48 replies
22h45m
The most interesting for me is the offspring, reproducing a different structure with the same genes. I think mathematically this could be the missing link in evolution, where random gene modifications are just not probable enough to drive evolution. 3 billion DNA pairs cannot evolve randomly, there is not enough time and matter in the universe to randomly try successful generations of life forms. However, bioelectric might be a much much more straightforward and fast way of driving evolution instead of randomly mutating DNA.
the objection to the process described here is reasonable. thankfully this isn't how it works.
Care to elaborate what lowers this probability down to "computable within adolescent age" levels?
I offer paid tuition. For £50/h, I will learn stuff for you and then teach you. Prep time is typically ~3h for each hour I teach you. Minimum 1h lessons.
I will pay you £50,000/h if you could give me a convincing answer like "the computational complexity of a beached fish to invent and grow a leg is O(n^2 log n) hours where n is the number of neural spikes in frontal cortex".
If neural spikes had anything to do with it, if any of this worked like that, bacteria wouldn't develop resistance to antibiotics (they can), and I would be able to shapeshift (I can't).
So that question is like asking for a route finding algorithm that's O(n) where n is the number of letters in the destination.
The point was to give me a correct estimate based on some measure of time. Pick whatever works for you and give me a formula one can use.
And my point is the the question suggests a worldview so incorrect that the question is meaningless.
If you seek understanding, you must decide upon a specific better question of your choice; if you leave it up to us to devise the question, we can do that, but it's overwhelming unlikely that our free choice will connect with whatever it is that led you to ask the question in the first place.
For example, I could ask you to consider a model of a fish where each bone length is controlled by some gene, and then evolution converting fins to legs is some function of the magnitude of reproduction selection pressure on those changes over multiple individuals and generations… and nothing at all to do with one individual's brain.
Or were you thinking of a specific fish species which develops legs when it reaches adulthood?
You were giving examples of local adaptations (bacteria building resistance) instead of paradigm shifts (beached fish growing legs). The science behind the former is established (mutations favored by environment); the science behind the latter is not. You are mixing the two together and complaining the second one is non-sense, but is it? Somehow fish had to learn to walk ("evolution from one organism to another") in a limited time including complex mechanics that our computers can't solve exactly; I am waiting for any computational biologist to give us some mechanism behind it that is realistic, i.e. computable. So far nothing and people keep mentioning local adaptations only.
That's not even an example of a paradigm shift. Continuous transformation trivially gets us between superficial differences like mere body shape, there are many examples of us applying selection pressure to other species to make that category of thing happen, including our crops, livestock, and pets — no more than 10k years separated Chihuahuas and Corgis from Newfoundlands and Afghan Hounds. Likewise even more extreme changes between crops and their wild relatives, the wild versions are almost unrecognisable except to experts.
What I'm calling nonsensical is your description. You're calling for the time complexity for a brain to invent changes that aren't caused directly by brains.
1) Exact solutions aren't necessary; 2) computers have solved walking; 3) the boundary between walking and floundering is an arbitrary one. And #4 after the next quote…
4) One of the ways computers solve problems like this is simulated evolution.
If you don't consider the working demonstrations to be realistic, that's a "you" problem, not something the rest of us care to waste time on.
Do you also insist nobody has ever climbed Mount Everest on the grounds that nobody has legs long enough to do it in one step?
Or that motion pictures are impossible because each frame is stationary?
a beached fish doesn't grow legs. the problem isn't what you're willing to pay here, the problem is what you are willing to learn.
my fees are not conditional on you liking the lessons. they are to be paid upfront. i accept the higher offer though.
Can you prove it? Show me some sort of an environment where a water-based complex organism is able to survive and thrive in dry environment prompting it to grow a new movement organ useless in the water but needed on surface and give me some less-than-exponential algorithmic complexity bound for it. If you can't do it, you don't offer valuable lessons.
i told you something that you claim to be true isn't what is claimed to happen by the theory of evolution by natural selection, and you want me to provide proof that it does in fact happen? have you taken leave entirely of your senses?
edit: sorry dang, I fell for it again, didn't I?
edit 2: actually treprinum, I have a sensible answer here, although you're not going to like it. if you were smart enough to understand what you are asking, you really wouldn't have picked body plan as your "gotcha". you would have picked something truly wonderful like the genetic code, or the ribosome, or mechanisms of gene regulation, or embryology, or eukaryotic cells.
the evolution of new body plans is very well understood. i won't explain it to you though, until and unless I get paid. I believe we agreed £50,000/h for an hour minimum lesson which is three hours of prep - so £200,000 total for the first paid lesson? this one here is free.
You want people to explain natural selection and evolution to you?
No, I want the computational feasibility explanation with some nice O(function) on biological processes. To the best of my knowledge, we still have no idea.
Something like "the computational complexity of a beached fish to invent and grow a leg is O(n^2 log n) hours where n is the number of neural spikes in frontal cortex" or similar.
Fish aren't the only things that live in water. There are other marine organisms, some of which have leg-like things. What if one of those organisms, already equipped with legs, evolved to survive on the surface?
That would be fine; but we have some lineages coming from fish living on the surface. Those are the interesting ones.
While metabolic advantage is a thing, I'm not sure if organisms are expected to carry minimum amount of genetic code that they actually use; in what little I know about developmental biology, I recall there's a high-level structure to the genetic code - some genes are doing more of flow control than encoding actual proteins. It's conceivable that the fish which walked on Earth was the one that managed to accumulate inactive adaptations for walking and switched them on.
Also, there's horizontal gene transfer to account for. It further complicates the picture.
Have you ever tried genetic algorithms?
Those are great models for local adaptations. They won't grow a leg with extricate mechanical properties we have trouble modeling in state-of-art robotics/mechanics.
As a biologist, I don't think this really follows. From my perspective of studying life, 3 billion DNA pairs can definitely evolve randomly - it's not even really that hard. Eukaryotic life just happened to get that because the fitness deficit from the retrotransposons weren't too bad. On the contrary, I can't actually see how bioelectric could drive evolution - only the creation of more complex structures
As a biologist, how do you account for the existence of life?
There was an RNA molecule or molecules that could make more of themselves (probably really poorly, at first)
Have you read a book called The Stairway to Life: An Origin-of-Life Reality Check by Tan & Stadler? You can find it on Amazon. It's pretty short and will get you thinking rigorously about the problem.
No. But I feel like it is unlikely I'll find much value in it. Part 1 being on the Venter work does NOT inspire confidence at all. Not to dismiss them - they're great I've worked with them on a couple projects - but it frankly doesn't have anything to do with abiogenesis. The other fact that lots of creationists like it doesn't bode well either.
Like, of COURSE the Venter cell looks too complicated to originate from raw chemicals! The lineage it evolved from was far more complex, and Mycoplasma underwent minimization. Minimal life also does not equal simple life, or life that was most probable to arise from chemicals. Just a stupid premise, really.
There's no point engaging in good faith, or at all, with creationists. "You can’t reason someone out of a position they didn’t reason themselves into."
In fact exactly the opposite is the situation. I knew ahead of time that this guy wouldn’t read a short book, but I posted it for the sake of people who are interested in empiricism and evidence-based thinking.
It’s hard to see how it would be evidence based if the evidence’s premise is fundamentally flawed - just in such a niche way that people not in my field wouldn’t be able to see it. They’re kinda preying on the fact that people like you can’t see it, and that’s sad.
Just read the book. If it is so terrible then you can write a review demolishing it.
Also searchable by its other title "God of the Gaps Volume 6,000 - Forget the Other 5999, This Time We're Really Sure, Can You Stop Doing Research Now Please"
Yes, I bite the bullet on the god of the gaps when it comes to the origin of life.
And I'm not opposed to doing research, of course (hard to believe I have to clarify this)
In fact I want people to research the question of the origin of life as rigorously and exhaustively as possible because it is just going to make it that much more obvious that life was designed by God.
I have absolutely no fear that this "gap" is going to do anything but widen.
This suggests you have not tried writing a simulated evolution based optimiser.
They're quite easy to write, the hard part is what you mean by a "fitness function" (which doesn't matter for nature, it just is whatever it is).
Such algorithms are also more than fast enough — remember that for the first 3 billion years we only had single-celled life, and that can reproduce in 20 minutes, so we had potentially 79 trillion generations (edit because "78.84 trillion" would be overselling the precision) before the first multicellular life. You get good results faster than that.
The number of base pairs is also just a misleading statistic. For example: each of XXX, XXY, XYY, and Downs are found in around 0.1 of human births, each of which gets an extra copy of a chromosome. These specific changes may not be too good for us, but this kind of sudden massive increase is also found in some plants without negative repercussions.
I have no reason to expect bioelectric processes described in this article to be able to direct useful effects on the genome, for the same reasons I think it unlikely your own brain could by sheer willpower turn you into a werewolf.
Wrong layer of abstraction.
I learnt that evolution is random mutations of genes + natural selection (selecting the successful random trials). If you have 10^14 generations on 3 billion years, always use up the mass of the Earth, 10^28g, that is 10^40 cells, so you have 10^54 cells randomly trying the best permutation of DNA, that's suprisingly few to balance the vast amount of possible permutations. 4^100000 being 10^60205
Evolution doesn't find "best", it finds "slightly better" and "not disastrously worse" repeatedly.
Sure, but my question is what does evolution try? If it is full random, then it will TRY much better and much worse mutations as well, so will go back and forth, and will take a lot of time. If it is not fully random, e.g. it is not not able to try big changes, then what is the thing that actually determines what is "feasible", BEFORE trying it out.
Full random. Something like 50% of human babies have random mutations which make them unable to develop past the stage of being invisible to the naked eye. Such miscarriages seem like normal menstruation.
There's a knack to optimizing the mutation rate. If you mutate too much, 99.9999% of offspring can't develop and in the end there's too little reproduction. If you don't mutate enough, you don't evolve. Evolution has already optimized this hyperparameter.
IIRC, the rate is somewhat dynamic.
That said, my experiments in silico say that what matters most is the pressure from the utility function, more so than the rate of mutation.
So if some organism is in an environment where only a few mutations help, then evolution progresses slowly; and when most possible changes are improvements, then evolution progresses faster.
Both environments can happen even without any dynamic change to the rate of mutations themselves.
Environment. You seem to be missing the "natural selection" part of evolution. The optimization process works like this:
- Life reproduces; between imperfections in reproduction and environmental mutagenic factors, there is a certain amount of random mutations;
- The churn happens. Organisms compete for resources; winners reproduce, losers starve. Environment throws curveballs - spills, seasons, volcanos, radiation, oxygen, and a million different things. A lot of organisms are killed, some survive and reproduce. Now, mutations can make organisms better or worse at surviving the challenges. This is the asymmetry you're looking for, the driver of evolution. Helpful mutations propagate, unhelpful mutations die. Where "helpful" means, of course, "helpful locally, at a given moment".
Rinse and repeat. The randomness isn't the driver - it's just jitter preventing evolution from getting stuck in a local minimum. The life cycle of birth and death is what drives evolution, specifically because it depends on both how the organism is built, and on the environment.
A couple notes:
Downs is unlike the other defects you mentioned in that it severely impairs the patient while the various extra-sex-chromosome disorders vary from sterility through minor impairment to what basically amounts to behavioral differences.
Downs is unusual, though, in that most extra chromosomes make the fetus nonviable. As far as trisomy disorders go in general, Downs is unusually benign.
Plants are better known for increasing their -ploidy (number of sets of chromosomes) than the count of an individual chromosome. A triploid human, with three copies of every chromosome, would be hopelessly nonviable. Plants are different. Really different.
Indeed, they do not evolve randomly. There’s this thing called natural selection that is relatively crucial.
Your interpretation of bioelectric effects as summarized in this article seems to have missed something. The bioelectric network is itself an expression of the genes involved in development. It’s not a separate magical force.
Yes, you may need genes to express the proteins of ion channels and gap junctions, but there is no anatomy coded by genes, no genes code for how many limbs will a biosystem have (as reiterated by Levin). And it is this level of resolution that actually mattered for years before the launch of molecular biology and medicine.
Indeed, it sort of (suppose - by up to 70%) is. If the fine structure constant, which defines the strength of the interaction between a charge and an electric field, were 4% less or more than its current value, the current world and biosphere wouldn't exist. So far physics can't explain why the fine structure constant has this exact value (~1/137, which is also unique that it is a dimenionless constant). (I'm not inferring anything, just presenting raw data).
What's this supposed to mean? We are already able to develop bugs with missing or additional limbs by modifying their genes.
It's not any different from the nervous system, really, it's just that we're now recognizing that those fields are involved in things other than sensation, perception, etc..
As I understand, the worm cells act differently because the worm is placed in a solution which interferes with their electrical messaging, so it makes sense that the offspring growing up in the same solution would grow with the same defects as the parents. I think that's all there is to it.
The referenced paper (https://www.sciencedirect.com/science/article/pii/S009286742...) specifically states that it continues after the solution is changed to plain water.
Ok wow that's pretty strange.
This a-ha moment for me with respect to this is that some biological processes are of the type [random process -> selection -> stable result]. This means that the genetics actually _don't_ store the information for what is ultimately produced, only the information necessary to trigger a random exploratory process and to stabilize that process when it reaches a suitable target. This is one reason why animals can flexibly adapt their development to different conditions as described in the above article.
For example, human genetics encode how to make a big ball of neurons that can learn by themselves.