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Creation 37(3):16–17, July 2015

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Polypterus: Teaching a fish to walk?

Bichirs and a giant leap of evolutionary faith



Popular with aquarists, bichirs are a family of African fish [Polypteridae] able to breathe through lungs and to spend time out of water as do several other species of fish, notably lungfish and mudskippers. A study published in Nature describes observations of walking in captive-bred bichirs (Polypterus senegalus) that were raised to live wholly out of water, although in damp conditions.1

Of course, the fish would not naturally choose this lifestyle. However, after several months, the researchers could see that their movements were a little less awkward than those raised in water. The ‘stress’ of the environment (during eight months) had even led to very slight changes in the muscles and bones supporting the pectoral fins—termed ‘developmental plasticity’—making them more robust to support the body out of water.

Mixing facts with fiction

Quick to capitalize on yet another opportunity to promote fish as our ancestors, Nature released a YouTube video of the researchers’ land-raised bichirs ‘walking’: “The land-lovers lifted their heads higher, planted their fins more efficiently, and slipped less often than their aquatic associates.”2 This is not nearly as impressive as it sounds, as viewers can easily verify,3 but the bait-and-switch4 trap is now set for the unwary consumer of this propaganda piece. Having baited viewers with the demonstration of small changes, the switch is made to fish-to-philosopher evolution; they claim that the observed plasticity helped make possible the “major evolutionary step as our ancestors crawl[ed] out of the seas and onto land. … It might not look elegant, but don’t be deceived. After all, one small flappy step of our fishy ancestors may have led to the giant leaps of mankind!”2

Leap of faith

Regular readers of Creation will be familiar with other examples of ‘walking fish’. Claimed by evolutionists to cause problems for belief in biblical creation, axolotls,5 handfish,6 and mudskippers7 are actually powerful testimony to the Creator’s superlative design (Romans 1:20). In the case of all these fish, bichirs included, the facts are not problematic, rather the storytelling that is tacked onto them. Genesis does not teach that God created species fixed and immutable, rather the fixity of kinds (Genesis 1:11, 12, 21, 24, 25).

Wikimedia Commonsbichirs
The bichir species, Polypterus weeksii

Clearly, creatures were designed by God with the capacity to vary, and the sort of change observed in these bichirs is consistent with this. It seems to be an ecophenotypic (environmentally induced) change with no alteration of the DNA code. We see this in the muscles and bones of a body-builder that are strengthened with weight-training.8 Similarly, the pectoral anatomy of these bichirs has become more robust to better bear their weight on land—they pull their fins together more than those raised in water, so holding their heads a little higher. And just as the effects of bodybuilding are not passed on to one’s children, there is no evidence that the observed subtle flexibility in bichir behaviour and pectoral girdle anatomy is heritable, as evolution requires;9 nor yet that it is heading in the direction of the way land animals walk, with a bony connection between limbs and backbone.

The Apostle Paul taught that fish and various other animals are different in ‘kind’ from one another, and from human beings (1 Corinthians 15:39), agreeing with the teaching of Genesis 1. To parody the concluding remarks of the video mentioned earlier, the idea of fish-o-pod evolution really is one of the “giant leaps [of faith] of mankind”; Don’t be deceived.

Posted on homepage: 5 December 2016

References and notes

  1. Standen, E.N., Du, T.Y. & Larsson, H.C.E., Developmental plasticity and the origin of tetrapods, Nature 513:54–58, 4 September 2014. Return to text.
  2. Fish out of water, Nature videos, youtube.com, 27 August 2014. Return to text.
  3. Without doubt, as the researchers acknowledge, mudskippers (fish inhabiting mangrove swamps) are the masters of fishy locomotion on land. Return to text.
  4. See Walker, T., Don’t fall for the bait and switch. Sloppy language leads to sloppy thinking. Creation 29(4):38–39, 2007; creation.com/baitandswitch. Return to text.
  5. Dykes, J., The Axolotl: The fish that walks? Creation 27(4):21–23, September 2005; creation.com/axolotl. Return to text.
  6. May, K., Rare Australian fish has fins like hands, Creation 28(3):28–29, June 2006; creation.com/handfish. Return to text.
  7. Bell, P., Mudskippers—marvels of the mud-flats! Creation 34(2):48–50, April 2012; creation.com/mudskipper. Return to text.
  8. Another example is the archers of the powerful medieval English longbow, who won many battles. They trained in archery from childhood so they could draw bows that few modern archers could manage, and their skeletons show enlarged left arms, and bone spurs on the left shoulder and wrist and right fingers, those used most to bend the bow. Return to text.
  9. In the unlikely event that this environmentally induced change turns out to be inheritable, it would be an example of epigenetics. But this involves the switching on/off of existing genes, not the creation of new genes. See White, D., The genetic puppeteer, Creation 30(2):42–44, March 2008; creation.com/the-genetic-puppeteer. Return to text.