Using phylogenetic-based approaches, the Australian National University's Nicholas Matzke has traced the origins of creationist legislation in the US.
As he reports in Science, the US has been grappling with anti-evolution policies for some 90 years, and notes that these policies came in three waves. The first wave consisted of outright bans on the teaching of evolution, which lasted from the 1920s through the 1960s, when they were deemed unconstitutional. That's when the second wave began, which focused on balanced treatment of creationism and evolution. Now since the Kitzmiller v. Dover case in 2005, a new, third wave of "stealth creationism" has emerged. It's stealth, Matzke says, in that proposed policies or legislation avoid mentioning creationism or intelligent design and instead focus on promoting "academic freedom," with a particular focus on evolution, but have also expanded to include climate change and human cloning.
Many of these recent bills — which have become law in three US states — Matzke says, have grown out of earlier ones. In his analysis of some 65 bills, a model bill from the Discovery Institute, and policy from Ouachita Parish, Louisiana, he uncovered "strong evidence of bill-to-bill copying and 'descent with modification'" of those bills.
"[The analysis] lets you say not only do these bills share some kind of family resemblance, but these legislatures probably copied their bill from this specific bill," Matzke tells Vox's Brian Resnick. "Early on, Alabama bills were the source. After that, Louisiana and Tennessee — places where these policies passed — it's pretty clear that they inspired further policies."
The Ouachita policy that calls for "critical analysis" of scientific topics like evolution, global warming, and human cloning, Matzke adds in his paper, has been particularly influential.
"The creationist origins of modern anti-evolution strategies are clear," he says, "and at least 63 of 65 antievolution bills considered here can be tied directly to creationism through statements in the legislation or by sponsors."