Wednesday, 27 January 2010

Future major transitions in evolution


Evolution has capabilities that allow it to explore design space in areas adjacent to existing gene pools. How good an ecosystem is at doing that is sometimes referred to as its "evolvability". This video is about the evolution of evolvability. Nature's capabilities in that area have improved gradually over time, as useful technology for performing such exploration has accumulated.

Previous milestones in this area include:

  • Cell membrane - insulation against environmental perturbations;
  • Chromosomes - which allows genes to cooperate and build complexity;
  • Sexual recombination - which allows independent innovations to be combined;
  • Cooperation - which avoids wasting available resources fighting;
  • Immune systems - which allow organisms to grow large in comparison to their pathogens;
  • Nervous systems - a writable information storage and processing system that enhances an organism's developmental plasticity.

    Daniel Dennett says it takes some "heavy lifting" - in the form of "ressearch and development" - in order to explore design space. That "heavy lifting" requires what he calls "cranes":

    The basic idea is illustrated in this video of Dennett's:

    [...Dennett video footage]

    Transitions in evolution are topical because a major evolutionary transition appears to be currently underway.

    It started with the origin of brains - which exibit developmental plasticity and adaptation during a single lifetime.

    However, brains are mortal. What they really needed was a way to pass on their hard-won information to offspring.

    Wiring that information into DNA would be an obvious method - but it was not the solution nature came up with.

    Instead, a second inheritance channel was established. Information was no longer being passed from one generation to the next almost entirely by nucleic acids - some of it started being passed down the generations in the form of human culture.

    First it was chanting and hymns - but after a while writing appeared, and then it was printing presses, CDs, DVDs, and a plethora of other media.

    The new media have had a dramatic effect on evolution. They are user-modifiable - allowing for rapid change without any agents dying in the process. Previously, mutations had mostly been an undirected proces - but now intelligent agents could make modifications at will. Deductive and inductive reasoning came to the fore. Intelligent design could be employed. The tools of science, technology and engineering could be used to design of the next generation.

    The ramifications of this are currently playing out. The changes so far have been dramatic - life has gone to the moon, caused the planet to glow at night, and built fantastic skyscrapers, bridges, dams and tunnels the like of which has never been seen before. However, the true extent of the changes has yet to be seen - since most of them lie in the future.

    It seems likely that today's genotype and phenotype technologies will be replaced. A genetic takeover seems likely to lead to the end of the DNA-protein era.

    Mainstream evolutionary theory has not yet caught up with these modern developments - and the textbooks on the subject need rewriting to include deliberate mutations and intelligent design as fundamental mechanisms of evolutionary change.

    While evolutionary theory is being updated, it seems like a suitable time to look forwards - to see what other developments and shifts might occur in the future.

    One clear possibilty would be a shift to self-directed evolution in a population with only one organism in it. That has not happened yet - but there is a trend towards large organism size, and another that favours large-scale social systems. Humans are showing signs of developing into a social species - and this trend might well yet culminate in the formation of a universal organism.

    Such an organism might well reduce the force of natural selection to low levels - and evolution would then proceed mostly in the directions the superorganism dictated.

    I expect that - though evolvability might continue to increase, there won't be many more moments quite as dramatic as the current shift.

    In science, it is hard for modern day scientists to compete with Darwin or Newton. Scientists are rather less likely to make grand discoveries like those today.

    I expect we will see a similar thing with evolvability. The biggest discoveries and most significant milestones will happen early on.

    However, assuming that progressive adaptive evolution continues, it *does* seem reasonable to expect that living systems will still spend most of their time on adaptive peaks - with occasional leaps across design space to the lower slopes of higher peaks. So, there will probably be future dramatic transitions as well - even if these don't correspond to big changes in the underlying dynamics of evolution.