Walking fish evolve, claim scientists in articles in ScienceDaily, Science (AAAS) News, 27 August 2014 and Nature, doi: 10.1038/nature13708, 26 August 2014. Scientists looking for clues as to how swimming fish evolved into walking land-dwelling 4 legged animals have experimented with a fish named Polypterus, commonly called bichirs, which are able to breathe air, and are known to be able to ‘walk’ across land from one waterhole to another. They obtained 149 young bichirs and kept 111 of them in a terrarium (like an aquarium but with moist earth and air) for eight months. The remaining fish were kept in an aquarium. They then compared how well the terrarium fish moved compared with the aquarium dwellers, and looked for differences in their bones.

They found the “landed” fish were more efficient walkers, holding their heads up, and walking with fins closer to their bodies so their body weight was supported and their fins did not slip on the surface as much. These fish also had longer stronger bones in their pectoral girdle, and the connection

These changes were described as being due to “developmental plasticity”, meaning change that occurs during growth and maturation. The research team concluded: “Our results raise the possibility that environmentally induced developmental plasticity facilitated the origin of the terrestrial traits that led to tetrapods”. (Tetrapods are four-legged creatures). This claim is summarised in the title of the ScienceDaily article: “Walking fish reveal how our ancestors evolved onto land.”

ScienceDaily, Science

Editorail Comment: Let’s be brutally blunt. There is no evolution occurring here. The terrarium-raised fish, which could already walk and live on dry land, breathing air, are still the same species doing something that this species of fish could already do. This experiment actually does confirm something we have always known about bones – they can grow stronger, within limits, if subjected to stronger forces. However, these forces have never turned existing bones into different bones, or produced new bones that did not exist before, which is what needs to happen to turn a fish into a four-legged creature … and that’s an experimentally verifiable fact!

The clever sounding phrase “Environmentally induced developmental plasticity” is just another way of saying that the fish were already able to cope with the extra strain on their fins and pectoral girdles because they already had the genetic ability to make stronger bones and more flexible connections between head and pectoral bones given the right stimulus. We must never lose sight of the fact that in order for environmentally induced changes to facilitate “the origin of terrestrial traits that led to tetrapods”, the extra forces imposed on the fish fins would have to produce new genes that would convert fins into legs and feet and not just make them stronger.

Anyone out there want to scream “Lamarck” or “pangenesis”? Better to scream “Liar Liar!”, particularly when you read media headlines around the world from the 27/28 August 2014:
“Fish adapt to life outside water by learning to walk”. Telegraph.co.uk, 7 Aug 2014;
“How fish out of water found their feet to walk on land” The Australian, 27 Aug 2014;
‘Walking fish’ unveil mystery of human evolution on land” Daily News and Analysis 28/7/14.
(Ref. locomotion, ichthyology, biomechanics)

Evidence News vol. 14 No. 15
3 September 2014
Creation Research Australia