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Confirmed Oldest Fossils Show That Life Must Have Formed Very Early

Started by Recusant, December 19, 2017, 04:48:53 PM

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Recusant

I think the inference that these fossils show that life is likely very common in the Universe (2nd article below) is stretching things somewhat, but this finding is nonetheless important.

"Oldest fossils ever found show life on Earth began before 3.5 billion years ago" | ScienceDaily

Quote

An example of one of the microfossils discovered in a sample of rock recovered from the Apex Chert, a rock formation in western Australia that is among the oldest and best-preserved rock deposits in the world. The fossils were first described in 1993 but a 2017 study published by UCLA and UW-Madison scientists used sophisticated chemical analysis to confirm the microscopic structures found in the rock are indeed biological, rendering them -- at 3.5 billion years -- the oldest fossils yet found.
Credit: J. William Schopf, UCLA





Researchers at UCLA and the University of Wisconsin-Madison have confirmed that microscopic fossils discovered in a nearly 3.5 billion-year-old piece of rock in Western Australia are the oldest fossils ever found and indeed the earliest direct evidence of life on Earth.

The study, published today in the Proceedings of the National Academy of Sciences, was led by J. William Schopf, professor of paleobiology at UCLA, and John W. Valley, professor of geoscience at the University of Wisconsin-Madison. The research relied on new technology and scientific expertise developed by researchers in the UW-Madison WiscSIMS Laboratory.

The study describes 11 microbial specimens from five separate taxa, linking their morphologies to chemical signatures that are characteristic of life. Some represent now-extinct bacteria and microbes from a domain of life called Archaea, while others are similar to microbial species still found today. The findings also suggest how each may have survived on an oxygen-free planet.

[. . .]

Using a secondary ion mass spectrometer (SIMS) at UW-Madison called IMS 1280 -- one of just a handful of such instruments in the world -- Valley and his team, including department geoscientists Kouki Kitajima and Michael Spicuzza, were able to separate the carbon composing each fossil into its constituent isotopes and measure their ratios.

Isotopes are different versions of the same chemical element that vary in their masses. Different organic substances -- whether in rock, microbe or animal -- contain characteristic ratios of their stable carbon isotopes.

Using SIMS, Valley's team was able to tease apart the carbon-12 from the carbon-13 within each fossil and measure the ratio of the two compared to a known carbon isotope standard and a fossil-less section of the rock in which they were found.

"The differences in carbon isotope ratios correlate with their shapes," Valley says. "If they're not biological there is no reason for such a correlation. Their C-13-to-C-12 ratios are characteristic of biology and metabolic function."

Based on this information, the researchers were also able to assign identities and likely physiological behaviors to the fossils locked inside the rock, Valley says. The results show that "these are a primitive, but diverse group of organisms," says Schopf.

The team identified a complex group of microbes: phototrophic bacteria that would have relied on the sun to produce energy, Archaea that produced methane, and gammaproteobacteria that consumed methane, a gas believed to be an important constituent of Earth's early atmosphere before oxygen was present.

It took Valley's team nearly 10 years to develop the processes to accurately analyze the microfossils -- fossils this old and rare have never been subjected to SIMS analysis before. The study builds on earlier achievements at WiscSIMS to modify the SIMS instrument, to develop protocols for sample preparation and analysis, and to calibrate necessary standards to match as closely as possible the hydrocarbon content to the samples of interest.

[Continues . . .]





"Ancient fossil microorganisms indicate that life in the universe is common" | ScienceDaily

QuoteA new analysis of the oldest known fossil microorganisms provides strong evidence to support an increasingly widespread understanding that life in the universe is common.

The microorganisms, from Western Australia, are 3.465 billion years old. Scientists from UCLA and the University of Wisconsin-Madison report today in the journal Proceedings of the National Academy of Sciences that two of the species they studied appear to have performed a primitive form of photosynthesis, another apparently produced methane gas, and two others appear to have consumed methane and used it to build their cell walls.

The evidence that a diverse group of organisms had already evolved extremely early in the Earth's history -- combined with scientists' knowledge of the vast number of stars in the universe and the growing understanding that planets orbit so many of them -- strengthens the case for life existing elsewhere in the universe because it would be extremely unlikely that life formed quickly on Earth but did not arise anywhere else.

[Continues . . .]
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Dave

Though these are almost certainly more primitive I was reminded of endoliths whilst looking through this article.

I also think this indicating that "life in the universe is common" goes a bit far this, endoliths, algae that lives at sub-zero, bacteria that can survive near boiling water, does indicate that life can exist in many seemingly incredibly hostile environments. But it has to get started first!

Later: also reminded of the "Martian meteorite fossils" but I seem to remember it was later decided these were purely mineral in origin.

Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

Icarus


No one

infidel barbarian:
I think the inference that these fossils show that life is likely very common in the Universe

Anyone who truly believes Earth is it, as far as life goes, is a grade A quarter wit.

Recusant

Quote from: No one on January 15, 2018, 12:43:52 AM
infidel barbarian:
I think the inference that these fossils show that life is likely very common in the Universe

Anyone who truly believes Earth is it, as far as life goes, is a grade A quarter wit.

I think it's probable that there is other life in the Universe, but I also think that the early formation of life on our planet can't really be taken as evidence regarding that idea, let alone "strong evidence."
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
— H. L. Mencken


Dave

Quote from: Recusant on January 15, 2018, 01:48:10 AM
Quote from: No one on January 15, 2018, 12:43:52 AM
infidel barbarian:
I think the inference that these fossils show that life is likely very common in the Universe

Anyone who truly believes Earth is it, as far as life goes, is a grade A quarter wit.

I think it's probable that there is other life in the Universe, but I also think that the early formation of life on our planet can't really be taken as evidence regarding that idea, let alone "strong evidence."

Still waiting for someone to develope a system to detect oxygen on an extrasolar planet. That is a sure sign of ife ("...as we know it, Jim.")
Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

Ecurb Noselrub


Dave

Tomorrow is precious, don't ruin it by fouling up today.
Passed Monday 10th Dec 2018 age 74

xSilverPhinx

Quote from: Recusant on January 15, 2018, 01:48:10 AM
Quote from: No one on January 15, 2018, 12:43:52 AM
infidel barbarian:
I think the inference that these fossils show that life is likely very common in the Universe

Anyone who truly believes Earth is it, as far as life goes, is a grade A quarter wit.

I think it's probable that there is other life in the Universe, but I also think that the early formation of life on our planet can't really be taken as evidence regarding that idea, let alone "strong evidence."

Problem is we have a sample size of...one. Inferences, at least probabilistic ones, need a number that isn't so high on the loneliness scale.   
I am what survives if it's slain - Zack Hemsey


Ecurb Noselrub

Quote from: xSilverPhinx on January 16, 2018, 01:17:36 PM
Quote from: Recusant on January 15, 2018, 01:48:10 AM
Quote from: No one on January 15, 2018, 12:43:52 AM
infidel barbarian:
I think the inference that these fossils show that life is likely very common in the Universe

Anyone who truly believes Earth is it, as far as life goes, is a grade A quarter wit.

I think it's probable that there is other life in the Universe, but I also think that the early formation of life on our planet can't really be taken as evidence regarding that idea, let alone "strong evidence."

Problem is we have a sample size of...one. Inferences, at least probabilistic ones, need a number that isn't so high on the loneliness scale.

Yes, without a good baseline, probabilities are hard to calculate.