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Where the heck did all those structures inside complex cells come from?

arstechnica.com

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Re: Where the heck did all those structures inside complex cells come from?

#11

Post by tibbydudeza »

mcphage wrote: post #4

One thing I didn’t see mentioned in this article, that I thought was one of the major motivators for realizing that mitochondria originally came from outside the body, is that mitochondria have their own DNA independent of the cell’s nuclear DNA. But I wasn’t aware that any other animal organelles do (chloroplasts in plants do, and those are also assumed to have originally been an independent bacteria).

Mitochondria also can trigger cell death - there seems to be good reasons why evolution retained separated genome from the cell nucleus.

Re: Where the heck did all those structures inside complex cells come from?

#12

Post by pixl97 »

kupfer wrote: post #5
rwmj wrote: post #2

Back in the 1990s I spent a long time playing with Tierra ( https://en.wikipedia.org/wiki/Tierra_(computer_simulation) ) and actually wrote my own distributed version[1] so it could run over multiple machines (computers were really slow back in 1991), and a simplified instruction set. Now I know that Tierra has a number of serious shortcomings compared to real evolution. Nevertheless it does really surprising things…

Would you expand a bit on the shortcomings? I'm under the impression artificial life was an attempt in the 90s and after some disappointments fizzled away. Why is simple copying with mutation not sufficient for real evolution? In my naivety I hoped it would lead to digital evolution finding exploits to proliferate across the internet.

One issue with 'evolving' digital life is the primary competition is human assisted digital applications as the primary competition, effectively intelligent design, which is far more powerful ran random chance.

Non-artificial life actually gets massive benefits from horizontal gene transfer which is natures way of letting someone else do all the homework for you.

Re: Where the heck did all those structures inside complex cells come from?

#13

Post by roughly »

EMM_386 wrote: post #3

I find it fascinating how many bizarre, wide gaps we have in evolution where we are left wondering how something could have possibly come into existence at all in the first place. And clearly, the questions are completely valid. From the most basic "how did life start" to questions like in this article (where did mitochondrion come from?) ... it is very difficult to make sense of. The timescales involved are long, an…

Part of what makes this kind of thing difficult to really fathom is the time scales involved - e.coli can reproduce once every 20min or so, yeast can do so every 2 hours or so. 12 replications a day, 4380 replications per year, repeated over a billion years. It all seems phenomenally unlikely, but the combination of an unfathomable number of repetitions and even a small evolutionary thumb on the scale can take you an enormous distance.

Re: Where the heck did all those structures inside complex cells come from?

#14

Post by tetris11 »

EMM_386 wrote: post #3

I find it fascinating how many bizarre, wide gaps we have in evolution where we are left wondering how something could have possibly come into existence at all in the first place. And clearly, the questions are completely valid. From the most basic "how did life start" to questions like in this article (where did mitochondrion come from?) ... it is very difficult to make sense of. The timescales involved are long, an…

I'm guessing at the start it was incredibly easy to stick things together, like two Lego pieces. After a few thousand years and a few interesting Lego builds, some with interchangeable brick complexes with one another, a great calamity destroys the majority of those builds, leading a sparse minority of builds which seem to have legacy interchangeable brick complexes still for reasons unknown to us

Re: Where the heck did all those structures inside complex cells come from?

#15

Post by fallsoffbikes »

EMM_386 wrote: post #3

I find it fascinating how many bizarre, wide gaps we have in evolution where we are left wondering how something could have possibly come into existence at all in the first place. And clearly, the questions are completely valid. From the most basic "how did life start" to questions like in this article (where did mitochondrion come from?) ... it is very difficult to make sense of. The timescales involved are long, an…

I’d suggest the book Life Ascending. It talks about how certain major jumps in complexity occurs. It directly addresses the “bumping in the ocean” you mention — according to the book the likely explanation was these initial reactions occurred in local environments around certain types of thermal vents that were constrained by small geologic features. Interesting read.

Re: Where the heck did all those structures inside complex cells come from?

#17

Post by m463 »

rwmj wrote: post #2

Back in the 1990s I spent a long time playing with Tierra ( https://en.wikipedia.org/wiki/Tierra_(computer_simulation) ) and actually wrote my own distributed version[1] so it could run over multiple machines (computers were really slow back in 1991), and a simplified instruction set. Now I know that Tierra has a number of serious shortcomings compared to real evolution. Nevertheless it does really surprising things…

it's sort of amazing how a little visualization helps:

https://rednuht.org/genetic_cars_2/

Re: Where the heck did all those structures inside complex cells come from?

#18

Post by GoblinSlayer »

rwmj wrote: post #2

Back in the 1990s I spent a long time playing with Tierra ( https://en.wikipedia.org/wiki/Tierra_(computer_simulation) ) and actually wrote my own distributed version[1] so it could run over multiple machines (computers were really slow back in 1991), and a simplified instruction set. Now I know that Tierra has a number of serious shortcomings compared to real evolution. Nevertheless it does really surprising things…

>According to Thomas S. Ray and others, this may allow for more "open-ended" evolution, in which the dynamics of the feedback between evolutionary and ecological processes can itself change over time (see evolvability), although this claim has not been realized – like other digital evolution systems, it eventually reaches a point where novelty ceases to be created, and the system at large begins either looping or ceases to 'evolve'.

But of course, evolution merely reaches equilibrium, which takes finite time and then stagnates. In real world evolution continues due to change of environment that moves the goalpost of equilibrium, extincts overoptimized species, so evolution can go further. Just add slow change to environment, like ice age or warming.

Re: Where the heck did all those structures inside complex cells come from?

#19

Post by hackeraccount »

EMM_386 wrote: post #3

I find it fascinating how many bizarre, wide gaps we have in evolution where we are left wondering how something could have possibly come into existence at all in the first place. And clearly, the questions are completely valid. From the most basic "how did life start" to questions like in this article (where did mitochondrion come from?) ... it is very difficult to make sense of. The timescales involved are long, an…

The "not stranger then we suppose but stranger then we can suppose" part for me isn't the how did life start or how did that eukaryotes evolve from prokaryotes. Those are both genuinely mysterious.

The thing that gets me is why it was easier to go from no life to life.

If you said it took 2 billion years for life to emerge from inorganic molecules but 300 million years after that we had eukaryotes then I'd say, that seems about right - I wonder how it happened?

Tell me that (as I understand to be the case) life pops up a couple of hundred million years after it's possible to have life on earth - and then several billion years go by before you get eukaryotes then I'm really left scratching my head.

I'm not saying mitochondria aren't amazing but the leap seems closer to me to the evolution of warm blooded animals from cold blooded ones. Life from nothing seems fantastically more complicated.

I'm generally down on life's origins being an off-earth thin but ... sometimes I wonder.

Re: Where the heck did all those structures inside complex cells come from?

#20

Post by throwaway87651 »

mcphage wrote: post #4

One thing I didn’t see mentioned in this article, that I thought was one of the major motivators for realizing that mitochondria originally came from outside the body, is that mitochondria have their own DNA independent of the cell’s nuclear DNA. But I wasn’t aware that any other animal organelles do (chloroplasts in plants do, and those are also assumed to have originally been an independent bacteria).

The DNA in mitochondria has a slightly different genetic code compared to DNA in the nucleus, which is evidence that mitochondria were once free living organisms, and they separated from other organisms before the genetic code was fully established. A fascinating glimpse of a lost world.
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