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Author | Topic: Artificial Selection - Is the term simply convenient? | |||||||||||||||||||||||||||||||||
Taq Member Posts: 9973 Joined: Member Rating: 5.7 |
Probably more precise to use the phrase anthropogenic selection when referring to human intervention in the 'natural' selection process. That is probably the best suggestion so far. What we create is an environment where the fittest individuals are those that meet human preferences. As long as we select based on phenotype, then we are following natural selection. Where anthropogenic selection can diverge from natural selection is if we select based on genotype. Natural selection can not "see" gene sequences, so it always selects based on phenotype. This results in interesting adaptations and allows genotype to be independent of phenotype. If humans select based on gene sequence, then we are ending that independent relationship.
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AppleScratch Junior Member (Idle past 3493 days) Posts: 9 Joined: |
quote: This is something that I considered also, and I do agree with you that it is easy to perceive this difference. Ideas like the ones you posted were the only reason I felt compelled to even bring it up at all. The lines just get so blurry that it seems like an unscientific concept to my own ways of thinking. You seem to agree with most of what I had read, where deliberate intent or goals for the future are factors in differentiating artificial from natural. Would humans hunting a predator to extinction be considered Artificial Selection by your definitions? We determine with our foresight that this species poses a threat to our lives, and become a tremendous selective pressure against it. This example seems more mundane than proactively selecting crop traits that make cultivation easier. I feel less tempted to claim it as special or artificial, but don't know why in any scientifically justifiable way. I am honestly not trying to be dense I see why it makes discussion easier to have the distinction, I just can't get to any actual basis for it that is consistent, and it becomes interesting to ponder.
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1.61803 Member (Idle past 1504 days) Posts: 2928 From: Lone Star State USA Joined: |
All I know is someone needed to tell this guy he's doing it wrong!
"You were not there for the beginning. You will not be there for the end. Your knowledge of what is going on can only be superficial and relative" William S. Burroughs
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Minnemooseus Member Posts: 3941 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0
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I see no reason why 10,000 years of selective breeding (i.e. artificial selection) is less of a problem than 20 years of genetic recombination in a lab. But I think that if you're doing something with the possibility of leading to an ecological disaster, it would be better to do it slow and careful. I don't care if a genetically engineered (20 year variety) food turns out to be bad for human consumption. But if a genetically engineered plant turn out to be bad for bees, then you're heading for an ecological disaster. MooseProfessor, geology, Whatsamatta U Evolution - Changes in the environment, caused by the interactions of the components of the environment. "Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham "The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness." - John Kenneth Galbraith "Yesterday on Fox News, commentator Glenn Beck said that he believes President Obama is a racist. To be fair, every time you watch Glenn Beck, it does get a little easier to hate white people." - Conan O'Brien "I know a little about a lot of things, and a lot about a few things, but I'm highly ignorant about everything." - Moose
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Dr Adequate Member (Idle past 285 days) Posts: 16113 Joined: |
Would humans hunting a predator to extinction be considered Artificial Selection by your definitions? We determine with our foresight that this species poses a threat to our lives, and become a tremendous selective pressure against it. This example seems more mundane than proactively selecting crop traits that make cultivation easier. I feel less tempted to claim it as special or artificial, but don't know why in any scientifically justifiable way. Well in that case we're not selecting which ones to kill and which ones not to kill in order with the intention of producing a new type.
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AppleScratch Junior Member (Idle past 3493 days) Posts: 9 Joined: |
quote: I have a herd of sheep, and kill off the wolves in order for my herd to survive. This allows more successful survival of sheep. This provides more food and utility for myself than if I did not kill the wolves. I have a crop of corn. I kill off the new plants that have smaller kernels. This allows more successful survival of the larger kernels. This provides more food and utility for myself than if I did not kill the smaller kerneled plants. Is one of these Artificial selection and the other not? Is attempting to produce a new type, rather than prevent an existing type from undue pressure a difference that I don't understand?
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nwr Member Posts: 6408 From: Geneva, Illinois Joined: Member Rating: 5.1 |
I have a herd of sheep, and kill off the wolves in order for my herd to survive. This allows more successful survival of sheep. This provides more food and utility for myself than if I did not kill the wolves.
I expect that opinions will vary on this. I have a crop of corn. I kill off the new plants that have smaller kernels. This allows more successful survival of the larger kernels. This provides more food and utility for myself than if I did not kill the smaller kerneled plants. I would say that what you are doing to the wolves counts as natural selection, albeit anthropogenic natural selection. And what you are doing to the corn counts as artificial selection.Fundamentalism - the anti-American, anti-Christian branch of American Christianity
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Dr Adequate Member (Idle past 285 days) Posts: 16113 Joined: |
Well the difference is that what you're doing in the first case, though it's certainly artificial, isn't selection. You're not picking and choosing among the sheep, or among the wolves.
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AppleScratch Junior Member (Idle past 3493 days) Posts: 9 Joined: |
Can you elaborate?
Is elimination not considered selection against? How am I not selecting 'for' sheep and 'against' the wolves in this scenario?
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Dr Adequate Member (Idle past 285 days) Posts: 16113 Joined: |
Selection, in the biological sense, involves choosing among the members of a population, not between two whole species only distantly related.
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AppleScratch Junior Member (Idle past 3493 days) Posts: 9 Joined: |
Can you give a full definition of selection as it applies to biological evolution that we can use for this thread?
Dictionary, Encyclopedia and Thesaurus - The Free Dictionary lists it as: A natural or artificial process that favors or induces survival and perpetuation of one kind of organism over others that die or fail to produce offspring. If there is another one that is more accurate, I'd like to use it instead . I am not formally researching this field so I may have poor word choice and definitions in my brain.
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herebedragons Member (Idle past 858 days) Posts: 1517 From: Michigan Joined: |
Hi AppleScratch and welcome...
I see why it makes discussion easier to have the distinction, I just can't get to any actual basis for it that is consistent, and it becomes interesting to ponder. Biological systems rarely have clear cut distinctions unless there is some quantitative value by which to distinguish them. So a group of plants with leaves between 2 cm and 5 cm long belong to this species and those with leaves 7 cm to 10 cm belong to another species. There is something we can quantify and measure to assign a distinction. As you can see by the examples you are pondering, the distinction between "natural" and "artificial" selection is not something that can be quantified and so it becomes difficult to nail it down into distinct categories. As an example, white-tailed deer use their antlers to fight for the right to mate, so those with bigger, stronger racks have better chances to produce offspring, so we would say natural selection favors larger racks. However, hunters tend to shoot those deer with bigger racks, and since we could consider hunters to simply be apex predators, we could also say that natural selection also works against large racks. But, the way hunting seasons are typically scheduled, the mating begins before or very early in the hunting season and even though a particular male may get shot during the season, he may have already impregnated several females. The confusion comes in because the predator in question is humans, which makes one think that the selection is "artificial." But if you consider that humans are just a predator in a predator / prey relationship, it is pretty much a natural selection system. However (there's that word again that indicates how difficult it is to define distinct categories), selecting an individual based on antler size is hardly a "natural" choice. Deer with large antlers are typically older, wiser, stronger and warier than their younger, smaller racked comrades. Thus selection for rack size is not a choice based on what makes the animal suitable or preferable prey, but on some arbitrary human preference. So I would suggest that artificial selection is selection that favors or enhances a particular trait regardless of it's potential effect on fitness. These traits are selected for because of their benefit to humans, not because of their benefit to the organism undergoing selection (even though they may, in fact, improve the organisms ability to survive). I hope this helps some. HBDWhoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for... I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem. Ignorance is a most formidable opponent rivaled only by arrogance; but when the two join forces, one is all but invincible.
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AppleScratch Junior Member (Idle past 3493 days) Posts: 9 Joined: |
Very helpful, thank you.
I don't really think there is much else to discuss about this one from my end, I thought there might have been more to it that I was just missing. Thanks for all of the responses!
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Minnemooseus Member Posts: 3941 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
No references, but a number of years back I heard (public radio, I believe) about an lab experiment designed to mimic the results of commercial fishing (via nets).
In the wild, the larger fish are preferentially caught because the smaller fish get through the nets. So, to mimic this in the lab population, the larger fish were preferentially removed. This resulted in a population evolution resulting in smaller full grown fish. Moose Added by edit - What seems to be a related reference:
Evolutionary response to size-selective mortality in an exploited fish population Abstract:
quote: Full article at cite. Edited by Minnemooseus, : Added by edit.
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Stile Member Posts: 4295 From: Ontario, Canada Joined: |
AppleScratch writes: I have a herd of sheep, and kill off the wolves in order for my herd to survive. This allows more successful survival of sheep. This provides more food and utility for myself than if I did not kill the wolves. My thoughts would be that you are not doing any selection on the sheep. Therefore the sheep are still undergoing natural selection.Hmmmm... thought about that. Maybe you are doing artificial selection on the sheep too. That is, without any intervention can we safely assume that the wolves would indeed hunt some of the sheep? If so, then you are artificially removing this selective pressure and therefore causing some amount of artificial selection onto the sheep. You are, however, definitely doing some selection on the wolves... therefore, the wolves are undergoing artificial selection. You are artificially adding a selective pressure on the wolves for them to not eat sheep. Whether that actually has an effect on the wolves' population is another question... but that's irrelevant. You are still causing some artificial selection on the wolves.
I have a crop of corn. I kill off the new plants that have smaller kernels. This allows more successful survival of the larger kernels. This provides more food and utility for myself than if I did not kill the smaller kerneled plants. I don't see any trick to this one. Seems like simple artificial selection to me. Your interference is adding a selective pressure onto the corn growth.
Is one of these Artificial selection and the other not? Is attempting to produce a new type, rather than prevent an existing type from undue pressure a difference that I don't understand? Maybe I'm certainly no biologist and would drop my line of argument if anyone with such authority says otherwise.
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