The principle of "least energy" seems to be a fundamental law of the universe (is it?). I probably use the wrong word. I'm just talking about the reason why electrons are filling first the lower level of energy or why chemical reactions happen in a specific direction, or maybe even the "Path of least resistance". Is it a fundamental law/principle or the consequence of another principle (like the weak force)?

This principle also seems obvious in living beings. But how does it fit with evolution? I first thought that between two individuals, evolution will favor the one who needs/spends less energy, but it's not that simple because the "winner" is not the most efficient, but the one who will reproduce the most (replicate its genes). So an individual who is less energy efficient (or needs/spends more energy) but replicates, more will be selected. But the principle seems to apply for two individuals who replicate at the same rate: the one who spends the least energy will be selected by evolution.

So it seems that the principle of "least energy" applies to everything, including the things that replicate (living beings) and their evolution. But it also seems like evolution favors "the one who replicates the most" first and, only after, follows the principle of least energy. But if the principle of least energy is really fundamental, how evolution was able to overtake it and put it in second place?

For example, is it accurate to say, that evolution doesn't necessarily invent the most efficient things/strategy, and fancy stuff because (amongst other reasons) it's stingy, it only follows the path of the least energy?

I feel that I'm handling the problem in the wrong way. Please correct me if that's clear for you.

EDIT: (the question has been close: I can't answer...)

this is a difficult question because it points to (at least) 3 different concept that seems conflicting, but thanks to Joe Daniel and Paul Spencer (from quora) it seems solved.

  1. "living organisms will seek to minimize their energy output in a variety of ways. Those that do so effectively have an edge in survival and reproduction and are thus more likely to continue a population that can evolve." (Joe Daniel) "There is always selection pressure towards the systems that are most energy-efficient" (Paul Spencer)

  2. But in evolution, the one who replicates the most will be selected, even if it's less energy efficient. "Reproductive success is the filter that creates that evolutionary pressure on all traits, and is more fundamental than anything in terms of evolution itself" (Paul Spencer). "Conservation of energy is a distant second to surviving long enough to get offspring that survive and reproduce" (Joe Daniel)

1+2= If resources are plentiful, an individual can invest more in strategies that are costly, but increase one’s odds of success. If resources are scarce and patchy, the ones who can conserve their energies best may have an edge. (Joe Daniel)

  1. then there is the entropy problem (It wasn't my question, I focus on energy, entropy focus on order, but it answers a part of it) :

The problem: "Biological evolution does cause the system (living organisms)'s entropy to decrease. So, by the second law of thermodynamics, the entropy of the universe (in this case Earth), must have overall increased."(Yolo123)

The solution: Earth is not an isolated system. Life causes entropy of the earth to decrease. This is offset by increased entropy of the sun, which is the primary source of energy for the earth. Overall, the entropy of the universe increases.Canadianer

(What is the difference between entropy and energy? "The more energy present in a system, the more disorder or entropy there will be. [...] That increase in freedom that corresponds to an increase in disorder is entropy. Entropy is thus a measure of the random activity in a system, whereas enthalpy is a measure of the overall amount of energy in the system." src)

So what about the principle of least energy?

1+2+3= [it] is a theoretical concept explored by several mathematical papers that, on the surface, makes sense, if life was all about the flow of energy. But it’s not. Life is about survival, and that is often not energetically efficient. (Joe Daniel)

(An interesting implication ―which solves the seemingly paradoxical concepts, I was struggling with―: at the individual scale the principle of the least energy pushes the organism to come back to its natural state ―because it's the state that costs the less energy for it). But its natural state does not necessarily follow the 'least energy' for the reason mentioned above.)

  • 2
    $\begingroup$ It is possible that you thinking of the second law of thermodynamics? It would be best to be clear what that means before considering it in relation to evolution. It does indeed pose problems for cellular organization and life, but not, as far as I can see, specifically for evolution. But at the moment posing a question about something you call a fundamental law of the universe but are not sure what it is does not make a satisfactory question. $\endgroup$
    – David
    Jul 12 '21 at 12:00
  • 1
    $\begingroup$ @David posing a question about something you call a fundamental law of the universe. If you read carefully, you will see that don't "call" it fundamental law, I say it seems , then is it? and I ask Is it a fundamental law/principle or the consequence of another principle [...]?. Half of the question is about it... So to summarize, people who don't know the answer, or aren't sure shouldn't ask a question (that sin definitely deserves your downvote). $\endgroup$
    – JinSnow
    Jul 12 '21 at 16:02
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    $\begingroup$ At present the question qualifies for closure on the following grounds: it lacks clarity, it lacks research, it involves several questions, the first of which belongs in Chemistry, and it has been asked before. There is a fundamental law of chemical thermodynamics and concerns Entropy (not energy) changes. As evolution is not a chemical process I do not see how it relates to the second law, but see here. $\endgroup$
    – David
    Jul 12 '21 at 21:15
  • $\begingroup$ As suggested in these comments, some research (e.g. courses.lumenlearning.com/cheminter/chapter/… ) should help you better frame your question. $\endgroup$
    – Armand
    Jul 15 '21 at 1:22

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