March 24, 2009 | David F. Coppedge

Is a Hippo a Pig or a Whale?

Two teams of evolutionists are having a spat over whale evolution.  Thewissen and team (Northeastern Ohio U) say the hippo is close to the pig, but Jessica Theodor (U of Calgary) and Jonathan Geisler (Georgia Southern U) say it’s in the whale family tree.  Their arguments and counter-arguments were published in Nature last week.1  Science Daily gave Theodor and Geisler time to tell their side of the story.
    Theodor and Geisler feel that DNA phylogeny needs to be taken into account, which their opponents failed to do.  They worked several phylogenetic trees with living and fossil animals that put hippopotamids in the line with raoellids, Indohyus (an extinct Indian pig-like animal), and cetaceans (whales).  One of their trees treated all characters equally, another suppressed homoplasy (convergent characters).  They also omitted Andrewsarchus, a dog-like predator known only from one skull and a few bones.  In addition, they took into account the thickening of bones in the ears of both whales and hippos, which they took as evidence of common ancestry.
    Thewissen et al agree with parts of their opponents’ tree but think hippos are closer to true pigs.  They say the thickening of bones in the hippos and whales are due to different molecular mechanisms.  Hippos, they say, appeared after the cetaceans, and in Africa, not Pakistan, where most of the whale ancestor candidates have been found.
    Science Daily said, “Geisler and Theodor argue that leaving out the DNA data not only ignores important information, it implies that the evolution of swimming evolved independently in hippos and whales, when it may have evolved only once in a common ancestor.”  Thewissen et al said, “Geisler and Theodor place confidence in their results with regard to hippopotamids by stating that their analysis is consistent with ‘previous phylogenetic studies’.  However, one of the two articles that they cite was published after the publication of our paper, and they do not cite a recent paper that disagrees with their (and our own) results.”  Apparently there are other positions besides these two.  “We also believe that improving fossil collections of poorly known taxa is important in advancing understanding of cetacean relationships.”
    One position that was not considered by either team is creation.  For that perspective, see Jonathan Sarfati’s article on whale evolution from Creation Ministries International.

1.  Brief communication arising, J. H. Geisler and J. M. Theodor, Nature, E5 (19 March 2009) | doi:10.1038/nature07775; Reply by Thewissen et al, Nature E5 (19 March 2009) | doi:10.1038/nature07775.

Remember that whale evolution was #1 in Nature’s “15 Evolution Gems” published in January (01/02/2009).  They advertised this list again this month (03/18/2009).  But read their spiel and you’ll find it’s full of speculation and appeals to the future: “there is every reason to think that many others await discovery,” they said – so keep the credulity dollars flowing into the Darwin Party coffers.  Whale evolution was also the darling of the episode on “Great Transformations” in the PBS Documythary series, Evolution (see 12/20/2007).
    This little controversy appearing in Nature shows that the case is not so tight.  The arguments on both sides reveal the usual tricks of the Darwin Party: appeals to theory-laden concepts like convergent evolution, tweaking of tree-building software, and the weighting of uncooperative lines of evidence to get the results they want.  It’s time to step back and look at the big picture: can you really link a whale, a pig, a hippopotamus and a dog into a family tree?  The morphological differences between these groups are arguably greater than their similarities, despite the fact they are vertebrates and air-breathing mammals.  Each animal group is perfectly happy living in its specialized environment without trying to become something else.  Each animal is well adapted to its habitat, possessing all the machinery and systems needed to thrive (see news about hippo sunscreen).  Only by picking and choosing which pieces of evidence shall be garnered to support a preselected story would a silly human mind imagine joining them together into a genealogy.
    There’s another controversy brewing.  Two groups of evolutionary carpenters are fighting over the evolution of the concrete saw, which requires water for its operation.  Both agree it is related to the bench saw, but one party says both are related to the power drill, and another says they are related to the reciprocating saw.  One view makes the circular motion of the drill and the concrete saw a case of convergent evolution; the other makes the motors products of a common ancestor.  The evolutionary carpenter guild may have internal disputes about the details, but one thing is clear: these tools did evolve from each other, because they are all members of the electrical power tool clade.  All evolutionary carpenters agree: evolution is a fact!

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Categories: Mammals, Marine Biology

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