Evolutionary Fish Story

Posted on September 16, 2012 in Darwin and Evolution, Dating Methods, Genetics, Geology, Marine Biology

Similar-looking blind fish couldn’t have swum across the world, so did they evolve separately?

Where would a fish want to go be?  A goby fish wants to go be in dark caves.  The BBC News announced that “Goby fish 6,000km apart share eyeless common ancestor.”  Herein lies a puzzle: blind gobies in Madagascar and Australia are very similar.  How will evolutionary theory explain this?  Reporter Jonathan Ball said, “A study in PLoS One showed Madagascan and Australian cave fish inherited their blindness from a common ancestor”  (Source: Chakrabarty P, Davis MP, Sparks JS (2012) The First Record of a Trans-Oceanic Sister-Group Relationship between Obligate Vertebrate Troglobites. PLoS ONE 7(8): e44083. doi:10.1371/journal.pone.0044083).

Though living in different parts of the world the cave fish shared important features: they were small — under 10cm in length — eyeless, colourless and lived in freshwater, limestone caves.  How such similar fishes came to be living on different sides of the world was the question the researchers wanted to answer.

They considered convergent evolution: “When separate species are exposed to the same selective pressures they often come up with the same solutions — a process known as convergent evolution.”   An alternate possibility is that these species inherited their particular characteristics from a common ancestor: “In the case of the cave fish, an alternative possibility was that their odd features — or traits — were adaptations inherited from an ancestor common to both.”

A genetic comparison suggested the latter:

Though separated by thousands of kilometres of ocean, the cave-dwelling fish of Madagascar and north-western Australia were genetically more similar to each other than to any other goby: they inherited their unusual suite of characteristics from a common ancestor.

That they’re 6,000 km apart in Madagascar and Australia is pretty remarkable,” observed Dr Chakrabarty.

The researchers believe that the ancestor lived on Gondwanaland, which joined Madagascar and Australia in the past.  Their hypothesis is that those two lands split 60 million years ago, leaving the two species of cave-dwellers 4,000 miles apart, no longer able to share a common gene pool.

Nice hypothesis, Ball suggested, “But the study threw up some anomalies.”  Why didn’t the blind gobies go be in India, which was also part of Gondwanaland?  Maybe they went extinct there.  Or, perhaps evolutionary ideas of Gondwanaland “might need updating.

A researcher found it “intriguing” that some of the blind gobies in Madagascar had pigment; “they show that caves are not evolutionary dead-ends,” he said.

The observation of similar blind cave fish separated by 4,000 miles is a worthy puzzle for scientific investigation by both creationists and evolutionists.  How did they get there?  Evolutionists typically take the microphone and start waving their hands.  They reach into their story toolkit and pull out “convergent evolution”.  They grab the magic wand of “millions of years.”  They play their puzzle of slowly wandering continents, as they look into their genetic crystal balls for visions of long-lost common ancestors.

Unfortunately for them, these tactics flop. First of all, blindness is degeneration, not evolution.  Even creationists allow for that kind of change from an initial created kind of goby that diversified without adding new genetic information.  Second, “convergent evolution” is a distraction.  It is not a “process”; it is merely a story used whenever needed to show similar things that should not have been related.  And, the evolutionists admitted that their popular story of Gondwanaland’s separation “might need updating.”

The authors admitted in their paper that evolutionary theory is not sitting confidently in the seat of scientific explanation here: “A major issue plaguing our understanding regarding the evolution of cave animals has been a lack of basic information regarding the assembly of these biotas, including mechanisms of speciation and phylogenetic origin.”  Ahem; why, then, are you holding the microphone?

The most useless part of their hypothesis is time.  It doesn’t take 60 million years for eyes to degenerate; that can happen in one or two generations.  Sixty million years is far more time than all the alleged major transitions in mammals are said to have occurred.  Why would these fish just sit there in caves on opposite sides of the ocean, not changing at all, looking closer to one another genetically than to other gobies?  Does that make sense?

It is far more reasonable to believe they have not been separated anywhere near that long.  Biblical creationists believe the continents broke up and spread apart rapidly during the Flood.  Only pockets of fish populations would have survived, explaining why they are found where they are but not in India.  The genes for pigment were present but recessive, switchable back on by genetic or epigenetic mechanisms.    No tens of millions of years are needed to explain these observations; in fact, the explanation is better without them.

 

 

 

One Comment

snelldl September 16, 2012

Why didn’t the blind gobies go be in India” LOL.

Why did the gobi cross the ocean? To go be on the other side.

Leave a Reply