NOTE: This post is a year and a half old now (April 2009 now), and it’s still being linked to by people occasionally reading it as a support for the idea that Macroevolution = Microevolution plus Time. Please see down in the comments – I was shown to be incorrect on that. I was wrong. I misunderstood what evolutionary biologists mean when they use those terms, especially macroevolution. The key missing ingredient was *reproductive isolation*. Please leave a comment if you have further questions, or see John Wilkins’ explanation of Macroevolution: Its Definition, Philosophy and History, on TalkOrigins.org.
In other words, microevolution + time = macroevolution. Larry Moran takes issue with this, citing Gould, Eldredge, and the concept of “Species sorting.” Somehow, despite requests for explanation, Larry will not or cannot explain how species sorting cannot be explained by microevolutionary mechanisms of species competition.
Eldredge (1995) defines “species sorting” (also called “species selection) as “differential speciation or extinction of species within a larger group”; he clarifies that “Some lineages speciate at a higher rate than others, and some species are more prone to extinction than others” (119). These varying rates of speciation and extinction, according to Eldredge, produce definite patterns in the fossil record.
Differential rates of speciation and extinction sounds a lot like, well, a speciation process. Elsewhere, Eldredge and Gould are muddled in their descriptions of how macroevolution cannot be reduced to speciation processes, saying only that “macroevolution must be studied at its own level.” Great, we already know that ‘zooming out’ to view large-scale patterns of many small-scale events is a good strategy, just as a physician would be myopic to diagnose a patient he’s never seen or spoken to based on a single biopsy. But we still say that patients are made out of the cells collected during a biopsy.
Larry goes on to just make an ass out of himself, telling us we’re pitiful for not reading his essay that he spent 10 years writing on macroevolution. Except we did read it, and as Sven DiMilo said in the comments:
I read the essay. In fact, I just clicked on your link and read it again. I’m sorry to report that it didn’t help to clarify my understanding of why the “sufficiency of microevolution hypothesis” ought to be discarded. After a fine treatment of the history of this controversy, there are simply assertions, by you and quoted from Gould and Eldredge, that microevolution is insufficient. But see, that’s what I’m not getting–why is it insufficient?
That higher-level patterns are identifiable in hindsight does not require that new mechanisms are necessary. And statements like “Since speciation is not a direct consequence of changes in the frequencies of alleles in a population, it follows that microevolution is not sufficient to explain all of evolution.” don’t help–it’s the premise I don’t get. Why is speciation more than the simultaneous changes in allele frequencies in two populaitons that lead to reproductive isolation?
Larry continues with assertions, explains that he’s under no obligation to explain his assertions, tells us to go read his essay and leave him alone, and that his critics aren’t getting it (i.e. they’re not being credulous). Oh, and his best explanation “read up on species sorting” falls flat, because he’s skeptical that it’s valid – yep, you heard that right – we’re supposed to buy into microevolution being insufficient for explaining macroevolution based on an argument that he himself finds questionable.
Come on Larry – if it’s microevolution + time + X = macroevolution, then what is X? Transmogrification?
PS – Yes, as Sven also said:
But you’re right–you’re under no obligation to explain or try to convince me. And likewise, I’m under no obligation to buy into your unexplained conclusions just because you’ve been thinking about it for 10 years.
- Niles Eldredge (1995) Reinventing Darwin: The Great Debate at the High Table of Evolutionary Theory, Wiley.
- Stephen Jay Gould (1980) The Structure of Evolutionary Theory, Belknap Press.