Court Jester Hypothesis

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 that biotic competition between species, is a major driving force behind the processes in evolution that produce speciation.

History

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.

Content of Theory

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 Disequalibrium (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."

Metaphorical Reference

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.

References

1. ^ ^{a b c} Michael J. Benton, "The Red Queen and the Court Jester: Species Diversity and the Role of Biotic and Abiotic Factors Through Time", Science 6 February 2009: Vol. 323 no. 5915 pp. 728-732 DOI: 10.1126/science.1157719
2. ^ Anthony Barnosky, "Does evolution dance to the Red Queen or the Court Jester?", 3 Annual Meeting of the Society of Vertebrate Paleontology USA (1999).
3. ^ ^{a b c d} Anthony Barnosky, "Distinguishing The Effects Of The Red Queen And Court Jester On Miocene Mammal Evolution In The Northern Rocky Mountains" Journal of Vertebrate Paleontology 21(1):172–185, March 2001 http://www.ucmp.berkeley.edu/miomap/RESULTS-MIOMAP/barnoskyjvp2001.pdf
4. ^ ^{a b c d} Robert D. Westfall and Constance I. Millar, "Genetic consequences of forest population dynamics influenced by historic climatic variability in the western USA" Forest Ecology and Management 197 (2004) 159–170. http://www.fs.fed.us/psw/publications/westfall/Westfall%20&%20Millar%2004.pdf
5. ^ ^{a b c d} Thomas H. G. Ezard, Tracy Aze, Paul N. Pearson, and Andy Purvis, "Interplay Between Changing Climate and Species’ Ecology Drives Macroevolutionary Dynamics", Science 15 April 2011: Vol. 332 no. 6027 pp. 349-351 DOI: 10.1126/science.1203060
6. ^ ^{a b} Jeremy B.C. Jackson and Douglas H. Erwin, "What can we learn about ecology and evolution from the fossil record?" Trends in Ecology and Evolution)
7. ^ Sergey Gavrilets, et al., "Adaptive Radiation: Contrasting Theory with Data",Science 6 February 2009: 732-737.DOI:10.1126/science.1157966
8. ^ Eldredge, Niles and S. J. Gould (1972). "Punctuated equilibria: an alternative to phyletic gradualism" In T.J.M. Schopf, ed., Models in Paleobiology. San Francisco: Freeman Cooper. pp. 82-115. Reprinted in N. Eldredge Time frames. Princeton: Princeton Univ. Press, 1985.
9. ^ Anthony Barnosky, "Distinguishing The Effects Of The Red Queen And Court Jester On Miocene Mammal Evolution In The Northern Rocky Mountains" Journal of Vertebrate Paleontology 21(1):172–185 at Table 1, March 2001 http://www.ucmp.berkeley.edu/miomap/RESULTS-MIOMAP/barnoskyjvp2001.pdf