This is the heart of Wells' strategy: pick comments by developmental biologists referring to different stages, which say very different things about the similarity of embryos, and conflate them. It's easy to make it sound like scientists are willfully lying about the state of our knowledge when you can pluck out a statement about the diversity at the gastrula stage, omit the word "gastrula," and pretend it applies to the pharyngula stage.As background, it's important to note that the "developmental hourglass" (Myers provides a couple of diagrams to illustrate) is a summary of a century and a half of observations showing that organisms tend to be diverse in form in the earliest stages of development (blastula, gastrula, and neurula), converge on a similar form at the pharyngula stage (from which Myers' blog gets its name), and then diverge again into a diversity of adult forms. Thus, if a creationist engages in the above tactic, they will take a quote about differences at an early stage and make it look like a denial of similarity at the pharyngula stage.
Myers points out a specific example where Wells does exactly this with a quote from developmental biologist William Ballard. Wells writes, quoting Ballard:
It is "only by semantic tricks and subjective selection of evidence," by "bending the facts of nature," that one can argue that the early embryo stages of vertebrates "are more alike than their adults."As Myers points out, multiple quotes stitched together in a sentence like this are a red flag in the writings of creationists and intelligent design advocates. The full passage Wells is quoting says:
Before the pharyngula stage we can only say that the embryos of different species within a single taxonomic class are more alike than their parents. Only by semantic tricks and subjective selection of evidence can we claim that "gastrulas" of shark, salmon, frog, and bird are more alike than their adults.Ballard did not mean to assert that these "semantic tricks" and "subjective selection of evidence" are used to claim that there is similarity at the pharyngula stage, as he also writes:
All then arrive at the pharyngula stage, which is remarkably uniform throughout the subphylum, consisting of similar organ rudiments similarly arranged (though in some respects deformed in respect to habitat and food supply). After the standardized pharyngula stage, the maturing of the structures of organs and tissues takes place on diverging line, each line characteristic of the class and further diverging into lines characteristic of the orders, families, and so on.This is a clear case of deceptive writing by Jonathan Wells.
Read the rest, which includes further examples of dishonesty by Wells, at Pharyngula.