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Author | Topic: How is Natural selection a mechanism? | |||||||||||||||||||||||||||||||||
Riggamortis Member (Idle past 2416 days) Posts: 167 From: Australia Joined: |
quote: So no, the gas molecules won't go to the corner of a jar without some outside influence because they 'want' to find equilibrium and stay there at maximum entropy until otherwise disturbed. The earth is bombarded with energy from the sun which alters the air and ocean temperatures which in turn creates high and low pressure systems. These systems manifest as the weather we observe. It is never able to find a stable, high entropy state due to the energy input from the sun. Climate change is a result of the earth retaining more of the energy it receives from the sun, it follows and is expected that such should produce more extreme weather events. Is this a fair summary of the situation? It leads me to a somewhat related question. Solar converts the suns rays directly to electricity and therefore not only cuts down on carbon emissions but also somewhat reduces the amount of the suns energy which manifests itself as heat on earth. Since the energy of the wind is ultimately sun powered, in addition to reducing emissions, don't wind turbines reduce the impact of excess energy manifested as weather patterns by removing energy from the wind? It seems obviously true so the question is, to what extent could it scale? I've not bothered to look into climate change because I'm pro-sustainablility and renewables regardless. Does the climate modelling give numbers in joules of excess energy retained? Could this be compared to global energy usage if we assume we managed 100% wind and solar to see what sort of impact it could have? In 2014 wiki gives 150,000 TWh generated, anyone got a source for the warming energy and care to do the conversion and comparison?
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JonF Member (Idle past 194 days) Posts: 6174 Joined:
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The equation boils down to "entropy must incease or remain the same", and in reality it never stays the same.
Your reference goes on the say "Since entropy gives information about the evolution of an isolated system with time, it is said to give us the direction of "time's arrow". They do not address the information of an open system's evolution with time. IMHO they don't make this sufficiently clear.
How does a refrigerator relate to any of this? See the second box in your reference. Refrigerators move heat from a colder reservoir to a hotter one, which is impossible if the system is isolated. They reduce the entropy inside them at the expense of increasing the entropy outside them by more, for a*net* increase in entropy. So entropy flows out of the system due to the work preformed and the system is not isolated. In this case the entropy equation is: dS = Q(within the system)/T(within the system) + Q(to the outside)/T(outside) and as long as the appropriate work is performed by some engine the second term is negative and overrides the first for a net decrease of entropy in the refrigerator. See Does Life On Earth Violate the Second Law of Thermodynamics? for a moderately technical discussion; you may not be able to follow it all the way through but the beginning is the key.
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JonF Member (Idle past 194 days) Posts: 6174 Joined: |
Pretty much anything Man does doesn't affect the entropy of the Earth significantly, which is the entropy of the entire mass of the earth. Even the mass of the oceans is insignificant. What we do is just too small scale.
Heat flows and temperatures are another story. {ABE} Oh, and, all the Sun's energy that isn't reflected or otherwise prevented from being absorbed by something on the Earth winds up as heat. The path it takes to get there (Solar cells, ..) doesn't matter. Edited by JonF, : No reason given.
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RAZD Member (Idle past 1431 days) Posts: 20714 From: the other end of the sidewalk Joined: |
I'm a little confused. I went back to see what the original post asked and saw
Aren't mutating genes the sole mechanism by which organisms are formed? While the thread title is
How is Natural selection a mechanism? To answer the first question, single cell organisms produce offspring by budding, asexual reproduction, where they make a copy of themselves; sexual organisms produce offspring by mingling genes between parents, producing variety when there are more than one version of a gene in the genome. In both cases mutations can cause alterations of the genotype and produce modified organisms. They are part of the process of forming new forms of organisms. To answer the second question let me ask the converse:
How is Natural Selection not a mechanism? If I take a bag of coins and flip them, putting the "heads" in one pile and the "tails" in another, and then take all the "tails" and flip them again, adding the "heads" to the "heads" pile and continuing to flip the coins ...
I ask this because it seems that your topic has wandered away from your original question/s. Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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AndrewPD Member (Idle past 2441 days) Posts: 133 From: Bristol Joined: |
Here is a simple analogy of entropy.
You drop an uncooked egg and it shatters. I don't think there has ever been an instance where that egg has in the next moment or later returned to being an unbroken egg. Now you can imagine the same with a vase. A vase shatters. You could leave it for a million years and it would never reform into the same vase. However a human can intelligently intervene and quickly glue the vase into a whole again. Human interventions do seem to effect entropy because volitional actions and intelligent perception allow us to create improbable states of order. So it is this kind of intelligent intervention that can reduce the rate of entropy. This is a true selection process and very effective.
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AndrewPD Member (Idle past 2441 days) Posts: 133 From: Bristol Joined: |
I have found this definition of natural selection.
"Evolution acts through natural selection whereby reproductive and genetic qualities that prove advantageous to survival prevail into future generations." Mechanisms of Evolutionary Change | Nectunt This is survival of the fittest that has been described as tautologous because it means that anything that survives is defined as fit. But this led making a value judgement about traits which had a negative social effect. And so people decided which traits they thought were being or would be selected.But anything that survives is being selected. As soon as something dies without having offspring it is deselected, trivially so. There is no trait that can't easily be made extinct. Why a trait survives is down to the properties it was freely given by biochemistry. Natural selection seems entirely negative. It implies nature is deselecting bad traits. But all it seems to be is banal observation that somethings survive and somethings don't. When you start giving a hierarchy of desirable traits or reductive explanations we've seen where that leads. I am exclusively gay and that has led to the puzzle of how this ruthless mechanism wouldn't have weeded that out. That is a teleological standpoint like we knew the mind of nature and can describe what it wants to create. Then there is issue of what was selected as opposed to what is a spandrel. A Spandrel is certainly any easy way for any unevolutionary trait to get a free ride.
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NoNukes Inactive Member
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This is survival of the fittest that has been described as tautologous because it means that anything that survives is defined as fit. But this led making a value judgement about traits which had a negative social effect. And so people decided which traits they thought were being or would be selected. Yes. Some idiots did take that social step.
Natural selection seems entirely negative. It implies nature is deselecting bad traits. Negative selection is not the whole of it. That is part of it, yes. But some new traits are an improvement over the norm, and natural selection favors those. That would be a positive selection. Some traits are neutral in some environments, beneficial in others, and possibly even detrimental in another environment. So selection would not even remove the traits from the entire population, it would just emphasize different traits in different environments. You are telling half of a story.
I am exclusively gay and that has led to the puzzle of how this ruthless mechanism wouldn't have weeded that out. Unless being exclusively gay is an inheritable trait, "weeding" out exclusive gayness via natural selection is not really what the theory of evolution is about, now is it?. That is a further example of how natural selection is being misused in your rant. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) I was thinking as long as I have my hands up they’re not going to shoot me. This is what I’m thinking they’re not going to shoot me. Wow, was I wrong. -- Charles Kinsey I never considered a difference of opinion in politics, in religion, in philosophy, as cause for withdrawing from a friend. Thomas Jefferson Worrying about the "browning of America" is not racism. -- Faith I hate you all, you hate me -- Faith
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AndrewPD Member (Idle past 2441 days) Posts: 133 From: Bristol Joined: |
I like this quote from Dawkins. (In a non endorsing kind of way)
"We are survival machines — robot vehicles blindly programmed to preserve the selfish molecules known as genes. " It is is an extreme statement of what being a human is on his picture. It is not the case for him at least that evolution is just an observation but that it is a paradigm that should govern how we view ourself and our behaviour and how we should seek to interpret reality. This is where you cross the is/ought line. I don't think science is or should be in the service of an ideological stance such as the mechanical world view. I think Selfish and Selection are unfortunate "metaphors". Dawkins has also supported a theory for the universe being selected from a range of possible ones put forward by Lee Smolin.
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RAZD Member (Idle past 1431 days) Posts: 20714 From: the other end of the sidewalk Joined: |
I have found this definition of natural selection. "Evolution acts through natural selection whereby reproductive and genetic qualities that prove advantageous to survival prevail into future generations." Mechanisms of Evolutionary Change | Nectunt This is survival of the fittest ... Well and good, but I would say "survival of those able to survive and reproduce" as this de-emphasizes the relative abilities\merits of all who survive and reproduce.
... that has been described as tautologous because it means that anything that survives is defined as fit. Indeed, and yet it tells us the difference between fit and unfit: survival and reproduction.
But this led making a value judgement about traits which had a negative social effect. And so people decided which traits they thought were being or would be selected. "Social darwinism" imho is/was due to the emphasis on "fittest" and taking it to some ideological extreme. Republican ideology can be seen as "survival of the richest" or "survival of those rich enough to survive" and thus puts over arching emphasis on economic success at the expense of others.
But anything that survives is being selected. As soon as something dies without having offspring it is deselected, trivially so. It may seem trivial at first glance, but that is the mechanism by which the sick and weak are gleaned from the breeding populations, leaving the breeding population better adapted to their ecological niche. Evolution occurs in populations rather than individuals.
There is no trait that can't easily be made extinct. Why a trait survives is down to the properties it was freely given by biochemistry. Indeed. The genotype to phenotype expression -- the overall genetic chemistry of inheritance and mutation modifications -- can be beneficial in one case and detrimental in another.
Natural selection seems entirely negative. It implies nature is deselecting bad traits. But all it seems to be is banal observation that somethings survive and somethings don't. Indeed. The other half of the equation is mutations adding new traits:
When you start giving a hierarchy of desirable traits or reductive explanations we've seen where that leads. Not sure what you are saying here. The process of evolution makes no attempt to develop "desirable" traits other that survival and reproduction.
I am exclusively gay and that has led to the puzzle of how this ruthless mechanism wouldn't have weeded that out. That is a teleological standpoint like we knew the mind of nature and can describe what it wants to create. There are several possibilities. (1) Your genes are also carried by siblings, and their survival and offspring survival may benefit from your assistance. (2) It is not a genetic trait, but one that occurs during development as a fetus due to environmental effects. (3) It is a common mutation due to sexual reproduction mixing of DNA where the gene for sex and the gene for attraction are disassociated. etc. Whatever, it is not confined to the human species. Bonobos are known for open relationships, for example.
quote: quote: One thing for sure is that the fundamentalist ideologues have it wrong, it happens in nature and therefore is natural behavior.
Then there is issue of what was selected as opposed to what is a spandrel. A Spandrel is certainly any easy way for any unevolutionary trait to get a free ride. And many mildly deleterious mutations can go along for the ride when they are on selected genes. What happens when the spandrel becomes a trait for sexual selection ... Peacock tail? Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Pressie Member Posts: 2103 From: Pretoria, SA Joined: |
Thanks AndrewPD. I think I will buy The Selfish Gene this weekend. I think it would be an interesting read. Have you read it?
I've bought and read The God Delusion and The Greatest Show on Earth, written by that author, before. Excellent books. Climbing Mount Improbable will just have to wait! Edited by Pressie, : No reason given.
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CRR Member (Idle past 2268 days) Posts: 579 From: Australia Joined: |
AndrewPD writes:
Even though gay people can have children natural selection should work so long as on average they have less children than straights. I am exclusively gay and that has led to the puzzle of how this ruthless mechanism wouldn't have weeded that out. One explanation is that being gay is not due to genes, not heritable, so then natural selection won't have any effect. Perhaps it is a trait that appears randomly in each generation. Edited by CRR, : edited
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Percy Member Posts: 22490 From: New Hampshire Joined: Member Rating: 5.0 |
AndrewPD writes: Now you can imagine the same with a vase. A vase shatters. You could leave it for a million years and it would never reform into the same vase. However a human can intelligently intervene and quickly glue the vase into a whole again. The analogy is misleading you. Measuring the contribution to entropy of shaping material into a vase isn't really possible, but rest assured that the entropy of the system (which includes people) increases when the vase is made, when it shatters, and when it is reassembled. --Percy
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Pressie Member Posts: 2103 From: Pretoria, SA Joined: |
Even though gay people can have children natural selection should work so long as on average they have less children than straights. Nope. Do you have any idea what natural selection is?
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NoNukes Inactive Member |
It is not the case for him at least that evolution is just an observation but that it is a paradigm that should govern how we view ourself and our behaviour and how we should seek to interpret reality. You are lying. Dawkins, like Darwin, made observations about what natural selection and evolution produce. I don't see in the quote you posted any endorsement that things ought to be that way.
We are survival machines — robot vehicles blindly programmed to preserve the selfish molecules known as genes. You saw the words robot, blindly, and selfish did you not? Those words do not describe how we should govern our behavior. They instead state what Dawkins believes occurs. You simply lied and then attributed the lie to someone else. Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) I was thinking as long as I have my hands up they’re not going to shoot me. This is what I’m thinking they’re not going to shoot me. Wow, was I wrong. -- Charles Kinsey I never considered a difference of opinion in politics, in religion, in philosophy, as cause for withdrawing from a friend. Thomas Jefferson Worrying about the "browning of America" is not racism. -- Faith I hate you all, you hate me -- Faith
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ringo Member (Idle past 438 days) Posts: 20940 From: frozen wasteland Joined: |
AndrewPD writes:
Entropy is not about organization of "stuff"; it's about organization of energy. The entropy of a shattered egg is not necessarily more than the entropy of an intact egg. If you put an egg on a cold surface and its heat dissipates to the surface, that is entropy. It doesn't even matter if the egg is shattered or whole. Here is a simple analogy of entropy.You drop an uncooked egg and it shatters. The amount of information doesn't necessarily change either when the "stuff" is rearranged.
AndrewPD writes:
But life is not an improbable state of order.
Human interventions do seem to effect entropy because volitional actions and intelligent perception allow us to create improbable states of order.
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