Tuesday, May 19, 2009

Macro - Micro Evolution

PZ Myers, over at Pharyngula had an interesting post and buried within is a nice synopsis of the whole Macro-evolution vs Micro-evolution artificial dichotomy so popular with certain folks, and you know who you are! I have stated repeatedly that historically microevolution was the study on evolution on micro-organisms and that Creationists made up this dividing line based on whether or not that can self-justify ignoring evidence. PZ puts it in a historical timeline that I find fascinating. While it wasn't called 'Macro' at the time, it was actually well supported decades before the evidence supporting what Creationists now call 'microevolution'. Like I said, with eyebrow raised in appreciation, "Fascinating!"

"The whole creationist version of the micro/macro evolution distinction is complete nonsense. Scientists do make the distinction, usually reserving macroevolution for the larger scale accumulation of change over time that produces new species or lineages, but they don't argue that one is unsupported speculation.

What you have to understand is that the concept of macroevolution came first, although it wasn't called that; it was just called evolution or transformation theory, among other things ("evolution" was a term that actually became popular relatively late). Darwin himself examined biology largely on a grand scale, looking at biogeography and populations and fossils, and making an argument on the basis of what we would now call macroevolutionary phenomena for changes in form of species over geological time. He wasn't alone, either; many other authors preceded him in seeing that the evidence supported a history of evolutionary change. What made Darwin particularly persuasive, though, is that he coupled the evidence of changing species to a hypothetical mechanism, natural selection. He didn't have the tools or the details to work out how heritable change was accomplished, however; that took the discovery of genetics and molecular biology to allow us to see how this 'microevolution' actually worked.

When creationists argue that they believe in microevolution, but that macroevolution is dubious, they've got it backwards. Large scale historical change was confirmed and thoroughly documented in the 19th century! Darwin was a bridge, who explained how small scale, natural processes could produce the known variation between species, and the triumph of 20th century biology was to confirm and expand upon our understanding of how those changes occurred. Neither macro nor micro evolution are speculative. Neither one is lacking in evidence."

Not much more needs to be said!


  1. I think the distinction between micro-evolution and macro-evolution is the fuzzy, somewhat artificial line between changes within a species and changes from one species to another. Changes from one generation to the next are micro-evolution, changes over hundreds or thousands or whatever generations are macro-evolution, and changes over 10-500 changes are...some third, distinct, qualitatively completely different category, I'm not sure what's it called, ask a creationist.

    Creationists do tend to call micro-organic evolution micro-evolution, but I think that's because:
    a) the changes in single-cell organisms don't fit the traditional if-they-can-mate criterion for telling one species from another. There is a huge amount of genetic diversity within a single species of micro-organisms. And basically, despite that diversity, they all look pretty much the same under a microscope.

    b) evolution in micro-organisms is extremely well documented and useful, so the usual arguments against it hold even less water than arguments against evolution from, for instance, apes to man.

  2. I think that's why organizations like the Discovery Institute support what they call micro-evolution. Not because they actually agree with it, but because the evidence is so overwhelming they cannot deny it without looking like complete idiots.

    But then they make claims that speciation isn't caused by micro-evolution, but an intelligent designer, after all, have you seen speciation in a lab? The problem here is a bit of a goal post change. Just because speciation is much harder to see over the course of a few generations doesn't mean an intelligent designer was involved at all. But too many people don't seem to realize that.

    Actually the evidence for speciation is much broader than just lab work and the time frame involved does make the lab work much harder. The Richard Lenski E-Coli experiment took 20 years!

    It's all politics and marketing for them [DiscoInst], nothing about actual science.