A ‘lost world’ of early microbes thrived one billion years ago
science.anu.edu.au
science.anu.edu.au
In my experience, Nature News summaries are generally more trustworthy than university press releases. Nature News can suffer from hype problems seen in all scientific journalism, but it's one of the least bad sources. On the other hand, university press releases are basically unbound by journalism best practices; they can be almost pure marketing and should not be considered more authoritative just because they are associated with the university.
We know that deep underground, and in vents in the ocean floor, there is still some life. Is it possible there are some extreme environments on Earth where this ancient life is still going?
Suppose: on some planet untouched by man, there was a species identical to a species on earth, would you say they share the same ancestor?
Suppose: I generated an organism (that already exists) starting from raw chemistry, would that share the same ancestor as the one that already exists?
It's trivial to apply my hypotheticals to models in which life didn't all descend from a common ancestor.
We don't have such a thing to our knowledge so it's not trivial. If you still feel it is, do the application yourself - it's trivial after all.
I'm finding it very difficult to understand what you mean by "models of life". Actually I have no idea. What does this phrase even mean?
2) There are thoughts that life on Earth, presuming it started on Earth and wasn't seeded from meteorites, may have started from multiple populations. But it's presumed that if it did so those multiple populations were either out-competed by one population, or sufficiently alike that they effectively merged in their descendants.
At any rate, at this point, all life that we have so far detected shares similar enough features to presume a common origin. This includes incredibly separate lineages such as the bacteria and archaea.
Would you consider modern computers to be descended from IBM mainframes? Someone building a duplicate lifeform from parts based on existing knowledge and existing lifeforms does not negate that those existing lifeforms evolved into form since the beginning of terrestrial life. Your work is standing on preexisting evolutionary knowledge, processes, and a chain of life, even if it technically replaces biological reproduction with a human engineer.
From a dialectical point of view you're effectively invoking god to nitpick. If you believe you aren't you're going to have to spell it out for me.
Disclaimer: I'm bad at maths and good at dreaming.
The bare simplest genomes are viral genomes about 1000 bases long. These can only operate in environments created by more complex genomes. But even taking them, the theoretical diversity in a genome 1000 bases long, using the 4 canonical nucleic acids, is 4^1000. The number of atoms in the entire universe is around 10^80 (https://educationblog.oup.com/secondary/maths/numbers-of-ato... ).
There's a lot of complexity here: other life may use other nucleotides; those atoms and bases are constantly being rearranged; many base changes are relatively silent - they don't materially matter; etcetera.
I don't know how to calculate all of the rest of these factors, but I think the odds are more than astronomical.
OK, let's do this then. Here we will approximate the ratio 4^1000/10^80:
x = 4^1000 / 10^80
ln(x) = 1000 * ln(4) - 80 * ln(10) // You know your logarithm calculation rules, right? Right?!
ln(x) = 1386 - 184 // Who needs decimal places anyways? ;)
ln(x) = 1202
x = 10^522
Eh, at one point I did. I'll take your word for it. It seems familiar.
Now factor in number of rearrangements since the universe started. Or heck, let's keep it simple to the last 4.5 billion years.
I count about 30 atoms in a nucleotide, so X is a bit more than 10^523.
Let's say 2 rearrangements per day (this will vary dramatically, but I have to pull some number out of a hat). Over 4.5 billion years that's on the order of a bit more than 10^12. so X is around 10^511.
Yep, still more than astronomical.
And I'm very sad to (re?)learn this finite number of atoms in the universe, that's quite underwhelming for something expanding all the time.
Most combinations of nucleotides aren't functional, or even capable of being synthesized by natural processes. This limits what can be created quite a bit. The true odds are still extremely high, but not nearly as high as these calculations guess.
This is incorrect. It's an unsolved question in modern physics if the universe is finite or infinite. Even if it's finite most theoretical physicists believe that visible universe (94 billion light years across) is only a small piece of a far larger universe - so there are probably far more atoms.
If the universe is infinite it may be that there are infinite number of copies of every living organism on Earth out there.
2. Seems like you're broadly stretching the definition of a biological ancestor.
It's like saying a standard opener move in a boardgame is unlikely because there's a lot of other moves available. It's standard move because the game have an optimal set of opener move to achieve victory.
So if another planet with similar environment exist, the range of solutions for self preservation goal might be a tiny subset out of the hundreds of millions of bits of genetic information.
For example, the Great_Oxidation_Event (https://en.wikipedia.org/wiki/Great_Oxidation_Event) that killed off many anerobic organisms. So there are still pockets environments that can support such anaerobes, but they are rare.
Many Archaea (https://en.wikipedia.org/wiki/Archaea) are inhabitants of extreme environments - the extremophiles - but are they the same organisms as the ancient life here, or also relatives?
The Movile cave [1] has been sealed off from the atmosphere for 5.5 million years, and it's filled with very unique creatures. They survive off of chemosynthesis, rather than photosynthesis. It's an extremely low-oxygen environment!
The oldest I can think of are the Movile Cave [1] which was isolated for 5.5 million years before it was discovered and Lake Vostok [2] which has been isolated for tens of millions of years.
https://www.theguardian.com/sport/2021/jun/02/do-not-touch-t...
Not sure where this sentiment is coming from… Considering it’s fat traces of a primordial species that is a common ancestor of all complex life on earth, which went extinct over 800 million years ago, and is found in ancient rocks around waterways literally all over the world; I think we are fine to touch it.