Why is natural selection not random?
- Thread starter darryl
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Spencer was only 17 when Darwin got back from Galapagos. Darwin himself said:
"In October 1838... I happened to read for amusement Malthus on Population... it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species."
If you're looking for the smoking gun, it's not in philosophy, but in economics. The bird will eat the green bug, so that trait is selected for elimination from the gene pool. It's as simple as that.
No. Birds choose green bugs because they see them against the brown brush, and the one that gets eaten can't reproduce. Even this highly simplified generalization for all of evolution is good enough to explain the basic principles to a child. So why all the denial? Why pretend you've never heard this?
If you look at the social environment, once the rules of that environment are set, such as wearing the correct shoe, this defines fitness and selection within that environment. In the case of social environment, although fitness based on a shoe is irrational, a direction will nevertheless be defined, which will create social pressure and/or acceptance. Selection in that environment has a defined path implicit of this push/pull.
The natural environment makes use of rational laws of nature and science. These also have a sense of push and pull, with selection near the sweet spot. This will not be true 100% of the time, because short term wildcard variables also possible. These can act too fast, thereby creating insufficient time for adaptation.
A tree could fall on the otherwise selected. The sweet spot still holds true, but in this case, the time scale is too fast for the sweet spot. If the tree fell in slow motion the selected would be the same.
A social analogy of the wild card, is a child who didn't hear about the new shoe rule and goes to the party with the color of yesterday. If he had enough notice he would have wore the right shoe. In this case the environment changed too fast to find the sweet spot. Now someone else is the star of the party and get selected as best costume. But if all had the same notice, he would spend the bucks and become selected at the party as best shoe.
If you look at eco-systems, there is a delicate balance since each aspect is in a sweet spot. Based on input and output potentials, created by the environment and each species, the adjacent species have found the sweet spot. This is true of all eco-systems. If we alter parameters or potentials, we can alter the sweet spots. This can lead to extinction of some species if they cannot adjust to the new sweet spot. It may encourage other systems to enter who find the new sweet spots. This may begin with only a single instance of a species, who then evolves from that sweet spot, fine tuning as the sweet spot ebbs and flows.
The natural environment makes use of rational laws of nature and science. These also have a sense of push and pull, with selection near the sweet spot. This will not be true 100% of the time, because short term wildcard variables also possible. These can act too fast, thereby creating insufficient time for adaptation.
A tree could fall on the otherwise selected. The sweet spot still holds true, but in this case, the time scale is too fast for the sweet spot. If the tree fell in slow motion the selected would be the same.
A social analogy of the wild card, is a child who didn't hear about the new shoe rule and goes to the party with the color of yesterday. If he had enough notice he would have wore the right shoe. In this case the environment changed too fast to find the sweet spot. Now someone else is the star of the party and get selected as best costume. But if all had the same notice, he would spend the bucks and become selected at the party as best shoe.
If you look at eco-systems, there is a delicate balance since each aspect is in a sweet spot. Based on input and output potentials, created by the environment and each species, the adjacent species have found the sweet spot. This is true of all eco-systems. If we alter parameters or potentials, we can alter the sweet spots. This can lead to extinction of some species if they cannot adjust to the new sweet spot. It may encourage other systems to enter who find the new sweet spots. This may begin with only a single instance of a species, who then evolves from that sweet spot, fine tuning as the sweet spot ebbs and flows.
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wellwisher
Nature doesn't notice your shoes and these types of things come and go so fast that they have little or no effect on Nature. Natural Selection and sexual selections are two different things. Intellect can overrule the forces of Natural Selection, we call that Artificial Selection, like man did with wolves to produce dogs. Or the variations in the cabbage/brocolli family. Or the female Peacocks choosing the males with the biggest, brightest tail feathers. Understanding the difference is important if we are all going to talk about the same thing.
Grumpy
Nature doesn't notice your shoes and these types of things come and go so fast that they have little or no effect on Nature. Natural Selection and sexual selections are two different things. Intellect can overrule the forces of Natural Selection, we call that Artificial Selection, like man did with wolves to produce dogs. Or the variations in the cabbage/brocolli family. Or the female Peacocks choosing the males with the biggest, brightest tail feathers. Understanding the difference is important if we are all going to talk about the same thing.
Grumpy
We all start young, and even more ignorant than we are now. There is no shame in simply not knowing stuff, in being a beginner at a trade or field or arena of human knowledge and accomplishment - and we are all beginners at the study of the world.darryl said:
Look here: "deliver" not "delivers"; "exposé" is wrong; "inane" is wrong; "natural selection" is neither logical nor illogical, and is not a theory; and you don't know what "nonrandom" means. Overall, your use of adjectives is inappropriate in your chosen context.
None of that has anything to do with Darwin or Darwinian theory in particular. It is simply a blue pencil approach to your sentence, considered as rhetoric.
The basic problem is that you do not have a decent liberal arts education. There is nothing wrong with that - it's a lot of work, takes a few years at least, and not everyone needs one. But in certain arenas of debate and discussion, you are vulnerable to crackpots and charlatans who can imitate the rhetoric of plausible reasoning. Whoever set you up with the term "stunning exposé", for example, is not someone you can trust - you are being conned, for some reason.
The reason species diverge is because of imbalance, not because of a sweet spot. Two dissimilar phenotypes will struggle within the same niche while that dithering un-sweet spot keeps the pressure up. At some point, one will typically win and a true split occurs. But it may come only after a prolonged period of uncertainty in which no sweet spot is found.
Consider the polar bear and arctic wildlife in general. They may be on a trajectory of crashing slowly, perhaps over decades. And there's nothing sweet about it.
iceaura,
I think that was well done - respectful yet frank. You have my attention now for sure. I will try to look out more closely for your posts. I think I have been confusing you with someone else whose name is almost an anagram of yours, who is almost opposite of you in persona. Now I finally have it straight!
I think that was well done - respectful yet frank. You have my attention now for sure. I will try to look out more closely for your posts. I think I have been confusing you with someone else whose name is almost an anagram of yours, who is almost opposite of you in persona. Now I finally have it straight!
The existence of ecosystems preclude only randomness as the basis for selection. You cannot use random selection to form millions of eco-systems, each of which can achieve a balance.
If we look at one particular life form, out of the context of its ecosystem, it may look random, since we will ignore variables that exist in the bigger picture. But once you scale up to the bigger picture, the odds of millions of delicate ecosystems precludes randomness in selection.
I agree that ecosystems can split due to internal pressures, which can be created by genetic changes. Life can create its own version of environmental pressure, adding new variables to the environment. These can result from genetic changes.The predator can get faster and alter the potentials. But once the potentials change, there is a new set of sweet spots that give an advantage.
Another variable has to do with migration. There is no rule that says animals cannot leave an environment, where there is no sweet spot for them, and migrate to another environment where they can find a sweet spot. Sometimes the new genes in an environment are old genes from another place.
As an analogy, this is no different from the pioneer who drives his wagon through the desert west and keeps moving, since there is no sweet spot for him in that harsh environment. Once he arrives in a fertile valley, the displaced DNA starts to thrive since now the environmental potentials suit his DNA. He may alter the ecosystem in the valley by creating new potentials. Life fills in the void or decides to leave for better sweet spots.
If we look at one particular life form, out of the context of its ecosystem, it may look random, since we will ignore variables that exist in the bigger picture. But once you scale up to the bigger picture, the odds of millions of delicate ecosystems precludes randomness in selection.
I agree that ecosystems can split due to internal pressures, which can be created by genetic changes. Life can create its own version of environmental pressure, adding new variables to the environment. These can result from genetic changes.The predator can get faster and alter the potentials. But once the potentials change, there is a new set of sweet spots that give an advantage.
Another variable has to do with migration. There is no rule that says animals cannot leave an environment, where there is no sweet spot for them, and migrate to another environment where they can find a sweet spot. Sometimes the new genes in an environment are old genes from another place.
As an analogy, this is no different from the pioneer who drives his wagon through the desert west and keeps moving, since there is no sweet spot for him in that harsh environment. Once he arrives in a fertile valley, the displaced DNA starts to thrive since now the environmental potentials suit his DNA. He may alter the ecosystem in the valley by creating new potentials. Life fills in the void or decides to leave for better sweet spots.
Why is it then with most scientific terms they are defined in the same language or with very similar terms but when it comes to natural selection, nobody can define it and everyone has their own opinion about what it is? I am seeing much different terminology here. Can you imagine opening up a physics or biology textbook and looking up any word they would all get the same meaning, but come to natural selection and everybody has their own spin on it.
See the different definitions that I listed, there are some big differences!
The medical dictionary and other websites claim natural selection is survival of the fittest, but other websites disagree.
Note the words "better adapted" in this definition and organisms.
This definition suddenly adds gradual and non-random, and now there is no mention of organisms, but suddenly now natural selection applies to a population.
You think all these are the same do you?
So which is it? A main mechanism, a key mechanism, an evolutionary process, "the natural filtering process", "the directional process", "the concept", "the process", the "theory" or "the driving force"? And you still think all this terminology means the same thing. LOL!
No mention of "genetic combinations" in the other definitions.
Mutation has been added to this definition, why not in the others?
Really? I thought natural selection according to the others was about reproduction?
Yep, then its nothing but a worthless tautology is it? It explains nothing but everything at the same time.
The other definitions do not mention "fitness" how can "fitness" be defined?
Whos directing it? Why do none of the other definitions mention directed?
Oh? So now its species AND a population? Then why do other definitions only mention populations?
So its a concept not a "directed evolutionary process" like the other definitions say?
So it's a theory and not a process like the others say?
So natural selection IS survival of the fittest according to this definition, but the others don't say that.
Evidence? The other definitions define natural selection as a concept or filtering process or process, but now it is the "driving force"?
"differential reproductive success" .... INDIVIDUALS WITHIN A SPECIES! Then why do the other definitions mention natural selection occurs within a population and not within species?
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All those definitions say more or less the same thing in different ways.
The main mechanism of evolutionary change ”
“ It is a key mechanism of evolution ”
“ An evolutionary process ”
“ The natural filtering process ”
“ The directional process of evolutionary change ”
“ The concept ”
“ The process in nature ”
“ Natural selection is the theory ”
“ the driving force "
Which one is it?
All of the above.
So an example of natural selection is a bird eating a green bug, it selected the green bug so natural selection is not random. So natural selection operates on a single species basis and not amongst entire populations now? And how can natural selection be "mindless", do birds not have any consciousness now? Birds are mindless? Birds are "mindless" but they somehow select which green bug to eat? How is that possible!!?? :shrug:
How about the developmental biologist, paleontologist, geneticist, embryologist Conrad Hal Waddington who was critical of natural selection as an evolutionary process? Im sure he would meet your "qualification standards".
Waddington, C. H., 1960. Evolutionary adaptations. In S. Yax (Ed.), The Evolution of Life, p. 385. Chicago: University of Chicago Press.
By that logic, the deliciously tasting organisms/animals are eaten first, until their species becomes extinct. By that logic, the taste of food, evolutionarily speaking, gets worse over time. :shrug:
darryl
You have a glimmer of understanding there. It is the green bugs that get eaten more than the camoflaged bug(thus reproduces less), making green bug genes less frequent in the genome of those bugs.
You are confusing Natural Selection and Evolution here. Natural selection works on the individual, it is a test of their fitness to survive. Evolution occurs because the survivors of the individual test(NS)are the ones who determine change in the species("populations" means all members of that species, "gene pool" refers to the entire DNA content of that species). Species evolve because NS determines the content of the gene pool by determining the individual winners who get to spread their genes. Those sets of genes in the losers of the test are eliminated from that gene pool. So random variations within a population are tested by survival(NS)giving a non-random result of greater survival success, lesser survival success is eliminated by the simple fact they died before they reproduced(or at least did more often). Natural Selection is a non-random criteria, a pass/fail test , a yes/no test where the correct answer allows a creature to continue to have descendents and failure means you are dust.
All of the above statements are true about NS. "The main mechanism of evolutionary change” is Natural Selection, "It is a key mechanism of evolution". It is "An evolutionary process" where "The natural filtering process" of survival to reproduce provides "The directional process of evolutionary change".
Darwin developed "The concept" of Natural Selection to explain "The process in nature" that would account for the equal but seperate discovery of Evolution. And Evolution is a fact(the evidence is on a par with the sun rising tommorrow), "Natural selection is the theory" that explains the facts, it is "the driving force" behind Evolutionary changes. "The concept" that only the survivors, the winners, get to determine the genes of the next generation is very, very simple to understand.
Grumpy
You have a glimmer of understanding there. It is the green bugs that get eaten more than the camoflaged bug(thus reproduces less), making green bug genes less frequent in the genome of those bugs.
You are confusing Natural Selection and Evolution here. Natural selection works on the individual, it is a test of their fitness to survive. Evolution occurs because the survivors of the individual test(NS)are the ones who determine change in the species("populations" means all members of that species, "gene pool" refers to the entire DNA content of that species). Species evolve because NS determines the content of the gene pool by determining the individual winners who get to spread their genes. Those sets of genes in the losers of the test are eliminated from that gene pool. So random variations within a population are tested by survival(NS)giving a non-random result of greater survival success, lesser survival success is eliminated by the simple fact they died before they reproduced(or at least did more often). Natural Selection is a non-random criteria, a pass/fail test , a yes/no test where the correct answer allows a creature to continue to have descendents and failure means you are dust.
All of the above statements are true about NS. "The main mechanism of evolutionary change” is Natural Selection, "It is a key mechanism of evolution". It is "An evolutionary process" where "The natural filtering process" of survival to reproduce provides "The directional process of evolutionary change".
Darwin developed "The concept" of Natural Selection to explain "The process in nature" that would account for the equal but seperate discovery of Evolution. And Evolution is a fact(the evidence is on a par with the sun rising tommorrow), "Natural selection is the theory" that explains the facts, it is "the driving force" behind Evolutionary changes. "The concept" that only the survivors, the winners, get to determine the genes of the next generation is very, very simple to understand.
Grumpy
A bird isn't mindless (for the sake of argument), but not every selection factor is a living one. It only works on species because they are the ones reproducing, making up what we call the gene pool. In fact, however, selection acts on the level of the gene or sets of genes.
Yep.mazulu said:
Sometimes it gets not only bad tasting, but downright poisonous.
Fortunately for our dining pleasure, tasting evolves along with taste, digestion evolves with the ingested.
Even more fortunately, being eaten is not necessarily a barrier to reproductive success - can even be used for advantage, so that fruits and berries evolve to be more tasty over time.