A challenge to the fossil record

  • #1
Pythagorean
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Following is a non-peer reviewed journalism. Is there merit to this?

The scientists say they were surprised when the results indicated the fossilized cell clusters were not animals or embryos. That is because it had long been thought that fossils showing this apparent pattern cell division represented the embryos of the earliest animals.

Instead, they say the finely detailed X-ray images exposed features pattern that led them to conclude the organisms were, “the reproductive spore bodies of single-celled ancestors of animals.”

Study co-author Phil Donoghue of Britain’s University of Bristol said the new results mean much of what has been written about the fossils for the last 10 years is “flat wrong.”


http://www.voanews.com/english/news...Fossils-Upend-Evolution-Theory-136172283.html
 

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  • #2
atyy
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http://www.sciencemag.org/content/334/6063/1696
Fossilized Nuclei and Germination Structures Identify Ediacaran “Animal Embryos” as Encysting Protists

Therese Huldtgren, John A. Cunningham, Chongyu Yin, Marco Stampanoni, Federica Marone, Philip C. J. Donoghue, Stefan Bengtson

Globular fossils showing palintomic cell cleavage in the Ediacaran Doushantuo Formation, China, are widely regarded as embryos of early metazoans, although metazoan synapomorphies, tissue differentiation, and associated juveniles or adults are lacking. We demonstrate using synchrotron-based x-ray tomographic microscopy that the fossils have features incompatible with multicellular metazoan embryos. The developmental pattern is comparable with nonmetazoan holozoans, including germination stages that preclude postcleavage embryology characteristic of metazoans. We conclude that these fossils are neither animals nor embryos. They belong outside crown-group Metazoa, within total-group Holozoa (the sister clade to Fungi that includes Metazoa, Choanoflagellata, and Mesomycetozoea) or perhaps on even more distant branches in the eukaryote tree. They represent an evolutionary grade in which palintomic cleavage served the function of producing propagules for dispersion.
 
  • #3
Pythagorean
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Integrating all that new terminology is not an easy task; the abstract seems to make the same challenge. But I still don't know what pitfalls might be associated with their analysis or what the community reaction is. We've had lots of neutrino's faster than light and higg's detections lately...
 
  • #4
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It was published in Science magazine which is a peer reviewed journal so I would say that yes it's very credible.
 
  • #5
Pythagorean
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It was published in Science magazine which is a peer reviewed journal so I would say that yes it's very credible.

I know Science and Nature are the holy grails of scientific publishing and all, but I don't think that's a good place to stop a critique.
 
  • #6
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I know Science and Nature are the holy grails of scientific publishing and all, but I don't think that's a good place to stop a critique.

I am not an expert on biology or morphology and apparently you aren't either. I'll leave it to the experts to decide what those organisms were.
 
  • #7
Andy Resnick
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Following is a non-peer reviewed journalism. Is there merit to this?

http://www.sciencemag.org/content/334/6063/1696
Fossilized Nuclei and Germination Structures Identify Ediacaran “Animal Embryos” as Encysting Protists

Integrating all that new terminology is not an easy task; the abstract seems to make the same challenge.

Yeesh.... terminology overload.

I needed to look up 'metazoan' (basically 'animal') and 'holozoan' (a superset of animals that excludes fungi and includes single-celled organisms). Then the sentence "Study co-author [...] said the new results mean much of what has been written about the fossils for the last 10 years is “flat wrong.” ", if taken to refer only the particular fossils under study, is not that extreme.

Basically, the fossils used to be interpreted in terms of early animal development and instead should be interpreted as “the reproductive spore bodies of single-celled ancestors of animals.”

At least that's my interpretation of the Science abstract (I can't get the full article at home).
 
  • #8
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A problem with the embryo identification of the Doushantuo fossils is the lack of better-developed embryos.

One can find some well-developed embryos in the fossil record, like the early Cambrian to early Ordovician worm Markuelia. Its closest relatives are the priapulids, kinorhynchs, and loriciferans, obscure seafloor worms. Priapulids are also known from the Cambrian: Ottoia.

PZ Myers has a nice discussion of this recent work in http://scienceblogs.com/pharyngula/2011/12/protists_not_animals.php [Broken], and he shows some pictures of them.
 
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  • #9
Evo
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A problem with the embryo identification of the Doushantuo fossils is the lack of better-developed embryos.

One can find some well-developed embryos in the fossil record, like the early Cambrian to early Ordovician worm Markuelia. Its closest relatives are the priapulids, kinorhynchs, and loriciferans, obscure seafloor worms. Priapulids are also known from the Cambrian: Ottoia.

PZ Myers has a nice discussion of this recent work in http://scienceblogs.com/pharyngula/2011/12/protists_not_animals.php [Broken], and he shows some pictures of them.
Thanks for the link!! I love PZ Meyers.
 
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  • #10
atyy
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Myers also discusses a Nature paper of 2006 by Bailey and colleagues that, while agreeing the fossils are not metazoan embryos, takes a completely different view.
 
  • #11
Moonbear
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As far as I can tell, it's not a challenge to THE fossil record, just to the identification of one particular fossil type. That's the nature of science, to adjust hypotheses as new evidence emerges.
 

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