نتایج جستجو برای: microfossils

تعداد نتایج: 531  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2000
S Xiao X Yuan A H Knoll

Phosphatic sedimentary rocks preserve a record of early animal life different from and complementary to that provided by Ediacaran fossils in terminal Proterozoic sandstones and shales. Phosphorites of the Doushantuo Formation, South China, contain eggs, egg cases, and stereoblastulae that document animals of unspecified phylogenetic position; small fossils containing putative spicules may spec...

2017
Tara Djokic Martin J. Van Kranendonk Kathleen A. Campbell Malcolm R. Walter Colin R. Ward

The ca. 3.48 Ga Dresser Formation, Pilbara Craton, Western Australia, is well known for hosting some of Earth's earliest convincing evidence of life (stromatolites, fractionated sulfur/carbon isotopes, microfossils) within a dynamic, low-eruptive volcanic caldera affected by voluminous hydrothermal fluid circulation. However, missing from the caldera model were surface manifestations of the vol...

2004
E. E Stoermer M. B. Edlund C. H. Pilskaln

Examination of surficial sediments at 16 stations shows minor, but consistent differences in the numbers and kinds of siliceous microfossils deposited in different regions of Lake Baikal. There is a general north-south decreasing trend in total microfossil abundance on a weight basis. Endemic plankton diatom species are the most abundant component of assemblages at all stations. Chrysophyte cys...

2017
Michael Siccha Michal Kucera

Census counts of marine microfossils in surface sediments represent an invaluable resource for paleoceanography and for the investigation of macroecological processes. A prerequisite for such applications is the provision of data syntheses for individual microfossil groups. Specific to such syntheses is the necessity of taxonomical harmonisation across the constituent datasets, coupled with der...

Journal: :Critical reviews in microbiology 2007
Elena V Pikuta Richard B Hoover Jane Tang

Prokaryotic extremophiles were the first representatives of life on Earth and they are responsible for the genesis of geological structures during the evolution and creation of all currently known ecosystems. Flexibility of the genome probably allowed life to adapt to a wide spectrum of extreme environments. As a result, modern prokaryotic diversity formed in a framework of physico-chemical fac...

Journal: :Palaios 1996
M R Walter D Desmarais J D Farmer N W Hinman

The Devonian to Carboniferous sinters of the Drummond Basin, Australia, are among the oldest well established examples of fossil subaerial hot springs. Numerous subaerial and subaqueous spring deposits are known from the geological record as a result of the occurrence of economic mineral deposits in many of them. Some are reported to contain fossils, but very few have been studied by paleobio...

2014
Xianguang Hou Mark Williams David J. Siveter Derek J. Siveter Sarah Gabbott David Holwell Thomas H. P. Harvey

Nidelric pugio gen. et sp. nov. from the Cambrian Series 2 Heilinpu Formation, Chengjiang Lagerstätte, Yunnan Province, China, is an ovoid, sac-like metazoan that bears single-element spines on its surface. N. pugio shows no trace of a gut, coelom, anterior differentiation, appendages, or internal organs that would suggest a bilateral body plan. Instead, the sac-like morphology invites comparis...

2015
Xiaoyan Yang Dorian Q Fuller Xiujia Huan Linda Perry Quan Li Zhao Li Jianping Zhang Zhikun Ma Yijie Zhuang Leping Jiang Yong Ge Houyuan Lu

Rice (Oryza sativa) is regarded as the only grass that was selected for cultivation and eventual domestication in the Yangtze basin of China. Although both macro-fossils and micro-fossils of rice have been recovered from the Early Neolithic site of Shangshan, dating to more than 10,000 years before present (BP), we report evidence of phytolith and starch microfossils taken from stone tools, bot...

Journal: :BioEssays : news and reviews in molecular, cellular and developmental biology 2000
D E Ingber

This essay presents a scenario of the origin of life that is based on analysis of biological architecture and mechanical design at the microstructural level. My thesis is that the same architectural and energetic constraints that shape cells today also guided the evolution of the first cells and that the molecular scaffolds that support solid-phase biochemistry in modern cells represent living ...

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