Hibernating life means that it can’t reproduce, which means that it can’t exist in asteroids, or else it would just all die off in a few centuries, also, how did it get to the asteroid in the first place if it’s hibernating? One must assume that non-hibernating asteroid life exists too. And as such life in mars would exist too.
It being proto-DNA doesn’t change the fact that it can’t survive for long periods of time.
Microbes start hibernating when conditions get worse. Anyway, I’d like to change my stance from panspermia to assisted abiogenesis.
I agree. We are likely to find life on Mars, it was very similar to Earth.
It could work, they would evolve over billions of years, and with a simple version of DNA, different stuff could be possible, such as pseudo-hibernation, where they could consume food and reproduce.
If it had a different atomic makeup, it could change the lifespan.
Not necessarily, they could evolve that just in case or maybe even if need it more.
@Nigel how is it impossible? It would be easier as it would allow them to evolve and better suit their new environment with gravity and atmosphere and other new stuff.
If the microbe originated from an asteroid enviroment or something similiar then it wouldn’t hibernate.
If it has a different atomic makeup then why did it change? That would be a radical change which would require the microbe to retroactively change all of its genes too.
(which is impossible in @CatSquared 's argument btw)
Additionally, there are practically NO elements capable of forming dna that are simpler than DNA, thus the problem of half life is still a very real threat to your argument. This is mostly due to the fact that most elements cant bind to other atoms in the way the the elements that makeup normal DNA can.
(@CatSquared)
Okay, the proto-DNA was a bit of a stretch, when it was just backup evidence, but the pseudo-hibernation would still be possible. Sort of.
Well you see, tartigrades cant hibernate forever because eventually they need to restock on resources. I feel as if this issue would similarly arise in this hypothetical scenario. Feel free to list points on why it would work though.
Complex molecules could have formed in the early universe.
I don’t get why nucleotides can survive, but nucleotide chains have a shorter half life.
edit:
DNA doesn’t have a half life of 521 years. That is only true on Earth. Cells in asteroids in space wouldn’t degrade.
The issue now isn’t that they will degrade, its that the cells, even if they are on asteroids, will eventually run out of resources. Since living things require more resources to, well, live, they eventually would die off due to lack of resources. It seems impossible for something to go into an indefinite hibernation without ceasing to live. Also, we aren’t taking into account the universe has also changed over time - what temperatures were 10-12 million years after the universe’s beginning were not what they were when the solar system came into existence. These factors, along with space radiation, effectively gets rid of the possibility of life on earth starting from something out of the solar system. Even from Mars or even Venus, it would be implausible that panspermia would occur.
Maybe the ametabolic one can be reversed too. But even if that can’t happen, a dead microbe is way better candidate to creating life than the earliest organic compounds, because the molecules present are already the ones that are needed to support fully functioning life.
Life could have appeared in any rogue planet in the early universe, and from there, it could have spread to all the other rogue planets and asteroids. They wouldn’t be able to survive on the surface, the first generation stars were very large and they went supernova, there would be too much radiation. The microbes would survive in the cores of the planets, still hot enough to have water or non lawk liquids, evolving as the chemosynthetic food is depleated. They would be ejected to space when an impact removes material from that planet. They or their corpses would do the journey. The center of an asteroid is uneffected both from space radiation and the heat during an impact.
i watched the video and it failed to account for the fact that primitive enough prokaryotes could have just doubled their genomes in one generation by failing to perform binary fission or performing binary fission without any RNA in one half of the cell and having all the RNA in the other half, and while that would make only one able to undergo biological evolution the other would have twice the RNA to have mutations in, and that could’ve happened several times, and we already know not all of anything’s dna originally belonged to it, so foreign dna must also be accounted for. though it may not be more likely based on chance over time it is more likely that gene stealing happened several million times before our LUCA than it is life started directly after the big bang, though it is possible that happened one must look at every single variable to determine the past, the more variables you look at the higher your accuracy, and, if you look at too few you will get impossible pasts leading to wildly different presents than yours
Eukariotes and multicellular species can do gene duplication too. In fact, that is how evolution happens. You don’t make point mutations and create genes from scratch. You copy a gene (evolution is faster when a whole genome duplication happens), keep using one copy for its previous job, and assign the new copy to a similar job. If a copy is not used, it remains inactive and it may eventually be deleted.
The video said the functional genome size was increasing exponentially, doubling every 350 million years.
What does horisontal gene transfer have to do with genome size? Do you suggest it causes more complex genomes to appear faster than they do today?
is that anywhere close to a single generation though?
yes actually, it allows things to take genes and add them to their own genome meaning the functional genome size thing is merely a suggestion and nowhere close to a rule, especieally when you throw viruses into the mix since they move genes aroud a lot, sometimes only adding genes, sometimes just taking them, and sometimes getting its funcional genome neutralized and fully incorporated into a bacterial plasmid
Doubling the genome in a single generation keeps the functional genome the same size. The copies need to mutate so that they can be assigned to new jobs.
The genes are useful to only their already existing jobs. They become useful to new jobs as time passes. Time can only modify the genes you already have, so the rate of evolution is proportional to the size of the genome already present, hence the exponential.
No species creates a completely a random chunk of DNA 100 times the size of its current DNA, waits it to mutate and checks once in a while if any segment of it can be used in a useful way. They don’t build up usefulness from scratch.
Why faster back then? The observed pattern is that evolution has a constant exponential speed and life must be 10 billion years old (the times when it hibernated or remained dead doesn’t count)
It doesn’t become functional when you double it. It doesn’t take new functions.
We can write a formula for the speed of evolution in the following way:
E = C x M
The speed of evolution is equal to the speed of copying times the speed of modifying. Copying refers to when you double your genes one by one or the whole genome at the same time. Modifying refers to turning those non functional copies into functional ones. What causes copying is mutations, and what causes modifying is mutations and natural selection.
The speed of copying is proportional to your genome size, because if you have a large genome, you would have more genes to copy.
Life goes from less complexity to more complexity, because if you have only a few genes, the information they are coding can’t be that much. And genome sizes have been increasing. What I referred to as “the speed of evolution” in the formula above is the speed of the increase in complexity. If you kept the same genome size, and only changed what it coded for, it would still be evolution, but it wouldn’t be “progress”
When you are copying your genome, the copying you can make is proportional to the genome size you already have. So after some time passes, a small genome would have grown by a small amount, and a large genome can grow by a large amount. Which function’s derivative is equal to itself? Its the exponential function.
The complexification or progress can stop when new progress is no longer needed. But the fact that life needs 10 billion years to get to where it is right now suggest that life on earth has to be 10 billion years old or older.
Well, it would be possible, as these creatures would barely move, but could still absorb tiny amounts of nutrients and reproduce. That’s why it’s pseudo-hibernation, not a full hibernation.
Even if it isn’t possible, if the lifeforms were viruses they could potentially be consumed by a very simple, and under the right circumstance, the virus could transfer their genomes to the Earth cells.
Why not consider some extreme situations:
A habitable planet with twins in a stellar system, and their environment is similar. Only one of the planets gave birth to life and unexpectedly arrived on another planet.
the functional genome size doubling over a single generation several times would make that time get cut way down
I dont beleive single celled organisms that can somehow hibernate for eons on a space rock that crashed into earth is more likely than evolution through natural selection just here on earth. Even though both are extremely unlikely.
why not just use a large hollow ball full of salt water, microbes(yeast would work really well, since it can easily survive in salt and fresh water), lipids, sugars, and a baked potato, and they’re mass-produced and yote in random directions at escape velocity from orbit. or, if you need it to form naturally, water full of microbes occasionally gets trapped in glass that’s completely airtight, and it’s possible for that glass full of water to get into the perfect spot to get yote into space once the planet gets a sufficiently heavy rock chucked into it. the glass could keep the water warm enough for the water to not freeze at all for a few years, and in that time the bacteria could evolve a way to keep the water unfrozen(or at least their own cells) until the water is cold enough that only radiation will be breaking down the dna, rather than heat, motion, and radiation(realistically, most of them would just go into a cyst form a while before the water completely froze, but if it’s sea water, there’ll be ice without much salt below the glass, and brine below the salt, where bacteria could live and replicate, if they can adapt to it, but they’d need to fall into a brine pool almost as soon as they get to a new planet if they adapt. luckily though, there will be unadapted bacterial cysts in the ice below the surface, making sure that, as long as few enough half lives have passed that at least one bacterium has one full plasmid worth of uncorrupted DNA, life will persist.)
Don’t these bacteria also need to be adapted to survive atmospheric reentry?