In my post below where I try to synthesize The Superficial and The Causes of Evolution I used the term "fitness." Well...as Matt McIntosh pointed out the term itself is problematic, and so using it as a reference of any sort is really sketchy. Evolgen has slammed the use of "genetic load", and I I think the skepticism is warranted to some extent. The originator of the formula for genetic load, JBS Haldane, famously quipped "fitness is a bugger!" Part of the problem is that the term "fitness" has unique connotations in evolutionary biology. Physical fitness, health and longevity, often correlate with reproductive fitness, but the correspondence is not 1:1. In fact, in many species there is likely a correlation between extremely fecund but short-lived individuals and fitness, their reproductive value, while longer-lived individuals within the population would exhibit less fitness. This is antagonistic pleiotropy at work, short-term benefits outweigh long-term consequences, evolution is not "concerned" with long-term designs when weighed against short-term success. Those who fail in the present do not live to fight another day.
Ultimately the issue here is the distinction between the fact of evolution and the theory of evolution. The process, the description, is pretty clear via a wide range of inferences. But the specific theoretical models are still being worked out, and many of the constructs of population genetics can be accused of excessive reification. Yet, as I said, evolution is about short-term windfalls, and the utility that abstractions offer us may simply be a necessary aspect of doing the science in the present as opposed to waiting for a future when our empirical methods and analytic techniques catch up to our ambitions. Hubris is in our nature. Charles Darwin formulated his theories before Mendelian genetics, and the Modern neo-Darwinian Synthesis rests upon the tenuous backs of the Wright-Fisher models. Myself, I believe that the work of Haldane, Sewall Wright and R.A. Fisher may finally be brought down from the heavens and tested in the trenches because of rise of the genomics, quantitative evolutionary models necessarily needed an enormous quantity of raw data to explore their assumptions and consequences with sensitivity.
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Damn! And here I thought I was going to be reading something about buggery. Does evo-bio have much to say about buggery, come to think of it?
Does evo-bio have much to say about buggery, come to think of it?
spandrel :)
Haldane, Fisher, Wright, et al were working with a different paradigm of genes and alleles. The pre-molecular concept of alleles in a population were like colored marbles in a bag. There was some concept of epistasis (eg, Dobzhansky's model of coadaptation), but the molecular revolution of the last few decades has totally changed how population genetics is done. Molecular populations genetics has changed how population genetics is done (the coalescent has replaced the Wright-Fisher population as the neutral model). Of course, the early population geneticists laid the foundation for the theory used on molecular data, even though their models are now outmoded.
i was under the impression that s. wright emphasized statistical epistasis quite a bit? (part of the shifting balance)
Yeah, epistasis doesn't really fit with the rest of my argument. I was mostly agreeing with your point that DNA sequences will challenge the classical genetics model. Mostly, because they require different models of evolution than the simple alleles and loci model of Wright and Fisher.
I guess you could say that microorganisms are the most fit. Short time horizons. They reproduce & adapt faster than macro-organisms can. Come to think of it, it seems as if evolution really hasn't made much "progress" in terms of fitness in the "design" of complex life.
It seems that we're not as optimally streamlined for survivival as are our microbial cousins. Whatever technological innovations do for humanity, i still think microorganisms will be around for much longer into the future than we will. Microorganisms aren't concerned with physics or god or the origins or fate of the universe, and they certainly wouldn't succeed academically at MIT or Caltech, but i have a feeling that they(& cockroaches) are fitter than we are.
Although, if the singularity eventually comes, we may have unimaginable mastery over every aspect of our environments, making us pretty darn fit & swiftly adaptable, at least temporarally.
ooooh! bettah not let godless hear you say that!
what happens if we substitute "parasite load" for "genetic load", and recompute the equations with agnostic's selfish germs instead of the more traditional selfish genes?
homo cyberneticus
;-)