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Science says evolution occurs from random mutations. Because they're random, there's no guarantee that every place with tops of trees evolve animals with long n

Science says evolution occurs from random mutations. Because they're random, there's no guarantee that every place with tops of trees evolve animals with long necks to eat them, just as flipping a coin no matter how many times gives no guarantee it ever comes out heads.

tobr 5y ago
I don’t know much about this subject, but logically that seems to only be a good explanation if the long giraffe neck happened in a single lucky coin flip, ie in one mutation in one individual. That goes against my intuition of how evolution works, through many small steps over many, many generations. Happy to be corrected by someone who knows more.
- naasking 5y ago
  It's an arm's race. A lucky coin flip evolved a longer neck, they survived better and bred more, but then trees evolved to be taller because of the proliferation of longer necks, then a luck coin flip evolved an even longer neck, etc. Long necks aren't the only possible adaptations to get to taller trees though. For instance, tree climbing is another.
  - eurasiantiger 5y ago
    Forests are another (competition for sunlight).
  - tobr 5y ago
    So if it requires multiple lucky coin flips, shouldn’t we expect it to happen in many places, not just in giraffes? What explanatory power does “randomness” really have, then?
    - saalweachter 5y ago
      It depends how common the niche is and how accessible the body-plan is in the genetic search-space. We do see convergent evolution into the "tree" and "crab" body-plans. Dozens of unrelated species have evolved along similar lines, filling similar niches by evolving similar forms. There were long-necked animals in the past -- a well-known type of dinosaur comes to mind -- but the niche isn't so large or successful as the "eat a bunch of grass" niche.
    - xbmcuser 5y ago
      larger the number of coin flip needed the less likely it s to happen not more.
      - tobr 5y ago
        I don’t think so? A larger number just demonstrates that lucky coin flips are common and abundant.
- hliyan 5y ago
  I think chromosome selection plays a much larger role in generation-to-generation variation than mutations do (which are rare).
eurasiantiger 5y ago
On the contrary, coin flips are probabilistically independent from each other, while evolutionary events certainly are not, however small the causal influence between them may be. Thus, while an infinite number of coin flips does not guarantee a single heads, an infinite number of evolutionary events must eventually result in any given adaptation. Lim P(p) = 1.0 as p -> inf.
0898 5y ago
Apologies if this is a very stupid question but is random mutation a fact or a theory? It’s something I’ve never quite been able to wrap my head around. If you corrupt a line of code you don’t get a different program you just get something that won’t compile. I suppose nature works very differently to programming - but it’s still something I struggle with.
- hliyan 5y ago
  The correct analogy is more like this: DNA in nucleus - source code on disk Messenger RNA - source code in memory Ribosome - JIT compiler Protein - tiny running program, think unix utilities. Also, not saved to disk. There is source code for millions of such programs in the DNA. The compiler (Ribosome) recognizes any combination of the base constructs of the language (C, G, T, A) as valid, but the compiled program may not work.
- prepend 5y ago
  Lots of mutations. Most result in not compiling, but some result in long necks.
- Smaug123 5y ago
  This question is something of a category error - there are no "facts", only "theories which have a greater or lesser amount of evidence in favour of them". Some theories have such an overwhelming amount of evidence in favour of them that we call them "facts". But the presence of random mutation is extremely well documented, yes - how else do you explain why identical twin humans don't have identical genomes? A great majority of corruptions have no effect, because biological systems are highly resilient to change; the analogy you want is less "delete a line of code" and more "delete a single machine from AWS". Some corruptions are so bad that they cause the organism to fail completely at the embryo stage. Some corruptions have an effect which is detrimental in one environment but beneficial in another; the whims of nature decide whether such an organism survives. Some corruptions are simply beneficial, and if they're sufficiently beneficial then they take over the gene pool in not many generations.
  - shadowgovt 5y ago

tobr 5y ago

I don’t know much about this subject, but logically that seems to only be a good explanation if the long giraffe neck happened in a single lucky coin flip, ie in one mutation in one individual. That goes against my intuition of how evolution works, through many small steps over many, many generations. Happy to be corrected by someone who knows more.

naasking 5y ago
It's an arm's race. A lucky coin flip evolved a longer neck, they survived better and bred more, but then trees evolved to be taller because of the proliferation of longer necks, then a luck coin flip evolved an even longer neck, etc. Long necks aren't the only possible adaptations to get to taller trees though. For instance, tree climbing is another.
- eurasiantiger 5y ago
  Forests are another (competition for sunlight).
- tobr 5y ago
  So if it requires multiple lucky coin flips, shouldn’t we expect it to happen in many places, not just in giraffes? What explanatory power does “randomness” really have, then?
  - saalweachter 5y ago
    It depends how common the niche is and how accessible the body-plan is in the genetic search-space. We do see convergent evolution into the "tree" and "crab" body-plans. Dozens of unrelated species have evolved along similar lines, filling similar niches by evolving similar forms. There were long-necked animals in the past -- a well-known type of dinosaur comes to mind -- but the niche isn't so large or successful as the "eat a bunch of grass" niche.
  - xbmcuser 5y ago
    larger the number of coin flip needed the less likely it s to happen not more.
    - tobr 5y ago
      I don’t think so? A larger number just demonstrates that lucky coin flips are common and abundant.
hliyan 5y ago
I think chromosome selection plays a much larger role in generation-to-generation variation than mutations do (which are rare).

eurasiantiger 5y ago

On the contrary, coin flips are probabilistically independent from each other, while evolutionary events certainly are not, however small the causal influence between them may be. Thus, while an infinite number of coin flips does not guarantee a single heads, an infinite number of evolutionary events must eventually result in any given adaptation. Lim P(p) = 1.0 as p -> inf.

0898 5y ago

Apologies if this is a very stupid question but is random mutation a fact or a theory? It’s something I’ve never quite been able to wrap my head around. If you corrupt a line of code you don’t get a different program you just get something that won’t compile. I suppose nature works very differently to programming - but it’s still something I struggle with.

hliyan 5y ago
The correct analogy is more like this: DNA in nucleus - source code on disk Messenger RNA - source code in memory Ribosome - JIT compiler Protein - tiny running program, think unix utilities. Also, not saved to disk. There is source code for millions of such programs in the DNA. The compiler (Ribosome) recognizes any combination of the base constructs of the language (C, G, T, A) as valid, but the compiled program may not work.
prepend 5y ago
Lots of mutations. Most result in not compiling, but some result in long necks.
Smaug123 5y ago
This question is something of a category error - there are no "facts", only "theories which have a greater or lesser amount of evidence in favour of them". Some theories have such an overwhelming amount of evidence in favour of them that we call them "facts". But the presence of random mutation is extremely well documented, yes - how else do you explain why identical twin humans don't have identical genomes? A great majority of corruptions have no effect, because biological systems are highly resilient to change; the analogy you want is less "delete a line of code" and more "delete a single machine from AWS". Some corruptions are so bad that they cause the organism to fail completely at the embryo stage. Some corruptions have an effect which is detrimental in one environment but beneficial in another; the whims of nature decide whether such an organism survives. Some corruptions are simply beneficial, and if they're sufficiently beneficial then they take over the gene pool in not many generations.
- shadowgovt 5y ago