Asexual to sexual reproduction? How?

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In reading through this thread I have seen a great deal of misunderstanding on both sides regarding both the origin and terms involved in the evolution of sexual systems.

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Good post, L-Man, and a valuable contribution to the subject. You have been given a well deserved Post of the Month nomination.However, to be fair to the previous posters, I should try to write a brief post in support of their attempts to show that the evolution of sexual reproduction is possible.The question started with the claim (implied if not explicit), "It is impossible for sexual reproduction to evolve because there is no way it could have happened through natural selection acting on small changes."The counter to this argument is simply to come up with a scenario by which sexual reproduction may evolve that is plausible with what is known. It doesn't have to be the correct scenario, especially since the correct scenario may be unknown or since it may have been assumed that the correct scenario cannot have been elucidated by contemporary science. I do this all the time: often someone will try to "disprove" evolution by showing that some feature is beyond the capabilities of natural selection to produce. If I cannot find a proposed scenario anywhere, then I will usually attempt to make one up, simply to show that, yes, it is possible, and therefore it is not foolish to assume that the feature is a product of evolution.However, it is always better to have the best possible explanation, as well-confirmed as possible by current scientific standards, and so I appreciate your contribution. I just want to make sure that the previous posters don't feel that their attempts at an explanation aren't appreciated.Added by edit:

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I am in no way trying to insult prior posters on this thread, just trying to clarify some info.

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I just want to make sure it's understood that I am not thinking that you are belittling the previous posters, L-man.Edited by Chiroptera, : No reason given.

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

I don't understand your continued questions. Well, no, Lithodid-Mand was not silent. He attempted to answer the question. What was unconvincing about L-man's explanation?-

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The mechanism gives a scent that only attracts the sperm cells that it was designed to attract. How could this mechanism evolve step-by-step?

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Is this really hard? Let's imagine a scenario. Cells always emit waste products. Some of these waste products will be proteins and metabolic wastes that are only produced by cells. Many single-celled organisms exhibit chemotaxis -- that is, they are attracted or repelled by sources of certain chemicals in the environment, indicating food to be consumed or poisons to be avoided. It may take a slight change in the detection machinery to become sensitive to particular metabolic products, and so be attracted to a potential food source and (in the case of sexual reproduction, or the pseudo-sexual reproduction described by L-man) potential mates.Once a species exhibits this sort of attraction to other cells, a cell which produces (and so emits) a protein that is better at triggering the attraction mechanism in a member of the same species will attract more mates than other cells which do not. Now you have a positive feedback system, where the emitted chemicals are better at attracting the other cells, and the detecting mechanisms become better at detecting this chemical.This system is then incorporated into the sexual reproduction mechanism as multicellularity evolves.

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

Hi, tim.I have to give you a bit of a warning before the moderators do: it is considered bad form here to simply quote other sources without adding content of your own. In your case, you are giving the impression that you are not reading the other posts. For example:

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For one, I don't believe he adequetly addressed the following by Dr. Thompson:

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How could nature evolve a female member of a species that produces eggs and is internally equipped to nourish a growing embryo, while at the same time evolving a male member that produces motile sperm cells?

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A moderator is going to pop in here and get angry if you don't give a more detailed explanation why L-man's description is not adequate. I mean, he did explain how female and male differentiation occurred. I'm not sure myself that it is correct, but what problems do you have with it?-

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Secondly, I don't think he adequately adressed CreationWiki's objections.

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I don't understand the CreationWiki quote. Why don't you explain the problem in your own words?

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

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What is it that you don't understand about the CreationWiki quotes I cited in my post?

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Given this is admitted: I don't understand why this is a problem:

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

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CreationWiki doesn't admit the validity of that quote.

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What? It is almost the entirety of the passage that you quoted. You see? This is the problem. It's not clear what you are trying to say here.Write a passage in your own words what the problem is. If you cannot explain, in your own words, the problem you see with the evolutionary explanation, then I will assume that you do not understand your own sources and that you are merely spamming the board with cut'n'paste quotes you do not comprehend.I will also warn you that the moderators of this board are going to make the same assumption.

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

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No need to carry on our "dialogue".

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I agree that this is clearly pointless.However, I will be game if and when you decide that you want to discuss the issue.

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

Yeah, but I didn't reel him in very well, did I? You, on the other hand, look like you're going to have fun. I wish I knew Biblical archaeology, too.

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus

Because of this post? Yeah, I sort of thought of kendemyer, too, when I saw that. But are there more definite signs that this is kendemeyer?But I've missed kendemeyer. He's welcome back as far as I'm concerned (even if the new ID would be a violation of rules).Added by edit:Okay. Now I'm convinced.Edited by Chiroptera, : No reason given.

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Kings were put to death long before 21 January 1793. But regicides of earlier times and their followers were interested in attacking the person, not the principle, of the king. They wanted another king, and that was all. It never occurred to them that the throne could remain empty forever. -- Albert Camus