Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
Francis Galton, Darwin’s cousin, did not believe that species could be created “gradually”, as Darwin’s theory implied. Galton believed that new species can arise only in bursts, and so he modified Darwin’s theory in a key way. He reasoned that variation allows for a lot of change, but only within a species. A species is a stable state, and has a lot of resilience. When something destabilizes that state, then there occurs a sudden change, and a new species is created, i.e. a new stable state is rapidly reached.
The weakness of Darwin’s theory to explain the complexity of life led the German geneticist Richard Goldschmidt in the 1930s to similarly conclude that evolution must proceed by great leaps rather than by small steps.
Expanding on Galton’s theory, Gould introduced the idea of "punctuated equilibrium" ("Punctuated equilibria", 1972): evolution occurs through rapid bursts of speciation after long periods of stasis, as opposed to the traditional view of gradual, continuous unfolding of species. Mostly nothing happens; however, when something happens, it happens quickly. Incidentally, we know for sure that this is the way progress occurred in human civilization: long periods of stasis were followed by sudden bursts of progress (we are living in one of those).
About 600 million years ago the first living beings that exhibited bilateral symmetry appeared on Earth. These “bilaterians” were symmetrical beings, characterized by the mirror-image balance of most limbs and organs (the notable exception being the heart, which is still asymmetric to this day). Today bilaterians rule the planet. Bilaterians include most species, from insects to mammals: two legs, two wings, two eyes, two lungs, two brain hemispheres, two kidneys, two nostrils, etc. Organs and limbs that are not duplicated (such as the mouth or the anus or the penis) are located exactly along the axis of symmetry.
It is not clear what the evolutionary advantage of bilaterians was. Although many possible candidates can be advanced, none seems to justify the sudden domination by bilaterians. The early ones were microscopic, and already rather complex. Basically, the rest of evolution was only a magnification of something that had already been created 600 million years ago.
A few million years later there was a sudden explosion of species (the “Cambrian explosion”). Again, several hypotheses have been advanced to explain why suddenly species multiplied rapidly (that animals began to alter the environment, that animals developed emotional responses that made them more likely to survive, that they started eating each other, etc), but none seems to justify the fossil record.
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