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The baffling intelligence of a single cell: The story of E. coli chemotaxis

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Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#71

Post by wslh »

talkingtab wrote: post #45

The way I think about this comes from reading John Holland's "Hidden Order". If you read that book not as a book but as a way to build a Complex Adaptive System, then it comes down to a few essentials. An environment, a bunch of entities, a read/write messaging bus so the entities can interact. The entities need a set of rules and sensors. Put it together and what have you got? Thinking. Or intelligence. Try building…

> Part of our problem is the way we think. I am a person. I am not a complex adaptive system.

I agree that, in general, we humans, downgrade the importance of external stimulus and interactions with our environment (including other people). My two cents is that this is downplayed where we live in cities and don't move too much, once you move to very distanct places and cultures (and not assuming yours is the best one) more things tick in the brain.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#72

Post by Jensson »

yehosef wrote: post #68

Am I allowed to think this is too complicated to be an accident?

Yes, but that doesn't mean people will take you seriously.

In order to evolve such a system all you need is for the separate components to be useful. A cell laying still and multiplying is useful enough, so that is the baseline. Then adding a flagella to move randomly so it can move away from its waste product and keep hitting new nutrients is also useful. From there it can start to detect waste and move when it is near waste and stop moving when it is near food. Then yo just continue such steps, not very hard to imagine compared to imagining macro evolution.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#74

Post by photochemsyn »

Great writeup. Here's a full-text review that contains all the math needed to build a model of this process (2013):

"Quantitative modeling of bacterial chemotaxis: Signal amplification and accurate adaptation, Yuhai Tu"

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3737589/

The main points are:

* Both receptor cooperativity and accurate adaptation can be described quantitatively by simple mathematical models.

* An integrated model (the “standard model”), which contains both signal amplification and adaptation, is developed to predict responses of it E. coli cells to any time-dependent stimuli quantitatively.

* Exponential ramps induce activity shifts, which depend on the ramp rate through the methylation rate function F(a).

* Responses to oscillatory signals reveal that E. coli computes time-derivative in the low-frequency regime.

* E. coli memorizes the logarithm of the ligand concentration and the Weber-Fetcher law holds in E. coli chemotaxis.

It also goes into cooperative phase transitions in the receptor complexes as a means of signal amplification, using the same model as in Ising ferromagnetic spin-spin interactions in physics.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#75

Post by begueradj »

> An individual E. coli has no brain, obviously, and is even many orders of magnitude simpler than a human cell, and yet already it possesses something like a sense of smell, drive, even a memory.

A person is billions of billions of more effective cells than an E.coli cell: still our sense of smell, drive and memory do not seem to be billions of billions times more efficient.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#76

Post by GirkovArpa »

Jensson wrote: post #66
swayvil wrote: post #62

Earlier quoted context omitted.

So the more identical the committee members are, the smarter the committee?

At least a committee of 10 identical members wont be dumber than a single member most of the time. A committee of clones is just scaling up compute in order to solve larger problems. Imagine if you could clone yourself with your knowledge and mental state, much more useful than trying to cooperate with another human.

According to Condorcet's jury theorem, a committee of 10 identical members may be smarter than a single member.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#77

Post by voidmain0001 »

wiz21c wrote: post #70
yehosef wrote: post #68

Am I allowed to think this is too complicated to be an accident?

Given the size of the universe and its age, I'd say we have waited long enough for probabilities to line up and produce such a complicated design.

I read a quote once that said “Simple bacteria can divide about every 20 minutes and have many hundreds of different proteins, each containing 20 types of amino acids arranged in chains that might be several hundred long. For bacteria to evolve by beneficial mutations one at a time would take much, much longer than three or four billion years, the time that many scientists believe life has existed on earth.” I haven't performed the math to back up the quote. As well would it change the time required if the bacteria mutate in parallel rather than in series?

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#78

Post by FartyMcFarter »

prmph wrote: post #65
beders wrote: post #8

Earlier quoted context omitted.

I know. But this is very well understood and researched. All it requires is mutations, time and selection pressure. The Blind Watchmaker is still a good read.

So if a monkeys bangs on keys forever it will eventually produce Shakespeare? I'm quite skeptical

There's no selection pressure when a monkey bangs their hands on a keyboard. It's just randomness without any consequence. The letters are not interacting with each other or their environment in any significant way.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#79

Post by whelp_24 »

jvanderbot wrote: post #39
whelp_24 wrote: post #35

Earlier quoted context omitted.

How many simple physics combinations until you get intelligence? Remember that you are made of cells, and everything you do (probably) can be reduced to a group effect of your cells.

Complexity is not magic. It's just a long search for the right combo. In fact we have untold trillions of branching iterations in evolution.

This does not answer the question.

Re: The baffling intelligence of a single cell: The story of E. coli chemotaxis

#80

Post by whelp_24 »

bell-cot wrote: post #47
whelp_24 wrote: post #34

Earlier quoted context omitted.

I think intelligence is the correct word. Why not?

Useful languages can succinctly distinguish things which are qualitatively quite different. Describing everything in the world as "intelligent" sounds kinda cool and Zen, and may reflect some peoples' worldviews - but it also make "intelligent" pretty useless as an adjective.

Why is intelligence a bad descriptor?
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