In a new paper in Science (paywalled), Nicholas J. Matzke from the National University of Australia demonstrates the evolutionary connection between anti-evolution bills introduced into US state legislatures in a series of iterated attempts to ban or weaken the teaching of evolution by natural selection and to promote Biblical creationism in various guises in its stead.

The bills universally failed, either through a failure to pass the legislature, or through subsequent church/state-separation court challenges. Consequently, the groups that advocated for these bills (national or nationally coordinated in nature, though they worked at the state level) adapted them through directed mutation and trial, using each setback as a fitness test and modifying their next attempt accordingly.

Matzke fed the text of these bills to an algorithm that traces "trees of common descent" to see how the bills combined and recombined to make new, more fit versions of themselves.

It's a fun piece of research, but the fact that anti-evolution bills evolve wouldn't surprise most creationists. The creation movement generally admits that evolution occurs (for example, by selective breeding of livestock, or through the processes that have given rise to antibiotic resistant bacteria), but deny that evolution through natural selection is responsible for the diverse life on Earth, especially humans.

The fact that humans can "selectively breed" legislative proposals, in other words, supports both the creationist hypothesis (which says that modern evolution is the result of human experimentation) and the evolution through natural selection hypothesis (because it shows that mutation and selection produce more fit organisms).

Matzke's tree identified a key event in 2006: a Louisiana Parish adopted a policy that covered evolution, the origin of life, human cloning, and climate change. Its language was merged with that of the earlier Academic Freedom Acts, creating a binge of "Science Education Acts" that appeared in Louisiana and a number of other states in 2008. One of these went on to become the first law of its kind to be enacted. This success inspired copies in states like Texas, Maryland, Missouri, and Virginia. All told, similar language appeared in over 10 state legislatures, although some of these bills dropped specific areas of science. This led to a second success in Tennessee. Critically, this lineage has entirely displaced the earlier Academic Freedom Acts, which have only seen a single version introduced since 2011. In contrast, five science education acts were introduced this year. Overall, Matzke concludes that opponents of evolution have reinvented themselves twice over the last dozen years or so, starting with academic freedom bills and later switching to science education acts. During that time, there were also some successful innovations, such as bringing along climate change in an attempt to attract wider conservative support.

The evolution of antievolution policies after Kitzmiller v. Dover

An evolutionary analysis of anti-evolution legislation

[John Timmer/Ars Technica]