Irritations

Darwin's finches show how man harms evolution

This was a dumb headline and also a dumbed-down article. The contextual quotes in the headline alleged that evolutionary adaptation 'harms evolution', because two previously divergent Galapagos finch species are becoming morphologically similar in terms of beak length. Are these divergent species anatomically different in factors other than beak-length, and (most importantly) are they interbreeding, adding a genetic overlay to the adaptive picture?

Let's get this straight. Evolution no knows direction except that exerted by time and circumstance. It's a fallacy that evolution always results in more complex, more differentiated specialisms with time. It's a broad fact, generally true, that animals have complexified from unicellular to multicellular, and protistic to eukaryotic over 2+ billion years. But- the longevity and proliferation of the protists to this current day attests to a preservation of primitive characteristics when suitable. And the loss of specialised characteristics is not a new or earth-shattering finding, nor 'retrograde' in any qualitative sense.

Eukaryotic examples of the rule that adaptations can be lost when environmental conditions dictate have; fish, amphibians and arthropods losing the mechanical and cortical apparatus for sight and vision in subterranean caves. Sea mammals re-developing fused, webbed limbs, but in the same pentadactid morphology as their land-bound forbears.

The drive can pull towards specialisation or generalisalation, as the flow of time and environment dictate, but not necessarily in the linear or 'progressive' path suggested. To assume so is a fundamental misunderstanding of the laws of natural selection, and the fact that evolution in all it's forms only moves forward, forward.