Part 1: the Elephant’s Trunk
On Monday 9 August 2004, BBC Radio 4 broadcast the first of a series on “Real Just So Stories”. Stimulated by Rudyard Kipling’s stories for children, the programme presenter, Alistair McGowan, asks: “What really happened?” This episode was entitled “How the Elephant Got Its Trunk”
Adrian Lister, Professor of Palaeobiology at University College London, explained that the trunk leaves no fossils. However, the skull can be studied for evidence of muscle attachment points. He said that all the potential ancestors for the elephant were small, possibly amphibious, and rather like a hippo in not having a trunk. However, as the animals grew in size, they would have found it difficult to get supplies of water. They could not stoop to drink because of their short necks and stocky legs. A trunk would allow them to get water without stooping. The ancestral elephants were “blessed by evolution with this wonderful structure”.
Lister commented on Stephen Jay Gould’s assault on Darwinian “just so stories”, reducing science to an exercise in creative imagination, whereby intelligent people would “guess why [a character] arose”. One example of Gould’s writing on this follows:
"Evolutionary biology has been severely hampered by a speculative style of argument that records anatomy and ecology and then tries to construct historical or adaptive explanations for why this bone looked like that or why this creature lived here. These speculations have been charitably called "scenarios"; they are often more contemptuously, and rightly, labelled "stories" (or "just-so stories" if they rely on the fallacious assumption that everything exists for a purpose). Scientists know that these tales are stories; unfortunately, they are presented in the professional literature where they are taken too seriously and literally. Then they become "facts" and enter the popular literature, often in such socially dubious form as the ancestral killer ape who absolves us from responsibility for our current nastiness, or as the "innate" male dominance that justifies cultural sexism as the mark of nature." (Gould 1980)
Lister said that scientists who study fossils are better maintaining a “humble silence” until they find hard evidence on which to build their theories.
The programme then (conveniently) provided an example of a modern “just so story” relevant to the elephants trunk. This came from John West, Professor of Physiology in San Diego University, a specialist in respiratory physiology, particularly blood flow in the lungs. He noted that humans can only snorkel just below the water surface because otherwise the blood vessels around the lung will rupture. Yet there are several reports of elephants snorkelling at greater depths. They can walk entirely underwater, breathing through their trunks held above their heads. The bottom of the lung may be 2 metres below the water surface. This is only possible because they have a different physiology, something that is not acquired because it is also apparent in fetal elephants. This raises the question: did the elephant evolve a trunk living in water? Was it a case of not needing water – but air? The basic answer to the question “Why does the elephant have a trunk?” is (according to West): “to have a snorkel”.
Lister was having none of this! The present use of a character is no sure guide to its past use. Also, look at the other marine mammals: none of them have evolved a trunk. The “snorkel” story is a “classic just-so story” he said. But then he wisely conceded that his own preferred “feeding” explanation was essentially the same: a modern just so story.
Those of us who approach these questions from the perspective of creation-oriented biology do not think that the present-day animals are those that came from the hand of God. We do not postulate the fixity of species, but rather that the original kinds were created with massive potential for variation and diversification.
Kipling's questions are in principle legitimate. It is valid to ask whether certain features were present in the original kinds, and what the limits of variation were. Present research indicates that the original kinds not necessarily equivalent to 'family', though often around that taxonomic level were: equids (including horses, zebras, and the entire fossil horse family), camellids (llamas, camels, etc), proboscidea (an order including elephants, mammoths, mastodons etc), giraffids (giraffe, okapi) and cetaceans (whales, dolphins, porpoises).
Evidence for 'design' is by the same token evidence that chance mutations, those variations on which the Darwinian notion of natural selection depends, are not what is going on here. The capacity for variation is there, designed and created, from the beginning. That is the truly revolutionary concept that creationism has to offer: creation and evolution, not either/or.
The elephant belongs to the order Proboscidea, and all members of that order have rather distinctive protruding noses. A developmental mechanism exists in all members of this order, but it is expressed in different ways. The Elephant family includes the mammoth, but the ancestral relationships between these animals and the other members of their Order have been explored only in limited ways. We know how the elephant uses its trunk, but the origin of the biological mechanism for producing a trunk is not known. The characters seen in the trunk can be linked to many other features of elephants. We have already noted one example: the use of the trunk as a snorkel. The trunk is needed also to assist the elephant to eat large quantities of vegetation, and in turn, this is related to the elephant’s place in ecosystems as a pioneer grazer – opening up grazing opportunities for many other species. So, apart from the complexity of the trunk itself, it is part of a complex body system that develops and operates within a total ecology. For example, the elephant's partial digestive system makes the dung highly nutritious for beetles and other insects that depend on it. There is no scientific underpinning for a gradual route by which the elephant’s trunk would evolve. For the whole system to be evolving in the same direction at once creates a high information load which is more consistent with a design or creation model than with Darwinian evolution (which cannot, by definition, have a purposeful direction or goal).
Summary
A developmental explanation must be an integral part of this story, but we do not yet know what it is. It is possible that the long trunk has emerged during the process of speciation, but this sophisticated structure should be linked to the intelligent design of ancestral organisms rather than random mutations moulded by natural selection.
David J. Tyler (August 2004)
Reference
Gould, S.J. 1980. From: "Introduction" to Björn Kurtén, Dance of the Tiger: A Novel of the Ice Age. N.Y.: Random House,. Pp. xvii-xviii. (c), Random House, Inc.
