[dohboi]

https://www.washingtonpost.com/news/spe ... ge%2Fstory

3.7-billion-year-old fossils may be the oldest signs of life on Earth

Scientists probing a newly exposed, formerly snow-covered outcropping in Greenland claim they have discovered the oldest fossils ever seen, the remnants of microbial mats that lived 3.7 billion years ago.

It's a stunning announcement in a scientific field that is always contentious. But if confirmed, this would push the established fossil record more than 200 million years deeper into the Earth’s early history, and provide support for the view that life appeared very soon after the Earth formed and may be commonplace throughout the universe.

[ROCKMAN]

Interesting dohboi. And some think even older. From 2015:

UCLA geochemists have found evidence that life likely existed on Earth at least 4.1 billion years ago—300 million years earlier than previous research suggested. The discovery indicates that life may have begun shortly after the planet formed 4.54 billion years ago.

The research is published today in the online early edition of the journal Proceedings of the National Academy of Sciences. "Twenty years ago, this would have been heretical; finding evidence of life 3.8 billion years ago was shocking," said Mark Harrison, co-author of the research and a professor of geochemistry at UCLA.

From: http://phys.org/news/2015-10-life-earth ... omuch.html

Here's a very long and detailed report on the evolution of life on earth. One except I found interesting: "The similarities between all present-day organisms indicate the presence of a common ancestor from which all known species have diverged through the process of evolution. More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described."

https://en.m.wikipedia.org/wiki/Evoluti ... ry_of_life

[SumYunGai]

https://www.washingtonpost.com/news/speaking-of-science/wp/2016/08/31/3-7-billion-year-old-fossils-may-be-the-oldest-signs-of-life-on-earth/?hpid=hp_hp-top-table-main_fossil-sos-120pm%3Ahomepage%2Fstory

3.7-billion-year-old fossils may be the oldest signs of life on Earth

Scientists probing a newly exposed, formerly snow-covered outcropping in Greenland claim they have discovered the oldest fossils ever seen, the remnants of microbial mats that lived 3.7 billion years ago.

It's a stunning announcement in a scientific field that is always contentious. But if confirmed, this would push the established fossil record more than 200 million years deeper into the Earth’s early history, and provide support for the view that life appeared very soon after the Earth formed and may be commonplace throughout the universe.

The origin of life has been pushed back, while human extinction has been pushed forward.

[onlooker]

I think this pushing back of dates is consistent with fairly recent discoveries that life exists in the most inhospitable places on Earth. Also it tantalizes by tending to support the controversial theory that life on this planet was bought here from space via perhaps a meteor (s) or comets

[dohboi]

Thanks for that report, ROCK, I had missed it.

SYG: Good point!

o, yeah, I hadn't thought about that before. I guess pushing it back so early makes it seem like life either arises fairly spontaneously whenever the conditions are even remotely hospitable, or it means that there are a lot of life 'seeds' zipping around the universe at large enough concentrations that they hit even tiny planets regularly, and whenever there is a remotely hospitable spot, they thrive upon landing.

I still think the previous is the more likely hypothesis. Otherwise we should have been continually bombarded by various alien forms of life many of which would have thrived. But instead we have, for all its diversity, a lot of commonality across all forms of life (DNA/RNA for one), and, as ROCK's comment above points out, they all probably go back to one unitary form.

But maybe I'm missing something?

[GHung]

So if Rock's posited date is correct, life became evident only about 300 million years after the "Giant Impact" that formed the moon (currently the most accepted theory),, or about 700 million years if the Greenland discovery is valid as earliest evidence. Either way, the Earth went from a molten fireball to a planet with liquid water in less than 0.7 billion years. Time for life (fairly advanced life, in the case of the Greenland fossils) to evolve from a primordial soup? Or evidence that the planet was being bombarded all along with seeds of life, until conditions were suitable for life to take hold? Maybe there was some sort of Johnny Appleseed buzzing around the galaxy sprinkling seeds of life on any planet that looked good

It's no wonder some folks think God waved his magic wand really hard, and, POOF! Adam. Eve. Snakes. Pomegranates.....

[dissident]

I do not think that the early appearance of life is surprising. We are talking about millions of years after the formation of oceans. The chemical conditions for life to form would have been there at the same time. They did not pop up a billion years later. The time scales for the chemical reaction chains in various heterogeneous environments are fast (seconds to hours). So there were billions of natural "experiments" conducted that finally led to the emergence of some precursor to DNA with sufficient complexity.

The question I have is: is there new life forming on this planet today? Why would it be a one-time event? Does existing life crowd out any primitive new life? Or are there environments where the new life could establish itself.

[rockdoc123]

Although, as a geologist, I love to see new information like this I have to say ….so what? If you look at the history of the earth as if it were a 24 hour clock the old thought would have been the oldest proof of life showed up at 5:36 AM. Now that would be around 5:00 AM. Everything else of import remains unchanged as far as we know. EG: Trilobites show up at 9 PM, Dinosaurs at 10:56 PM, Mammals at 11:39 PM and humans at 11:58:43 PM.

Hopefully you picked up how insignificant we are.

[dohboi]

"is there new life forming on this planet today? Why would it be a one-time event? Does existing life crowd out any primitive new life?"

Good questions. As I understand it, there's a lot of microbial life that we don't know much about. Do we really know for sure that there was just one origin to all life forms on the planet?

(Nice to hear the baby rock finally figured out how insignificant he is! )

[rockdoc123]

(Nice to hear the baby rock finally figured out how insignificant he is! )

at least several score more significant than someone who has zero science background but pretends to be a guru in that field of endeavour. Perhaps you need to reassess your contribution to life let alone this forum.

[SumYunGai]

Time for life (fairly advanced life, in the case of the Greenland fossils) to evolve from a primordial soup? Or evidence that the planet was being bombarded all along with seeds of life, until conditions were suitable for life to take hold?

There are many problems with the old primordial soup theory and panspermia is pretty fringe. Perhaps there was a much simpler, more direct way for life to begin. Here is one of the best lectures I have ever seen:

Inevitable life?

https://www.youtube.com/watch?v=ElMqwgkXguw

Many researchers have supposed that the emergence of life hinged on a sequence of improbable events, at the same time as they have taken for granted the ability of life on earth to persist indefinitely and to "freeze in" the consequences of early accidents. Smith argues that there is ample evidence for a different interpretation: the emergence of life was an inevitable outcome of geochemistry on the early earth, and the same forces responsible for emergence have continued to support the persistence of life ever since.

I think this is the most compelling explanation for the origin of life. It turns out that life is an inevitable biochemical process. Life was pushed into existence because it is the best way to release the energy trapped in hydrogen and carbon dioxide that builds up because of geothermal processes. Hydrogen can give electrons to carbon and oxygen to form methane and water. That is the most energy energy available from the system. Life had to begin to release this constantly building trapped energy, providing a downhill run to lower energy molecules. There is no other chemical process that can do it. It has to run through the molecules of life (fatty acids, amino acids, sugars, cofactors, and nucleic acids). Krebs cycle (in reverse, actually).

The emergence of life is a chemical breakdown. The metabolic processes of life began before life did. Life exists and persists to enable metabolism. The biosphere arises from the geosphere. Life began at the bottom of the oceans around hydrothermal vents. Some of the oldest forms of life ever discovered are autotrophs that live around hydrothermal vents.

[ROCKMAN]

"Otherwise we should have been continually bombarded by various alien forms of life many of which would have thrived." Not so sure about that: might explain the trumphite subspecies. LOL.

[GoghGoner]

DNA is advanced computer code. Did computer code appear spontaneously? No, it didn't -- thinking DNA replication happens accidentally is preposterous.

[ROCKMAN]

Goner - That reminds me of a report long ago arguing that viruses might not be considered life forms. Their primary "life characteristic" was replacating itself via self-copying. No respiration or other interactions with the environment. More like chemical molecules that can "clone" themselves in a non-biological manner.

[GHung]

DNA is advanced computer code. Did computer code appear spontaneously? No, it didn't -- thinking DNA replication happens accidentally is preposterous.

Citations?

[dissident]

DNA is advanced computer code. Did computer code appear spontaneously? No, it didn't -- thinking DNA replication happens accidentally is preposterous.

Straw man argument. It did not appear spontaneously. It appeared via trial and error from chains of amino acids that can be readily produced via simple chemistry. We have RNA viruses which indicates that RNA may have developed before DNA. Of course viruses are super-specialized and need to hijack more developed cells to reproduce.

The development of DNA is evolution in action. There must have been an advantage to increasing complexity.

https://en.wikipedia.org/wiki/Models_of_DNA_evolution

Nothing spontaneous here.

[Tanada]

Goner - That reminds me of a report long ago arguing that viruses might not be considered life forms. Their primary "life characteristic" was replacating itself via self-copying. No respiration or other interactions with the environment. More like chemical molecules that can "clone" themselves in a non-biological manner.

I read an article a couple months ago that I intended to post online but I didn't find it just now. In any case geneticists have determined that something like 15% of the human genome is fragments of viruses that infected our ancestors reproductive organs and got accidentally incorporated into their ovum and spermatozoa. You are quite literally a tent virus sitting there reading my post, and you never even noticed lol.

It came up because someone came down with some extinct viral illness when a completely different virus reactivated one of the viruses in their DNA that was incorporated from their ancestors getting sick. Over many generations the viruses become fragmented and can no longer be reactivated, but apparently this takes about 500 years depending on how long the generations are. So think on that, if one of your ancestors had the Spanish Influenza in 1919 and they incorporated the virus into their germ cells some random bought of the common cold could give you Spanish Influenza.

Found it, http://phys.org/news/2016-04-ancient-re ... n-dna.html

Advances in whole genome sequencing have revealed a huge diversity of ERVs in the genomes of vertebrates with considerable difference between species. Many are extremely ancient, while more recent ERVs are more intact and less degraded by mutation. In some species such as mice, the genome contains many ERVs capable of producing infectious viruses, but almost all ERVs in humans (known as HERVs) appear to be non-functional remnants of extinct retroviruses. The only exception is one group, called HERV-K, which is potentially capable of replication despite being many millions of years old.



Previous studies of HERV-K sequences in the human genome have indicated that it has been recently active in humans, and that it could even still circulate through infection. This recent study's co-authors, Julia Wildschutte and Zach Williams, working in the laboratory of John Coffin at Tufts University, searched for evidence of HERV-K using data from the 1000 Genomes Project and the Human Genome Diversity Project. The team developed approaches that allowed them to dig exceptionally deep into these catalogues and establish that the human genome contains a total of 36 unique HERV-K copies not present in the standard, reference human genome sequence – including 19 new discoveries.

Most intriguingly of all, one of these new discoveries was an intact virus without any of the mutations that would be expected to degrade its function. The discovery of an intact virus lurking in the human population strengthens the possibility that this HERV-K retrovirus has remained "alive" within humans up until relatively recently, and could still be circulating somewhere even today.

[GoghGoner]

It appeared via trial and error from chains of amino acids that can be readily produced via simple chemistry. We have RNA viruses which indicates that RNA may have developed before DNA. Of course viruses are super-specialized and need to hijack more developed cells to reproduce.

The development of DNA is evolution in action. There must have been an advantage to increasing complexity.

https://en.wikipedia.org/wiki/Models_of_DNA_evolution

Nothing spontaneous here.

You ain't telling me anything I haven't already researched. I have yet to read any sensible ideas that go from molecules to life. Life coming to us from comets also requires a huge leap of faith... I can't believe they actually put that "soup" experiment in college level science books.

To Model the Simplest Microbe in the World, You Need 128 Computers




Anyway, I think you are on to something with evolution since we can actually test and observe that.

[SumYunGai]

I have yet to read any sensible ideas that go from molecules to life.

I hope you're not trying to invoke a god or something. Please watch this video to understand the leading scientific theory that explains how molecules in action led directly to life on Earth:

https://www.youtube.com/watch?v=0cwvj0XBKlE

McCloskey Speaker Series – New Theories on the Origin of Life with Dr. Eric Smith

The Aspen Institute
Published on Jul 10, 2015

Featuring Dr. Eric Smith, professor at the Earth-Life Science Institute in Tokyo and the Santa Fe Institute. For most of the 20th century, complex biological views of evolution have been central to the way scientists think about the origin of life. But progress over the past 40 years in such fields as ocean exploration, microbiology, and planetary science has come together to suggest that life's origin may have been built on a core chemical blueprint. Dr. Smith argues that we need a new understanding of the nature of life, in which the dominant, Darwinian view of a “struggle for existence” comes second, and life at its core came about as a necessary layer of our maturing planet.

Eric Smith began scientific work in high-energy physics, with Bachelor degrees in math and physics from Caltech, and a Ph.D. from the University of Texas in 1993. His work moved increasingly into topics in complex systems, during appointments in the University of Texas and the Los Alamos National Laboratories, culminating in eleven years spent at the Santa Fe Institute. At SFI he began parallel threads of work in non-equilibrium thermodynamics, economics and finance, and the history of human languages, and began studying the geochemistry, biochemistry, and evolution of the earliest life. He is currently a professor and Principle Investigator of the Earth-Life Science Institute in Tokyo, and external professor at SFI. His goal is to understand the origin and nature of the living state through the many windows that science provides on it: the physical, geochemical, biochemical, ecological, and evolutionary.

[GoghGoner]

I have yet to read any sensible ideas that go from molecules to life.

I hope you're not trying to invoke a god or something. Please watch this video to understand the leading scientific theory that explains how molecules in action led directly to life on Earth:
/quote]

Does that video itself invoke God? The main message was:

"success is actually written into the fabric of the universe"

Implying that life started with a metabolic cycle -- that isn't a theory.

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.