Macro and Micro Evolution

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Well, first off the real difference between micro and macro deals with levels. When used, and that is damned seldom in most literature, macro really is discussing the larger shifts deaing with orders or classes or even higher (although there ain't much higher, number wise). SO when most people are talking evolution and micro vs macro they are really kind of screwing it up when they say speciation and up is macro. Second, I would say the beginning of evolution is whenever life started. Everything since then has been a combination of mutation and selection (and by that I include survival and extinction). Mutation includes genetic drift and both silent and non-silent mutations.

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As a geneticist I find this explanation quite confusing. First, macro and micro are used differently by different scientists. I've seen it used (mainly by paleontologists) to mean (rather poorly defined) large-scale morphological changes, like changes in body plans. This seems to be what most creationists mean by it. Evolutionary theorists, on the other hand, mean by macroevolution any evolution above the level of the species. The reason the dividing line is at the formation of species is that this line is the only one that corresponds to something real in nature (at least for sexually reproducing organisms), since speciation is the point at which one evolving population becomes two. In this second meaning of evolution, it is not automatically true that macroevolution is just lots of microevolution added together, because it is possible that there are different mechanisms operating at higher levels -- for example, natural selection favoring species with certain traits, rather than favoring individuals. This a highly technical (and unresolved) debate, and has little to do with anything being discussed here, since everyone involved knows that macroevolution occurs and is mostly, if not entirely, the product of lots of microevolution.Second, extinction is not always the result of selection, since sometimes it's just random. (It's also a purely macroevolutionary process, not a micro one, by the way. Genetic drift, fitness and selection within a population describe the species microevolution, but may tell you nothing about whether the population will become extinct.)Third, mutation does not include genetic drift -- that's just wrong. Genetic drift occurs in the absence of any new mutations, as long as there are alleles in the population.

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Microevolution: comparatively minor evolutionary change involving the accumulation of variations in populations usually below the species level. (this means small genetic changes in a population and could include speciation as long as new organs are not being developed.)

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Macroevolution: evolution that results in relatively large and complex changes. -as in species formation- (this is any speciation which would start or end a development of new organs)

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You can define words however you want, but these definitions don't correspond to anything used by biologists -- there's no focus on new organs in the definitions they use. The M-W definition of macroevolution is incoherent to start with, since it mixes two different meanings in a single definition. You can define macroevolution as including any species formation, or you can define it as large or complex changes, but they're not the same definition -- sometimes species formation involves large changes, but often it doesn't. Your additions make the situation even more confusing, since species formation pretty much never results in the formation of a new organ. Also, by your definition, apes, monkeys and humans are all connected by microevolution, since we all have the same organs. Are you really comfortable with that position?