Non-Haeckelian Development

Some fun weirdness in the tangled “tree of life.”  Donald Williamson, a marine biologist who wondered why very different larval forms pop up willy-nilly in very different species, has a bold hypothesis.  Although his explanation is very heterodox (though it received serious support from Lynn Margulis) and is yet to be supported by any molecular data, what is much more fascinating is the extent of the problem his theory aims to solve, including the following oddities:

1. Very similar larval forms appear in phyla with dissimilar adult body plans.
2. Wholly different larval forms appear in the same phylum
3. Some echinoderms are develop as protostomes, some as deuterostomes. 
4. Some mollusks, annelids, sipunculids, and even some deuterostomes have rotifer-like trochophore larvae.

These larval variations not only challenge the Haeckelian expectations of neo-Darwinism, but they potentially put the whole protostome/ deuterostome division in question.  Here’s Williamson’s attempt to fit these larval epicycles into a Darwinistic history:

   … Brittle stars and sea urchins are very different as adults but share the unique pluteus form of larva. Why would similar larvae produce dissimilar adults [in different phyla]? Larval transfer proposes that the basic pluteus larva evolved only once, in a sea urchin, and was retained in this sea urchin’s descendants.  An ancestor of most existing brittle stars then acquired a pluteus larva by hybridizing with a sea urchin. 

    One member of this group, Kirk’s brittle star, develops directly from the fertilized egg, with no trace of a bilateral larva, and its blastopore becomes a mouth. It is, therefore, a protostome.  All echinoderm larvae are in a different developmental class, the deuterostomes, in which the mouth is a new opening; several echinoderms that have lost their larvae develop as deuterostomes. If Kirk’s brittle star lost its larva, it must have also adopted a fundamentally different pattern of cell division in the embryo. We believe, however, that Kirk’s brittle star has no larva because none of its ancestors hybridized with a sea urchin. The heart urchin Abatus cordatus and the three known species of sea daisies also have no larvae and develop as protostomes.  We suggest that this is the ancestral method of echinoderm development, and the pattern called deuterostomy came with the transferred larvae. 

  Two sea urchins, Lytechinus variegatus and Lytechinus verruculatus, are of the same genus, but the similar adults each develop from very different pluteus larvae. Such cases are difficult to explain if larvae and their corresponding adults evolved from one common ancestor.

 

It’s pretty curious stuff.  

Randy Olson's Flock of Nonsense (Update on John Angus Campbell)

Well, it seemed like it was time to link all these Flock of Dodos write-ups of yesteryear in one place.

• Is Haeckel's Recapitulation a Strawman?
• Randy Olson's Creationist Shill
• Questions about Flock of Dodos and Jonathan Wells
• Randy Olson's Flock of Anti-Creationist Statism
• Punches Pulled: Michael Behe Doesn't Care
• Punches Pulled: Haeckel's Embryos in Peer Reviewed Literature

To sum it up, Olson's unprofessional (and unethical, I think, as a documentarian) treatment of John Angus Campbell, Jonathan Wells, John Calvert, and Michael Behe, either in the film or in the "Pulled Punches" follow-up, marks the film as schlockumentary.  Olson highlights some matters as essential that he is later free to dismiss as trivial when he's shown to be wrong.

In other words he engages in the very thing he defines as "Trivia Tackling": "trying to take down a large institution, idea or individual, not by assailing the large and significant parts, but by doggedly locking on to pieces of trivia."  The closest thing to "assailing the large and significant parts" in Flock is when he talks briefly about Behe's mousetrap analogy.  We see no intense discussion between Olson and Behe about the mousetrap, which would have been interesting, nor about any evolutionary matter with Behe that Olson has any expertise.

Something I noted recently is that John Angus Campbell (the "fake" Darwinist in the film) has his own website in which he clarifies his beliefs and his position on ID, and how Wikipedia mischaracterizes him.  He is politically liberal, and a subscriber to neo-Darwinism who has long advocated "teaching the controversy."  He ended his association with Discovery Institute when he started to find himself in the cross-hairs of Discovery Institute's political enemies.

When Wikipedia and The Weekly [a tabloid] mistakenly assumed I was supporting ID (and the religious right!) rather than promoting argument as a way of engaging a classic text [Darwin's Origin] - (and this before audiences who particularly needed to read it) the DI [Discovery Institute] affiliation had outlived its usefulness [for what?] and it was time for me to move on.*

Like Kenny Rogers, Campbell knew when to fold 'em, when to walk away, when to run.  Congratulations, Campbell. You too are a "secular creationist" for aiding and abetting "anti-science."  Question: Did Randy Olson consult anything other than Wikipedia to learn about Campbell?

See Campbell's concise rebuttal to Wikipedia and the Seattle Weekly:

• Overview  
• Errors in Fact  
• Errors in Implication  
• Conclusion 

.

links: Peer Reviewed Journal Defends Recapitulation

http://ncse.com/creationism/analysis/richardson

Richardson Haeckel embryo    https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1RNNM_enUS449US449&ion=1&espv=2&ie=UTF-8#q=Michael%20K.%20Richardson%20haeckel%20drawins

Michael K. Richardson "highly conserved" embryos
no highly conserved embryos
http://www.toriah.org/articles/richardson-1997.pdf

http://www.evolutionnews.org/2011/06/haeckels_embryos_make_multiple047321.html#backfn6

http://www.evolutionnews.org/2011/07/three_flawed_evolutionary_mode048541.html

http://www.ichthus.info/Evolution/DOCS/Richardson2.pdf


http://www.talkorigins.org/faqs/wells/iconob.html#raraff2


Recapitulation is dead!  Long live Recapitulation!

Is Haeckel's Recapitulation a Strawman?

When Eugenie Scott says that Haeckel's drawings are still used because they are basically correct, what does that say about evolutionary teaching?  Haeckel is still claimed to have bolstered and rallied support for Charles Darwin's theory with his acclaimed knowledge of embryology.

The exaggerated similarities of Haeckel's vertebrate embryos thus better demonstrate the truth of common descent through gradual modification than does the reality, and therefore can be considered a boon to education, since students can be finally showed the real deal after "mountains of evidence" have cowed them into ideological commitment.  (Maybe in upper division courses.)  

P.Z. Myers denounces Dr. Jonathan Wells for (among many other things) the low grade he awards Campell's Biology for its treatment of the vertebrate embryo.  Campbell dispenses altogether (in my 4th edition) with visual comparisons, Haeckelian or realistic, and simply displays a human embryo and points out the "post-anal tail" and the "gill pouches" as though they were vestiges of our evolutionary history.  However much Haeckel's particular version of recapitulation is said to be outmoded and repudiated, it sounds awfully like these features pointed out by Campbell are vestigial developmental characters left over from our evolutionary past.

When Randy Olson in his Flock of Dodos documentary displays the bones of the pentadactyl limb as prima facie evidence (an obvious example of the "mountains" of self-evident proofs of evolution) what he is implicitly arguing is: These are all alike, and they'd have no good reason for being alike if it weren't for common descent (one major hypothesis of the neo-Darwinian Synthesis) as well as undirected selection (the other major hypothesis). Since Olson's film is about "anti-science" vs. Evolution, for Olson the pentadactyl limb speaks truth to power about Evolution.  The pentadactyl limb is highly conserved among non-fish vertebrates, like the ideal vertebrate embryo is more or less conserved among vertebrates.