Paleontologist presents origin of life theory

Paleontologist presents origin of life theory
Meteorite bombardment left large craters that contained water and chemical building blocks for life, which ultimately led to the first organisms.

It has baffled humans for millennia: how did life begin on planet Earth? Now, new research from a Texas Tech University paleontologist suggests it may have rained from the skies and started in the bowels of hell.

Sankar Chatterjee, Horn Professor of Geosciences and curator of paleontology at the Museum of Texas Tech University believes he has found the answer by connecting theories on chemical evolution with evidence related to our planet's early geology.

"This is bigger than finding any dinosaur," Chatterjee said. "This is what we've all searched for – the Holy Grail of science."

Thanks to regular and heavy comet and meteorite bombardment of Earth's surface during its formative years 4 billion years ago, the large craters left behind not only contained and the basic chemical building blocks for , but also became the perfect crucible to concentrate and cook these chemicals to create the first simple organisms.

He will present his findings Oct. 30 during the 125th Anniversary Annual Meeting of the Geological Society of America in Denver.

As well as discovering how ancient animals flew, Chatterjee discovered the Shiva Meteorite Crater, which was created by a 25-mile-wide meteorite that struck off the coast of India. This research concluded this giant meteorite wreaked havoc simultaneously with the Chicxulub meteorite strike near Mexico, finishing the dinosaurs 65 million years ago.

Ironically, Chatterjee's latest research suggests meteorites can be givers of life as well as takers. He said that meteor and comet strikes likely brought the ingredients and created the right conditions for life on our planet. By studying three sites containing the world's oldest fossils, he believes he knows how the first single-celled organisms formed in hydrothermal crater basins.

Paleontologist presents origin of life theory
Crater basin may have been the crucible of life.

"When the Earth formed some 4.5 billion years ago, it was a sterile planet inhospitable to living organisms," Chatterjee said. "It was a seething cauldron of erupting volcanoes, raining meteors and hot, noxious gasses. One billion years later, it was a placid, watery planet teeming with microbial life – the ancestors to all living things."

Recipe for Living

"For may years, the debate on the origins of life centered on the chemical evolution of living from organic molecules by natural processes. Chatterjee said life began in four steps of increasing complexity – cosmic, geological, chemical and biological.

Paleontologist presents origin of life theory
Most researchers believe that Life originated in deep-sea hydrothermal vents. About 4 billion years ago, Earth was a watery planet; ocean stretched from pole to pole; any life synthesis would be diluted. It needed a protected basin.

In the cosmic stage, a still-forming Earth and our solar system took a daily pounding from rocky asteroids and icy comets between 4.1 to 3.8 billion years ago. Plate tectonics, wind and water have hidden evidence of this early onslaught on our planet, but ancient craters on the surfaces of Mars, Venus, Mercury and our moon show just how heavy the meteorite showers once were.

Larger meteorites that created impact basins of about 350 miles in diameter inadvertently became the perfect crucibles, he said. These meteorites also punched through the Earth's crust, creating volcanically driven geothermal vents. Also, they brought the basic building blocks of life that could be concentrated and polymerized in the crater basins.

Paleontologist presents origin of life theory
Hierarchical Origin of Life: Historical Contingency Parsimony principle chooses the simplest explanation for the origin of life.

After studying the environments of the oldest fossil-containing rocks on Earth in Greenland, Australia and South Africa, Chatterjee said these could be remnants of ancient craters and may be the very spots where life began in deep, dark and hot environments.

Because of Earth's perfect proximity to the sun, the comets that crashed here melted into water and filled these basins with water and more ingredients. This gave rise to the geological stage. As these basins filled, geothermal venting heated the water and created convection, causing the water to move constantly and create a thick primordial soup.

"The geological stage provides special dark, hot, and isolated environments of the crater basins with the hydrothermal vent systems that served as incubators for life," he said. "Segregation and concentration of organic molecules by convective currents took place here, something like the kinds we find on the ocean floor, but still very different. It was a bizarre and isolated world that would seem like a vision of hell with the foul smells of hydrogen sulfide, methane, nitric oxide and steam that provided life-sustaining energy."

Then began the chemical stage, Chatterjee said. The heat churning the water inside the craters mixed chemicals together and caused simple compounds to grow into larger, more complex ones.

Paleontologist presents origin of life theory
Crater Basin with Hydrothermal Vent System Meteorites brought biomolecules of cell membrane.

Protecting Important Information

Most likely, pores and crevices on the crater basins acted as scaffolds for concentrations of simple RNA and protein molecules, he said. Unlike a popular theory that believes RNA came first and proteins followed, Chatterjee believes RNA and proteins emerged simultaneously and were encapsulated and protected from the environment.

"The dual origin of the 'RNA/protein' world is more plausible in the vent environments than the popular 'RNA world,'" he said. "RNA molecules are very unstable. In vent environments, they would decompose quickly. Some catalysts, such as simple proteins, were necessary for primitive RNA to replicate and metabolize. On the other hand, amino acids, from which proteins are made, are easier to make than RNA components."

The question remains how loose RNA and protein material floating in this soup protected itself in a membrane. Chatterjee believes University of California professor David Deamer's hypothesis that membranous material existed in the primordial soup. Deamer isolated fatty acid vesicles from the Murchison meteorite that fell in 1969 in Australia. The cosmic fatty bubbles extracted from the meteorite mimic cell membranes.

Paleontologist presents origin of life theory
Endosymbiotic origin of Eukoryote cells.

"Meteorites brought this fatty lipid material to early Earth," Chatterjee said. "This fatty lipid material floated on top of the water surface of crater basins but moved to the bottom by convection currents. At some point in this process during the course of millions of years, this fatty membrane could have encapsulated simple RNA and proteins together like a soap bubble. The RNA and protein molecules begin interacting and communicating. Eventually RNA gave way to DNA – a much more stable compound – and with the development of the genetic code, the first cells divided."

The final stage – the biological stage – represents the origin of replicating cells as they began to store, process and transmit genetic information to their daughter cells, Chatterjee said. Infinite combinations took place, and countless numbers must have failed to function before the secret of replication was broken and the proper selection occurred.

"These self-sustaining first cells were capable of Darwinian evolution," he said. "The emergence of the first cells on the early Earth was the culmination of a long history of prior chemical, geological and cosmic processes."

Chatterjee also believes that modern RNA-viruses and protein-rich prions that cause deadly diseases probably represent the evolutionary legacy of primitive RNA and . They may be the oldest cellular particles that predated the first cellular life. Once cellular life evolved, RNA-viruses and prions became redundant, but survived as parasites on the living cells.

The problem with theories on the origins of life is that they don't propose any experiments that lead to the emergence of cells, Chatterjee said. However, he suggested an experiment to recreate the ancient prebiotic world and support or refute his theory.

"If future experiments with membrane-bound RNA viruses and prions result in the creation of a synthetic protocell, it may reflect the plausible pathways for the emergence of life on early Earth," he said.

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New findings challenge assumptions about origins of life

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Oct 29, 2013
Very interesting. I hope that these processes are actually experimentally replicable enough that we can at least get a plausibility determination. As we know in the hard sciences (i.e. physics, chemistry, mathematics), even the most convincing theories typically need a lot of underlying experimental work to keep the theorists from marching off into fantasy land. That tendency is an unfortunate side effect of our limited cognitive abilities.

Oct 29, 2013
Not really useful, life can arise in only two ways, spontaneously, whenever conditions are right, or miraculously only once, only one place and then spread. The key events lead from inanimate to animate, all else is a diversion.

Oct 29, 2013
I think it is a step in the right direction to place the origins of lifes specific steps in order. If the most simple life is a prion or a virus how do you get from a greasy bioite mineral to a cyclic system running on available chemical energy. Make a flow chart. If the geological-chemical origin of life is true, then we should find the first stages of life around the oldest geological formations. You should be able to guess where it resides. Can't find a trace from the bombardment? Then the origin is further back in time and distance and must be a cosmic origin. Life on this planet is very rare. Calculate the volume of life versus the volume of earth. Comet material would have to have a high concentration of life pieces in order to seed life. Perhaps looking at the orbit of solar systems that have been in near collision with our solar system will show exoplanets terraformed like our own. You still havn't found the origin of the complexity of life. Evolution is after life starts.

Oct 30, 2013
I have a hard time believing that the energy which a comet or a large meteorite capable of punching through to magma would release would allow the site to remain at a low enough temperature for liquid water to remain. If one hit in water the reflow would dilute and disperse any chemical payload that wasn't ejected.

Oct 30, 2013

For those of us who believe in God, this part of our history is not baffling.

And for those of us that don't, people like you look damn silly. Especially with such claptrap nonsense as "it was God."

Oct 30, 2013
I find it difficult to get past the anthropomorphic-biased sequence of presumed events. The author presupposes that the end product, eukaryotic life, is the reason for the precursors, RNA & proteins and then goes on to imbue them with purposeful actions such as enveloping themselves in membranes and communicating. These are the actions of the complex end product, life, not of oily bubbles and acidic carbon-based slime. RNA, sans life, is no more pre-determined to evolve than halite. This view merely pushes the mystical life spark on to RNA as the protogenerator of life without explaining how RNA gained a deterministic purpose to become life.

Oct 30, 2013
"Chatterjee discovered the Shiva Meteorite Crater, which was created by a 25-mile-wide meteorite that struck off the coast of India. This research concluded this giant meteorite wreaked havoc simultaneously with the Chicxulub meteorite strike near Mexico, finishing the dinosaurs 65 million years ago."
"Earth scientists in general remain unconvinced that the "Shiva Crater" is indeed an impact crater. For example, Christian Koeberl, a professor of impact research and planetary geology at the University of Vienna, Austria, regards the Shiva crater to be "a figment of imagination."[4][5] Currently, it is not recognized as an impact crater by the Earth Impact Database of the Planetary and Space Science Centre at the University of New Brunswick, Canada."

Oct 30, 2013

1. RNA is catalytically active on its own. The ribosome, for example, is able to polymerize amino acids without any of its protein subunits. RNAseP is another. Plausible prebiotic synthesis routes and extraterrestrial origins have been found for all the RNA nucleotides and spontaneous polymerization is possible on certain minerals like montmorillonite clay. Current research is also leading toward better and better general RNA polymerase ribozymes. These ribozymes are subject to Darwinian natural selection as those capable of replicating themselves faster would use up the precursor molecules and flourish over those with lower fecundity.

2. Encapsulation is not a purposeful event. It occurs spontaneously in solutions containing lipids due to their self-assembling properties. Cycled hydration and dehydration on surfaces is sufficient to encapsulate large macromolecules. This would easily occur on shores and rocks exposed to waves or tidal movement.

Oct 30, 2013
This theory is showing DNA in the first cells. I seriously doubt the first life had DNA. There's no way something as complex as DNA just sprang up full blown in the first life. My guess would be RNA came first.

Oct 30, 2013
Voted it down.
"Came from the sky"
"born in hell"
"holy grail... more important than any dinosaur..."

Not to mention, this isn't a theory at all, it's a hypothesis, and one that's been brought up before, sans the religious overtones.

Oct 30, 2013
Chatterjee is a cook, he is the one behind Protoavis [ http://en.wikiped...atterjee ] and the not accepted 'Shiva crater'. His ideas here is a cookbook on ideas already presented elsewhere.

Btw, hydrothermal vents produce lipids by themselves.

Oct 30, 2013
@axemaster: Too true. Since Lane & Martin already established that life clades within alkaline hydrothermal vents, these ideas are but a variant.

@adave: "Evolution is after life starts." Not a fact, chemical evolution is seamlessly led into biological evolution, see the established phylogeny above.

@Moebius: Indeed, that RNA was first is well established (and implicitly led to a Nobel prize for elucidating the RNA core of the ribosome protein translator).

As for the hilarious creationist trolling, it is this time notable that they can't publish their magic ideas in peer publication, simply because it is nonfactual and clash with how life evolved. The only result they get with their antics and inanities is deconverts from magic beliefs, see Dawkins's Convert's Corner.

Oct 30, 2013
I should add that Chatterjee does his presentation in order to get it published as an abstract in a conference proceeding.

If the GSA is on their toes they will stop the abstract, since it doesn't seem to present anything new, i.e. isn't peer review publishable.

Oct 30, 2013
once you have chemistry, life is inevitable..

Oct 31, 2013
if you took all the if, ands, or but's out of this story.....all you have left is the author's name

Nov 01, 2013
I cannot add anything new to the discussion but that won't stop me.
I am with Terrance Mckenna. Panspermia. There is something wacky at the foundations of our understanding of reality on this planet.
Douglas Adams tried to express this feeling with his allegory of the mice doing subtle experiments on the scientists.
Anyway, here is Mckenna's tale. Do try it-it will rattle your Ego-which is a good thing.

Nov 02, 2013
Since we have had large recent and early impacts, where are the signs of life in some of the early rock still available or the most recent craters? Genesis of life should be possible more than one time. We should find the mineral changes caused by newly formed life at different ages. Stromatolites have had a very low rate of evolution in the past 3.5 billion years. How many steps do they take to exhibit life? If a virus is more simple, how many steps for the virus to step through its possible states before it inputs energy quanta again? There should be evidence of the generation of life existing over an epoch. If the answer is panspermia, life must still be preserved in rock, ice, or interstellar organic concretions in order to impact the Earth and live. It is hard to seperate life from its growth medium. If life grew best in water on the earth under high pressure, then wherever it began, the origin must have been the same. We are still left with a mystery.

Nov 03, 2013
@adave: The earliest (arguable) fossils are from a period right after the presumed late bombardment that shows on Moon, Mars, Mercury and if so have erased earlier rock records. It is the Isua BIFs which on microscale shows Fe oxidizers @ > 3.8 Ga.

If life is extant, later chemical evolution merely serves as nutrient. Already Darwin had grokked and formulated that prediction of why we don't see life forming still. This is no mystery at such, and it hasn't been for over a century.

Stromatolites bacteria consists of new species compared to the first we see, and those bacteria evolves as fast as others - faster than we, due to large populations. Stromatolites are, like viruses, more a niche than a specific set of species.


Nov 03, 2013

As I note above, where and how life evolved is likely solved now, by Lane & Martin, at the resolution that we are able to easily see (after 4 billion years!). To resolve more detail of how it happened, we need Russell's lab work, he got 8 MUSD from NASA to look into chemical reactors that works like the first life did.

[Refs: Like last time I'm out of time here. The Isua results are googeable. Lane & Martin: "The Origin of Membrane Bioenergetics", Cell 2012 - a must read!]

Nov 03, 2013
@Torbjorn - great article.
I'd read the earlier works on alkaline hydrothermal vents, but had missed Lane & Martin's broader paper. Thanks for the reference!

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