Emmanuelle J Javaux and Andrew H. Knoll and Malcolm R. Walter},
Molecular phylogeny and biogeochemistry indicate that eukaryotes differentiated early in Earth history. Sequence comparisons of small-subunit ribosomal RNA genes suggest a deep evolutionary divergence of Eukarya and Archaea; C27–C29 steranes (derived from sterols synthesized by eukaryotes) and strong depletion of 13C (a biogeochemical signature of methanogenic Archaea) in 2,700 Myr old kerogens independently place a minimum age on this split. Steranes, large spheroidal microfossils, and rare… 

Paleobiological perspectives on early eukaryotic evolution.

  • A. Knoll
  • Geography, Biology
    Cold Spring Harbor perspectives in biology
  • 2014
Protists continued to diversify along with animals in the more pervasively oxygenated oceans of the Phanerozoic Eon, and the Mid-Neoproterozoic establishment or expansion of eukaryophagy provides a possible mechanism for accelerating eUKaryotic diversification long after the origin of the domain.

Eukaryotic organisms in Proterozoic oceans

Focus on character evolution permits inferences about the innovations in cell biology and development that underpin the taxonomic and morphological diversification of eukaryotic organisms.

Shale-hosted biota from the Dismal Lakes Group in Arctic Canada supports an early Mesoproterozoic diversification of eukaryotes

Abstract. The Mesoproterozoic is an important era for the development of eukaryotic organisms in oceans. The earliest unambiguous eukaryotic microfossils are reported in late Paleoproterozoic shales

Micropaleontology of the lower Mesoproterozoic Roper Group, Australia, and implications for early eukaryotic evolution

Roper fossils provide direct or inferential evidence for many basic features of eukaryotic biology, including a dynamic cytoskeleton and membrane system that enabled cells to change shape, life cycles that include resting cysts coated by decay-resistant biopolymers, reproduction by budding and binary division, osmotrophy, and simple multicellularity.

TEM evidence for eukaryotic diversity in mid‐Proterozoic oceans

Biomarker molecular fossils in 2770 Ma shales suggest that the Eucarya diverged from other principal domains early in Earth history. Nonetheless, at present, the oldest fossils that can be assigned

Recognizing and Interpreting the Fossils of Early Eukaryotes

Recognition of eukaryotic fossils in Proterozoic rocks is key to the integration of geological and comparative biological perspectives on protistan evolution.

The early eukaryotic fossil record.

  • E. Javaux
  • Geography, Environmental Science
    Advances in experimental medicine and biology
  • 2007
The record of biological innovations documented by the fossils shows that eukaryotes had evolved most cytological and molecular complexities very early in the Proterozoic but environmental conditions delayed their diversification within clades until oxygen level and predation pressure increased significantly.

Estimating the timing of early eukaryotic diversification with multigene molecular clocks

Taxon-rich multigene data combined with diverse fossils and a relaxed molecular clock framework are used to estimate the timing of the last common ancestor of extant eukaryotes and the divergence of major clades, suggesting that long stems preceded diversification in the major eUKaryotic lineages.

Origin and early evolution of photosynthetic eukaryotes in freshwater environments: reinterpreting proterozoic paleobiology and biogeochemical processes in light of trait evolution

  • C. Blank
  • Environmental Science
    Journal of phycology
  • 2013
It is proposed that early photosynthetic eukaryotes may have never experienced the widespread anoxia or euxinia suggested to have characterized marine environments in the Paleoproterozoic to early MesoproTerozoic, and that earliest acritarchs may have been produced by freshwater taxa.



Archean molecular fossils and the early rise of eukaryotes.

The presence of steranes, particularly cholestane and its 28- to 30-carbon analogs, provides persuasive evidence for the existence of eukaryotes 500 million to 1 billion years before the extant fossil record indicates that the lineage arose.

Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya.

It is proposed that a formal system of organisms be established in which above the level of kingdom there exists a new taxon called a "domain." Life on this planet would be seen as comprising three domains, the Bacteria, the Archaea, and the Eucarya, each containing two or more kingdoms.

Megascopic eukaryotic algae from the 2.1-billion-year-old negaunee iron-formation, Michigan.

Hundreds of specimens of spirally coiled, megascopic, carbonaceous fossils resembling Grypania spiralis (Walcott), have been found in the 2.1-billion-year-old Negaunee Iron-Formation at the Empire Mine, near Marquette, Michigan, placing the origin of organelle-bearing eukaryotic cells prior to 2.

Early life on earth

This study is organized around three themes: the origin and early diversification of life during the Archean Eon; the maturation of life and the Earth during the long Proterozoic Eon; and the

A new model for Proterozoic ocean chemistry

There was a significant oxidation of the Earth's surface around 2 billion years ago (2 Gyr). Direct evidence for this oxidation comes, mostly, from geological records of the redox-sensitive elements

Clastic facies microfossils from the Chuanlinggou Formation (1800 Ma) near Jixian, North China

  • Zhang Zhongying
  • Geography, Environmental Science
    Journal of Micropalaeontology
  • 1986
Abundant organic-walled microfossils are well preserved in petrographic thin sections of shales from the c. 1800 Ma old Chuanlinggou Formation (Changchengian System) near Jixian, North China. The