You are here
Rather than presenting an account of how embryology is studied in the 21st century, the "Embryology" chapter concludes by exhorting students to pretend they are jurors in a court case against evolution. It's unclear what the charges might be, but it is certain that the students would be diverted from a fair verdict by the chapter's studious avoidance of current science in the field.
Michael Richardson and colleagues in 1997 were instrumental in pointing out the discrepancies between Haeckel's popular diagram and genuine embryos. However, Explore Evolution simply accepts a flawed creationist interpretation of Richardson's work. The claim that the common ancestry of vertebrates requires that embryos be most similar at the earliest embryonic stage was not accepted by Darwin nor Haeckel nor any modern evolutionary or developmental biologist.
Explore Evolution asserts that in 1894, Adam Sedgwick challenged Darwin's two claims about embryos, 1) early embryos of related organisms are more similar than adults and 2) the younger the embryos, the greater the resemblance. A comprehensive comparison of vertebrate embryos does not support Sedgwick's challenges about the similarity of embryos.
Evolutionary developmental biology is a vital and active field of study. High school biology textbooks rarely cover it in detail, so Explore Evolution might have done a service by offering a brief exploration of that modern field. Instead, it focuses on creationist hobbyhorses from the history of biology. Most prominent of these historical arguments is a debate over illustrations by Ernst Haeckel.
Explore Evolution wrongly state that biologists originally maintained that the genetic code is absolutely universal (invariant); that this absolute universality was considered evidence for common descent; that this would be a reasonable inference because changing the code would be invariably lethal ("not survivable"); and finally, that the claim of universality fell apart in the 1980s with the discovery of variant genetic codes.
Knight RD, Freeland SJ, Landweber LF. Rewiring the keyboard: evolvability of the genetic code. Nat Rev Genet. 2001; 2:49-58,
Explore Evolution claims that the common ancestry of life is disputed because:
Explore Evolution claims that certain scientists dispute the existence of a single universal ancestor, citing authors would not actually dispute universal common descent. They just disagree about the form it took, and the nature of the population of organisms from which modern living things evolved.
Explore Evolution claims:
Explore Evolution's arguments against molecular clocks are a bungled mishmash of actual facts, misinterpretations and completely spurious claims. First, the authors raise the issue of calibration of the molecular clock. This is an acknowledged potential problem in using the clock to date certain evolutionary events, especially those in the very deep past. Nevertheless, when appropriate methodology and controls are used, molecular clock dating has been shown to be reliable and consistent.