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#abiogenesis

1 post1 participant0 posts today
Public
Mikko Tuomi

The last universal common ancestor lived off #hydrogen gas and carbon dioxide, boasted a genome as large as that of some modern #bacteria, and already had an immune system

Its genomic complexity suggests that it was one of many lineages living about 4.2 billion years ago, a turbulent time early in Earth’s history and long thought too harsh for life to flourish.

#Life evolved from a simple replicator into something resembling modern microbes very quickly.

#abiogenesis
quantamagazine.org/all-life-on

An illustration shows a diverse menagerie of modern life forms — human, fern, fish, bird, lion, octopus, crab, tree, and more — inside a cell membrane.
Quanta Magazine · All Life on Earth Today Descended From a Single Cell. Meet LUCA. | Quanta MagazineThe clearest picture yet of our “last universal common ancestor” suggests it was a relatively complex organism living 4.2 billion years ago, a time long considered too harsh for life to flourish.
Public
Mikko Tuomi

Ancient #Earth was nothing like our current home.

It was a much more hostile place; rich in metallic iron with an #atmosphere containing hydrogen and methane.

These molecules contain an important clue to how #life was initially formed.

When exposed to solar #ultraviolet radiation, they undergo a chemical reaction that produces organics: precursors to essential biomolecules, such as amino acids and nucleic acids.

#astrobiology #abiogenesis
phys.org/news/2024-10-life-beg

Phys.org · How life began on Earth: Model suggests ancient Earth had organic-rich atmosphereBy Tohoku University
Public
Mikko Tuomi

The nature of the last universal common ancestor (#LUCA) have been the subject of vigorous debate across diverse disciplines.

Age estimates for LUCA are usually based on the fossil record, varying with every reinterpretation while #metabolism has proven equally contentious.

New results indicate that LUCA lived ~4.2 Ga ago and had a genome of at least 2.5 Mb, encoding around 2600 #proteins.

#evolution #abiogenesis
nature.com/articles/s41559-024

NatureThe nature of the last universal common ancestor and its impact on the early Earth system - Nature Ecology & EvolutionIntegration of phylogenetics, comparative genomics and palaeobiological approaches suggests that the last universal common ancestor lived about 4.2 billion years ago and was a complex prokaryote-grade anaerobic acetogen that was part of an ecosystem.
Continued thread
Public
Knowledge Zone

Within a few billion years atoms formed, then stars formed from atoms, galaxies formed from stars and gas, our Sun formed, soon followed by our Earth, about 4.6 billion years ago.

#Abiogenesis is the natural process by which life arises from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single event, but a process of increasing complexity.

knowledgezone.co.in/kbits/62ce

Public
Mikko Tuomi

What implications does the #flare frequency have on #ozone depletion and #abiogenesis in #exoplanets orbiting M dwarfs?

Even when #stars have a sufficiently high rate of energetic flares, such that they are likely to have a positive impact on abiogenesis on Earth-like #planets, there might simultaneously be significant ozone depletion.

#astronomy #astrobiology
link.springer.com/article/10.1

SpringerLinkTransiting Exoplanet Survey Satellite (TESS) Observations of Flares and Quasi-Periodic Pulsations from Low-Mass Stars and Potential Impact on Exoplanets - Solar PhysicsWe have performed a search for flares and quasi-periodic pulsations (QPPs) from low-mass M-dwarf stars using Transient Exoplanet Survey Satellite (TESS) two-minute cadence data. We find seven stars that show evidence of QPPs. Using Fourier and empirical mode decomposition techniques, we confirm the presence of 11 QPPs in these seven stars with a period between 10.2 and 71.9 minutes, including an oscillation with strong drift in the period and a double-mode oscillation. The fraction of flares that showed QPPs (7%) is higher than other studies of stellar flares, but it is very similar to the fraction of solar C-class flares. Based on the stellar parameters taken from the TESS Input Catalog, we determine the lengths and magnetic-field strengths of the flare coronal loops using the period of the QPPs and various assumptions about the origin of the QPPs. We also use a scaling relationship based on flares from the Sun and solar-type stars and the observed energy, plus the duration of the flares, finding that the different approaches predict loop lengths that are consistent to within a factor of about two. We also discuss the flare frequency of the seven stars determining whether this could result in ozone depletion or abiogenesis in any orbiting exoplanet. Three of our stars have a sufficiently high rate of energetic flares, which are likely to cause abiogenesis. However, two of these stars are also in the range where ozone depletion is likely to occur. We speculate on the implications of the flare rates, loop lengths, and QPPs for life on potential exoplanets orbiting in their host star’s habitable zone.
Public
Teixi

97yo genie #HHPattee published a chapter just few months ago in #OpenSemiotics vol4, in which expands & pushes his theoretical argumentation framework, embracing the recent biology research on #abiogenesis & spontaneous #folding

top quote:

» #RNATieClub did not discover the “mechanism” of the code because there was no #mechanism
The code is symbolic or “chemically gratuitous” in #Monod words
There was nothing to discover from laws or logical thinking «

academia.edu/114451075/Symbol_

www.academia.eduSymbol Grounding by Folding: The Primary BiosemiosisInterpretation of human language is an obscure process that constructs meaning from symbol vehicles. Less obscure is the symbol grounding of genetic language by copolymer folding. Folding is an energy-dependent dynamics that removes sequence
#biosemiotics
Public
Knowledge Zone

#DidYouKnow: In biology, #Abiogenesis or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds.

Stages in the origin of life range from the well-understood, such as the habitable Earth and the abiotic synthesis of simple molecules, to the largely unknown, like the derivation of the last universal common ancestor (LUCA) with its complex molecular functionalities. (1/2)

knowledgezone.co.in/kbits/62ce

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