3 ms·

I'm a touch confused, the lead in has "plants shift their flowering times to cope with the heat, rather than adapting through natural selection." How is that n

by taeric 9mo ago

I'm a touch confused, the lead in has "plants shift their flowering times to cope with the heat, rather than adapting through natural selection." How is that not just part of natural selection? Plants that are unable to shifting their flowering time will die off. No?

__MatrixMan__ 9mo ago
It's not worded very well, but the distinction has to do with whether the plant has a built-in system for adjusting flowering times based on heat (all necessary code already present, no genetic mutations needed for it to adjust flower timing), or whether the shift in flowering times is directly caused by favorable genetic mutations. It's a bit like the distinction between being able to swim around, like a fish, versus just having offspring who end up a bit closer to some goal, like a coral. Both end up in a place where they can live, but only one got there by being the lucky survivor against a background of alternatives that were born elsewhere. It's made clear in the title of one of their papers: "Plasticity and not adaptation is the primary source of temperature-mediated variation in flowering phenology in North America" (https://pubmed.ncbi.nlm.nih.gov/38212525/ https://pubmed.ncbi.nlm.nih.gov/38212525/)
- taeric 9mo ago
  I think that makes some sense, but I would think that is still part and parcel for natural selection? To require specific mechanisms just feels wrong. Granted, my teaching for what drives evolution is colored by the idea of the peppered moth, which clearly had everything necessary for both colors. The population change on dominant color, though, was driven by environmental changes. Even that title you give seems to preclude that increased plasticity can itself be an adaptation? Wouldn't we need to show that there was no change in plasticity during this time in order to show otherwise?
  - __MatrixMan__ 9mo ago
    It's a meaningful distinction because adaptation has the potential to introduce novel mechanisms while plasticity doesn't. So if you mistook one for the other, you might assume that a given crop will continue to adapt to a warming climate when what's actually happening is that it's approaching the bounds of its plasticity and yet another degree of warming will cause it to fail. You could also make bad assumptions related to rates. One might assume that adaptation will occur within some time window when actually they're extrapolating based on plasticity. Sure, plasticity and its limits are themselves the result of natural selection, but there are still experiments you can do to distinguish the two (e.g. does the change show up in the genome versus the transcriptome or the proteome?). I guess I'm just uncertain about how useful it is to split hairs beyond a certain point. Like, you could say that everything is caused by the big bang, case closed, but that's not going to affect any subsequent decisions that people might make.
    - taeric 9mo ago
      Fair that I think it is valuable to know some things are stronger adaptations than others. I just don't see the point in claiming it is not, itself, an adaptation. Feels very "not actually evolution" in claim. It is, but there are obvious limits to what it can achieve. As an easy example, to your point, would you say that adaptation and evolution lead to land creatures? There are obvious limits to how quickly and how well that could have possibly worked. But it also feels safe to say that some organisms almost certainly had a level of plasticity that made it more likely for them to survive the process?
      - __MatrixMan__ 9mo ago
        Re: your questions, yes and yes. If its both plasticity and adaptation at play in all cases then there's not much sense drawing a line, such as the evolution of land creatures. And its also probably silly to worry about adaptation without plasticity. But it does make sense in the plasticity without adaptation case. For instance there are people born in Tibet with adaptations for altitude, and people born in the Andes with adaptations for lead tolerance. And if those of us without those adaptations were to try to tolerate such heights, and such concentrations of lead, we wouldn't do as well because we lack the genes for that particular adaptation. Even though we are partially adapted to those things in general. The "X is not a result of adaptation" predicate makes sense in relation to other things that are more directly a result of adaptation.
        taeric 9mo ago
        But doesn't this just go to my point that you would more expect further adaptations from those that already have the plasticity? Fair that you could get them in either, but the point of evolution/adaptation is that often the mechanism is not a first class one. To the peppered moth example, it isn't like there was a specific mutation that caused them to change color. Both colors always existed. The prevalence at the population level was essentially the result of external drivers to the species. So, in plants, it is fair to say that those with more plasticity are able to change when they flower in response to environmental changes. Why is it not fair to expect that those most able of doing that are the ones you are likely to see further adaptations on to keep adjusting? Yes, we can see individual mechanisms and we can focus on them. Such that we don't have to hope for random mutations that further advantage things. But, adaptation and evolution are not defined as only random mutations. (Or have they been somewhat redefined into that?) I think more cleanly stated for my point, I am not arguing against the idea of plasticity. I am arguing that adaptation is not defined as only random mutations introducing novel characteristics. Specifically because the fundamental example for evolution that used to be taught was definitively not a novel characteristic of the species.

by taeric 9mo ago

__MatrixMan__ 9mo ago

It's not worded very well, but the distinction has to do with whether the plant has a built-in system for adjusting flowering times based on heat (all necessary code already present, no genetic mutations needed for it to adjust flower timing), or whether the shift in flowering times is directly caused by favorable genetic mutations. It's a bit like the distinction between being able to swim around, like a fish, versus just having offspring who end up a bit closer to some goal, like a coral. Both end up in a place where they can live, but only one got there by being the lucky survivor against a background of alternatives that were born elsewhere. It's made clear in the title of one of their papers: "Plasticity and not adaptation is the primary source of temperature-mediated variation in flowering phenology in North America" (https://pubmed.ncbi.nlm.nih.gov/38212525/ https://pubmed.ncbi.nlm.nih.gov/38212525/)

taeric 9mo ago
I think that makes some sense, but I would think that is still part and parcel for natural selection? To require specific mechanisms just feels wrong. Granted, my teaching for what drives evolution is colored by the idea of the peppered moth, which clearly had everything necessary for both colors. The population change on dominant color, though, was driven by environmental changes. Even that title you give seems to preclude that increased plasticity can itself be an adaptation? Wouldn't we need to show that there was no change in plasticity during this time in order to show otherwise?
- __MatrixMan__ 9mo ago
  It's a meaningful distinction because adaptation has the potential to introduce novel mechanisms while plasticity doesn't. So if you mistook one for the other, you might assume that a given crop will continue to adapt to a warming climate when what's actually happening is that it's approaching the bounds of its plasticity and yet another degree of warming will cause it to fail. You could also make bad assumptions related to rates. One might assume that adaptation will occur within some time window when actually they're extrapolating based on plasticity. Sure, plasticity and its limits are themselves the result of natural selection, but there are still experiments you can do to distinguish the two (e.g. does the change show up in the genome versus the transcriptome or the proteome?). I guess I'm just uncertain about how useful it is to split hairs beyond a certain point. Like, you could say that everything is caused by the big bang, case closed, but that's not going to affect any subsequent decisions that people might make.
  - taeric 9mo ago
    Fair that I think it is valuable to know some things are stronger adaptations than others. I just don't see the point in claiming it is not, itself, an adaptation. Feels very "not actually evolution" in claim. It is, but there are obvious limits to what it can achieve. As an easy example, to your point, would you say that adaptation and evolution lead to land creatures? There are obvious limits to how quickly and how well that could have possibly worked. But it also feels safe to say that some organisms almost certainly had a level of plasticity that made it more likely for them to survive the process?
    - __MatrixMan__ 9mo ago
      Re: your questions, yes and yes. If its both plasticity and adaptation at play in all cases then there's not much sense drawing a line, such as the evolution of land creatures. And its also probably silly to worry about adaptation without plasticity. But it does make sense in the plasticity without adaptation case. For instance there are people born in Tibet with adaptations for altitude, and people born in the Andes with adaptations for lead tolerance. And if those of us without those adaptations were to try to tolerate such heights, and such concentrations of lead, we wouldn't do as well because we lack the genes for that particular adaptation. Even though we are partially adapted to those things in general. The "X is not a result of adaptation" predicate makes sense in relation to other things that are more directly a result of adaptation.
      - taeric 9mo ago
        But doesn't this just go to my point that you would more expect further adaptations from those that already have the plasticity? Fair that you could get them in either, but the point of evolution/adaptation is that often the mechanism is not a first class one. To the peppered moth example, it isn't like there was a specific mutation that caused them to change color. Both colors always existed. The prevalence at the population level was essentially the result of external drivers to the species. So, in plants, it is fair to say that those with more plasticity are able to change when they flower in response to environmental changes. Why is it not fair to expect that those most able of doing that are the ones you are likely to see further adaptations on to keep adjusting? Yes, we can see individual mechanisms and we can focus on them. Such that we don't have to hope for random mutations that further advantage things. But, adaptation and evolution are not defined as only random mutations. (Or have they been somewhat redefined into that?) I think more cleanly stated for my point, I am not arguing against the idea of plasticity. I am arguing that adaptation is not defined as only random mutations introducing novel characteristics. Specifically because the fundamental example for evolution that used to be taught was definitively not a novel characteristic of the species.