Ghostly coincidence in an unusual fish
At first glance, you might think that a passing barracuda took a bite out of the underside of this fish. This unusual and beautiful creature is the black ghost knifefish (Apteronotus albifrons), which lives in the Amazon River.
There is an amazing feature to this curious-looking organism. The black ghost knifefish is an electric fish which hunts for small prey using what is known as an ‘active’ electrical sense.1
Every second, its specialized electric organ generates a stream of hundreds of tiny electrical pulses outwards into the water. These pulses then travel back to the organ through thousands of special conductive pores on the fish’s body, especially its head. As the pulses return, specialized electric receptors under the pores, connected to the brain, sense any changes in the returning pulses caused by an object in the water distorting the electric field radiating from the fish.
This fish has rather poor vision, but its astounding ‘electric sense’ helps it to ‘see’ its prey in the murky river water.
Hunting in reverse
Most electric fish are very skilled at swimming backwards. The black ghost knifefish pictured here approaches its prey in this way, because the electric sense is not focused like an eye, but more like a ‘scanner’. If the fish were to swim forwards towards its prey, by the time the scan was finished, the prey fish would be at its tail. By swimming up to its prey backwards, the predator is ready to grab it with a forward lunge when it has been identified by the electric scan.
It is difficult enough to envisage how such a complex system could have developed through trial and error mutation/selection. An even greater difficulty for a thoughtful evolutionist is the remarkable fact that this same sort of electric sense exists in other fish, such as the African elephant snout fish. According to evolutionary theory, it is universally agreed that this fish could not have inherited it from the same ancestor as the black ghost knife.
In other words, if evolution is true, the same sort of complex system must have evolved more than once! These sorts of conundrums are common for believers in evolution.
Where different creatures have similar complex organs, this is regarded as evidence that they had a common ancestor, rather than a common Designer. However, often this ‘common ancestor’ explanation is recognized as impossible for other reasons. For example, the eye of the squid and the eye of man are remarkably similar, but there could not, in consistent evolutionary theory, be a common ancestor for man and squid from which both inherited the eye.
In such cases, no matter how incredible the similarity, it has to be passed off as so-called ‘convergent’ or ‘parallel’ evolution. This means that, by chance, the two groups of electric fish ‘developed’ a virtually identical system. This would require substantial numbers of chance mutations to provide the right genetic information on which selection could operate to produce the near-identical result.
This sort of ‘convergence coincidence’ occurs so frequently that the argument that similarities prove evolution really loses any philosophical force it may have had. Any evidence from similarity can be made to fit. Where similarities fit the theory of common ancestry, it’s called evidence for evolution—where it doesn’t, it’s called evidence for ‘convergent evolution’, regardless of how large the mathematical improbabilities might be.
The evidence of electric fish beautifully fits the creation explanation—the use of similar intelligent design features in more than one separately created kind of fish.2
Reference and footnote
- New Scientist, 17 April 1993, p. 13.
- A kind is a genetically inter-related group, not genetically related to any other groups.