windy wrote:BillHamp wrote:windy wrote:
You're wrong.
Did you want to elaborate on that or is this the "assertions without support or evidence stand as facts in and of themselves" argument?
If you insist:
viewtopic.php?p=166370#p166370
BillHamp wrote:Argument from authority. Coyne argues that group selection isn't a great way of accounting for altruism, which I would tend to agree with, if Coyne understood the difference between kin selection and group selection. Kin selection, which Wilson has rejected, says that organisms protect kin because they know that at least some of their genes will be passed on. That is preposterous at first glance, so why it was ever thought viable is unclear.
Wrong: the organisms don't need to "know" anything. Kin selection theory says that since organisms that help their kin will help pass on copies of their genes in those kin, helping kin is favored by selection in situations where the genetic benefits outweigh the costs.
Nothing like an argument with someone who uses inflammatory phrases like "Wrong:" First of all, Jan was making an argument from authority.
Second, I wasn't careful there and, as you rightly pointed out, used an athropomorphic term that muddied the discussion. That was a mistake. It doesn't change the fact, however, that my basic point was correct. Kin selection requires that organisms not only know that they are related, but that they know to what degree they are related. In other words, I have to be able to tell a brother apart from a cousin if I am to be more likely to lay down my life for a brother than I am for a cousin. So, in fact, the organisms do need to "know" something or at least have the capacity to distinguish degrees of relation.
The problem is, animals can demonstrate kin selection, as you define it (helping pass on their genes by helping kin) even when they cannot distinguish one relative from another. That means that degree of relatedness is not, in fact, the driving factor.
More to the point, what I was saying, admittedly poorly, is that kin selection is based on relatedness and not on ideas like reciprocal altruism or quid pro quo. The subtely was lost in my efforts to keep the response to the alotted number of characters, but suffice it to say that pure altruism has no place in the grand scheme of evolution and that is why Wilson rejected kin selection.
BillHamp wrote:Group selection says that cooperative groups can out-compete non-cooperative groups in certain situations. In those situations, altruism genes will be favored because the more coherent groups (by virtue of the altruism they express) will survive. This is only applicable to certain situations, mind you, but it is a very powerful hypothesis which Coyne is a fool to reject outright.
Perhaps the biggest problem with group selection is its ties with kin selection. It still carries a number of vestigages from kin selection that prevent it from being taken seriously.
But your summary of "group selection" above is identical to inclusive fitness/kin selection arguments, you've just framed it in terms of groups instead of kin.
No, it isn't the same. The key is in the subtlety. We are talking about reciprocal altruism versus pure altruism. That is the subtle difference that leads Wilson to reject kin selection.
BillHamp wrote:1. First of all, the dandelions have not changed in the sense that they are a new species, they have adapted to their new environment through physiologic means. Their phenotypes remain intact..
Wrong, if they have changed in their observable traits, the phenotype has changed:
http://en.wikipedia.org/wiki/Phenotype
Yes, that was a mistake. I meant genotype, not phenotype. We are getting quite technical and I see where the confusion arises, so maybe I can clarify. I've not been clear enough reading back through my posts, so let me try to make sense of the confusion.
The original argument arose because Jan was insisting that evolution was not defined by changes in inherited characteristics, but rather by genetic changes only. That is not correct. While genetic changes are necessary for evolution, they are not sufficient. A genetic change must produce a phenotypic change if it is to be acted on by forces like natural selection. A simple DNA sequence change is not evolution even though it is heritable. That is why I was initially trying to make the distinction between genotypic and phenotypic changes.
Now, something got lost in translation there and I didn't explain every detail of my point. I assumed most of it was implied, but can see that it was not and so confusion arose. The confusion results from my trying to emphasize what natural selection operates on.
My argument about the dandelions arose from Jan's point that you will observe phenotypic changes if you move dandelions to a different environment, but that they have not evolved. Jan is right about them having not evolved, but that is not the point I was responding to. A lot of confusion came out of that because Jan was addressing one point and I was addressing another. We were clearly speaking at right angles to one another. That was my point about bell curves, but it was poorly made.
BillHamp wrote:2. "Evolution consists of changes in the heritable traits of a population of organisms as successive generations replace one another. It is populations of organisms that evolve, not individual organisms."
Note the population level distinction there, which is what I was really driving at when I said "population." You were suggesting that a simple mutation in one organism was evolution.
A mutation in one organism
is evolution (if it's a heritable and not a somatic mutation): it changes the allele frequencies in a population.
No, a mutation is not evolution. A mutation is a mutation. It can lead to evolution, but a mutation itself is not evolution. We don't say that people with CF have evolved, even though they have a mutation. In fact, we never say that individuals have evolved. That is because evolution relates only to population level changes. You need a statistically significant change in allele frequency that affects phenotype before you can call it evolution.
Beyond that, mutations can produce the same phenotypic trait, making them "netural." THus, you cannot say that a mutation is evolution. Further, allele changes are not enough to constitute evolution in and of themselves.
BillHamp wrote:You are quite correct about the "founder effect" and yet also quite wrong. The error is in thinking that the founder effect makes it possible for negative mutations to become predominant. It does no such thing.
Wrong:
http://homepage.univie.ac.at/Reinhard.B ... uerger.pdf
...deleterious mutations in a large population are kept at a low frequency within a balance between the forces of selection and those of mutation. A population with relatively fewer individuals, however, will have lower fitness on average, not only because fewer beneficial mutations arise, but also because deleterious mutations are more likely to reach high frequencies through random genetic drift.
(a founder effect is a special case of drift due to small population size)
see also:
http://darwin.eeb.uconn.edu/eeb348/lect ... node3.html
No, no, no, no, no. You misunderstand the founder effect entirely. Go back and read the rest of my response before creating a strawman. The quote that you have there is precisely what I said in the rest of my post. There were four additional paragraphs explaining what I meant by that, but you chose to cherry pick. I'm starting to think that if you and Jan aren't the same person, you must be close because you continually make the same logical errors.
We'll probably end up with more confusion here because I don't have time to write in the detail I need to. I'll return though. If you will, narrow it down to one argument at a time so that I can give a full response. Otherwise, we will repeat this problem ad infinitum.