Worms Evolved Backwards

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Worms evolved backwards, according to articles in ScienceDaily 10 February 2011 and Nature vol. 470, p161 doi: 10.1038, published online 9 February 2011. An international team of scientists have studied the genetics of small marine flatworms named Xenoturbella and a group of worms named Acoelomorpha to see where they fit in the evolutionary tree of life. They were thought to be an evolutionary link between very simple animals such as sponges or jellyfish and more complex animals, but the study has concluded they actually belong in the more complex group.

Max Telford, from the UCL Department of Genetics, Evolution and Environment, who led the research, commented: “We can no longer consider the acoelomorphs as an intermediate between simple groups such as jelly fish and the rest of the animals. This means that we have no living representative of this stage of evolution: the missing link has gone missing!” The worms have now been re-classified into their own phylum, named ‘Xenacoelomorpha’ and placed among the more complex animals.

These ‘Xenacoelomorpha’ worms were thought to be the link between two main evolutionary branches in the animal tree of life because they have a very simple body structure. The researchers now suggest they have lost some features such as a body cavity, anus and gill slits that the more complex animals have. ScienceDaily summarised this conclusion as “This implies that the worms have in effect ‘evolved backwards’ into much simpler looking organisms.” Telford commented: “Because the simple Xenacoelomorpha are descended from the same ancestor that gave rise to complex groups such as vertebrates, echinoderms and hemichordates, these simple worms must have lost a lot of the complexity that they originally possessed.”

Some evolutionary biologists are not happy about having the evolutionary tree of life rearranged, especially as it means losing “their key example of that crucial intermediate stage of animal evolution” and leaves a gap in the supposed unbroken line of descent from single cell to complex animals. The debate has been so vehement that Telford commented to Nature: "I will say, diplomatically, this is the most politically fraught paper I've ever written."


Editorial Comment: Losing the use of a limb or loss of a tail is survivable, but arguing that a group can survive loss of their anus, entire body cavity and mechanisms such as gill slits, as they evolve backwards is nothing more than a silly story which shows what a useless waste of time, effort and research grant money the theory of evolution is becoming. Biologists could save a lot of unhappiness by admitting these creatures are separate kinds of animals that show no sign of having been any other kind.

As Dr Michael Denton pointed out years ago – every creature is a unique combination of non unique features and that doesn’t help evolution one bit. The finding of creatures that do have a unique combination of characteristics is what you would expect from the Biblical description of how living creatures originated. They were created according to their kinds to function together in a designed working ecosystem. As the science of genome biology advances we predict that it will become harder and harder to fit living creatures anywhere on a neat evolutionary tree. (Ref. invertebrates, taxonomy, classification, prediction)

Evidence News 9 March 2011