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Author Topic:   Can Domestic Selection cause Macroevolution?
Quetzal
Member (Idle past 5953 days)
Posts: 3228
Joined: 01-09-2002


Message 121 of 157 (301997)
04-07-2006 12:24 PM
Reply to: Message 114 by EZscience
04-07-2006 10:08 AM


Re: Domestication redefines 'fitness' for an organism
not a biologist although I play one on TV
Cool.
I was kidding. Most of the places I work don't even have electricity, let alone TV.
I think this would qualify as 'cleptoparasitism' - an organism stealing resources intended for symbiont. Just like some 'nectar thieves' - insects that bore a hole in the side of the flower to extract nectar from the base, but without providing the pollination service.
I am now totally in love with that word. Did you just invent it or is it in common usage? I have a "cleptoparasite" living in my back yard - the glossy flowerpiercer (Diglossa lafresnayii) that bypasses the pollen and punches a hole in the bottom of the flower's nectary. Pretty bird, tho'.

This message is a reply to:
 Message 114 by EZscience, posted 04-07-2006 10:08 AM EZscience has replied

Replies to this message:
 Message 126 by EZscience, posted 04-07-2006 3:00 PM Quetzal has replied

  
kuresu
Member (Idle past 2594 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 122 of 157 (302026)
04-07-2006 1:12 PM
Reply to: Message 110 by crashfrog
04-07-2006 9:02 AM


I did not consider our relationship with corn to be either commensualistic or mutualistic, but only parasitic. Since that was the only relationship I was considering, it makes logical sense to say that the only symbiotic relatioship would be parasitic.
It also seems that you do not want to call mankind parasites, though we potentially can be and are (never mind that most parasites are incredibly small, like fleas or mosquitos).
If the ecologists have separated a parasitic relationship as falling under a symbiotic relatioship, so that it is now one on its own, then what you are saying is not contraditcory.
The final option is that we both misunderstood each other's post. You were trying to point out that other relationship's are symbiotic, and I was saying that our relationship with corn is symbiotic only if it is parasitic, becasue I did not consider the other two as possible descriptions of our relationship with corn. Not to say that I didn't know about them, but that I thought the relationship did not fit under those further defined categories.

This message is a reply to:
 Message 110 by crashfrog, posted 04-07-2006 9:02 AM crashfrog has replied

Replies to this message:
 Message 134 by crashfrog, posted 04-07-2006 8:00 PM kuresu has replied

  
pink sasquatch
Member (Idle past 6104 days)
Posts: 1567
Joined: 06-10-2004


Message 123 of 157 (302038)
04-07-2006 1:42 PM
Reply to: Message 119 by U can call me Cookie
04-07-2006 11:52 AM


Re: the kama sutra for dachsunds
I'm basically asking whether the scientists are aiming at non-interfertility, or is it a by-product of the karyotype that they are aiming for?
Scientists aren't aiming for anything. They are maintaining naturally-occurring mutations for various reasons.
While chromosomal mutations are more common than single base mutations, you'd have to look at the karyotypes of a few thousand mice before you found a natural rearrangement.
A few thousand mice is nothing, though, in the world of mass-production and highthroughput mouse genetics. The Jackson Lab, for example, has a few thousand different lines of mice actively breeding - I'm guessing at least a few thousand mice are born every day in their facility.
Besides, many mutations are found because they produce abnormal phenotypes, which are particularly obvious in homogeneous inbred mouse strains. No detailed genetic testing needed.
I expect most of them are induced though.
Not sure of the ratio of induced to natural. But, that doesn't really matter for the question that serves as the topic title. What does matter is that humans selectively bred natural variation within one population to produce two populations that are no longer interfertile. Thus, artificial selection can produce speciation.

This message is a reply to:
 Message 119 by U can call me Cookie, posted 04-07-2006 11:52 AM U can call me Cookie has replied

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pink sasquatch
Member (Idle past 6104 days)
Posts: 1567
Joined: 06-10-2004


Message 124 of 157 (302041)
04-07-2006 1:57 PM
Reply to: Message 120 by U can call me Cookie
04-07-2006 12:09 PM


why rank?
Two founder populations break off from a highly diverse ancestral population; with each accrueing a distinct subset of alleles that differs from the alleles of the other due basically to drift. Over enough time, with total isolation, and the accruement of new variation, it should theoretically be possible for speciation to occur.
Yes, drift could potentially result in speciation, which is why I said "generally" different selective pressures would be required. The accruement of intergroup variation is going to be stochastic and relatively much slower in the absence of selection. If both groups stay under strong normalizing selection, variation will be kept at a minimum (selection would maintain them as a single species).
There is at least one example of a species with populations that have been isolated since Pangea split into continents (some sort of lettuce-like plant?), but remain one species - despite an enormous time of isolation (and drift). On the other hand, there are cases of explosive sympatric speciation of hundreds of fish species occurring in the past million years or so in the African rift lakes - I would argue under very strong selection, and largely without isolation events.
I guess my overall point is that I don't see the point in trying to rank processes like isolation, selection, and drift when it comes to their contribution to speciation.

This message is a reply to:
 Message 120 by U can call me Cookie, posted 04-07-2006 12:09 PM U can call me Cookie has replied

Replies to this message:
 Message 127 by PaulK, posted 04-07-2006 3:10 PM pink sasquatch has replied
 Message 130 by U can call me Cookie, posted 04-07-2006 3:49 PM pink sasquatch has replied

  
Belfry
Member (Idle past 5166 days)
Posts: 177
From: Ocala, FL
Joined: 11-05-2005


Message 125 of 157 (302046)
04-07-2006 2:29 PM
Reply to: Message 118 by EZscience
04-07-2006 10:34 AM


Re: Changing usage
EZscience writes:
We have a longhorned borer that has become a serious pest of cultivated sunflowers and now has even colonized soybeans, and it is now really hard to find this insect in any of its original wild host plants. It is coming to specialize on crop plants exclusively - they are more nutritous and more available. I don't consider it likely to speciate any time soon, but we have inadvertantly created a very different species without necessarily precipitating a speciation event.
Really, a cerambycid? Sounds interesting, I'll have to look it up.
Sounds like we have some things in common... I work with forest insect pests. And I'm a cyclist, too .

This message is a reply to:
 Message 118 by EZscience, posted 04-07-2006 10:34 AM EZscience has replied

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EZscience
Member (Idle past 5235 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 126 of 157 (302057)
04-07-2006 3:00 PM
Reply to: Message 121 by Quetzal
04-07-2006 12:24 PM


Re: Domestication redefines 'fitness' for an organism
Cleptoparasitism is an accepted term within parasitology.
For example, here is an article about one wasp that follows searching females of another species to steal their hosts.
Q writes:
Most of the places I work don't even have electricity, let alone TV.
(edited to fix link)
I'm betting Guatemala, for one, based on the moniker.
This message has been edited by EZscience, 04-07-2006 02:01 PM
This message has been edited by EZscience, 04-07-2006 02:17 PM

This message is a reply to:
 Message 121 by Quetzal, posted 04-07-2006 12:24 PM Quetzal has replied

Replies to this message:
 Message 133 by Quetzal, posted 04-07-2006 5:11 PM EZscience has not replied

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


Message 127 of 157 (302060)
04-07-2006 3:10 PM
Reply to: Message 124 by pink sasquatch
04-07-2006 1:57 PM


Re: why rank?
In allopatric speciation it is unlikely that there would be direct selection for infertility. Therefore I would tend to the view that drift is generally the most important factor.
In sympatric speciation selection would almost certainly be needed for speciation to occur, but that is generally regarded as far less common than allopatric speciation.!

This message is a reply to:
 Message 124 by pink sasquatch, posted 04-07-2006 1:57 PM pink sasquatch has replied

Replies to this message:
 Message 132 by pink sasquatch, posted 04-07-2006 4:57 PM PaulK has not replied

  
EZscience
Member (Idle past 5235 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 128 of 157 (302061)
04-07-2006 3:14 PM
Reply to: Message 125 by Belfry
04-07-2006 2:29 PM


Re: Changing usage
You can see a picture of the insect here and read a recent article about this pest
here
I did a post-doc at U of F for 7 years - did the Cross Florida ride twice. Best time was 7 h, 23 min.
My faculty position kind of killed my cycling 'career', but I hope to revive it. (Picture is from Terrible Two ride, Santa Rosa CA, 2001)

This message is a reply to:
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U can call me Cookie
Member (Idle past 5034 days)
Posts: 228
From: jo'burg, RSA
Joined: 11-15-2005


Message 129 of 157 (302074)
04-07-2006 3:37 PM
Reply to: Message 123 by pink sasquatch
04-07-2006 1:42 PM


Re: the kama sutra for dachsunds
So they're pretty much looking for the karyotype, and then breeding a strain which has that karyotype. This karyotype predisposes to incompatibility; so essentially they are breeding for incompatibility. It might not be their expressed aim, but it is a trait caused specifically by the karyotype they are breeding for.
And it goes to what i said at the end of my last post... artificial selection is causing speciation, by being directed to do so.
I didn't mean to imply that DS can not cause speciation.

"The good Christian should beware the mathematician and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of hell." - St. Augustine

This message is a reply to:
 Message 123 by pink sasquatch, posted 04-07-2006 1:42 PM pink sasquatch has not replied

  
U can call me Cookie
Member (Idle past 5034 days)
Posts: 228
From: jo'burg, RSA
Joined: 11-15-2005


Message 130 of 157 (302087)
04-07-2006 3:49 PM
Reply to: Message 124 by pink sasquatch
04-07-2006 1:57 PM


Re: why rank?
Yes, drift could potentially result in speciation, which is why I said "generally" different selective pressures would be required. The accruement of intergroup variation is going to be stochastic and relatively much slower in the absence of selection. If both groups stay under strong normalizing selection, variation will be kept at a minimum (selection would maintain them as a single species).
Of course this is a theoretical situation, so normalizing selection does not necessarily have to apply.
Its one thing to know that speciation involves the factors, but why wouldn't one want to know how each factor contributes to a specific case of speciation, especially if there is a possibility of differential contribution. At the very least it allows for an increase in knowledge.

"The good Christian should beware the mathematician and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of hell." - St. Augustine

This message is a reply to:
 Message 124 by pink sasquatch, posted 04-07-2006 1:57 PM pink sasquatch has replied

Replies to this message:
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pink sasquatch
Member (Idle past 6104 days)
Posts: 1567
Joined: 06-10-2004


Message 131 of 157 (302116)
04-07-2006 4:45 PM
Reply to: Message 130 by U can call me Cookie
04-07-2006 3:49 PM


Re: why rank?
Its one thing to know that speciation involves the factors, but why wouldn't one want to know how each factor contributes to a specific case of speciation, especially if there is a possibility of differential contribution.
Absolutely, sorry if I misread you. It had seemed to me that you were trying to rank them in a general sense that would apply to all speciation events; now I see you are referring to understanding specific instances - which I take no issue with.

This message is a reply to:
 Message 130 by U can call me Cookie, posted 04-07-2006 3:49 PM U can call me Cookie has not replied

  
pink sasquatch
Member (Idle past 6104 days)
Posts: 1567
Joined: 06-10-2004


Message 132 of 157 (302126)
04-07-2006 4:57 PM
Reply to: Message 127 by PaulK
04-07-2006 3:10 PM


Re: why rank?
In allopatric speciation it is unlikely that there would be direct selection for infertility.
It doesn't have to be direct, and I didn't mean to imply such. Selection for other phenotypes can indirectly, and readily, cause reproductive isolation.
Therefore I would tend to the view that drift is generally the most important factor.
Doesn't follow for me from your previous statement.
Selection that indirectly alters reproductive compatibility is still selection, not drift. Selective forces that differ between the two niches that the two isolated populations inhabit will cause divergent evolution between those populations.
And, as in my comments to Cookie above, I think it is a mistake to make generalized comments about the processes involved during speciation.

This message is a reply to:
 Message 127 by PaulK, posted 04-07-2006 3:10 PM PaulK has not replied

  
Quetzal
Member (Idle past 5953 days)
Posts: 3228
Joined: 01-09-2002


Message 133 of 157 (302140)
04-07-2006 5:11 PM
Reply to: Message 126 by EZscience
04-07-2006 3:00 PM


Last OT Comment
Thanks for the article. I've downloaded it into my "neat to keep" files.
Guatemala, nope. Formerly Nicaragua, now Ecuador (they still have quetzals, but they're pretty pitiful compared to the Nica or Guatemalan subspecies).

This message is a reply to:
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crashfrog
Member (Idle past 1548 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 134 of 157 (302223)
04-07-2006 8:00 PM
Reply to: Message 122 by kuresu
04-07-2006 1:12 PM


I did not consider our relationship with corn to be either commensualistic or mutualistic, but only parasitic.
Right, and that's the source of your mistake. If you had not ignored, or forgotten, that there were at least 2 other symbiotic relationships, you would not have stated that the human-corn relationship could not be symbiotic if it were not parasitic.
Since that was the only relationship I was considering, it makes logical sense to say that the only symbiotic relatioship would be parasitic.
There's nothing logical at all about that conclusion; in fact, it's fallacious. It's the fallacy of denying the antecedent.
It also seems that you do not want to call mankind parasites,
It's simply not an accurate description of our relationship with corn. We protect corn, we rear it, we spread its seed in the course of our use of it as a crop. It benefits from our husbandry. The relationship is one of mutualism, not one of parasitism. According to the definitions of these words there's really no other conclusion.
Not to say that I didn't know about them, but that I thought the relationship did not fit under those further defined categories.
Then it would have been better for you to rebut my argument that it did fit under the category of mutualism, rather than blowing your stack about an imagined contradiction.
At any rate, water under the bridge. Would you care to address my argument at this time?

This message is a reply to:
 Message 122 by kuresu, posted 04-07-2006 1:12 PM kuresu has replied

Replies to this message:
 Message 135 by kuresu, posted 04-08-2006 9:55 PM crashfrog has replied

  
kuresu
Member (Idle past 2594 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 135 of 157 (302552)
04-08-2006 9:55 PM
Reply to: Message 134 by crashfrog
04-07-2006 8:00 PM


it appeared to be a contradiction. 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?
When I said that mutaulism could take the place of parastism in my origninal statement of "its only symbiotic if it's parasitic" I was not implying (or I did not think I was implying) that the two are the same (mutualism and parasitism), but that M would still fit into my statement for the purpose of discussion. That was why we said the same thing, for the most part. The only difference--how we classify the exact relationship.
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. But does it grow as a species? Does it evolve? I would say no. Everything we do for corn is soley for our benefit, or at least that's how I interpret the evidence.
That first quote isn't a mistake. I did not forget or ignore the other relationships. 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. Nothing wrong with that.

This message is a reply to:
 Message 134 by crashfrog, posted 04-07-2006 8:00 PM crashfrog has replied

Replies to this message:
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