The Court Jester hypothesis is a term coined by University of California, Berkeley professor Anthony D. Barnosky in 1999, that describes the antithesis of the Red Queen Hypothesis in evolutionary theory. It refers to the idea that abiotic forces including climate, rather than biotic competition between species, is a major driving force behind the processes in evolution that produce speciation.
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The Red Queen hypothesis is a term coined by Leigh Van Valen, in 1973,[1] in a reference to the Lewis Carroll book Through the Looking Glass and refers in evolution theory to the arms race of evolutionary developments and counter-developments that cause co-evolving species to mutually drive each other to adapt. There is dispute over how strongly evolution at the scale of speciation is driven by these competitions between species, and how much it is driven instead by abiotic factors like meteor strikes and climate change, but there was not an artful metaphor to capture this alternative until one was coined by Anthony Barnosky. The term "Court Jester hypothesis" was coined by Anthony Barnosky in 1999 in reference to the Red Queen hypothesis.[2]
In a 2001 paper on the subject,[3] Barnosky uses the term without citation, suggesting that he is the one who coined it. Westfall and Millar attribute the term to him (citing the 2001 paper) in a paper of their own from 2004.[4] Michael Benton also credits Barnosky with coining the phrase.[1]
Since 2001, many researchers in evolution (such as Tracy Aze,[5] Anthony Barnosky, Michael J. Benton,[1] Douglas Erwin,[6] Thomas Ezard,[5] Sergey Gravilets,[7] J.B.C. Jackson,[6] Constance I. Millar,[4] Paul N. Pearson,[5] Andy Purvis,[5] Robert D. Westfall,[4] and Constance I. Millar[4]) have all started to use the term "Court Jester hypothesis" to describe the view that evolution at a macro scale is driven by abiotic factors more than the biotic competition called the Red Queen hypothesis. The Court Jester hypothesis is a term that has largely replaced many of the earlier names for this general concept in the scientific literature.
The Court Jester hypothesis builds upon the punctuated equalibrium theory of Stephen Gould (1972)[8] by providing a primary mechanism for it.[3] The 2001 paper by Barnosky that is one of the first to use the term appropriates for the Court Jester side of the debate: the Stability hypothesis of Stenseth and Maynard Smith (1984), Vrba's Habitat Theory (1992), Vrba's Turn-over pulse hypothesis (1985), Vrba's Traffic light hypothesis and Relay Model (1995), Gould's Tiers of Time (1985), Brett and Baird's Coordinated Statis (1995), and Graham and Lundelius' Coevolutionary Disequilibrium (1984) theories.[9]
Barnosky's 2001 paper that was one of the first to introduce the term,[3] explains what the Court Jester hypothesis means, describing it as one side of a debate over:
"[W]hether this march of morphology and species compositions through time, so well documented not only for mammals but throughout the fossil record, is more strongly influenced by interactions among species (Red Queen hypotheses), or by random perturbations to the physical environment such as climate change, tectonic events, or even bolide impacts that change the ground rules for the biota (Court Jester hypotheses). . . . A class of alternative ideas, here termed Court Jester hypotheses, share the basic tenet that changes in the physical environment rather than biotic interactions themselves are the initiators of major changes in organisms and ecosystems. . . . Court Jester hypotheses imply that events random in respect to the biota occasionally change the rules on the biotic playing field. Accelerated biotic response (relative to background rates) is the result."
Barnosky acknowledges in the 2001 paper[3] that the Court Jester hypothesis is not necessary inconsistent with the Red Queen hypothesis:
"Indeed, as Ned Johnson remarked (after listening to a lecture expressing these ideas), ‘‘Maybe it is time for the Court Jester to marry the Red Queen.’’ That is, perhaps the dichotomy between the two hypotheses is really a dichotomy of scale, and that as we look for ways to travel across biological levels, we will find ways to resolve the dichotomies."
Despite the fact that the Court Jester metaphor is coined in reference to the Red Queen hypothesis, the Jester reference, metaphorically, is not a direct reference to Through The Looking Glass, the Lewis Carroll book from which the Red Queen metaphor is derived, or his companion book about Alice, Alice in Wonderland. There is no Court Jester in either book.
Instead, the term plays on the notion of both a Queen and a Jester historically both being part of a royal court.
The Court Jester metaphor uses the term "Court Jester" in the sense of its meaning in the Tarot, where the Jester or Fool is the symbol of death triumphing over all. As the Wikipedia entry on the term Jester explains, this card "includes a man (or less often, a woman) juggling unconcernedly or otherwise distracted, with a dog (sometimes cat) at his heels. The fool is in the act of unknowingly walking off the edge of a cliff, precipice or other high place. Another Tarot character is Death. In the Middle Ages, Death is often shown in Jester's garb because "The last laugh is reserved for death." Also, Death humbles everyone just as jesters make fun of everyone regardless of standing."
Additionally, the Court Jester terminology metaphorically implicates the Joker card in a deck of cards that can upset the settled order and the related notion that a Court Jester is a disinterested player that has no stake or interests in the impact of his actions on any of the competing parties (since this theory posits a natural, random, abiotic cause). As the Wikipedia article on the Jester explains:
"The position of the Joker playing card, as a wild card which has no fixed place in the hierarchy of King, Queen, Knave, etc. might be a remnant of the position of the court jester. This lack of any place in the hierarchy meant Kings could trust the counsel of the jesters, as they had no vested interest in any region, estate or church."
Thus, the Court Jester hypothesis posits that all living things are overcome when they go extinct as a result of the random intervention of an abiotic outsider (the Jester) who is not a party to their Red Queen hypothesis struggles, upsetting the old status quo and opening the door for a spurt of rapid adaptive macroevolution.