Refuting Creationism - How New Genetic Information Can Arise Rapidly, Naturally

Lake Malawi cichlids

Source: Wikipedia

A small selection of Lake Malawi cichlids

How ‘supergenes’ help fish evolve into new species | University of Cambridge

Creationists like William A. Dembski constantly reassure their fellow believers that new genetic information cannot arise naturally and therefore requires divine intervention. This claim depends on a misrepresentation of the laws of thermodynamics and a deliberate confusion of information with energy. It is clung to despite the obvious and overwhelming evidence to the contrary, with the same tenacity that creationists bring to their insistence that evolution either does not happen at all or, if it does, must somehow have occurred at an impossibly rapid rate after the Flood to produce such enormous variation within their invented ‘kinds’ from just a single surviving pair.

So now we have yet more contrary evidence for creationists to ignore, this time in the form of an explanation for how the cichlid fishes of Lake Malawi in East Africa were able to evolve into more than 800 species in a fraction of the time it took humans and chimpanzees to diverge from a common ancestor. Readers of this blog with long memories may recall that, back in 2012, I described these fish as a particularly powerful argument against creationism.

The fact of this rapid adaptive radiation, taking place on a timescale that could be independently verified, was already indisputable. What we lacked at the time was a clear understanding of the underlying mechanism that made it possible. That gap has now been filled by researchers from the Universities of Cambridge and Antwerp, who have shown that the source of this new genetic information lies in genetic inversions, where an entire section of DNA is inserted in reverse orientation. They have recently published their findings in the journal Science.

During the normal process of meiosis, in which reproductive cells are formed, crossing-over reshuffles genes to produce new combinations in offspring. But when a segment of DNA has been inverted, that section cannot take part properly in the crossing-over process. As a result, the genes within it remain linked together as an intact block, forming what geneticists call a ‘supergene’. These supergenes can then be inherited largely unchanged across generations. The effect is to create barriers to hybridisation much more quickly than would otherwise be possible, effectively isolating a new gene pool within the wider population and allowing new species to evolve far more rapidly than usual, instead of having novel gene combinations continually diluted by interbreeding across the whole population.

Refuting Creationism - How Long-Necked Dinosaurs Refute Intelligent Design.

Uberabatitan ribeiroi

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Neuquensaurus australis

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South American long-necked dinosaur could easily stand on two legs

Evolution works only with whatever variation happens to be available at the time, favouring traits that improve reproductive success in the short term. Unlike the imaginary “intelligent designer” of creationist fantasy, evolution has no foresight, no long-term plan, and no concern for what happens once reproduction has been achieved. The result is not elegant perfection, but a patchwork of compromises that work well enough for long enough.

That is why nature is full of structures and processes that serve an immediate purpose while carrying harmful longer-term consequences. Ageing itself is one obvious example, as damage accumulates, repair systems falter, and tissues and organs gradually fail. Cancers and degenerative diseases are others, arising when biological control mechanisms begin to malfunction. A genuinely intelligent designer would have no excuse for such shoddy, failure-prone systems; evolution, by contrast, explains them perfectly.

In humans, physical and reproductive fitness generally peaks in early adulthood, then declines steadily with age, until the very old, if they live that long, may become frail and dependent. From an evolutionary perspective, this makes perfect sense: once genes have been passed on, natural selection becomes progressively less effective at eliminating traits that cause harm later in life. What looks like incompetence from a design perspective is exactly what we should expect from an undirected evolutionary process.

And this is not some recent peculiarity of human biology, but a deep feature of evolution itself. A recent study by researchers from Brazil, Germany and Argentina illustrates the point with two South American sauropod dinosaurs, the Brazilian Uberabatitan and the Argentinean Neuquensaurus. These giant herbivores could apparently rear up on their hind limbs to reach high foliage, and perhaps also gain advantages in defence or display. But that ability came at a cost. As body size increased, so did the mechanical stress on the femur, making the posture progressively more difficult to sustain. In other words, evolution had produced a useful adaptation, but not a perfect one. The benefit came with a built-in structural penalty.

The researchers reached this conclusion by applying computational techniques from mechanical engineering to digital models of sauropod femurs, calculating the stresses imposed by gravity and increasing body mass when the animals reared up. Their results are published, open access, in the journal of the Palaeontological Society, Palaeontology.