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Author Topic:   Artificial Selection - Is the term simply convenient?
Dr Adequate
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Joined: 07-20-2006
Member Rating: 3.4


Message 31 of 37 (735941)
08-28-2014 10:17 AM
Reply to: Message 26 by AppleScratch
08-27-2014 8:55 PM


Re: Missing the Real Issue
Well, I'd have said that it was the differential reproductive success of the members of a population based on their traits. If this is because someone is picking and choosing which members survive and reproduce, that's artificial selection, if it just happens because some traits are more conducive to survival and reproduction, that's natural selection.
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Taq
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Posts: 6629
Joined: 03-06-2009
Member Rating: 4.1


Message 32 of 37 (735949)
08-28-2014 12:57 PM
Reply to: Message 30 by Stile
08-28-2014 9:11 AM


Re: Missing the Real Issue
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.

As a counter example, we can look at ants and colonies of ants who take honeydew from aphids:

http://www.ncbi.nlm.nih.gov/pubmed/15125209

Ant behavior towards aphids spans the gamut from straight foraging to actually protecting aphids. When ants protect aphids from their natural predators, is this "artificial" selection? I think most people would describe it as natural selection.

Overall, I think we are getting hung up on the details of the analogy. More than anything, Darwin was looking for a way to communicate his ideas with his readers. One really good way of doing this is to use an analogy where you can say, "It appears that you all accept the idea that Mechanism A occurs here. Well, I am saying that Mechanism A also happens over here." In this case, he referred to animal breeding which most people understand and accept.

Whether or not artificial and natural selection or different, or if they differ on the finer points, is really not the point. If the analogy of animal breeding helped you understand natural selection, then the point was made.


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Stile
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From: Ontario, Canada
Joined: 12-02-2004
Member Rating: 3.4


Message 33 of 37 (735950)
08-28-2014 1:14 PM
Reply to: Message 32 by Taq
08-28-2014 12:57 PM


Re: Missing the Real Issue
Taq writes:

Ant behavior towards aphids spans the gamut from straight foraging to actually protecting aphids. When ants protect aphids from their natural predators, is this "artificial" selection? I think most people would describe it as natural selection.

I would certainly describe it as natural selection, there is no human involvement.

My point with the sheep was not that the selection pressure (wolves) were removed. My point was that humans did the removing.
That's what moves it from 'natural' to 'artificial.'

The only fine-line-problem I can see with that is if humans unintentionally affect an ecosystem.
For example: humans build houses/shelters to live in. We have built all sorts of cities and all sorts of animals (like pigeons) have adapted to live in our cities as well. Is this artificial selection on the pigeons because of the human involvement? Or is it natural selection because there was no motivated intention against the pigeon, it's just what humans (and pigeons) "naturally" do...

Whether or not artificial and natural selection are different, or if they differ on the finer points, is really not the point. If the analogy of animal breeding helped you understand natural selection, then the point was made.

Totally agreed.
It's not really a big deal what we call it as long as we understand the concepts of what's going on.
Just babbling for the sake of seeing my thoughts on the internet. My post count isn't going to increase itself, you know!


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New Cat's Eye
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Posts: 11440
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 34 of 37 (735953)
08-28-2014 2:34 PM
Reply to: Message 33 by Stile
08-28-2014 1:14 PM


Re: Missing the Real Issue
My point with the sheep was not that the selection pressure (wolves) were removed. My point was that humans did the removing.
That's what moves it from 'natural' to 'artificial.'

The only fine-line-problem I can see with that is if humans unintentionally affect an ecosystem.

I think we should leave the artificial qualification to those that are intentional.

That counts the sheep out.

That also counts the pigeons out.

But the corn, that stays in 'cause we did that shit on purpose.

For the sheep, I suppose you could ask: What is the desired trait that we are selecting for?

There really isn't one, is there? We just don't want the wolves eating them.

With the corn its obvious.


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Taq
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Posts: 6629
Joined: 03-06-2009
Member Rating: 4.1


Message 35 of 37 (735957)
08-28-2014 4:03 PM
Reply to: Message 34 by New Cat's Eye
08-28-2014 2:34 PM


Re: Missing the Real Issue
For the sheep, I suppose you could ask: What is the desired trait that we are selecting for?

That's an easy one. We are selecting for temperment, wool production, meat production, time to maturity, short time between giving birth and becoming fertile again, and milk production.

These are some of the basic things we have selected for in all of the species we have domesticated for food/clothing.

Interestingly, our domesticated animals have also selected for us.

http://www.npr.org/...w-did-humans-develop-lactose-tolerance

Edited by Taq, : No reason given.


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New Cat's Eye
Member
Posts: 11440
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 36 of 37 (735962)
08-28-2014 4:41 PM
Reply to: Message 35 by Taq
08-28-2014 4:03 PM


Re: Missing the Real Issue
That's an easy one. We are selecting for temperment, wool production, meat production, time to maturity, short time between giving birth and becoming fertile again, and milk production.

Oh, yeah, sure. For that stuff its definitely artificial selection. I was trying to keep my assessment within the parameters that the OP set out:

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.

In that case, since he's not selecting for any particular traits, I'd reserve calling that artificial selection.

But yes, if your breeding sheep to have more wool then that's definitely artificial selection.

Interestingly, our domesticated animals have also selected for us.

Yup, disease tolerance too. Did you read/see "Guns, Germs, and Steel"?

If not, the video is available online for free:

http://topdocumentaryfilms.com/guns-germs-and-steel/

I thought it was pretty cool.


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AppleScratch
Junior Member (Idle past 932 days)
Posts: 9
Joined: 08-26-2014


Message 37 of 37 (735965)
08-28-2014 5:19 PM
Reply to: Message 33 by Stile
08-28-2014 1:14 PM


Re: Missing the Real Issue

Totally agreed.
It's not really a big deal what we call it as long as we understand the concepts of what's going on.
Just babbling for the sake of seeing my thoughts on the internet.

That pretty much sums up my thoughts as well. I appreciate the replies, interesting things to read!


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