"Microevolution" vs. "macroevolution."

I'm not sure what you mean here. Are you implying that evolution predicts that organisms would appear to be half finished at some point, and presumably some organsims would be half finished still?Evolution predicts that populations will always be 'finished' or they will go extinct. 'Finished' in evolutionary terms means 'able to maintain population size through reproduction'. As has been pointed out, cumulative selection can have astonishing results, as Dawkins' biomorphs amply demonstrate. Evolution is blind, but there is an enormous amount of viable options all clustered around each other. As long as evolution procedes with small steps it gets to test many many many many different avenues. Most of the avenues will terminate, but some will continue.If you want to analogize the term blind, consider a blind person who searches inch by inch the entire house for his lost keys. He will eventually find them. Compare this to the blind man that randomly picks somewhere to look in his house. Its going to take a very long time to find his keys. The analogy isn't perfect I know, but it at least gets things pointed in the right direction. It might make more sense if there was someone occasionally saying 'warmer, cooler, hotter' etc effectively selecting out non-viable search locations. Personally, I do consider it mind boggling. However, I don't consider something mind boggling as being indicative of it not happening. My brain is equipped to deal with things in terms of centimetres and seconds. At the very best it can comprehend processes that take a small number of decades to complete - after that the mind begins to boggle.That said, cumulative selection combined with reproductive fecundity is a massively powerful designing mechanism as long as certain conditions are met (in the case of biology there is good evidence that those conditions have been met). Its totally elegant in its simplicity, but awe-inspiring in its scale. Can you honestly know how long? It is likely that a single step selection mechanism would mean that it would take longer than the universe will exist with workable energy in it before it becomes a remote possibility.However, cumulative selection might provide the solution much much quicker. I'm not going to call this incredulity. I am going to call it an erroneous analogy. The million monkeys are assumed to be truly random, but each time they 'reproduce' (ie type another manuscript) it is from scratch with no regard to the previous thing that has been typed. This is single step selection. If the solution isn't right an entirely new solution is attempted.In cumulative selection things work differently. If we take the first million manuscripts and select 25% of them that most closely resemble any work by Shakespeare, we then get the monkeys to each make a copy of these manuscripts, with inevitable mistakes being made - the selection and reproduction process is repeated. It will still take a long time to produce Shakespeare, but we'd very likely end up with a variety of different plays.The analogy fails because English language is very specified. There are specific spelling and meanings to words and senteces have to follow strict grammar to make sense. Genetics is a less specific than this. You can change one letter and get an entirely different (but meaningful) word, on the other hand you can change maybe 60% of the letters and still have the same meaning. So we need to be careful when comparing random Shakespeare generation with random mutation of a genome.Finally, it will take a long time because we were simulating asexual reproduction. I'd wager that if we created some kind of analogue to sexual reproduction (where sentences from one monkey's typings were recombined with another monkey's typings, half from one and half from the other) we'd probably find we arrive at solutions considerably faster.Consider this an advanced version of the 'Methinks its like a weasel' discussion in 'The blind watchmaker'. I say advanced because instead of a single target sentence, I'm allowing for many different solutions (or targets) ie, all of Shakespeares works.

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To tie this into the topic: Microevolution is a description of changes in a population of Hamlet plays versus the changes in a population of Tragedies. Once a play is looking like its going to be a tragedy, it is likely to remain in that category and never change. Thus: We'll never see macroevolution, it's more a concept than an event.OK, tenuous at best, but I typed all the above out before realising its probably irrelevant to the topic at hand and needed some kind of justification for it This message has been edited by Modulous, Thu, 06-April-2006 09:50 PM