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Author Topic:   Can Domestic Selection cause Macroevolution?
crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 136 of 157 (302555)
04-08-2006 10:08 PM
Reply to: Message 135 by kuresu
04-08-2006 9:55 PM


Is it not illogical to say that a rectangle is not the same as a sqaure and then to include, as part of the defintion of a rectangle, a square?
No, it's not. In fact it's the reverse reasoning that's illogical - the fallacy of denying the antecedent. (I told you this already.)
That was why we said the same thing, for the most part. The only difference--how we classify the exact relationship.
Even though symbiotic relationships are on a continuum, there's a big difference between mutualism and parasitism. It's the difference between black and white, or the difference between 1 and -1.
I still don't see how corn derives any benefit from our relationship. We grow it. We care for it. We control it genes. We use it. We plant it.
Yeah. That's the benefit. Thanks to us Zea mays mays has gone from a short grass indiginous only to Mexico to the most popular cereal crop on the planet, grown on all but one continent in countless varieties and diversities, and protected from insect and fungal parasites. In fact American farmers, this year, will spend 100 million dollars or more to protect their corn crop from pests.
Above and beyond that, we've actually improved the genetics of corn so that each plant grows faster and produces more seeds. So that corn can shrug off the effects of glyphosphate herbicides that slaughter its lesser cousins. So that corn can express the Cry protiens of Bacillus thuringensis to protect its roots and stalks from such pests as the European corn borer and the various Diabrotica subspecies.
Everything we do for corn is soley for our benefit, or at least that's how I interpret the evidence.
Look, if a massive increase in the population size of corn isn't a benefit, what would be? If resistance to pests isn't a benefit, what is? I mean what would you consider a benefit to corn?
So in order for the relationship to be symbiotic, it then has to be parasitic. You know how on a multiple-choice test, if you eliminate all possibilities except one, that last one then has to be it? I did the same thing.
No, you didn't, because you didn't eliminate mutualism. You just ignored it or forgot about it. That doesn't count. The arguments of your opponents are no less valid simply because you do not choose to address them.

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extremophile
Member (Idle past 5672 days)
Posts: 53
Joined: 08-23-2003


Message 137 of 157 (302571)
04-09-2006 1:36 AM
Reply to: Message 1 by U can call me Cookie
04-04-2006 4:03 AM


I've not read all the replies yet so I may be redundant.
First of all, I'd equate natural selection and domestic selection, or, better phrasing, I'd say that domestic selection is a subcategory of natural selection. Does not matter that the results of both are somewhat different, there are a few analogues to domestic selection, such as ants farming aphids, which probable led to some degree of selection of aphids that might not be so well adapted for living without the protection of ants.
Then there’s a little issue of what is macroevolution. It could possible have two different meanings: speciation, and the accumulation of a greater level of differences usually found within a single species. I will not argue to which one would be the "true" definition, I think it does not matter.
For the first possible meaning of macroevolution, DS could probably generate it, even though I do not know for sure about that happening. Maybe because it would not have a crucial application in anything, but basically could probably be achieved by selection for two lineages to-be-species lineages whose hybrid offspring would be infertile. It could be more easily achieved if the breeders could search for Robertsonian translocations and a viable population only with this translocation.
But that would result in two different species that can not generate fertile offspring, but are barely distinguishable. Then creationist would say that they’re just mutually sterile lineages, not different kinds.
I think that it would not be any more expected in DS than as a result of NS. There’s first the point that NS disposed of much more time, and yet, tigers and lions can interbreed generating partially fertile offspring (apparently females are fertile, or so I've read), despite of the fact that jaguars, leopards and lions are more closely related with themselves than lions and tigers. Also, could be that eventually the physiological speciation is adaptative, so both populations diverging adaptatively are selected for mutual sterility, which I don’t know if was ever tried in breeds. Also, could be that physiological speciation has barely nothing to do with NS (thus with DS), happening prior to that and then the reproductive barrier "suddenly" formed then forces the just-formed species to diverge adaptatively to different niches in order to not become extinct. That would probably not occur with DS because the variations with increasing or sudden infertility in relation with other lineages would more likely be discarded by the breeders.
The other sense of speciation, which is a bit more meaningful, which would be of creating something more different, closer of being of other "kind", can also be done, the better example is dog breeds. But then they’re usually rejected as macroevolution despite of these lineages differing morphologically with each other at a level that I think (and I guess I've read this stated somewhere) that could be enough to the classification of them in different genera or maybe even families, if they were extinct and we did not know that they would generate fertile offspring.
I say that it would be more meaningful in the context of this debate, not that the term "macroevolution" should be regarded as so. Since it shows that the same species, dogs, can change into this skull, of a Shar Pei, and other one, of a Chihuahua. And didn’t take millions of years. If such degree of change is possible, why not would be possible then to a wolf-like animal evolve in a otter-like animal, and then progressively become more and more aquatic, losing its legs in a manner that is no fundamentally different than the morpholigical changes between these skulls? Then sum it with the fact that whales which do not have bakc limbs have the limb buds in their embryos, which disappear in the further development. And that their flippers have much of the anatomy of the front limbs of terrestrial mammals. When none of these clues for a fake biological relatedness needed to exist without biological relatedness, only regarding the specific functions.
And etc. There are no biological real arguments setting which are the independently originated "kinds". In fact, I've read something in the sense of a admission that it's totally impossible to test, since one could argue that as god created from nothing the first populations or couples of each kind, those would had evidence for biological relatedness since they were all of the same species, even though they haed never born, so were not really related at all.
And "coincidently", none organism which would disprove evolution was created, despite of the range of possibilities of organisms incompatible with evolution is incalculable wider than those that are possible with the restrictions imposed by descent.
This message has been edited by extremophile, 04-09-2006 03:43 AM

"Science comits suicide when it adopts a creed."
Thomas H. Huxley

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randman 
Suspended Member (Idle past 4976 days)
Posts: 6367
Joined: 05-26-2005


Message 138 of 157 (453624)
02-03-2008 1:15 PM
Reply to: Message 1 by U can call me Cookie
04-04-2006 4:03 AM


Haven't read the whole thread, but according to evos, it strikes me as incorrect if you believe homo sapiens evolved to separate mankind from being part of nature. In that regard, domestic selection is natural selection.

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randman 
Suspended Member (Idle past 4976 days)
Posts: 6367
Joined: 05-26-2005


Message 139 of 157 (453628)
02-03-2008 1:22 PM
Reply to: Message 137 by extremophile
04-09-2006 1:36 AM


Haven't read the whole thread, sort of started with the first post and then your's.
There’s first the point that NS disposed of much more time, and yet, tigers and lions can interbreed generating partially fertile offspring (apparently females are fertile, or so I've read), despite of the fact that jaguars, leopards and lions are more closely related with themselves than lions and tigers.
This is a very interesting fact on it's own. Can you speculate more on why they can interbreed despite being less related to jaguars and leopards, or maybe they can interbreed with leopards and jaguars too, but no one has tried to do that....maybe they would fight too much or something?
One could test the idea by impregnating them under medication....but cruel, but still, it would be interesting to see?

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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 140 of 157 (453632)
02-03-2008 1:27 PM
Reply to: Message 138 by randman
02-03-2008 1:15 PM


In that regard, domestic selection is natural selection.
Agreed. However, with regards to the topic this doesn't matter.
Hypothesis: Road cars can travel as fast as 250mph.
Observation: The Nissan Micra, a road car, has a top speed of 120mph.
Therefore, road cars cannot travel as fast as 250mph.
It might be the case that macroevolution can result from domestic selection. It might not. That does not mean that natural selection as a general process (rather than a specific kind of natural selection) cannot result in macroevolution.

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randman 
Suspended Member (Idle past 4976 days)
Posts: 6367
Joined: 05-26-2005


Message 141 of 157 (453642)
02-03-2008 1:58 PM
Reply to: Message 140 by Modulous
02-03-2008 1:27 PM


not following you
Not following your argument at all. Maybe not using the analogy can help.
First, there is no reason to think DS cannot create macroevolution if NS can create macroevolution.
Secondly, one needs to avoid just viewing this from a superficial, simplistic perspective. What really happens with selection either domestic or natural? What happens generally is a reduction in genetic variation over longer periods of time. Not saying that there are no examples of genetic complexity being added, but what occurs with geographic or sexual isolation, for example, is a process decreasing genetic complexity or range within the group.
That's why you can evolve dog breeds, but the further you evolve them, the less further you can. In other words, Darwinian evolution is really evolution in the wrong direction for what needs to take place to produce macroevolution or the type of evolution to evolve all the major classifications.

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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 142 of 157 (453647)
02-03-2008 2:25 PM
Reply to: Message 141 by randman
02-03-2008 1:58 PM


Re: not following you
First, there is no reason to think DS cannot create macroevolution if NS can create macroevolution.
Correct. And there is no reason to think DS will lead to macroevolution just because NS can.
What really happens with selection either domestic or natural? What happens generally is a reduction in genetic variation over longer periods of time.
Which is a good thing. Otherwise nature would be monstrous. We need a method to increase genetic variation and a method for pruning that variation - otherwise no adaptation will occur.
That's why you can evolve dog breeds, but the further you evolve them, the less further you can.
If you aggressively breed animals you will see a reduction in variation. If 80% of modern thoroughbred racehorses share a common ancestor from the late 18th Century, then we would expect that thoroughbreeds will not exhibit a lot of diversity.
We humans provide an enormous selection pressure on the animals we breed. By doing so, we are putting a strain on the populations in question - essentially we reduce the sizes of those populations. If these populations were allowed to grow and breeding was free, we might find the diversity will increase.
In other words, Darwinian evolution is really evolution in the wrong direction for what needs to take place to produce macroevolution or the type of evolution to evolve all the major classifications.
Genetic bottlenecks occur in cladogenesis, they are difficult - but not always impossible for a population to recover from. If the bottleneck is severe, there may be no recovery.
Take for example, web-footed otterhound - as few as 41 puppies were registered in 2007. That's one heck of a bottleneck and if web-footed otterhounds are prevented from breeding with other breeds, what genes they possess could well vanish, reducing overall diversity of dogs.

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randman 
Suspended Member (Idle past 4976 days)
Posts: 6367
Joined: 05-26-2005


Message 143 of 157 (453653)
02-03-2008 3:18 PM
Reply to: Message 142 by Modulous
02-03-2008 2:25 PM


Re: not following you
And there is no reason to think DS will lead to macroevolution just because NS can.
Why not? If NS can create macroevolution, then certainly DS can provided someone figures out how it is possible within NS.
If these populations were allowed to grow and breeding was free, we might find the diversity will increase.
This is what evos claim, but can you show me the peer-reviewed studies that compare mutational rates (remember studies of mutational rates exist) that are considered beneficial with rates of genetic decrease due to isolation processes envisioned with microevolution.

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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 144 of 157 (453659)
02-03-2008 3:35 PM
Reply to: Message 143 by randman
02-03-2008 3:18 PM


Re: not following you
Sure, it is possible for DS to do so, but it doesn't have to. It could be the case that long term planned DS could produce large scale changes without critically reducing genetic diversity beforehand. However, if DS is done aggressively, limiting the amount of diversity - then it is perfectly possible to drive a population into extinction.
This is what evos claim, but can you show me the peer-reviewed studies that compare mutational rates (remember studies of mutational rates exist) that are considered beneficial with rates of genetic decrease due to isolation processes envisioned with microevolution.
I might give it a try. Can you tell me what metric you would accept for defining a beneficial mutation?

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randman 
Suspended Member (Idle past 4976 days)
Posts: 6367
Joined: 05-26-2005


Message 145 of 157 (453664)
02-03-2008 3:54 PM
Reply to: Message 144 by Modulous
02-03-2008 3:35 PM


Re: not following you
Let's don't worry about the metric for beneficial although evos should have to present something there. Let's just see the studies showing higher beneficial mutation rates exceeding the rates of genetic decrease through isolation. We can discuss their definitions and metrics once the study is provided.

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PaulK
Member
Posts: 17838
Joined: 01-10-2003
Member Rating: 4.1


Message 146 of 157 (453665)
02-03-2008 3:54 PM
Reply to: Message 143 by randman
02-03-2008 3:18 PM


Re: not following you
quote:
This is what evos claim, but can you show me the peer-reviewed studies that compare mutational rates (remember studies of mutational rates exist) that are considered beneficial with rates of genetic decrease due to isolation processes envisioned with microevolution.
As I pointed out to Faith when she introduced the idea, that is not a useful comparison. We only need neutral mutations to top up genetic diversity.

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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 147 of 157 (453667)
02-03-2008 3:59 PM
Reply to: Message 145 by randman
02-03-2008 3:54 PM


Re: not following you
Let's don't worry about the metric for beneficial although evos should have to present something there. Let's just see the studies showing higher beneficial mutation rates exceeding the rates of genetic decrease through isolation. We can discuss their definitions and metrics once the study is provided.
I have no idea how a beneficial mutation could be discriminated from a negative or neutral one in a study to do with mutation rates.

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Wounded King
Member (Idle past 110 days)
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 148 of 157 (453705)
02-03-2008 7:09 PM
Reply to: Message 139 by randman
02-03-2008 1:22 PM


Ligons and Tigards and Leguars, oh my!
Can you speculate more on why they can interbreed despite being less related to jaguars and leopards, or maybe they can interbreed with leopards and jaguars too, but no one has tried to do that
I think you will find in fact that there are known cases of all of these species hybridising, see wikipedia's entry on Panthera genus hybrids for some more details, although I don't know what the fertility of such crosses has been.
Despite that I don't see any reason why two more genetically distant species might no be interfertile when not interfertile with a third species more closely related to one of them.
Interfertility is not a simple matter of genetic distance. There can be specific genes forming the basis of incompatibility and there is no need for them to be more distant just because two species are more genetically distant overall, although we might well expect this to be the case under a neutral evolution scenario for the divergence of the species.
Similarly a large scale chromosomal change might cause a loss of fertility but would not necessarily result in the measurement of a further genetic distance between species depending on the metric being used
TTFN,
WK

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RAZD
Member (Idle past 1482 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 149 of 157 (453720)
02-03-2008 8:39 PM
Reply to: Message 1 by U can call me Cookie
04-04-2006 4:03 AM


One element or breeding that is missing from natural selection
This goes back to me calling DS corrupted. I say this because that, which is selected for in DS, is what humans regard as desirable; this is not the same as naturally advantageous.
One thing that "domestic selection" or breeding programs frequently do is back breed with other stock to (a) reinforce a trait common to both, and (b) introduce some additional genetic variation into the program (see hybrid vigor).
This also happens to reintroduce gene flow between populations and thus prevents speciation.
Enjoy.
Edited by RAZD, : and

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randman 
Suspended Member (Idle past 4976 days)
Posts: 6367
Joined: 05-26-2005


Message 150 of 157 (453721)
02-03-2008 8:42 PM
Reply to: Message 147 by Modulous
02-03-2008 3:59 PM


Re: not following you
Presumably, the evo study substantiating this most basic claim would give it's reasons. Just show where a peer-review study has been done, or perhaps there hasn't been any? Just evos asserting something with no real published science to back it up....that's my guess since I have never been able to find anything, nor has anyone I have ever asked, despite it being a very basic factual claim of evos.

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