Traits are Linked. "Re-Thinking the Fundamentals of Evolution"

 Their headline, not mine. A study of a wide-spread African fish group has turned a quarter-century of evolutionary assumption upside down. Cichlids have a very complex set of double-jaws. Well, I will let the article tell it...

Researchers have long thought that the two sets of jaws are evolutionarily decoupled and can evolve independently of one another, pushing the boundaries of morphological evolution. However, Conith and Albertson demonstrated that such decoupling does not appear to be the case for cichlids, challenging a quarter-century-old assumption. "What we've found is not just that the evolution of the two sets of jaws is linked, but that they're linked across multiple levels, from genetic to evolutionary," says Albertson.

Traditional thinking is that genetically linked traits led to features that were constrained in terms of evolution. You could not tinker with the one without messing up the other, making accumulated changes much harder. You had to have a hail-mary that changed everything at once in a way that somehow still worked. 

any models of evolution theorize both that organisms are constructed from repeated units—digits on your hand or teeth in your mouth—and that these individual units evolve independently from one another. "It is this 'modularity' of organisms that is thought to facilitate the evolutionary process," Albertson notes.

Linked systems are usually thought to lack evolutionary potential. "They just cannot evolve in as many dimensions," Conith says. This is referred to as an evolutionary constraint, and it plays an important role in shaping biodiversity. Constraints determine what body structures are possible.

The article then does what such pieces typically do- take a discovery which ought to challenge naturalist premises and instead use it to claim support for them. All discoveries that naturalists were wrong about evolution automatically get re-interpreted to "this is how evolution works". When a quarter-century fundamental assumption is overturned, they don't even blink. Linked or unlinked, nature saw to all the changes unaided. It's a naturalism-of-the-gaps at work. 

"The constraint is actually facilitating cichlid evolution, rather than impeding it," says Conith.

Of course it is, because whatever happened, evolution did it.

"This tells us that we need to rethink the fundamentals of evolutionary mechanisms," says Albertson. "Perhaps constraints play a wider role in the evolutionary success of species around the world."

That sounds like however the constraints got imposed, it helped promote adaptation. Sort of like how God's commandments are not cages, but guard-rails. The so-called "constraints" imposed by the creator give us freedom, they don't remove it. 

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My book about early Genesis is far more about Theology than science, and that's good. I've come to see we won't really get the science right, big picture anyway, without getting the theology right.  

 

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