Oldest Life On Earth (Earliest Organisms; Early Evolution)

[Mighty_Emperor]

Source:
University Of Alberta

Date:
2004-01-13

Researchers Show Evolutionary Theory Adds Up

All living plants and animals are likely derived from two primitive species of bacteria, a mathematics professor at the University of Alberta has shown.


Dr. Peter Antonelli and a former post-doctoral student of his, Dr. Solange Rutz, used an original mathematical modeling system and software program to evaluate and compare the two main theories of biological evolution.

One theory, put forward by Dr. Lynn Margulis of the University of Massachusetts, proposes that a "mother" bacteria (Bdellavibrio) and a "father" bacteria (Thermoplasma acidophilum) "exchanged energy" in a stable, dependable, and consistent way about 3.2 billion years ago to form all subsequent multicellular organisms, Antonelli explained.

Another theory, put forward by Dr. Carl Woese of the University of Illinois, proposes multicellular organisms developed from many different bacteria interacting in many different ways 3.2 billion years ago.

Antonelli and Rutz's research showed that Woese's theory does not account for stability in the chemical exchange processes of many bacteria interacting, whereas Margulis's theory holds up under the scrutiny of Antonelli's modeling system. The study is published in the latest edition of Nonlinear Analysis: Real World Applications.

"We showed that the chemical production necessary to support Woese's theory is not dependable and not conducive to the formation of multicellular organisms, but Margulis's theory proves to be reliable," Antonelli said.

Antonelli decided to test the two theories after reading an article on the subject in the New York Times about three years ago. "I try to solve scientific problems with mathematics, and when I read this article, I thought, 'Hey, this is a problem I can solve.'"

Antonelli has also solved other problems with the 'Volterra-Hamilton' mathematical model that he developed. He has solved the mystery of succession in the crown of thorns population of the Great Barrier Reef. He is now working to define the succession of the Amazon Rain Forest to its current climax state. He is also seeking a unified theory of ecological evolution, and he feels he can achieve this in the not too distant future.

"I haven't always been trying to develop a unified theory, but as we have been putting pieces together, study by study, I can see now that's it's possible," said Antonelli, who has mentored more than 35 post-doctoral students and sits as an editor for eight journals.

Antonelli uses differential equations to explain social interactions and biological behaviours, and he laments that more biologists aren't attuned to this type of research.

"What we do is new and not a lot of people understand it yet," he said. "I've published in biology journals before, but most biologists don't read these articles because of the mathematics involved. We've got to convince [biologists] that it's worth the effort to learn the mathematics."

http://www.sciencedaily.com/releases/2004/01/040113075946.htm

 

[Anonymous]

Kicks the Bible to the Kerb, unless Adam & Eve where evolved forms of Bacteria Never belived the bible anyway...

 

[Mighty_Emperor]

More developments on the evolution of the early bacteria and its implications for other factors in the Earth's early evolution:

Biologist's find alters the bacteria family tree

14 Apr 2004


The bacteria family tree may be facing some changes due to the recent work of an evolutionary biologist at Washington University in St. Louis. And that may change our understanding of when bacteria and oxygen first appeared on earth.

Carrine Blank, Ph.D. , assistant professor of earth and planetary sciences in Arts & Sciences, has found that the currently accepted dates for the appearance of oxygen-producing bacteria and sulfur-producing bacteria on the early earth are not correct. She believes that these bacteria appeared on earth much later than is now believed. "It sets up a new framework of new hypotheses to be tested," she says of the new findings.

Blank's findings appear in the February 2004 issue of Geobiology.

As an evolutionary biologist, Blank said she is, "really interested in the view of the earth and microorganisms and how they come together." She uses elements of biology and geology to understand how the earth and its inhabitants co-evolved.

It is known that earth's earliest organisms were thermophilic, or able to dwell in hot environments. These organisms engaged in chemotropic metabolism — they converted inorganic substances, such as sulfur and carbon, into energy to live. This process is similar to how we use food, water, and oxygen to generate energy.

The predecessors of modern bacteria differ in much more than age. The Archean era, which records the first billion years of Earth's geologic history, ended 2.5 billion years ago. It was at this point that the earth's biosphere must have changed and the atmospheric temperature reached 72 degrees Celsius. This is the maximum temperature at which photosynthesis can take place. Near the end of this era, about 2.7 to 2.9 billion years ago, according to Blank, stromatolites, organisms of the group Bacteria that use photosynthesis to create energy without producing oxygen, first appeared.

Blank's approach is to understand organisms by determining what materials they metabolized. Using genetic analysis, she looked at the early rock record to determine when the first substantial amounts of oxygen and sulfur appeared on earth. While she mapped the evolution of several bacteria, Blank believes the dating of the emergence of cyanobacteria - bacteria that use light, water, and carbon dioxide to produce oxygen and biomass - is most crucial.

Blank explains that the precise dating of the emergence of cyanobacteria is so important because, "once you have oxygen, you have a whole new biosphere."

Cyanobacteria are the only bacteria that produce oxygen as a byproduct of their metabolism. It was not until these creatures appeared on earth that oxygen was found in the earth's atmosphere. "No other photosynthetic microbe is as efficient," said Blank.

Scientists initially believed that cyanobacteria were present on earth as early as 2.7 billion years ago. Blank has challenged this view by presenting dates she feels give a more accurate chronology of the evolution of cyanobacteria and other bacteria lineages in general. With this data, she was also able to better pinpoint the emergence of other organisms

She has determined that cyanobacteria can only be dated to as far back as 2.3 billion years ago.

Genetic analysis

Blank, an assistant professor of geomicrobiology in the Department of Earth & Planetary Sciences at Washington University in St. Louis, used an evolutionary analysis technique pioneered by Carl Woese, Ph.D., professor emeritus of microbiology at the University of Illinois, to construct evolutionary trees of the bacteria.

Woese pioneered the technique of using ribosomal RNA genes to make the first family trees of microbes. He was also the first person to distinguish between the two domains of microbial life - Bacteria and Archaea. These Archaea are not related to the Archean era mentioned previously.

Using many genes that are common to all these creatures, Blank was able to construct evolutionary trees with better chronological accuracy than those produced previously, which used fewer genes. Based on the extent of the changes, Blank could determine how distant the organism was from the last common ancestor.

Blank obtained her gene sequences from whole genome sequences that are available in GenBank, a public database hosted by the National Institutes of Health. This provided large amounts of data to enhance the evolutionary trees.

From this data, Blank's diagrams show how different types of metabolism evolved. For example, her data show that oxygen-producing organisms evolved from organisms that metabolize sulfur. Her diagrams are based on the idea that evolution is a branching process in which a common ancestor's descendants slowly diverged into a few organisms, each of which diverged into a few more, and so on until the multitude of the organisms we see today developed.

These family trees also show which organism's genes are least like the last common ancestor's genes. These organisms will be more toward the tips of the lines, while those with genes that closely resemble the genes of the last common ancestor will be closer to the center of the tree. "The tips of the tree use oxygen, so they first originated the use of oxygen," explained Blank.

Opening new areas of study

While Blank sites evidence in the geologic record as the reason her findings are more accurate than previous ones, she does acknowledge that there is one piece of evidence that may disprove her proposed chronology.

Lipid markers, similar to fossils in the rocks in that they provide evidence of species' presence in the past, in the rock record indicate that cyanobacteria may have been present as early as 2.7 billion years ago. But, because ancient lipid research just started in 1999, this evidence is still being examined.

Blank's research also brings up the question of how nuclei functioned for a billion years before mitochondria appeared. Mitochondria are the powerhouse of the cell; they process resources and convert them into cellular energy. While mapping genomes for her research, Blank noticed that prior to 2.2 billion years ago, mitochondria were not present in eukaryotic cells - more highly developed cells that contain mitochondria and other organelles in a membrane. "This is an intriguing insight into eukaryote evolution," said Blank.

http://www.medicalnewstoday.com/index.php?newsid=7240

Emps

 

[Mighty_Emperor]

New Case for Oldest Life on Earth

By Robert Roy Britt
Senior Science Writer
posted: 02:30 pm ET
22 April 2004



Using a method never applied to rock from ancient Earth, researchers have found possible signs of biological activity dating back nearly 3.5 billion years, earlier than any other agreed-upon discovery of life on this planet.



The primordial life appears to have eaten rocks to survive.


Meanwhile, separate work is turning up intriguing similar structures in Mars rocks found on Earth, though no claims of life have yet been made with regard to this ongoing Martian investigation.



If the terrestrial finding is confirmed, it means life was thriving not long after this world had been presumably sterilized several times over by asteroid and comet impacts that were common in the earliest era of the solar system, which is about 4.6 billion years old.



The researchers found microscopic tubes in ancient, glassy lava that they say were created by microbes eating into the lava after it cooled on the ocean floor. Similar signatures of life, including genetic material, have been found in lava that formed more recently in Earth's history. Scientists generally agree that the tubes in the more modern lava were indeed creating by boring organisms.



The 3.5-billion-year-old tubes contain carbon and traces of carbonates that could represent organic material left behind by the primitive organisms. The research was led by Harald Furnes atNorway's University of Bergen and is reported in the April 23 issue of the journal Science.


Of life, evolution and sex



Separately, scientists are engaged in an ongoing debate over purported microfossils in rock found in Australia, also said to be about 3.5 billion years old, and even older "graphite inclusions" in rocks from Greenland. Meanwhile, the oldest solid evidence for life dates back 3.2 billion years.



Nobody knows how life began. Scientists aren't even sure if it started on Earth first or was transported here by Mars rocks or in the bellies of comets. They do know that Earth was initially inhospitable and probably dry as a bone when it formed about 4.5 billion years ago.



Pockmarks on the Moon testify to an early history of asteroid and comet impacts that might have killed any living things on Earth or thwarted the development of life for the first few hundred million years. (Earth would have a similar frequency of scars but they were folded inward and eroded away.)



Or, others argue, catastrophe may have been the mother of evolution, wiping out all but the hardiest life and forcing certain favorable mutations. For example, one study suggests a later, milder bout of cosmic poundings led primitive creatures down the path of mutation toward their first sexual encounters.


The latest findings



The newest discovery was made in lava that was once buried at the bottom of the sea but is now exposed in the so-called Barberton Greenstone belt in South Africa.



"Our data come from entirely different rocks than those in which the search for early life has done previously," study leader Furnes told SPACE.com.



"The biosignals we have applied are different from those previously used," Furnes said. "I think comparing our results with those on which the controversies presently are going on, would be like comparing apples and oranges."



Little is known about the microbes and what they ate, Furnes explained. They apparently created some sort of microenvironment that dissolved the glassy lava rock, in order to drill into it.



"We know very little about this, and from the biosignals we see in the Barberton lavas it is impossible to tell," Furnes said. "Attempts to culture microbes that settle and dissolve young glassy lavas are few. From the few data that exist, however, it appears that the microbes gain energy from oxidizing iron."



In an analysis of the work in Science, other researchers not involved in the study offered varying perspectives.


Controversy continues



“To me, it’s unequivocal that the textures they see were created by microorganisms," petrologist Martin Fisk of Oregon State University told the journal. "I think they’ve got the best evidence I’ve seen for life at that time.”



Microbial geochemist Jennifer Roberts of the University of Kansas called the evidence compelling but said it's not a smoking gun. She said nonbiological processes can create similar tube-like structures.



In a telephone interview, Fisk said he is "still open" to the interpretation that the tubes were created by something other than living things, but he added that no one has demonstrated what nonbiological process would actually be at work.



Fisk has been aware of Furnes' work for some time, and separately he's been trying to find similar microscopic signatures of life in Mars rocks that have been found on Earth. So far, he said, he's not found anything that conclusively suggests life on Mars. But in a few grains of the mineral olivine, from Mars meteorites, he's noted shapes similar to those found in terrestrial rocks by Furnes and others.



Fisk and his colleagues presented their preliminary findings last month at the Lunar and Planetary Science Conference, held in Houston.

http://www.space.com/scienceastronomy/lava_life_040422.html

 

[ramonmercado]

Battle between bubbles might have started evolution

Battle between bubbles might have started evolution
03 Sep 2004

Howard Hughes Medical Institute researchers are proposing that the first battle for survival-of-the-fittest might have played out as a simple physical duel between fatty bubbles stuffed with genetic material. The scientists suggest that genetic material that replicated quickly may have been all the bubbles needed to edge out their competitors and begin evolving into more sophisticated cells. This possibility, revealed by laboratory experiments with artificial fatty acid sacs, is in sharp contrast to a current theory of the earliest evolution of cells, which suggests that cellular evolution was driven by primordial genetic machinery that actively synthesized cell membranes or otherwise influenced cell stability or division.

The researchers, led by Howard Hughes Medical Institute investigator Jack W. Szostak, published their findings in the September 3, 2004, issue of the journal Science. Szostak and first author Irene Chen, both from Massachusetts General Hospital and Harvard Medical School, collaborated on the studies with Richard Roberts of the California Institute of Technology.

Cells are basically sacs encapsulated by bilayered membranes of fatty acids and other lipids, plus proteins. A central question in evolution is how simple versions of these cells, or vesicles, first arose and began the process of competition that drove the evolution of life.

"Most of the previous thinking about how cells grew and evolved was based on the idea of the initial evolution of structural RNAs or ribozymes -- enzymes that could synthesize membrane molecules," said Szostak. The ribozymes might have made more membrane material while the structural RNAs might have formed a cytoskeleton that influenced stability, shape, growth or division, he said.

However, Szostak and his colleagues theorized that a far simpler physical process might explain why cells would compete with one another for the materials necessary to expand their size.

"We proposed that the genetic material could drive the growth of cells just by virtue of being there," he said. "As the RNA exerts an osmotic pressure on the inside of these little membrane vesicles, this internal pressure puts a tension on the membrane, which tries to expand. We proposed that it could do so through the spontaneous transfer of material from other vesicles nearby that have less internal pressure because they have less genetic material inside."

In order to test their theory, the researchers first constructed simple model "protocells," in which they filled fatty-acid vesicles with either a sucrose solution or the same solvent without sucrose. The sucrose solution created a greater osmotic pressure inside the vesicles than the solvent alone. The membranes of the simple vesicles were not as sophisticated as the membranes of today's living cells, said Szostak. However, they closely resembled the kinds of primordial vesicles that might have existed at the beginning of evolution.

When the scientists mixed the two vesicles, they observed that the ones with sucrose – in which there was greater membrane tension – did, indeed, grow by drawing membrane material from those without sucrose.

"Once we had some understanding that this process worked, we moved on to more interesting versions, in which we loaded the vesicles with genetic molecules," said Szostak. The researchers conducted the same competition tests using vesicles loaded with the basic molecular building blocks of genetic material, called nucleotides. Next, they used RNA segments, and finally a large, natural RNA molecule. In all cases, they saw that the vesicles swollen with genetic material grew, while those with no genetic material shrank.

It is important to note, said Szostak, the concentrations of genetic material that his group used were comparable to those found in living cells.

"In contrast to the earlier idea that Darwinian competition at the cellular level had to wait until the evolution of lipid-synthesizing ribozymes or structural RNAs, our results show that all you would need is to have the RNA replicating," said Szostak. "The cells that had RNA that replicated better -- and ended up with more RNA inside -- would grow faster. So, there is a direct coupling between how well the RNA replicates and how quickly the cell can grow. It's just based on a physical principle and would emerge spontaneously," he said.

According to Szostak, the next step in the research will depend on another major effort under way in his laboratory to create artificial, replicating RNA molecules.

"If we can get self-replicating RNAs, then we can put them into these simple membrane compartments and hope to actually see this competitive process of growth that we are hypothesizing," he said.

Contact: Jennifer Michalowski
[email protected]
301-215-8576
Howard Hughes Medical Institute http://www.hhmi.org/

http://www.medicalnewstoday.com/medicalnews.php?newsid=12836

 

[ramonmercado]

Possibility Of Finding Traces Of Ancient Life

Source: University Of Chicago


Study Resolves Doubt About Origin Of Earth’s Oldest Rocks, Possibility Of Finding Traces Of Ancient Life

Experiments led by Nicolas Dauphas of the University of Chicago and Chicago’s Field Museum have validated some controversial rocks from Greenland as the potential site for the earliest evidence of life on Earth.

A study led by Nicolas Dauphas of the University of Chicago and Chicago's Field Museum has clarified the sedimentary origin of the world's oldest rocks, reinforcing the possibility that they contain the earliest evidence for life on Earth. These rocks are found in southwest Greenland, including Iron Mountain of the Issua region pictured here. (Photograph courtesy of Nicolas Dauphas)


“The samples that I have studied are extremely controversial,” said Dauphas, an Assistant Professor in Geophysical Sciences at the University of Chicago and a Field Museum Associate. Some scientists have claimed that these rocks from Greenland’s banded iron formations contain traces of life that push back the biological record of life on earth to 3.85 billion years ago. Others, however, dismiss the claim. They argue that the rocks originally existed in a molten state, a condition unsuitable for the preservation of evidence for life.

“My results show unambiguously that the rocks are sediments deposited at the bottom of an ocean,” Dauphas said. “This is an important result. It puts the search for life on the early Earth on firm foundations.”

Dauphas will announce his findings in the Dec. 17 issue of the journal Science. His co-authors are Meenakshi Wadhwa and Philip Janney of Chicago’s Field Museum, Andrew Davis of the University of Chicago, and Mark van Zuilen and Bernard Marty of France’s Centre de Recherches Petrographiques et Geochimiques.

The oldest-known microfossils, which come from Australia and are themselves disputed, are more than 3.4 billion years old. Scientists have now turned their attention to Greenland for evidence of even older biological activity.

The controversy over the Greenland rocks stemmed from changes they underwent over the long history of the Earth. “During burial they were cooked under high pressure and temperature, which completely modified the chemistry and mineralogy of the rocks,” Dauphas said. Consequently, scientists found it difficult to determine whether the rocks were igneous (those that had cooled from a once-molten state) or sedimentary (eroded and deposited by wind or water). Only sedimentary rocks would be able to preserve evidence of life.

That question was finally answered by a state-of-the-art mass spectrometer in Wadhwa’s laboratory at the Field Museum. The spectrometer was among the resources that led Science co-authors Davis, Dauphas, Wadhwa and others earlier this year to form the Chicago Center for Cosmochemistry.

The center is a collaboration between the University of Chicago, the Field Museum and Argonne National Laboratory to study the elements and their many atomic variations in meteorites and other materials from Earth and space. Dauphas used the spectrometer to measure with high precision the subtle atomic variations in the composition of iron, called isotopes, preserved in rocks on the southwest coast of Greenland and Akilia Island. The variations in these isotopes told them what type of process formed the rock, Wadhwa said.

“From the standpoint of these isotopes, there’s very convincing evidence that these rocks cannot be of igneous origin,” she said.

Unlike igneous rocks, the Greenland samples contained a considerable range of isotopic variation in iron isotopics, said Davis, Director of the Chicago Center for Cosmochemistry and Senior Scientist at the University of Chicago’s Enrico Fermi Institute. “All igneous rocks on the Earth have pretty much the same iron isotopic composition, so it was really a pretty simple test.”

The question that remains is whether the Greenland rocks actually contain evidence for early life. Circumstantial evidence suggests that they do. These ancient rocks have been oxidized, meaning that they have chemically reacted with oxygen. But the atmosphere of the early Earth contained much less oxygen than it does today. Where did the oxygen come from?

Photosynthesis, a chemical process signaling the presence of bacteria, might be the answer. It’s a question that Dauphas intends to pursue in his new Origins Lab at the University of Chicago.

“We can’t claim at this stage that there is unequivocal evidence for biological activity four billion years ago,” Davis said. “There are more experiments that need to be done.”

http://www.sciencedaily.com/releases/20 ... 171437.htm

Editor's Note: The original news release can be found here:
http://www-news.uchicago.edu/releases/0 ... phas.shtml

 

[Mighty_Emperor]

Posted on Thu, Jun. 09, 2005

Scientists zero in on suspected common ancestor of all living things

By Robert S. Boyd

Knight Ridder Newspapers

WASHINGTON - Thanks to the tools of modern genetics, scientists are working to identify a little bug that they believe was the ancestor of every creature alive today.

They call it LUCA - shorthand for the "last universal common ancestor" - and they think it inhabited the Earth 3 billion to 4 billion years ago.

LUCA consisted of only a single cell, like a bacterium, scientists say, but its descendants comprise modern humans, animals, plants, fungi and invisible microbes.

"Amazingly, every living thing we see around us, and many more that we can only see with the aid of a microscope, is related," said Anthony Poole, a molecular biologist at Stockholm University in Sweden.

In effect, LUCA's genealogy makes us distant cousins of everything from whales to bumblebees and pond scum.

"All contemporary life is descended from a single last common ancestor that had a biochemistry closely related to contemporary biochemistry," said Max Bernstein, a biochemist at NASA's Ames Research Center in Moffett Field, Calif.

"If we go sufficiently far back, everybody's ancestors are shared," evolutionary biologist Richard Dawkins wrote in his latest book, "The Ancestor's Tale." "Go backward and no matter where you start, you end up celebrating the unity of life."

Researchers say the effort to understand LUCA can shed light on evolution and genetics, help medical science, and even improve the chances of finding primitive life on other planets.

Despite its great age, LUCA was "a sophisticated, essentially modern organism," said James Lake, a molecular biologist at the University of California, Los Angeles.

Lake calls it "the lucky bug" because its descendants survived while other ancient microbial lines died out. "It wasn't the first life," he pointed out. "Life had already been going on for a long time."

LUCA "set the stage for 4 billion years of evolution," said Blair Hedges, a biologist at Pennsylvania State University in University Park. Understanding the evolution of genes and their functions "is like having a blueprint for modern medicine," he added.

The quest for a universal common ancestor is made possible by the fact that all organisms from LUCA on down share a few hundred or thousand basic genes that enable them to eat, grow and reproduce. Those universally inherited genes provide the clues that evolutionary scientists are using to figure out what LUCA must have been like.

The nature of the last common ancestor is "one of the big questions" in evolution, David Penny, a molecular biologist at Massey University in New Zealand, said in an e-mail message.

Defining LUCA would be "a major step in determining what life was like on Earth and how life arose," Lake said. "If we get close to the right answer, then we can follow the history, geography, environment, everything about early life."

"We are now entering a very exciting period in uncovering the history of the LUCA," said Poole, who presented the results of his latest research at a conference last week in Hamilton, Ontario.

Nevertheless, the field is filled with uncertainty and doubt. Researchers disagree on many points.

"Ask any two researchers to give an overview of what they think the LUCA was like, and you will no doubt get different answers," Poole wrote in a paper published in 2002. "With such a tricky scientific endeavour as this - working out what an organism that lived billions of years ago was like - this is hardly surprising."

Some researchers, for example, think LUCA stored its genes in strings of DNA, like modern organisms. Others think it used a more primitive storage medium called RNA.

Some even doubt that there was a LUCA.

"I think the story is more complex," said Mitchell Sogin, an evolutionary biologist at the Marine Biological Laboratory in Woods Hole, Mass. "Rather than a single last common ancestor as implied by the concept of LUCA, there were probably populations of organisms that readily exchanged or assimilated genetic information from neighboring genomes.

"Currently there is no consensus and I don't think we should expect one in our lifetime."

---

For more information online, go to www.actionbioscience.org/newfrontiers/poolearticle.html

www.realcities.com/mld/krwashington/11862850.htm

 

[Mighty_Emperor]

My name is Luca. I live in the Precambrian

Posted on Thu, Jun. 09, 2005

Scientists zero in on suspected common ancestor of all living things

By Robert S. Boyd

Knight Ridder Newspapers

WASHINGTON - Thanks to the tools of modern genetics, scientists are working to identify a little bug that they believe was the ancestor of every creature alive today.

They call it LUCA - shorthand for the "last universal common ancestor" - and they think it inhabited the Earth 3 billion to 4 billion years ago.

www.realcities.com/mld/krwashington/11862850.htm

More stuff - its interesting that it may challenge Darwinian evolution:

Last Universal Common Ancestor

Alok Jha
Monday October 10, 2005
The Guardian

Call it the ultimate search in genealogy - the hunt for a lifeform that existed more than 3bn years ago and is the common ancestor of everything alive today. The scientists on this search might not agree what the organism might be, but they already have a name: Luca (Last Universal Common Ancestor). Evolutionary biologists who believe that Luca did exist argue that everything from bacteria to birch trees to blue whales is descended from this one living thing.

It's a controversial topic. Not least because some scientists suggest that, if Luca existed, the evolutionary processes at work on primordial Earth might have been quite different to the Darwinian model of natural selection. That's scientific heresy, but it is not stopping the search. At the National Centre for Biotechnology Information in Maryland, for example, a team led by the evolutionary biologist Eugene Koonin is trying to identify Luca's genes. So far they have 600 possibles. Once they can pare it down to the bare minimum, they hope to assemble Luca's genome in the lab.

Despite its differences from Darwinism, Luca is descended from Darwin's theory of evolution by natural selection. Darwin proposed that similar species must have had common ancestors. Each species belonged to a huge family tree but even Darwin was unable to work out whether those trees were connected.

After Watson and Crick's discovery of the structure of DNA and the subsequent birth of molecular biology, scientists began to unpick the differences between different species. But as well as differences, they found similarities - the common molecules of life such as DNA, amino acids and proteins - that suggested differing forms of life were more closely linked than even Darwin had thought. But the latest research on Luca suggests another scientific heresy, this time concerning DNA. It has long been thought that Luca existed when genes were made from DNA's less sophisticated cousin, RNA. But some scientists now believe Luca was DNA-based, suggesting DNA evolved twice.

So what was Luca? The answer depends on which of the three branches of life on Earth is shown to be the oldest - bacteria, archaea (single-celled organisms such as the extremophiles, which can endure incredibly high temperatures and pressures) and prokaryotes (everything else, including all plants, animals and fungi). The answers could be decades or even centuries away but there's no real rush among scientists. Luca has been waiting to be discovered for some time already.

www.guardian.co.uk/g2/story/0,,1588491,00.html

 

[ramonmercado]

Clay Material May Have Acted As 'Primordial Womb' For First Organic Molecules

Williams and her team mimicked the conditions found in hydrothermal vents along the lines where tectonic plates converge on the ocean floor. The vents are fissures in the seafloor that spew out super-hot water much like an underwater volcano.
Tempe AZ (SPX) Nov 11, 2005
Arizona State University geochemist Lynda Williams and her colleagues have discovered that certain clay minerals under conditions at the bottom of the ocean may have acted as incubators for the first organic molecules on Earth.
Williams' research suggests how some of the fundamental materials necessary for life might have come into existence deep in the sea. The results of Williams' experiments were published in the article, "Organic Molecules Formed in a Primordial Womb," in the November issue of Geology.

Williams and her team mimicked the conditions found in hydrothermal vents along the lines where tectonic plates converge on the ocean floor. The vents are fissures in the seafloor that spew out super-hot water much like an underwater volcano.

From earlier work, the researchers knew that with high enough temperatures and pressure, volcanic emanations could produce the chemical compound methanol. What scientists did not know was how the methanol could survive intense temperatures of 300 to 400 C.

"When I first heard that, I thought, 'that's strange,'" Williams said of the methanol formation. "Methanol is supposed to break down at those temperatures. I asked myself, 'what can protect it?' The answer is common clay minerals."

Williams hypothesized that the expandable clay surrounding the hydrothermal vents might have served as a "primordial womb" for infant molecules, sheltering them within its mineral layers. She devised an experiment that would test whether the organic compound methanol would be protected between the clay layers.

Williams and her team simulated the intense heat and pressure of the ocean floor within a pressurized vessel. The reaction of the clay and methanol was monitored over six weeks. The team found that the expandable clay not only protected the methanol, but also promoted reactions that formed even more complex organic compounds. The mineralogical reaction between the clay and methanol was facilitating the production of new organic material.

Scientists theorize that the diverse organic molecules protected within the clay might eventually be expelled into an environment more hospitable to life, leading to an "organic soup." What makes the finding so exciting is that the experimental conditions reflect scientists' best estimations of the simplest conditions that likely existed when life began, Williams said.

"This research tells us that as long as there is water and the right chemical ingredients, common clay minerals can help produce the ingredients for biomolecules (chemical components used by living organisms)," Williams said.

Because the reactions simulated in these experiments can be found anywhere volcanic activity exists, Williams added, it is likely that similar organic compounds could be produced on other volcanically active planets that have water. Additional experiments are planned to find out what chemical conditions would be required to form the building blocks of life.

"We have only started investigating the influence of clays on the origin of life," Williams said.


http://www.terradaily.com/news/life-05zzzzzzzu.html

 

[Zilch5]

Fossils of Earliest Animal Life Possibly Discovered

Fossils of what could be the oldest animal bodies have been discovered in Australia, pushing back the clock on when animal life first appeared on Earth to at least 70 million years earlier than previously thought.

The results suggest that primitive sponge-like creatures lived in ocean reefs about 650 million years ago. Digital images of the fossils suggest the animals were about a centimeter in size (the width of your small fingertip) and had irregularly shaped bodies with a network of internal canals.

The shelly fossils, found beneath a 635 million-year-old glacial deposit in South Australia, represent the earliest evidence of animal body forms in the current fossil record. Previously, the oldest known fossils of hard-bodied animals were from two reef-dwelling organisms that lived around 550 million years ago.

Researchers have identified controversial fossils of soft-bodied animals that date to the latter part of the Ediacaran period between 577 and 542 million years ago.

More and pics here: http://www.livescience.com/animals/earl ... 00817.html

 

[Zilch5]

Palaeolithic cutlery 400 000–200 000 years ago: tiny meat-cutting tools from Qesem Cave, Israel

Minuscule flakes made from recycled flint were identified at the late Lower Palaeolithic site of Qesem Cave in Israel (Figure 1), dated to 400–200 thousand years ago (kya) (Barkai et al. 2003; Gopher et al. In press). Our ongoing research at this exceptionally well-preserved site indicates that it was repeatedly occupied by early hominins, ancestral to Homo sapiens and/or Neanderthals (Hershkovitz et al. In press), who left ample evidence of their lifestyle. Our analysis of the tiny flakes (Figure 2) suggests that they were used to cut meat.

The occupants of Qesem Cave produced innovative flint tools, and in particular sharp flint blade knives, using cutting-edge technology of the time (Barkai et al. 2009). They hunted cooperatively, bringing body-parts of fallow deer back to the cave, which were then butchered, shared (Stiner et al. 2009), and — as suggested by fire usage throughout the cave's 7.5m-deep stratigraphy — eventually barbecued. Microscopic use-wear analysis of flint artefacts from Qesem Cave, complemented by experimental replication work, revealed that a diversified assemblage of flint blades was manufactured and used. Thick-edged blades, shaped through retouch, were used for scraping semi-hard materials such as wood or hide, whereas blades with straight, sharp working edges were used to cut soft tissues (Lemorini et al. 2006). Functional studies point to short-lived usage of these meat-cutting blades, which were hardly ever re-sharpened for further use. This behaviour was evidently sustained by an innovative systematic blade production technology, providing a constant supply of fresh cutting edges (Barkai et al. 2009).

Much more and pics here: http://antiquity.ac.uk/projgall/barkai325/

 

[rynner2]

Colony of stromatolites found in Giant's Causeway
By Mike McKimm, BBC NI environment correspondent

In a small grey puddle tucked into a corner of the world famous Giant's Causeway, scientists have made an extraordinary find.
A colony of stromatolites - tiny structures made by a primitive blue-green algae.
Stromatolites are the oldest known fossils in the world.
The tiny algae or bacteria that build them are also thought to be the most ancient life form that is still around today, after more than three billion years.

What makes the discovery in Northern Ireland so remarkable is that until now these structures have been found mainly in warm and often hyper saline waters which discourage predators.
The stromatolites in the Giant's Causeway are in a tiny brackish pool, exposed to the violence of waves and easy prey to the animals that are already living amongst them.

Stromatolites are formed by a blue-green algae that excretes carbonate to form a dome-like structure. Over thousands of years these build up into a hard rock that continues to grow.
Stromatolite fossils have been dated as far back as three and a half billion years.

The colony at the Giant's Causeway on Northern Ireland's wind-swept north coast was found by accident.
Scientists from the School of Environmental Sciences at the nearby University of Ulster were looking for very different geological formations when Professor Andrew Cooper spotted the stromatolites.
"I was very surprised", explained Professor Cooper.
"I was walking along with a colleague looking at something else. Out of the corner of my eye I spotted these structures which, had I not seen them before in my work in South Africa, I probably wouldn't have known what they were."

The colony is very young, just a layer thick, so it's recently formed. One thing that is puzzling scientists is why its chosen this spot.
"There is some unusual set of circumstances that occurs just here that doesn't occur even 10 metres away along the beach," said Professor Cooper.
"So whatever it is, it's very special to this particular time and space."

One clue could be the myriad of shells in the grass banks just about the tiny pool. Rain water is leaching through the ground and the shells, dissolving out calcium carbonate and carrying to the stromatolites.

The blue-green algae that forms the stromatolites helped create our present atmosphere by breaking down carbon dioxide and excreting oxygen. Their appearance on this planet is seen as a turning point in the earth's evolution.

While living examples are thought to be rare, it could be that we haven't found them because we aren't looking for them.
"The chances are that they may be more widespread than we actually know", explained Professor Cooper.
"Geologists have spent a lot more time studying the ancient stromatolites that are two billion years old than we have spent on living stromatolites.
"So this is an important site where we can look at the circumstances in which stromatolites actually occur."

News of the find is only starting to leak out but its expected to start a frenzied search around the coast of Ireland to see if there is more of this primitive organism to be discovered.

http://www.bbc.co.uk/news/uk-northern-ireland-15299220

 

[rynner2]

Right, let's push this fossil business way back in time...
British scientists discover 'oldest known' fossils which could help search for alien life on Mars
The 'microfossils' date from around 4.3 billion years ago
John von Radowitz
Thursday 2 March 2017 07:48 GMT

Remains of microbial bugs thought to be the oldest known on Earth have been unearthed by British scientists.
The “microfossils” consist of tiny filaments and tubes formed by bacteria that lived at least 3,770 million years ago.

They were found encased in quartz layers in a rock formation in Quebec, Canada, known as the Nuvvuagittuq Supracrustal Belt (NSB).

The bugs, which lived on iron, are believed to have thrived in a deep sea hydrothermal vent system, a region of volcanic activity on the ocean floor.
Scientists believe the mineral-rich, hot waters surrounding hydrothermal vents may have provided habitats where the Earth's earliest life forms evolved as long as 4.3 billion years ago.

Matthew Dodd, a member of the UK team from University College London (UCL) working on the remains, said: “Our discovery supports the idea that life emerged from hot, sea floor vents shortly after planet Earth formed.
“This speedy appearance of life on Earth fits with other evidence of recently discovered 3,700 million year old sedimentary mounds that were shaped by micro-organisms.”
Previously the oldest reported microfossils, from Western Australia, were dated at 3,460 million years old.

However, some experts believe they may be non-biological features in the rocks.
To be sure of their discovery, the UCL researchers systematically looked at different ways the tubes and filaments could have been made by non-biological means, such as temperature and pressure changes during burial of the rock sediments. All these possibilities were ruled unlikely.

The structures, made from a form of iron oxide called haematite, had the same characteristic branching pattern as that associated with bacteria found near hydrothermal vents today.
In addition they were discovered alongside minerals such as graphite, apatite and carbonate which are commonly found in living organisms.

Lead scientist Dr Dominic Papineau, from UCL’s Earth Sciences department, said: “The structures are composed of the minerals expected to form from putrefaction, and have been well documented throughout the geological record, from the beginning until today.

“The fact we unearthed them from one of the oldest known rock formations suggests we’ve found direct evidence of one of Earth's oldest life forms.”

The scientists believe the find, reported in the journal Nature, could help the search for life on other planets including Mars.
The bugs were living on Earth at a time when Mars is thought to have had oceans or lakes of liquid water on its surface.
Mr Dodd, a PhD student, added: “Therefore, we expect to find evidence for past life on Mars 4,000 million years ago, or if not, Earth may have been a special exception.”

PA

http://www.independent.co.uk/news/science/oldest-fossils-microfossils-bacteria-mars-a7606576.html

 

[OneWingedBird]

World's oldest fungus found in Aldi.... just kidding, really found in rocks dating back 2.4 billion years.

Fungus-like life forms have been found in rocks dating back 2.4 billion years.

The fossils, drilled from rocks that were once beneath the seafloor, resemble living fungi.

Scientists say the discovery could push back the date for the oldest fungi by one to two billion years.

The find suggests that fungi arose not on land but in the deep sea. If not a fungus, the organism could be from an extinct branch of life that has not been described before.

Prof Stefan Bengtson of the Swedish Museum of Natural History led the research team.

He said, in the past, scientists may have been looking in the wrong place for the oldest fossil fungi - on land or in shallow seas rather than in the deep sea.

"The deep biosphere (where the fossils were found) represents a significant portion of the Earth, but we know very little about its biology and even less about its evolutionary history," Prof Bengtson told BBC News.

The fossils are almost indistinguishable from those found in similar environments on land, although they are much older.

BBC

 

[Xanatic*]

That sounds like quite a groundbreaking find, if true.

 

[EnolaGaia]

This study offers some tantalizing - though still only suggestive - evidence that pushes the demonstrable timeframe for the origin of life on earth farther back than could be previously supported ...

Oldest Evidence of Life Found in 3.95-Billion-Year-Old Rocks

... The oldest evidence of life on Earth ever discovered may lie within rocks that are 3.95 billion years old, a new study finds.

The new finding represents the earliest sign of life yet on Earth by 200 million years or more, the researchers said. ...

Until now, the earliest hints of life in the 4.5-billion-year history of Earthwere inside a 3.7-billion-year-old rock from Greenland revealed in 2016. Prior work, from 1996, also claimed to have found signs of life in 3.8-billion-year-old rocks from Greenland's Akilia Island, although those findings remain hotly debated. ...

Now, scientists analyzing 3.95-billion-year-old rocks from northern Labrador in northeastern Canada suggest they have found materials generated by microbes. These may represent the oldest evidence of life found yet on Earth, said study senior author Tsuyoshi Komiya, a geologist at the University of Tokyo.

The researchers examined the oldest known metasedimentary rocks, ones made from sediment that got buried underneath subsequent rock and subjected to high pressures and temperatures, causing the sediment to crystallize. ...

The scientists focused on grains of graphite, a material made of sheets of carbon. Previous research suggested that life could result in graphite that is enriched in lighter isotopes of carbon. ...

Based on the carbon isotopes found in the graphite within the Labrador rocks, the researchers suggested it was biological in origin. The way ancient rock encased this graphite suggested that these newfound signs of life did not originate as contamination from later periods in time. ...

FULL STORY: https://www.livescience.com/60537-oldest-evidence-of-life-found.html

 

[Mythopoeika]

I'm thinking that if the gap between earliest origin of life and the oldest age of the planet is (relatively) small, it's possible that could point towards extraterrestrial origin. At least, I consider that to be very likely.

 

[EnolaGaia]

New research indicates the first widespread color imparted by earth's earliest life may well have been ...

Pink! :nelly:

Earth's Oldest Color Dates Back More Than 1 Billion Years

Is bright pink the new black? Well, not exactly, but it is the world's oldest-known color, according to new research.

Researchers extracted the pigment from bacteria fossils preserved in rocks under the Sahara Desert in Mauritania, West Africa. Inside those teensy bacteria, the scientists found chlorophyll — a pigment used today by plants for photosynthesis — dating back to about 1.1 billion years ago. That's about 600 million years older than similar chlorophyll fossils found previously, scientists reported in the new study. ...

Their findings hint that cyanobacteria, bacteria that survive on sunlight, appeared much earlier than algae, which have been traced to around 650 million years ago. And bacteria likely dominated Earth's ancient oceans for hundreds of millions of years, according to the study.

Chlorophyll is what gives modern plants their green color, though the fossilized chlorophyll in the cyanobacteria samples was dark red and deep purple in its concentrated form, the scientists reported.

When they pulverized the fossils to analyze the bacteria molecules, the researchers distilled the colors to find a brilliant pink. This colorful remnant suggests that ancient sunlight-eating organisms cast a pink tint to a long-gone ocean, lead study author Nur Gueneli, of the Research School of Earth Sciences at the Australian National University (ANU), said in a statement.

Chlorophyll this ancient is preserved only under exceptional circumstances, study co-author Jochen Brocks, an associate professor with ANU's Research School of Earth Sciences, told Live Science in an email. First, dead organic matter — a bloom of cyanobacteria, for example — sinks quickly onto the seafloor. Once there, it must be isolated from any exposure to oxygen, which spurs decay, and then the rock that holds the material has to remain in one piece for a billion years ...

Her reaction to seeing colors produced by organisms that lived more than a billion years ago? "Sheer amazement," Brocks said. Even algae, one of the most ancient forms of life, was absent or scarce at the time of these chlorophyll-swallowing bacteria, the researchers wrote in the study.

It was a few hundred million years until algae would begin to multiply, ultimately forming the base of a food web that would eventually fuel the evolution of larger animals ...

But until the rise of algae, and more-complex organisms, the planet belonged to the bacteria.

"This was truly an alien world," Brocks said.

The findings were published online July 9 in the journal Proceedings of the National Academy of Sciences.

SOURCE: https://www.livescience.com/63022-earths-oldest-color-found.html

 

[Gizmos Mama]

Well, that's a weird coincidence! I was cleaning out my small ornamental fish pond this weekend, that has been out of commission for a full year now, so it's pretty bubbly and murky, and basically totally oxygen deprived from all the dead leaves and no circulation. I noticed some bright purple stuff in among the layers of dead leaves and gunk I was shoveling out. I noticed it because it really was a bright bubble gum purple, and I've never seen that before.

I can't guarantee that it wasn't some thin cardboard litter that was disintegrating from water, but it didn't seem that cohesive to itself, and I did take a closer look when I first noticed it. My first thought was that it was a weird layer of algae. Was it possibly some kind of anaerobic bacteria instead of algae, of the type they are talking about in the article??

Perhaps I was visited by some long lost relatives? (really more like completely decimated their entire local population... oops!)

 

[EnolaGaia]

Similar tunnels / tubes / burrows from Australian rocks have prompted another such claim ...

These Tiny Burrows Might Be Some of the Oldest Fossils on Earth

Tiny filaments burrowed in 3.4-billion-year-old rocks may be evidence of some of Earth's earliest life, scientists argue in a new study. But not everyone is convinced these burrows are fossils of ancient lifeforms.

These so-called microfossils, found in a shallow lake known as Strelley Pool in Western Australia, have been a source of contention for decades, with some scientists arguing that the mysterious tunnels were forged by volcanic processes, rather than primordial life.

The authors of the new study say their analysis of the rocks — which date to the early Archean eon, 4 billion to 2.5 billion years ago — "all but confirms" that these Strelley Pool microfossils were once home to some of Earth's earliest life-forms.

The research, published in the peer-reviewed journal Geochemical Perspectives Letters and presented Aug. 16 at the Geochemical Society's Goldschmidt Conference in Boston, was conducted by a team of scientists led by study author Julien Alleon, a researcher at the Massachusetts Institute of Technology. ...

FULL STORY (With Images): https://www.livescience.com/63386-oldest-microfossils-strelley-pool.html

 

[EnolaGaia]

Here's the publication data and abstract of the article published regarding the Australian finds / claims ...

Chemical nature of the 3.4 Ga Strelley Pool microfossils
J. Alleon, S. Bernard, C. Le Guillou, O. Beyssac, K. Sugitani, F. Robert

Affiliations | Corresponding Author | Cite as | Funding information

Geochemical Perspectives Letters v7 | doi: 10.7185/geochemlet.1817
Received 13 March 2018 | Accepted 21 June 2018 | Published 16 August 2018

Abstract
The biogenicity of putative traces of life found in early-Archean rocks is strongly debated. To date, only equivocal lines of evidence have been reported, which has prevented a full consensus from emerging. Here we report elemental and molecular data from individual organic microfossils preserved within the 3.4 billion-year-old cherts of the Strelley Pool Formation, Western Australia. The present results support the growing body of evidence advocating their biogenicity, promoting them as the oldest known authentic organic microfossils. These microfossils consist of nitrogen- and oxygen- rich organic molecules that have been only slightly degraded despite experiencing temperatures of ~300 °C. Such molecular preservation emphasises the palaeobiological potential of the Earth’s oldest geological record, whilst providing a promising window into the early biosphere.

SOURCE: https://www.geochemicalperspectivesletters.org/article1817

 

[EnolaGaia]

There's controversy over geological evidence in Greenland that's been proposed as proving the existence of stromatolites as of circa 3.7 billion years BP - even farther back than the Australian evidence (see above) suggests ...

Are These Earth's Oldest Fossils of Life? Dispute Has E.T. Implications

Rocks found at Isua in Greenland may contain the oldest fossils of life on Earth, but not everyone agrees.

Scientists will gather in a remote and snowy part of southwestern Greenland next summer to try to determine if rocks from 3.7 billion years ago contain some of the oldest fossils of life on Earth — with implications for the search for evidence of life on Mars.

Tiny, triangular structures found in these rocks have been a source of controversy, with some scientists now saying they are not evidence of early life on Earth. The scientists who first reported that they were fossilized evidence of life are defending their claims.

In a paper published online Oct. 17 in the journal Nature, planetary scientist Abigail Allwood and colleagues, who examined the ancient rocks in Greenland, reported that purely geological processes could explain the triangular rock formations — and that while they might still be formed by microbial life, there was not enough evidence to show definitely that they were. ...

FULL STORY: https://www.livescience.com/64115-oldest-fossils-of-life-dispute.html

 

[ramonmercado]

They look more like modern North Norfolk teeth to me.

Fungus was more advanced than present day Cromerians.

Tiny fossils found in mudrock in the barren wilderness of the Canadian Arctic are the remains of the oldest known fungus on Earth, scientists say.

The minuscule organisms were discovered in shallow water shale, a kind of fine-grained sedimentary rock, in a region south of Victoria island on the edge of the Arctic Ocean. Tests on the shale, which accumulated over millions of years in a river or lake, revealed that it formed between 900m and 1bn years ago in what is now the Northwest Territories. The age of the rock makes the fungus half a billion years older than the previous record holder, a 450m-year-old fungus that was unearthed in Wisconsin.

Writing in the journal Nature, scientists describe how a battery of chemical and structural analyses identified the ancient organism as Ourasphaira giraldae. Spores of the fungus are less than a tenth of a millimetre long and connect to one another by slender, branching filaments.

https://www.theguardian.com/science...ctic-fossils-are-oldest-known-fungus-on-earth

 

[EnolaGaia]

This October 2018 item gives more details about the challenge to the Greenland claims ...

"World's Oldest Fossils" Might Actually Be Simple Rocks, And We're Here For The Drama

A contender for the world's oldest fossil may be out of the running, as recent evidence suggests it could simply be a rock and not a sign of biological life after all.

Holding the record for Earth's earliest-known remnant of life is about as tough as keeping the crown in Game of Thrones. It seems like every few years, the victor is being usurped by some more ancient and impressive find.

For a while there, the oldest known evidence for life was a 3.48 billion-year-old fossil stromatolite - a layered sediment found in shallow waters and formed by mats of single-celled microbes.

This particular stromatolite was found in the Pilbara region of Western Australia in 2011, and for several years it wore the crown for the oldest-known fossil in the world.

It wasn't long, however, before a formidable competitor was found.

In 2016, researchers described the ancient marks of 3.7 billion-year-old organisms found in southwest Greenland.

At the time, the team argued that the morphology, chemistry, mineralogy and layering of these conical rock structures - about one to four centimetres apiece - were evidence of stromatolites.

The extraordinary discovery made headlines worldwide. If the dating proved correct, the fossil record would be pushed back by no less than 200 million years to the very start of Earth's rock record - an incredible change, given Earth itself is thought to be only 4.5 billion-years-old.

Now, however, a new team of researchers is raising doubts about those Greenland fossils. They claim that the previously published results do not support the conclusion about the structures being the remnants of ancient organisms.

Instead, they might just be, well, really old rocks.

Analysing the three-dimensional shape, orientation and chemical composition of the site, the researchers have shown that these so-called 'stromatolites' are more likely the result of geological forces. ...

FULL STORY: https://www.sciencealert.com/doubt-raised-over-current-record-holder-oldest-fossil-sign-of-life

 

[EnolaGaia]

With the purported Greenland evidence ruled out, the Australian stromatolites would seem to be the leading contenders again. New research has confirmed the presence of organic materials in the Australian rocks / fossils, establishing the Australian fossils as the oldest verified evidence of life on earth.

A Mind-Blowing Study Just Confirmed Earth Had Living Organisms 3.5 Billion Years Ago

In the search for the earliest life on Earth, it can be hard to tell whether you're looking at an actual fossil, or crinkles in the rock itself. Such doubts have long shadowed the 1980s discovery of 3.5 billion-year-old fossils in the Australian desert. Now, scientists think they have finally put the matter to bed.

In ancient fossilised microbe formations called stromatolites, found in the Dresser Formation fossil site of the Pilbara region, researchers have finally detected traces of organic matter.

"This is an exciting discovery - for the first time, we're able to show the world that these stromatolites are definitive evidence for the earliest life on Earth," said geologist Raphael Baumgartner of the University of New South Wales (UNSW) in Australia.

You may remember the time scientists claimed to have found 3.7 billion-year-old fossils in Greenland. Later research determined that these fossils were just plain old rocks, and the crown was returned to the Pilbara fossils.

But, although everyone was pretty sure the Pilbara fossils were the real deal, it hadn't actually been conclusively proven. They had the shape and structure of microbial stromatolites, but no evidence of organic matter to back it up.

There's more riding on this than a tiara and a sash reading "Most oldest fossils." It's deeply relevant to one of the fundamental questions about our very existence: When and how did life develop on this sloshy blue marble?

So, Baumgartner and his team went digging. Not literally, though; they analysed previously drilled core samples from deep underground, below where the rocks could have been affected by weather. ....

FULL STORY: https://www.sciencealert.com/those-...lian-rocks-really-are-fossils-new-study-finds

 

[Comfortably Numb]

Tiny 2-billion-year-old fossil blobs may be the oldest complex cells

Source: New Scientist
Date: 15 February, 2020

Fossils of single cells have been found in 2-billion-year-old rocks in China. The microfossils may be the oldest examples of complex eukaryotic cells in the fossil record – in which case they may be our distant ancestors.

Leiming Yin at the Nanjing Institute of Geology and Palaeontology in China and his colleagues found the fossils in a set of rocks called the Hutuo Group in the Wutai mountains in northern China. Previous studies have shown that the rocks were laid down between 2.15 and 1.95 billion years ago. …

https://www-newscientist-com.cdn.am...fossil-blobs-may-be-the-oldest-complex-cells/

 

[EnolaGaia]

... New research has confirmed the presence of organic materials in the Australian rocks / fossils, establishing the Australian fossils as the oldest verified evidence of life on earth. ...

... And researchers have now put forward a hypothesis that the stromatolites' growth and persistence was facilitated by viruses.

Stromatolites – Fossils of Earliest Life on Earth – May Owe Their Very Existence to Viruses

It may pain us to hear this during a deadly viral pandemic, but life as we know it on this planet may never have occurred if it weren’t for viruses, scientists studying billion-year-old ‘living rocks’ say.

In a paper published in the March issue of Trends in Microbiology, a team of scientists from UNSW Sydney and the US looked at evidence of the world’s oldest lifeforms in fossils known as stromatolites, layered limestone rocks often found in shallow waters around the globe. They wanted to understand the mechanism that led colonies of single-celled organisms known as microbial mats to create these intriguing rock structures.

And they believe viruses may be the missing piece of the puzzle that could help explain how a soft microbial mat transitions – or lithifies – into the hard stromatolite features that are prevalent in such places as Shark Bay and the Pilbara, Western Australia. ...

FULL STORY: https://scitechdaily.com/stromatoli...arth-may-owe-their-very-existence-to-viruses/

 

[EnolaGaia]

Chemical signatures for compounds associated with biological life have been confirmed in Archean rocks from Australia.

Scientists Discover 'Ingredients For Life' in 3.5 Billion-Year-Old Rocks in Australia

Researchers have discovered organic molecules trapped in incredibly ancient rock formations in Australia, revealing what they say is the first detailed evidence of early chemical ingredients that could have underpinned Earth's primeval microbial life-forms.

The discovery, made in the 3.5-billion-year-old Dresser Formation of Western Australia's Pilbara Craton, adds to a significant body of research pointing to ancient life in this part of the world – which represents one of only two pristine, exposed deposits of land on Earth dating back to the Archean Eon.

In recent years, the hydrothermal rock of the Dresser Formation has turned up repeated signals of what looks to be the earliest known life on land, with scientists discovering "definitive evidence" of microbial biosignatures dating back to 3.5 billion years ago.

Now, in a new study, researchers in Germany have identified traces of specific chemistry that could have enabled such primordial organisms to exist, finding biologically relevant organic molecules contained inside barite deposits, a mineral formed through various processes, including hydrothermal phenomena. ...

FULL STORY: https://www.sciencealert.com/scient...fe-in-3-5-billion-year-old-rocks-in-australia

 

[bugmum]

I was offered the chance to do my PhD on stromatolites in Australia. Instead I stayed in the UK and looked at herbicide-degrading bacteria instead. These stories could have been me!

 

[Bad Bungle]

Those b*stard stromatolites poisoning the atmosphere with their photosynthetic oxygen waste, nearly wiped our purple sulphur (or nonsulphur) bacterial ancestors. Fortunately we ate something that agreed with us ie a mitochondrial precursor that could cope with the toxic pollution.