Random mutations shot down on this site.

Yes they are, but only when they say 'the two species separated about 6 million years ago', after that they are talking about all te cumulative changes in the protein sequences of those 2 divergent species which have accrued over the 6 million years since they shared a common gene pool.They don't say that speciation has a single thing to do with drift, they do say that the subsequent genetic constitution of the divergent populations was subsequently affected by drift and that 45% of that could be could be attributed to natural selection. That isn't 45% of the changes neccessary for speciation to occur but 45% of the differences which have ocurred in all the time when those two populations seperated right up to the present day. They identify 'approximately 270,000 positively selected amino-acid substitutions' which are different between the 2 species and go on to say... Is the reason why this paper doesn't concern genetic drift as a cause of speciation clear yet?I'm not saying that drift cant be a mechanism for speciation, or at least one forcing acting to cause speciation, it can; but this paper doesn't say that or show it. Did you actually read the paper?TTFN,WKEdited by Wounded King, : No reason given.

Just pointing out that my response to the above ad hominem can be found at: EvC Forum: The origin of new alleles

Apology accepted. However, I didn't take any offense. I have been insulted by far better. Okay - before we go any further down this road to misunderstanding, please provide a definition and example of what YOU are terming "microevolution". You started out talking about modes of speciation - in which you were invariably wrong. Now you appear to be shifting the goalposts and discussing adaptation. The tactic doesn't particularly bother me, but I would ask you to pick one or the other and stick with it. Once you let me know which one you want to discuss, I'll pick this up at that point. Errr, no. They're not talking about speciation due to drift. As WK pointed out, the article is talking about accumulated genetic distance caused by both selection and drift. An interesting piece - but it doesn't appear to be related to speciation. Not being a "research biologist " I can't access the full article - maybe WK can post relevant excerpts.

No worries . Besides, it's all just an excuse to play in the woods...

I'm with Hoot Mon on this one.Take the example of inbreeding in plants, where plants more often breed with the nearby plants. For there to be random mating, each tree in the forest should have equal chance of being pollinated by every other tree, which does not happen due to the long distances in the population.This is not sexual selection, because there is no selection of mates by either party. Just luck of the wind and insects usually.While there is a strong natural selection towards reproducing with another plant (because anything that affects reproductive success is selection), there is no selection towards which tree's pollen is used to reproduce.So, you can have non-random mating without selection, and vice versa. And, non-random mating will change the allele frequencies, so could be said to cause microevolution, through purely statistical means (i.e. inbreeding depression).

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"Der Mensch kann was er will; er kann aber nicht wollen was er will." (Man can do what he wills but he cannot will what he wills.) - Arthur Schopenhauer

But every tree has roughly the same chance of growing at any particular spot in the area, so, given one tree, the precise assortment of its neighbors is essentially random.

Only if the seeds are spread perfectly across the entire forest, rather than just falling nearby.

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"Der Mensch kann was er will; er kann aber nicht wollen was er will." (Man can do what he wills but he cannot will what he wills.) - Arthur Schopenhauer

It would be a pretty poor tree indeed that hadn't evolved some way of doing exactly that. It's in a tree's worst interests for its offspring to land nearby, because then the parent tree blocks resources from its own seedlings.

Yes, I do admit that trees do make an effort to avoid this through cunning means of dispersal. However, it is not perfect, and hardly results in an equal chance of the seeds landing at any spot in the forest. It is still less likely for the seed to appear on the other side of the forest rather than half a kilometre away.

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"Der Mensch kann was er will; er kann aber nicht wollen was er will." (Man can do what he wills but he cannot will what he wills.) - Arthur Schopenhauer

I'm not so sure about that, but first let's revisit your erroneous statement that Crash tried to correct: Can you imagine any species in the known universe where an individual has an equal chance of mating with all other living individuals of its species? No, of course not. So obviously that's not what random mating means. I'm not sure there's wide acceptance of such a thing as sexual selection in plants, though this has certainly been proposed since there is sexual dimorphism and other sexual differences in some plants. But I think in general people would have to agree that sexual selection is not widespread or easy to detect in the plant kingdom.But you're using the example of plants in support of an argument that Hoot Mon advanced concerning animals. In essence Hoot Mon is saying that sexual selection is not a type of natural selection, which is nonsense.--Percy

Who said that any species actually undergoes random mating anyway?Let me quote the definition on wikipedia:

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Random mating involves the mating of individuals regardless of any physical, genetic, or social preference. In other words, the mating between two organims is not influenced by any environmental, heriditary, or social interaction. Hence, potential mates have an equal chance of being selected.

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That is what random mating means. And, no species does it...so what?

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"Der Mensch kann was er will; er kann aber nicht wollen was er will." (Man can do what he wills but he cannot will what he wills.) - Arthur Schopenhauer

I said that no species does what you described as random mating, not what Wikipedia describes as random mating. Your description of random mating is not the same as Wikipedia's. Your description of random mating was incorrect. This is what Crash and I have been trying to tell you.Here's your original description of random mating from Message 35: That's not the definition of random mating. Obviously there is no population of anything anywhere where all organisms are equidistant from all other organisms of the same species. Such a definition of random mating is nonsensical and useless. In other words, it is self-evidently wrong.--PercyEdited by Percy, : Grammar.

Quetzal, I think you are right about this. I have a faulty tendency to regard speciation as the essential event of microevolution. This has been a habitual opinion of mine, and it is mostly wrong. Even Wikipedia makes clear that “Microevolution is the occurrence of small-scale changes in allele frequencies in a population, over a few generations, also known as change at or below the species level.” I should know better; I’ve make this mistake before.Conversely, I usually refer to macroevolution when I talk about events that involve evolution occurring beyond the species level. The Cambrian explosion, for example, would account for those major kind of events in macroevolution. How do you define it?The bottom line is that you scored on me. Congratulations! And thank you.”Hoot Mon

I think you are wrong. I bothered to go get the whole article through my public library. Try it. You would be impressed with their drift v. selection model.”Hoot Mon

Sorry. Could you elaborate as to how what I said

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each tree in the forest should have equal chance of being pollinated by every other tree

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Is different from what what wikipedia says

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potential mates have an equal chance of being selected

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I must be missing something....Let's find some other definitions Source

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A mating system in which there is an equal opportunity for all male and female gametes to join in fertilization.

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Source

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each individual in the population has the same probability of mating with every other individual

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Edited by Doddy, : Added other definitions.

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"Der Mensch kann was er will; er kann aber nicht wollen was er will." (Man can do what he wills but he cannot will what he wills.) - Arthur Schopenhauer