Journal ArticleDOI
Precambrian micro‐organisms and evolutionary events prior to the origin of vascular plants
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The nature of the early Palaeozoic life was a fertile subject for speculation as mentioned in this paper, however, evidence of this development remained largely undeciphered ; the nature of Precambrian life was also fertile subject to speculation.Abstract:
The nature of the Precambrian biota-its antiquity. composition and evolutionand the well-known faunal discontinuity near the beginning of the Palaeozoic. have long been recognized as particularly puzzling problems in palaeontology . The evolutionary continuum well-documented in Phanerozoic sediments and the diversity and complexity of the early Palaeozoic biota augur well for a substantial period of Precambrian evolutionary development . Until recently. however. evidence of this development remained largely undeciphered ; the nature of Precambrian life was a fertile subject for speculation. essentially unfettered by the poorly known fossil record . The past few years have witnessed a renewed interest in these classic problems and a marked proliferation of available data; this increased activity has resulted in theread more
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Thermodynamics of heterogeneous iron—Carbon systems: Implications for the terrestrial primitive reducing atmosphere
TL;DR: In this paper, it was shown that the primary source of carbon for biochemical genesis on the early earth was CO 2 and the fundamental chemical process was reduction by ferrous ion in the primitive ocean, for which radiation was required as an initiator but not as a source of free energy.
Journal ArticleDOI
Alkyl substituted cyclic ethers in 2,300 M yr old Transvaal algal stromatolite
TL;DR: Two cyclic ethers have been identified from insoluble polymer-like kerogen in a Precambrian rock by ozonolysis, gas chromatography, and mass spectrometry.
Journal ArticleDOI
Environmental parameters for the origin of life
TL;DR: It is suggested that the carbonaceous chondrites represent relics of such a protoplanetary phase and record five successive environments with a generally decreasing but fluctuating temperature range as mentioned in this paper.
Book ChapterDOI
Hydromedusan Photophysiology: An Evolutionary Perspective
TL;DR: For many groups of simple invertebrates, and particularly cnidarians, there has been insufficient information to begin to examine the correlation between the degree of structural complexity and photoreceptor function, revealed either by its photophysiology or by the behavior of the animal.
Book ChapterDOI
Modes and Tempos of Mitochondrial and Chloroplast Genome Evolution in Chlamydomonas : A Comparative Analysis
Aurora M. Nedelcu,Robert W. Lee +1 more
TL;DR: The level of ribosomal RNA gene sequence divergence in both mitochondrial and chloroplast genomes is higher in the Chlamydomonas lineage than in land plants and is most likely due to higher rates of nucleotide substitution in ChlamYDomonas organellar DNAs.
References
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Journal ArticleDOI
Microorganisms from the Gunflint Chert: These structurally preserved Precambrian fossils from Ontario are the most ancient organisms known.
Journal ArticleDOI
Carbon isotope fractionation during photosynthesis
R. Park,Samuel Epstein +1 more
TL;DR: In this paper, a study was made of the reasons for isotopic fractionation in photosynthesis and various factors controlling it, and the effects of high light intensities on the fractionation factors of photosynthesis were studied.
Journal Article
Microflora of the Bitter Springs Formation, late Precambrian, central Australia
TL;DR: In this article, 30 new species, representing 24 new genera, of green algae, blue-green algae, colonial bacteria, fungus-like filaments, and possible pyrrophytes, are described from the bedded carbonaceous cherts of the late Precambrian Bitter Springs formation, Ross river area, central Australia.
Journal ArticleDOI
Metabolic fractionation of C13 & C12 in plants
Roderic Park,Samuel Epstein +1 more
TL;DR: Analysis of chemical fractions from several plant phyla show that in all cases the lipid fraction is enriched in C/sup 12/ compared to the whole plant, which may be explained if selective preservation of plant lipids occurred during the sedimentation process.
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Microorganisms from the Gunflint Chert: These structurally preserved Precambrian fossils from Ontario are the most ancient organisms known.
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