purpledawn writes:
I did a search for macro-evolution to try and get an understanding of the issue. I found this post by Nuggin (
Message 4) that gave a good idea of the difference between micro and macro. Are there any more good explanations of the difference? Any that might be of interest to a doctor?
If Nuggin's explanation works for you then you should probably stick with that, but I'll attempt a shorter explanation, one I've used before.
Microevolution is the small number of mutations in each generation that cause tiny indetectable changes. These mutations, filtered by natural selection, accumulate over many generations into the significant changes of macroevolution. When does microevolution become macroevolution? Who can say? It's very gradual change.
We humans often define criteria for classification. There's an old Hugh Grant movie called
The Englishman Who Went Up a Hill But Came Down a Mountain. The English had defined a mountain as higher than 1000 feet, and the townspeople were anguished to discover that their local mountain fell slightly beneath that measure. By their efforts what had been a hill became a mountain, but in reality it's height changed very little.
We can do the same thing with micro and macroevolution, define some criteria. There are a variety of ways we could do this. For example, we could say that macroevolution is when one species becomes another species, but species have a variety of definitions, and I won't get into those details. It seems that the criteria for micro becoming macro always become very detailed.
And so I think the best definition of macroevolution is just a lot of accumulated microevolution.
--Percy