Sunday, May 1, 2016



The major line of animal evolution, known as deuterostomes and including chordates, hemichordates, and echinoderms, needs  to be recognized as having its origin in the early annelid worms via a group of polychaetes now called pogonophorans.  This recognizes the longer evolutionary history of protostomes.  It also sets aside changes made by the proposals of Lophotrochozoa and Ecdysozoa as significant groups of animals; the post of May 31, 2013 explains why they should be dismissed.

[Engemann's] Modification of the Annelid Theory of Chordate Origin

If you have read the recent posts of this blog, starting with SCIENCE PREJUDICE on March 17, 2016, you will understand why I didn’t say “The Creator’s Use of Annelids to Make Humans”.  My data driven conclusions leading to understanding of the evolutionary sequence of events involved do not discredit God by presenting it as a scientifically credible theory.  That is especially true because the multiple lines of evidence were unlikely to have been discovered by my feeble efforts.  I say the same thing about Darwin’s work on developing the Theory of Natural Selection underpinning our understanding of evolution.  I hope I will not withdraw recognition of the Creator’s role as Darwin may have done.  Maybe I should just say “Modified Annelid Theory of Chordate Origin”.

The lines of evidence

First, the observation of inverted systems, noted for annelids as compared to chordates, was responsible for the original proposal of annelid origin over a century ago.

Second, observations that evolution can occur in developmental stages independent of adult features.  This has been known for a long time without perception of its significance.

Third, evolutionary rates at the abyssal depths of the ocean can be so slow it makes molecular clocks for determining evolutionary rates in different branches of the tree of life almost meaningless.  Some evidence of it being known in 1915 exists*, but who would realize the importance of nothing happening?

Fourth, conditions in the abyssal depths were the driving force for natural selection to bring about the deuterostome embryological features from the original protostome annelid embryological features.

Fifth, the Pogonophora, unknown at the time of the original annelid theory, embed the major evidence of intermediate linking features.

Where is the evidence?

First, the inversion is illustrated in the post of March 2, 2015.  The concept was discussed in the June 28, 2013 post.

Second, this fact of some independent evolution of embryonic features is generally accepted since the “Biogenetic Law” was discredited.  I was impressed by the existence of an egg appendage (post of June 5, 2014) not found on more primitive isopods (post of June 6, 2014) illustrating the concept.

Third, factors responsible for the slow rate have accumulated but have not been linked with the remarkable longevity I have shown must exist, beginning with the evidence the pogonophorans present (Posted on October 24, 2015) discussed in the post of Jun 9, 2014 and illustrated in the post of June 13, 2014.

Fourth, a number of research reports have demonstrated the slowing of metabolic rates with depth in the ocean.  Some references are given in the post of June 22, 2013.  When data is limited some have assumed the ages of organisms fell at the lower end of the predicted range of error.  Isopod egg features noted in other posts apply to understanding the cleavage change (protostome to deuterostome type via pogonophorans) due to reduced egg membrane constriction as a possible selective force.

Fifth, the pogonophorans show a number of features intermediate between annelids and chordates noted in some of the posts referenced above and in the post of October 24, 2015.  Their importance is made clearer by their critical role in life surviving extinction events as discussed in my post on May 11, 2013.

The tree of life, revised

A simple correction for the tree of life is to leave the entire protostome line intact (from the version before the Lophotrochozoa/Ecdysozoa errors) and graft the deuterostome (or chordate) line on to the Pogonophora/Polychaeta basal group of the Annelida.  Echinoderms and perhaps some lophophorates may have ancestry among other pogonophorans than those leading to the chordate line.
*Brooks, William Keith.  1915.  The Foundations of Biology.  Columbia Univ. Press, New York.  339 pp.  He comments on - the unchanging nature of Lingula (page 219), and p. 217 “the diversity of the Lower Cambrian fauna and of its intimate relation to the fauna on the bottom of the modern ocean”.

Joseph G. Engemann   Kalamazoo, Michigan    May 1, 2016

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