Can Domestic Selection cause Macroevolution?

Teosinte. It's a group of Central American grasses, of which corn (Zea mays mays) is actually a member.What's interesting is that, in Mexico, where the corn crop has been hand-weeded for generations, they're having a big problem with a variety of teosinte (Zea mays mexicana) that has evolved a form that so visually resembles corn that it fools farmers into raising it alongside their crop.

When you say "variety of the same creature", what do you mean, exactly? If we had two creatures in front of you, and you were asked to determine if they were varieties of the same creature, or two different kinds of creatures, how would you do that?If you couldn't do that, do you know how anybody else would do it? If there's no way to do it at all, don't you think it's a pretty useless idea?

Well, ok, but if you're going to accept descent as the determinant of "same creature-ness" in this context, you have to do it in every context and accept the evolutionary position of common descent.I mean, you can't have it both ways. You can't use shared descent over here to substantiate "same creature-ness", and then use "different creature-ness" over there to refute common descent. It isn't consistent. It's just using whatever pesudo-scientific concepts are handy to, above everything, continue denying the scientific reality of evolution.

Symbiosis is not the same as parasitism. Symbiosis is defined as a relationship between two dissimilar species that is both intimate and potentially obligatory. Largely, the contiuum of symbiotic relationships can be described as:1) Mutualism, where the two organisms each benefit from the relationship;
2) Commensuralism, where one organism benefits and another is not affected;
3) Parasitism, where one organism benefits to the detriment of another.The relationship between humans and our crops could certainly be described as mutualism, and therefore does qualify as a symbiotic relationship. Humans benefit from the food source provided by corn; Zea mays mays certainly benefits from human husbandry to the extent that it has become the world's most popular and profitable cereal crop.This message has been edited by crashfrog, 04-05-2006 09:09 PM

I'm sorry? Where did I contradict myself?It's no contradiction to say "'doctor' does not mean 'dentist'" and then remind someone that dentists are doctors. I didn't say that mutualism wasn't symbiotic. In fact I said the exact opposite, if you'll read. Mutualistic symbiosis is not the same, however, as parasitic symbiosis. If you had bothered to read my post more carefully you would have seen that I was exactly right in what I said, there's no contradiction at all, because mutualism and parasitism are two different forms of symbiosis. Just because a relationship is symbiotic does not mean it is parasitic; it could be commensurate or mutualist.I don't know how I could be any clearer than that in two posts. Is English not your first language, or what?

I didn't say it wasn't, Kuresu. I mean I come right out and refer to parasitism as one kind of symbiosis.How can I be clearer than that? You haven't pointed it out the first time. Pointing out that symbiosis doesn't have to be parasitic isn't contradictory.I mean, c'mon, Kuresu. How dumb do you think I am? Why would I contradict myself in a single post? Where's the contradiction between D and E? Seriously, Kuresu, you're having reading problems of some kind. You keep quoting my exact words and then you keep failing to actually read them.

No, I haven't! It's like I'm in the Twilight Zone or something.How are all you people reading the exact opposite meaning of my words? Can anybody explain what's going on, here?

I don't see how discussion can continue between us.

I.Didn't.Say.That.It's really just that simple, K. If you can't read plain statements in English then discussion with you is not going to be possible.

No, I don't. Let me see if I can make it clearer.These two statements do not mean the same thing:"Symbiosis is not the same as parasitism.""Parasitism is not a kind of symbiosis."I repeat - these statements do not mean the same thing, so quoting my first statement to try to prove I said the second doesn't work.Is that clearer for you? Do you understand now that these two statements have two entirely different meanings? "Literary stuff", huh? Yeah I can't imagine what I was thinking, criticizing your reading prowess. Please accept my tenderest apologies, just as soon as you understand, once again, that those two statements have entirely different meanings.This message has been edited by crashfrog, 04-06-2006 10:50 PM

But it can't. Mutualism and parasitism are two different relationships. They're very different. Right. Two different words with two different meanings. Not the same thing; just as "doctor" and "dentist" aren't the same thing. Dentists are doctors, but that doesn't mean that if you're not a dentist, you're not a doctor.Do you understand the relationship, yet? This is pretty simple logic. But that's not the statement you made, or that I told you was wrong. What you said was that if we didn't consider the relationship parasitic, we couldn't say that it was symbiosis.That's wrong. The relationship isn't parasitic, it's mutualistic; because of that the relationship is still a kind of symbiosis, even though it isn't parasitic. To tell you that there are more kinds of symbiosis than parasitism, and that when someone says "symbiosis", they don't necessarily mean to say "parasitism", as you indicated in your post. I mean let's get back to your statement:

quote:

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There's nothing symbiotic about this relationship. Unless you want to call mankind a bunch of parasites.

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In other words "the only way this relationship can be symbiotic is if we mean to say that humans are parasites."But that's not true. We can consider the relationship mutualistic, and therefore symbiotic, and therefore we have no need to refer to humans as parasites.Clear, yet? No, we didn't. I said that the relationship was mutualistic and therefore symbiotic. You said that the relationship could not be said to be symbiotic unless it was parasitic. Those aren't the same thing at all. Your statement is wrong and mine is correct.

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. There's nothing logical at all about that conclusion; in fact, it's fallacious. It's the fallacy of denying the antecedent. 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. 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?

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.) 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. 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. 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? 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.