Daggah

Oops, missed this:

Atheism isn't a philosophy. It also isn't automagically associated with evolution.

Try harder next time.

pz

You seem to have your own private definition of what constitutes an "extreme pressure". Yes, organisms died and failed to reproduce. That's how natural selection carves populations. What are you looking for? A pressure that gives animals a mild headache? Uh, that's what I said. These are instances where observable changes occurred within a short window of time, the kind of time span that a single researcher can see. Nobody has directly observed equivalent changes over a period of a thousand years because people don't live that long, and because this is a theory that has only been established over the last century and a half. But...all you've been doing is "sayin’ it".

Do you have any knowledge of population genetics at all? Two or three times a century means it happens every 30-50 generations. Droughts and plagues also happen reasonably often. If you want to call events that are frequent enough to happen multiple times in a single area within the adult lifespan of a scientist "severe", then go ahead -- it just means that these "severe" events are so common that they can easily play a profound role in sculpting species.
Yeah. Look in the fossil record. That's where the pattern of prolonged change is preserved.
No. I suspect that you have another one of those peculiar private definitions of the term "direct observation", too.

"Just so stories" are plausible explanations invented in the complete absence of supporting evidence. We do have evidence of long term change in the history of life on this planet -- but if it is brought up, I'm sure you'll start chanting the usual silly creationist litany of "were you there?"
Yes. As has become apparent, your definition of "extreme and unusual" translates into "common and ordinary". Yes, drift is driven by chance. So? Drift is also real.

And again, what do you know of population genetics? Your claim that drift only happens in "tiny, isolated populations" again suggests that you don't know anything about it -- that is a false statement. Oh, dear. In other words, you are completely refractory to learning anything new. Why should anyone bother to do your homework for you? And I must refer you to my comment above. If you are not willing to even try to learn, then you are hopeless. If you don't already know this stuff, then how dare you argue that it is wrong? That is simply dishonest. "Raciation"?

Again, you seem to be completely oblivious to what the theory of evolution actually says. Natural selection is not considered a major factor in speciation.
You have already been informed by a moderator that we will try to regulate some of the flaming against you. That works both ways. Consider this an official warning: if you cannot control your tendency to attempt to incite flamage with your offensive commentary, I will be editing your posts. Do you understand? I'm sorry, but looking at that thread I can see that Clutch has actually described your performance quite accurately. You lobbed the same old claims on yet another board, got substantive replies which you failed to address, and proved yourself quite unwilling to learn anything. Now you've moved on to another board. It looks like you're just a post-and-run dogmatist. Look up a little higher where I gave you that warning. It applies here, too. Clean up your act.

Dr Rick

Well, I'm willing to learn even if others are not. I was under the impression, pz, that natural selection was an important factor in speciation along with random mutation and breeding segregation.

Can you please explain why it is not or provide a link that does?

Thanks, Rick

pz

Because speciation would at some point require reproductive isolation. Something that makes sexual individuals unable to reproduce with a majority of the individuals of their species isn't going to be an advantage! Selection is generally going to be a conservative process, while speciation is going to be the result of an accumulation of variation, and is more likely to be a consequence of drift.

Disruptive selection would be an exception, but even there a process that does not involve selection had to be present to generate the range of heritable variation that is subsequently selected for the extremes.

Dr Rick

That makes sense; thanks

Rick

Bubba

Hey, pz...once again THANKS! I learned something new about evolution today. I guess that's roughly what I was thinking when I was thinking "dieback" in my other thread.

Let me see then if I've got this strait-speciation seems to always involve some kind of isolation of a population, be it Darwin's finches on islands or Neanderthal man in Europe.

So in nature, then the reason that we have so many species of say, beetles in Hawaii is that there are many small ecological niches that these animals can fill. Also, beetles don't travel especially well, so it would make sense in a pre-human populated Hawaii for beetles to perhaps occupy one small area and become isolated by drift and isolation.

Do I understand this correctly or am I still off in my thinking somewhere?

Bubba

pz

That all sounds pretty good to me.

Bubba

Oh, and by the way on behalf of thiests everywhere I apologize for Evolskeptics actions.

We now return you to your regularly scheduled debate.

Bubba

RufusAtticus

Hello again, Evolskeptic.

Tip number 1 of web etiquette, if you don't want to be flamed, don't light the first match. Our rules do still apply to you, so I request that you cut out the imflamatory posts and stick to the topic at hand.

Now, if you'd rather deal with just one poster at a time, I'd be happy to engauge you in a debate in our structured debate forum. I have been waiting for almost a year for a creationist to take me up on my challenge to debate the existance/inexistance of multiple immutable kinds. Are you willing to spar with me? If not, is there a topic that you would be willing to debate me in?

However, before you accept, let me intorduce myself. I am a second-year graduate student in the Department of Genetics at the University of Georgia. I study evolutionary theory with respect to population genetics. Most of my work involves mathematical and computational modeling of flucuating gene pools. I currently have three projects: a frequency-dependent selection model for the evolution of language ability, an evolutionary algorithm for data mining of cyto-nuclear data, and a stocastic density dependent model for density-vagueness.

PZ already covered most of my points but I have one thing to add.

Earlier you said you couldn't be bothered with studying evolutionary theory, specifically the constant viability selection model. However, I happen to have already exposed the board to it in <a href="http://iidb.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=58&t=000207&p=" target="_blank">this thread</a>. I will assume that you have read it when I make the following statements.

A result of the model is that the change in allele frequency of a trait between generations is d=p*(1-p)*(w1-w2)/wbar. Thus it is clear from (w1-w2) that the change in the frequency an allele is proportional to the advantage that it has over the other allele. Directional selection (w11 &gt;= w12 &gt;= w22, one or no inequalities strict) is all that is required to drive an allele to fixation. It doesn't matter how strong the selection is, thus your "secret" doesn't exist.

~~RvFvS~~

smugg

Oh? Is there to be a debate in this thread?

I can't wait.