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.
