<https://www.msn.com/en-us/news/technology/scientists-say-textbooks-are-wrong-about-the-origin-of-life/ar-AA1es4FE?ocid=hpmsn&cvid=49d4459279da4a03978f3b0298937286&ei=11>
<https://tinyurl.com/4zd3uxvw>
"Scientists Say Textbooks Are Wrong About the Origin of Life"
The above is an exaggeration. The topic isn't the origin of life, but
the origin of multicellular, complex, animal life during the Avalon Explosion.
The prevailing view is that the abundance of oxygen
accelerate the evolution of more complex life. However, a recent
study claims the world's oceans were anoxic during that time.
Here's a link to the article cited above:
<https://science.ku.dk/english/press/news/2023/life-on-earth-didnt-arise-as-described-in-textbooks/>
<https://tinyurl.com/2syt6kk5>
Here's a link to the abstract of the paper cited above:
<https://onlinelibrary.wiley.com/doi/10.1111/gbi.12557> *************************************************
Reconstructing the oxygenation history of Earth's oceans during the Ediacaran period (635 to 539 million years ago) has been challenging,
and this has led to a polarizing debate about the environmental
conditions that played host to the rise of animals. One focal point of
this debate is the largest negative inorganic C-isotope excursion
recognized in the geologic record, the Shuram excursion, and whether
this relic tracks the global-scale oxygenation of Earth's deep oceans.
[...]
Contrary to a classical hypothesis, our interpretations place the
Shuram excursion, and any coeval animal evolutionary events, in a predominantly anoxic global ocean. *****************************************************
The full text is paywalled.
An hypothesis is that free oxygen was produced and consumed locally, literally within millimeters of each other. If that were true, it
would allow for the evolution of oxygen-dependent organisms within a generally anoxic ocean.
I'm surprised that nobody, not even John Harshman or erik simpson,
has commented on your OP in the last 3+ days.
On Thursday, July 27, 2023 at 10:45:54?PM UTC-4, jillery wrote:
<https://www.msn.com/en-us/news/technology/scientists-say-textbooks-are-wrong-about-the-origin-of-life/ar-AA1es4FE?ocid=hpmsn&cvid=49d4459279da4a03978f3b0298937286&ei=11>
<https://tinyurl.com/4zd3uxvw>
"Scientists Say Textbooks Are Wrong About the Origin of Life"
The above is an exaggeration. The topic isn't the origin of life, but
the origin of multicellular, complex, animal life during the Avalon
Explosion.
Your first two sources date the Avalon Explosion in a
time span that does not even overlap the Ediacaran period:
"For decades now, the prevailing scientific theory explaining the Precambrian Avalon explosion — in short, the era dating back to about 685 to 800 million years ago in which multicellular organisms began to proliferate in Earth's oceans — has, putsimply, been that an influx of oxygen into Earth's oceans accelerated the evolution of more complex life, ultimately paving the way for our planet's biosphere as we know it." [*ibid*]
685 mya was about halfway into the Cryogenian period, that lasted from 720 to 635 million years ago,Mesoproterozoic Era and followed by the Cryogenian. ...The first putative metazoan (animal) fossils are dated to the middle to late Tonian (c. 890-800 Mya)."
the latter figure marking the beginning of the Ediacaran period. It was the second period in
the Neoproterozoic era.
--https://en.wikipedia.org/wiki/Cryogenian
The Ediacaran was the first period in the Phanerozoic Eon. It marks the end of the Proterozoic Eon.
--https://en.wikipedia.org/wiki/Ediacaran
IF the above dates are accurate, the Avalon Explosion straddles the Cryogenian and Tonian periods, with more of it in
the earlier of the two:
"The Tonian (from Ancient Greek: ?????, romanized: tónos, meaning "stretch") is the first geologic period of the Neoproterozoic Era. It lasted from 1000 to 720 Mya (million years ago). ... The Tonian is preceded by the Stenian Period of the
-- https://en.wikipedia.org/wiki/Tonian
However, there is a SERIOUS discrepancy between those dates and the one given by Wikipedia; see below:
The prevailing view is that the abundance of oxygen
accelerate the evolution of more complex life. However, a recent
study claims the world's oceans were anoxic during that time.
I don't think sponges would have needed much oxygen, if they were sessile all through their life cycle
back in anoxic times. Known fossils of actively moving animals date only back to near the end of the Ediacaran period.
Here's a link to the article cited above:
To be precise: the article cited by the webpage that you link above.
<https://science.ku.dk/english/press/news/2023/life-on-earth-didnt-arise-as-described-in-textbooks/>
<https://tinyurl.com/2syt6kk5>
A popularization in a less rigorous magazine than "Science."
The article that you are linking here is such a poor popularization, that it contains neither links nor references.
The webpage that popularizes it, that you first linked, uncritically repeats the dating of the first,Ediacara assemblage—the Avalon assemblage (575 to 565 Ma)—already encompassed the full range of Ediacara morphospace. A comparable morphospace range was occupied by the subsequent White Sea (560 to 550 Ma) and Nama (550 to 542 Ma) assemblages,
but it ALSO gives us a link to the following article:
The Avalon Explosion: Evolution of Ediacara Morphospace >https://www.science.org/doi/abs/10.1126/science.1150279
SCIENCE 4 Jan 2008 Vol 319, Issue 5859 pp. 81-84 DOI: 10.1126/science.1150279
This "SCIENCE" is the real McCoy, and despite its long-ago date,
it is *still* paywalled. However, the abstract totally contradicts the dating >of those two popularizations. Here is how it begins:
ABSTRACT
Ediacara fossils [575 to 542 million years ago (Ma)] represent Earth's oldest known complex macroscopic life forms, but their morphological history is poorly understood. A comprehensive quantitative analysis of these fossils indicates that the oldest
Here's a link to the abstract of the paper cited above:
There is no abstract in the paper that you cited above.
The paper you cite next is titled:
"Widespread seafloor anoxia during generation of the Ediacaran Shuram carbon isotope excursion"
<https://onlinelibrary.wiley.com/doi/10.1111/gbi.12557>
*************************************************
Reconstructing the oxygenation history of Earth's oceans during the
Ediacaran period (635 to 539 million years ago) has been challenging,
and this has led to a polarizing debate about the environmental
conditions that played host to the rise of animals. One focal point of
this debate is the largest negative inorganic C-isotope excursion
recognized in the geologic record, the Shuram excursion, and whether
this relic tracks the global-scale oxygenation of Earth's deep oceans.
[...]
Contrary to a classical hypothesis, our interpretations place the
Shuram excursion, and any coeval animal evolutionary events, in a
predominantly anoxic global ocean.
*****************************************************
The Shuram excursion was relatively brief -- around 573 to 562 million years ago --
and predates many of the Ediacaran biota. [See dates in the abstract I cited above.]
The full text is paywalled.
An hypothesis is that free oxygen was produced and consumed locally,
literally within millimeters of each other. If that were true, it
would allow for the evolution of oxygen-dependent organisms within a
generally anoxic ocean.
No mouthparts were even hinted at in any Ediacaran biota until the very atypical *Kimberella*:
"Specimens were first found in Australia's Ediacara Hills, but recent research has concentrated on the numerous finds near the White Sea in Russia, which cover an interval of time from 555 to 558 million years ago.[2]"
-- https://en.wikipedia.org/wiki/Kimberella
I could not find dates for the Australian fossils anywhere. Anyway, there
is a hypothesis that the typical Ediacaran biota got their nourishment
from symbiotic bacteria, like the huge tube worms of today in deep ocean vents.
On Mon, 31 Jul 2023 08:12:26 -0700 (PDT), "peter2...@gmail.com" <peter2...@gmail.com> wrote:
I'm surprised that nobody, not even John Harshman or erik simpson,I'm not at all surprised. Now that you reposted it, perhaps someone
has commented on your OP in the last 3+ days.
complain about my typos.
On Thursday, July 27, 2023 at 10:45:54?PM UTC-4, jillery wrote:
<https://www.msn.com/en-us/news/technology/scientists-say-textbooks-are-wrong-about-the-origin-of-life/ar-AA1es4FE?ocid=hpmsn&cvid=49d4459279da4a03978f3b0298937286&ei=11>
<https://tinyurl.com/4zd3uxvw>
"Scientists Say Textbooks Are Wrong About the Origin of Life"
The above is an exaggeration. The topic isn't the origin of life, but
the origin of multicellular, complex, animal life during the Avalon
Explosion.
Your first two sources date the Avalon Explosion in a
time span that does not even overlap the Ediacaran period:
The above are links to the the *same* source.
The second mitigates
any wordwrap issues with the first. I have provided such duplicates
for many years.
simply, been that an influx of oxygen into Earth's oceans accelerated the evolution of more complex life, ultimately paving the way for our planet's biosphere as we know it." [*ibid*]"For decades now, the prevailing scientific theory explaining the Precambrian Avalon explosion — in short, the era dating back to about 685 to 800 million years ago in which multicellular organisms began to proliferate in Earth's oceans — has, put
Mesoproterozoic Era and followed by the Cryogenian. ...The first putative metazoan (animal) fossils are dated to the middle to late Tonian (c. 890-800 Mya)."685 mya was about halfway into the Cryogenian period, that lasted from 720 to 635 million years ago,
the latter figure marking the beginning of the Ediacaran period. It was the second period in
the Neoproterozoic era.
--https://en.wikipedia.org/wiki/Cryogenian
The Ediacaran was the first period in the Phanerozoic Eon. It marks the end of the Proterozoic Eon.
--https://en.wikipedia.org/wiki/Ediacaran
IF the above dates are accurate, the Avalon Explosion straddles the Cryogenian and Tonian periods, with more of it in
the earlier of the two:
"The Tonian (from Ancient Greek: ?????, romanized: tónos, meaning "stretch") is the first geologic period of the Neoproterozoic Era. It lasted from 1000 to 720 Mya (million years ago). ... The Tonian is preceded by the Stenian Period of the
-- https://en.wikipedia.org/wiki/Tonian
However, there is a SERIOUS discrepancy between those dates and the one given by Wikipedia; see below:
The prevailing view is that the abundance of oxygen
accelerate the evolution of more complex life. However, a recent
study claims the world's oceans were anoxic during that time.
I don't think sponges would have needed much oxygen, if they were sessile all through their life cycle
back in anoxic times. Known fossils of actively moving animals date only back to near the end of the Ediacaran period.
Here's a link to the article cited above:
To be precise: the article cited by the webpage that you link above.
The "webpage" is a web *article*, analogous to magazine articles, in contrast to webpages that for example help sell online junk.
<https://science.ku.dk/english/press/news/2023/life-on-earth-didnt-arise-as-described-in-textbooks/>
<https://tinyurl.com/2syt6kk5>
A popularization in a less rigorous magazine than "Science."
The article that you are linking here is such a poor popularization, that it contains neither links nor references.
Which is one reason why I also cited the link to the cited paper foundEdiacara assemblage—the Avalon assemblage (575 to 565 Ma)—already encompassed the full range of Ediacara morphospace. A comparable morphospace range was occupied by the subsequent White Sea (560 to 550 Ma) and Nama (550 to 542 Ma) assemblages,
in the article I cited.
The webpage that popularizes it, that you first linked, uncritically repeats the dating of the first,
but it ALSO gives us a link to the following article:
The Avalon Explosion: Evolution of Ediacara Morphospace >https://www.science.org/doi/abs/10.1126/science.1150279
SCIENCE 4 Jan 2008 Vol 319, Issue 5859 pp. 81-84 DOI: 10.1126/science.1150279
This "SCIENCE" is the real McCoy, and despite its long-ago date,
it is *still* paywalled. However, the abstract totally contradicts the dating
of those two popularizations. Here is how it begins:
ABSTRACT
Ediacara fossils [575 to 542 million years ago (Ma)] represent Earth's oldest known complex macroscopic life forms, but their morphological history is poorly understood. A comprehensive quantitative analysis of these fossils indicates that the oldest
Here's a link to the abstract of the paper cited above:
There is no abstract in the paper that you cited above.
The paper is cited in the article I cited above. The abstract is in
the paper. Articles almost never have abstracts.
The paper you cite next is titled:
"Widespread seafloor anoxia during generation of the Ediacaran Shuram carbon isotope excursion"
And this is the abstract of the paper cited above:
<https://onlinelibrary.wiley.com/doi/10.1111/gbi.12557>
*************************************************
Reconstructing the oxygenation history of Earth's oceans during the
Ediacaran period (635 to 539 million years ago) has been challenging,
and this has led to a polarizing debate about the environmental
conditions that played host to the rise of animals. One focal point of
this debate is the largest negative inorganic C-isotope excursion
recognized in the geologic record, the Shuram excursion, and whether
this relic tracks the global-scale oxygenation of Earth's deep oceans.
[...]
Contrary to a classical hypothesis, our interpretations place the
Shuram excursion, and any coeval animal evolutionary events, in a
predominantly anoxic global ocean.
*****************************************************
The Shuram excursion was relatively brief -- around 573 to 562 million years ago --
and predates many of the Ediacaran biota. [See dates in the abstract I cited above.]
That's exactly what you should expect for biota that precedes the
Ediacaran.
The full text is paywalled.
An hypothesis is that free oxygen was produced and consumed locally,
literally within millimeters of each other. If that were true, it
would allow for the evolution of oxygen-dependent organisms within a
generally anoxic ocean.
No mouthparts were even hinted at in any Ediacaran biota until the very atypical *Kimberella*:
Mouthparts? Consuming oxygen don't need no steekin' mouthparts.
"Specimens were first found in Australia's Ediacara Hills, but recent research has concentrated on the numerous finds near the White Sea in Russia, which cover an interval of time from 555 to 558 million years ago.[2]"
-- https://en.wikipedia.org/wiki/Kimberella
I could not find dates for the Australian fossils anywhere. Anyway, there
is a hypothesis that the typical Ediacaran biota got their nourishment >from symbiotic bacteria, like the huge tube worms of today in deep ocean vents.
The hypothesis to which I refer above I first read in a book by Nick
Lane, either "The Vital Question" or "Oxygen".
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