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Topic: Ediacaran


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In the News (Sun 24 Mar 19)

  
  BBC NEWS | Science/Nature | Geological time gets a new period   (Site not responding. Last check: 2007-10-11)
The Ediacaran begins at the end of the last ice age of the Snowball Earth, or Cryogenian Period, a term given to a series of glaciations that covered most of our planet between 850-630 or 600 million years ago.
Professor Ogg said many of the new life forms that appeared in the Ediacaran seem to be simple organisms, probably related to present-day sponges.
The Enorama Creek section of Flinders was designated the "boundary stratotype" for the Ediacaran by the Terminal Proterozoic Period subcommission.
news.bbc.co.uk /1/hi/sci/tech/3721481.stm   (567 words)

  
 Qwika - similar:Ediacaran
Ediacaran period Geologic timescale of the Precambrian (millions of years ago) ImageSize = width:175 height:355 PlotArea = left:40 right:5 bottom:135 top:45 AlignBars = justify Period = from:542 till:670 TimeAxis = orientation:vertical ScaleMajor = unit:year increment:25 start:550 ScaleMinor = unit:year increment:10 start:550 Colors = id:eon value:r...
Kimberella quadrata is a fossil animal from the Ediacaran or Vendian fauna.
Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years An ice age is a period of long-term downturn in the temperature of Earth's climate, resulting in an expansion of the continental ice sheets, polar ice sheets and mountain glaciers ("glaciation").
www.qwika.com /rels/Ediacaran   (1497 words)

  
 The Talk.Origins Archive Post of the Month: December 1997
In almost all cases, metazoan >>fossils of Ediacaran age are of the impressions of organisms (usually in >>sandstone).
In South Australia, the first Ediacaran fossils occur in eroded channels, suggesting a period of erosion and lower sea level prior to the deposition of fossil-bearing sediments.
The Ediacaran fauna appears to contain organisms with a cnidarian-grade of organisation, as well as the more derived, bilaterally symmetric, triploblasic annelid-grade, arthropod-grade and probably mollusc-grade.
www.talkorigins.org /origins/postmonth/dec97.html   (1291 words)

  
 Anatomical information content in the ediacaran fossils and their possible zoological affinities1 Integrative and ...   (Site not responding. Last check: 2007-10-11)
Various modes of preservation of Ediacaran fossils in different sediments, quartz sand at Zimnie Gory in northern Russia and lime mud at Khorbusuonka in northern Yakutia, show that the sediment was liquid long after formation of the imprints and that its mineralogy did not matter.
Vagile Ediacaran organisms belong mostly to the Dipleurozoa (somewhat resembling chordates and nemerteans), characterized by a segmented dorsal hydraulic skeleton, intestine with metameric caeca, and serial gonads.
The dominant view is that the bodies of Ediacaran organisms were extremely flat and lying on the sea bottom (e.g., Runnegar, 1991) or immersed in the sediment (e.g., Seilacher, 1999).
www.findarticles.com /p/articles/mi_qa4054/is_200302/ai_n9184771   (1081 words)

  
 The Ediacaran Assemblage
Ediacarans are a diverse group and earlier attempts to pidgeon-hole them into a limited number of phylogenetic types appear now to have been misguided.
The oldest of the diverse Ediacaran assemblages yet described is that from Mistaken Point, eastern Newfoundland, where fossils are spectacularly preserved on large bedding surfaces along the sea-cliffs of the Avalon Peninsula.
It is biogeochemistry that lends substance to the hypothesis that Ediacaran and Cambrian faunas are separated by mass extinction" (Knoll and Carroll 1999, p.
www.peripatus.gen.nz /paleontology/Ediacara.html   (7472 words)

  
 News in Science - You say Ediacaran, I say Vendian - 20/05/2004
Ediacaran expert Dr Mikhail Fedonkin of the Paleontological Institute of the Russian Academy of Sciences said the fauna are the oldest known community of animals.
Australian geologist Professor Malcolm Walter of Macquarie University was vice-chair of the ICS subcommittee that debated the issue and voted in favour of the decision.
He said the naming was based on the fact that the most distinctive fauna of the period was called the Ediacaran fauna, the jellyfish and the worms.
www.abc.net.au /science/news/stories/2004/1112450.htm   (851 words)

  
 The Ediacarans (aka The Vendians)   (Site not responding. Last check: 2007-10-11)
The Ediacarans lived some 565 million to 543 million years ago (right up to the beginning of the Cambrian era), yet were first discovered only 50 years ago and were named after the Australian mining area where they were first found.
Most scientists agree that the Ediacarans were the first multicelled animals to exist, a sort of experiment by nature (the first of many) to see what sort of new life could be cooked up after four billion years of algae, bacteria, and other one- celled organisms.
Many believe that the Ediacaran fauna were the precursors to the Cambrian fauna, and simply evolved into the Cambrian organisms.
library.thinkquest.org /3017/ediacaran.htm   (532 words)

  
 Ediacaran Period - Crystalinks
The Ediacaran Period is the last geological period of the Neoproterozoic Era, just before the Cambrian.
Unusual soft bodied fossils do occur in the Ediacaran Period, but these are limited to the latter parts of the Period, after about 580 million years ago.
Rather, the beginning is defined by the appearance of a new texturally and chemically distinctive carbonate layer that indicates a climatic change (the end of a global ice age).
www.crystalinks.com /edicaran.html   (1158 words)

  
 Past lives: Chronicles of Canadian Paleontology - An Ediacaran Pompeii   (Site not responding. Last check: 2007-10-11)
These imprints are the oldest Ediacaran fossils known in the world and the only ones that lived in deep water.
Ediacaran fossils were first discovered in the Flinders Range, South Australia in coarse sandstones lying beneath rocks with the first shelly fossils of Early Cambrian age.
Instead he interpreted the Ediacarans as unique quilted and immobile organisms constructed as a series of fluid- or jelly-filled cells -- like air-mattresses -- that must have absorbed sunlight and nutrients directly from seawater through their skin.
gsc.nrcan.gc.ca /paleochron/06_e.php   (516 words)

  
 Introduction to the Ediacaran Fauna
The Ediacaran fauna (pronounced edi-akran) is a Precambrian(Neoproterozoic) assemblage, which existed from about 600 million years ago to approx 545 million year [Note: the new timescale for the Cambrian has the Period dominated by the Lower Cambrian and the whole timespan has been reduced to approx.
Recent finds of 'sea-pen'-like organisms in the Burgess Shale, which are very similar to Ediacaran forms appears to extend the range of such forms well into the Cambrian.
Of 7 cnidarian divisions represented in the Ediacaran fauna, 4 appear to be anscestral to living taxa.
members.tripod.com /~Cambrian/IntrotoEdiacaran   (1889 words)

  
 Geoscience Australia: AusGeo News 80 - The ‘New' Ediacaran Period
The Ediacaran Period is the first period-level interval of geological time to be created in the Standard Global Chronostratigraphic Scale for well over 100 years.
The Ediacaran is perhaps most famous for its association with the Ediacara biota (figure 2), a peculiar group of organisms, many of which are of uncertain affinity.
Ediacaran assemblages in the Centralian Superbasin and Adelaide Rift Complex are taxonomically diverse, with two palynofloras and five assemblage zones recognised (figure 4).
www.ga.gov.au /ausgeonews/ausgeonews200512/timescales.jsp   (1218 words)

  
 Geotimes - September 2004 - Ediacaran fossil up close   (Site not responding. Last check: 2007-10-11)
The longest fossil from the site is 7 centimeters, but Ediacaran organisms are known to have reached 2 meters in length.
These fossils, many of which vaguely resemble spindles and flattened feathers, are part of a distinctive fossil assemblage known as the Ediacaran biota: They represent the oldest large and complex organisms and ecosystems in Earth history, Narbonne says.
Ediacaran fossils have been found in several sites around the world, but because the animals were soft-bodied creatures, the fossil evidence is scarce and little is known about them.
www.geotimes.org /sept04/NN_ediacaranfossil.html   (311 words)

  
 B16: The History of Life: Source Book
Thus, we have Ediacaran jellyfish, corals, and worms -a continuity of evolutionary relationship across the greatest of all geological boundaries.
Dolf began by showing that the similarities of Ediacaran and modern animals are misleading and superficial, and that the Ediacaran forms could not work as their supposed living counterparts.
The Ediacaran "worms" are segmented and bilaterally symmetrical like their supposed modern analogues, but so are many other creatures--and such a basic and repeatable architecture need not imply close relationship.
www.sjgarchive.org /library/text/b16/p0294.htm   (654 words)

  
 EVOLUTIONARY BIOLOGY: ON THE EDIACARAN ENIGMA
Ediacaran forms once thought to be "jellyfish" by Glaessner (1984) have been reinterpreted as the attachment discs of fernlike fronds.
The term "Ediacaran" refers to an assemblage (until recently the oldest) of soft-bodied marine animals, the assemblage first discovered in the Ediacara Hills in Australia.
Although the recent discoveries of Ediacaran metazoans have extended the record of sponges and bilateral animals to 570 million years ago, the biological affinities of many Ediacaran organisms remains controversial.
scienceweek.com /2004/sb041029-4.htm   (1571 words)

  
 Astrobiology Research: Evolution of Biological Complexity
Ediacaran organisms have been biologically enigmatic since they were first discovered (and thought to be pseudofossils) in Newfoundland during the 19th century (Gehling et al.
Ediacaran fossils are no longer limited to single stratigraphic horizons that are isolated by unfossiliferous strata from the succeeding Cambrian explosion.
In Newfoundland, for example, Ediacaran fossils have been found beneath virtually every volcanic ash layer (~65 in all) over some 2.5 km of stratigraphic thickness (Narbonne and Gehling 2003).
www.astrobiology.ucla.edu /pages/res4c.html   (1261 words)

  
 B16: The History of Life: Source Book
In conventional reconstructions of Ediacaran animals, they are depicted as the ancestors of modern forms--jellyfish, soft corals, and worms.
Be that as it may, the important point remains that if Seilacher is right, the Ediacaran fauna represents a different, unique, and coherent experiment in organic architecture--not a set of precursors for modern animals.
As for the theme of mass extinctions, we used to say that the first era boundary, between Precambrian and Paleozoic some 570 million years ago, was an anomaly marked by a profound radiation (the Cambrian explosion) but no previous extinction.
www.sjgarchive.org /library/text/b16/p0295.htm   (461 words)

  
 Anatomical Information Content in the Ediacaran Fossils and Their Possible Zoological Affinities -- Dzik 43 (1): 114 -- ...
faunal diversity is represented in the Ediacaran biota.
The preservation of Ediacaran fossils in limestone in the Khatyspyt
Gehling, J. The case for Ediacaran fossil roots to the metazoan tree.
icb.oxfordjournals.org /cgi/content/full/43/1/114   (5685 words)

  
 PALEONTOLOGY: ON EDIACARANS
Ediacarans appear in the latest Precambrian, towards the end of the Neoproterozoic, ranging between ca.
Through some eyes the Ediacaran sea-floor was also host to molluscs and arthropods, but none of these interpretations seems acceptable.
Maybe the Ediacarans were a parallel attempt at achieving a metazoan grade of organization, but where they fit into eukaryote phylogeny is largely guesswork.
scienceweek.com /2005/sw050325-2.htm   (1488 words)

  
 The Ediacaran Biotas in Space and Time -- Waggoner 43 (1): 104 -- Integrative and Comparative Biology
The "frondlike" Ediacaran taxa, and to a lesser
A biota of Ediacaran aspect from lower Cambrian strata on the Digermul Peninsula, arctic Norway.
Ediacaran remains from intertillite beds in northwestern Canada.
icb.oxfordjournals.org /cgi/content/full/43/1/104   (4478 words)

  
 Mark McMenamin Unveils New Theory   (Site not responding. Last check: 2007-10-11)
The Ediacaran organisms are a curious group of thousands of fossil specimens, known from rocks over a half billion years old located throughout the world.
Using his specimens from Mexico (which include the oldest Ediacarans known), McMenamin is now able to organize all known Ediacaran fossils based on the number of early cell divisions seen in each type of organism.
He hypothesizes that, unlike animals, Ediacarans never went through a blastula stage (an embryonic hollow ball of cells), but rather went directly from a one-, two-, three-, four-, or five-cell stage to a larger size.
www.mtholyoke.edu /offices/comm/csj/971017/theory.html   (485 words)

  
 Ediacaran Animals
Ediacaran reefs (formed by stromatolites) in the Ediacaran area near Adelaide, Australia.
Gehling comes across as a complete idiot in the quotes he is alleged to have made, though he is a respected worker on Ediacaran fossils.
Even if you'd like to have an explicit description of evolution, it's incredibly difficult to pin down which of the array of possible heterochronic changes actually took place in evolution, even in individual fossil creatures that lay down growth-lines to help us understand their growth (molluscs, or brachiopods).
www.geology.ucdavis.edu /~cowen/HistoryofLife/ediacarans.html   (682 words)

  
 Ediacaran Survivors
The following list of Ediacaran Survivors is drawn from references I have come across in the course of preparing a general account of the Ediacaran biota.
Crimes, T.P.; Insole, A.; Williams, B.P.J. A rigid-bodied Ediacaran biota from Upper Cambrian strata in Co. Wexford, Eire.
Gehling, James G. The case for Ediacaran fossil roots to the metazoan tree.
www.peripatus.gen.nz /Paleontology/EdiSur.html   (431 words)

  
 Ediacaran period
The Ediacaran is named after the Ediacara Hills, just west of the Flinders Ranges in South Australia, where peculiar fossils were found in the 1940s.
Later it was realized that examples had been reported earlier on other continents.
The Ediacaran is relevant to the search for extraterrestrial life because conditions similar to Snowball Earth might exist elsewhere in the solar system.
www.daviddarling.info /encyclopedia/E/Ediacaran_period.html   (205 words)

  
 The Cambrian Explosion Remains an Enigma for Organic Evolution
These organisms, from the so- called Ediacaran fauna, named after the town of Ediacara in southern Australia where their fossil remains were discovered in 1947, are said to be 600 million years old.
But Ediacaran fossils, Retallack observes, "were as compaction resistant as some kinds of fossil tree trunks!" If the Ediacaran forms were not animals, therefore, but lichens composed of sturdy molecules like chitin, their resistance to compaction would be much easier to explain.
Furthermore, Ediacaran organisms could be quite large: up to 1 meter across, in some instances.
www.rae.org /cambrian.html   (589 words)

  
 Spectacular fossils from the Ediacaran Period   (Site not responding. Last check: 2007-10-11)
Although the rangeomorphs appear to have dominated life during the middle Ediacaran, they are rare in the later Ediacaran, and have not been observed in Cambrian and younger rocks.
Narbonne suggests that they are a "forgotten" clade that is not related to or analagous to any more modern phylum.
The Ediacaran is now a Period in its own right, the first to be added to the Geological Time Scale in 120 years.
www.mala.bc.ca /~earles/ediacara-period-aug04.htm   (508 words)

  
 Matthew Clapham   (Site not responding. Last check: 2007-10-11)
The field area in the Mistaken Point Ecological Reserve includes the oldest-known Ediacaran communities, preserved as they appeared during life over 565 million years ago.
This research showed that Ediacaran communities possessed the same vertical tiering structure as Phanerozoic communities.
These deep slope communities also had similar diversity and spatial interactions as modern slope communities and were affected by many of the same processes, including ecological succession.
earth.usc.edu /research/paleolab/matthew_clapham.htm   (805 words)

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