Life is an information system.
Of photons are wrought the waves of the Earth. Of photons are the machinations of crust-dwelling monsters set in motion.
Oxygen is a toxin that wiped out life for a new form to evolve. It is a currently breathable reset-button.
Darwin’s warm little pond must have been fresh water because cell membranes cannot form in salt water. Early earth was a ball of water, no land. Actually, little specks of land, sporadic volcanic islands. Maybe it rained and a pond formed.
So soon did life arise after the formation of this first ocean. Does that mean that life is common in the galaxy? Or does it mean that we are special and can only lift the burden of our improbability with the many-armed god we call the multiverse?
Asteroids carry organic molecules. Sugars are formed of stardust clouds. It was thought that most carbon came from stellar nucleosynthesis, but now we know that most of it comes from the effects of UV irradiation. Carbon, Hydrogen, Helium, and Oxygen are the four most common elements in the universe, with Carbon being the fourth.
Life, also known as The Rage Against Entropy, needed a boundary to separate from the rest of the matter. What was that boundary?
Current life came from extremophiles and these in turn came from an RNA world, but this RNA world came from some other -NA world.
Our LUCA, our first father, was probably an extremophile. If you look at the base of the phylogeny of life, you’ll see that both in bacteria and archaea, the most ancient clades are extremophiles. If we find a bacteria-like organism under the ocean of some moon, this will lend credence to the idea that LUCA was a creature dependent on hydrothermal vents.
Short recap: The Big Bang, then Gravity, then Light, Andromeda, then Hera’s breast milk, then our solar system and Earth, (then ocean, then life), then oxygen, then photosynthesis, then the now of humans.
The first life might have been a super organism trading its innards amongst itself, without clearly defined boundaries. Only later did it form clear boundaries and gain the ability to move into the salty ocean. [Side note: This is the inspiration for LDL in Neon Genesis Evangelion.]
We know that ribosomes are actually ribozymes with an RNA core. RNA must have auto-catalyzed itself, but because its sugar backbone can be easily cut up (hydrolyzed) it couldn’t have been swimming naked.
As Boltzmann, the Austrian physicist pointed out and his compatriot Erwin Shrodinger later co-signed in his book, What is Life?: life is not competing for energy or limited resources, most life is actually competing for something more profound which is the safety from entropy afforded by some particular solar grace.
If we view life as an information system, it must have started from simplicity – just a slight betrayal of the thermodynamic equilibrium in it’s surroundings while simultaneously having a way to replicate that rebelliousness.
The similarity of blood to salt water is probably related to the fact that our ancestors evolved in salt water. Clay may have been essential to the initial formation of life. These are hypotheses that, while not proven, are taken seriously. One point for Bible thumpers, zero points for those Quranically-oriented. (The Quran claims that God fashioned man from a blood-clot.)
If we blur our eyes a little and look at it from a physicist’s perspective, it is a matter of mathematical probability that a clump of matter shot with constant UV will eventually form pockets that isolate and enclose themselves. Or is it?
Water with a metabolism came first and only then did it seal itself off as current cells do with a phospholipid bilayer. Phospholipid bilayers in the form of micelles form readily anyway.
Cyclic carbon molecules seem to be extremely common in space, so the carbon needed for organic molecules such as the simple CH4 (methane), and all the others, is easily explained as having rained down from space. We know that the Earth was heavily bombarded by meteors along with Mercury, Venus, the Moon, and Mars when a shift occurred in the orbit of Jupiter.
The spark for the initial thermodynamic departure may have been caused by lightning or a radioactive beach with uranium sand.
Then there are pseudo-mysteries like why the amino acids are particularly what they are. The truth is that they could have been different, but as soon as the first were formed – taking into account all causal variables such as the direction of the spin of the Earth, etc. – these first amino acids then had to be favored by natural selection.
There might have been several origins of life, some with different chemistry than others, but only one really took off. We might yet find evidence of the other failed geneses in ancient rocks.
The electrochemical gradient is very “natural” with protons (H+) going out and negatively charged ions going in. On the other hand, the storage of information in sequential packets like RNA and DNA seems like less obvious consequence of matter bouncing around in the primordial soup. So there was probably a step by step evolution by means of natural selection with regard to the formation of RNA and DNA as the hereditary machinery. There must have been a precursor to RNA, but we know that it wasn’t crystals because although these could replicate, they have been shown to not preserve information faithfully from mother to daughters.
People believed that frogs formed from slime, that rats formed from old hay, and that flies spawned from rotting meat. Even Aristotle believed that logs became crocodiles. Pasteur proved all this wrong, and what had been common knowledge was replaced with the idea that life only comes from life – for all living beings, there is an egg. But this created the scientific problem of where the initial life came from. Darwin said it was as unfounded to speculate about this initial origin of life as it was to speculate about the origin of matter. Ironically, the people who believed in abiogenesis were partially correct but for the wrong reasons. At some point, what we call life, must come from basic molecules which we choose to not call life.
Panspermia is the idea that life already existed and that microbes are spreading it through space, maybe even interstellar space. This doesn’t address the problem of abiogenesis but that doesn’t mean panspermia isn’t true. It is possible that life originated in Mars and that a chunk of Mars bearing that life seeded the Earth since early Mars might have been more hospitable to our current postulated conditions for abiogenesis than Hadean Earth.
Craig Venter’s team is reverse engineering life. Starting with a simple cell and subtracting until they can’t anymore. Others are trying to build it from scratch. Venter’s approach has been more successful so far.
Stellar nucleosynthesis created the heavy elements needed for life. As Lawrence Krauss likes to say, “Stars died so you could be born.”