Friday, 11 June 2021

How Science Works - Falsifying a Theory and Running Rings Around Creationism

Drone image of the fairy circles and a lonesome tree in the Giribes Plains. Hundreds of thousands of fairy circles occur in the Giribes without any Euphorbia damarana in the vicinity. These typical fairy circles of the Giribes have a regular pattern, mostly with an extraordinary degree of spatial ordering. By contrast, euphorbias in the isolated location where Theron marked the shrubs had an opposite clustered pattern, which cannot explain the origin of the regularly distributed fairy circles.
Photo credit: S Getzin, University of Göttingen
Origin of fairy circles: Euphorbia hypothesis disproved - Georg-August-Universität Göttingen

The great thing about science, and what gives it its power as the tool for discovering the truth, is that it has self-correction built in, and every properly-constructed theory is falsifiable. In this example, we see a theory proposed back in 1979 to explain the phenomenon of the 'fairy rings' of Namibia being systematically falsified by observations which could not be true if the theory is correct.

The 'fairy rings' of Namibia is a vast area on the edge of the Namib dessert in which there is a pattern of regularly-spaced circles of barren soil occurring in an essentially mono-specific grassland.

In 1979 a South African botanist, G.K. Theron, published a theory that the circles were caused by toxins in the decaying leaves of the plant Euphorbia damarana. This theory has now been falsified by researchers led by scientists from Göttingen University, as the Göttingen University news release explains:
A vital Euphorbia damarana shrub growing at the edge of a much larger fairy circle in the Brandberg region. The size distribution of the dead shrubs did not match the sizes of the fairy circles in the study.
Photo credit: S Getzin, University of Göttingen
As part of a new study, scientists from the University of Göttingen and the Gobabeb Namib Research Institute located the original euphorbia plants that were part of Theron’s study. Four decades later, the researchers are now able to conclusively disprove Theron’s original hypothesis. Their results were published in the journal BMC Ecology and Evolution.


As part of the current study, scientists went back to this same area and managed to locate the original metal pins that marked the plants. In 2020, the research team documented these remote sites in detail for the first time, using ground-based
A decaying Euphorbia damarana shrub that was marked by G.K. Theron more than four decades ago. Many large grasses were growing around the metal pin.
Photo Credit: S Getzin, University of Göttingen
photography as well as high-resolution drone imagery and historic satellite images. The researchers show that none of the marked euphorbia locations developed into a fairy circle. Instead, long-lived grass tussocks were growing around all the metal pins. This runs contrary to the hypothesis that poisons from euphorbia inhibited the growth of other plants because these grasses survived. Given that the euphorbia hypothesis proposes that only dead and decaying shrubs would induce a barren patch, the researchers also measured the sizes of the dying euphorbias and compared them to the sizes of fairy circles in the same study plots. As well as in Giribes, this
A georeferenced drone image of four decaying Euphorbia damarana that were marked by Theron. None of these euphorbia locations developed into a fairy circle over time. The dark spots in the image also show some living euphorbia shrubs, and the barren patches are the much larger fairy circles around them.
Photo credit: S Getzin, University of Göttingen
second part of the study was also carried out at Brandberg. In both regions, the diameters of decaying euphorbias could not explain the sizes of the much smaller or the larger fairy circles. In a third part of the study, the spatial patterns of the fairy circles were directly compared to the patterns of euphorbias within the same areas to investigate a potential link between both distributions in the regions Giribes, Brandberg and Garub. However, the patterns of shrubs and circles did not match: in four out of five plots the patterns differed significantly, with the circles being regularly distributed while the euphorbias were predominantly clustered. Hence the process that creates the pattern of fairy circles is different from the process that creates the pattern of the euphorbias.
The team's findings are published in the journal BMC Ecology and Evolution:
When Theron published his original euphorbia hypothesis more than four decades ago, he was a pioneer in fairy-circle research: almost nothing was known about them at that time. Today, however, we see the long-term outcome of his early experiment and – based on our detailed field observations – we have to reject the euphorbia hypothesis.

Disproving hypotheses about the origin of fairy circles is an important step in solving their mystery because it helps advance our scientific understanding. It enables us to identify more probable mechanisms which explain these stunning formations as well as other fascinating biological phenomena. [My emphasis]

Dr Stephan Getzin, Lead author
Department of Ecosystem Modelling
Georg-August-Universität Göttingen, Germany.

The Euphorbia hypothesis on the origin of fairy circles (FCs) in Namibia dates back to 1979. It proposes that the remains of decaying shrubs would induce an allelopathic interaction with the grasses and thereby cause bare-soil FCs. Here, we investigated this hypothesis based on revisiting marked Euphorbias after four decades, comparing the typical size distribution of dead Euphorbia damarana and FCs, and analyzing the spatial patterns of Euphorbias and FCs within the same drone-mapped study plots in three regions of Namibia.

We found four dead Euphorbias in the southern Giribes that were marked by G.K. Theron about 40 years ago. Those locations did not develop into FCs over this time span. However, for the four dead Euphorbias, we provide photographic evidence that grass tufts were growing at the metal pins of those decaying shrubs, agreeing with previous research findings that the soil taken from beneath dead E. damarana shrubs was stimulating rather than inhibiting the growth of grasses. In the Giribes, there were very large FCs that ranged in diameter from 13.0 to 19.1 m. By contrast, the measured dead E. damarana, including the largest plants that we could find, ranged in size only between 4.2 and 11.7 m. At Brandberg, we found particularly small FCs with diameters between 2.4 and 2.7 m but the dead E. damarana, including the smallest dead shrubs in the area, ranged in size between 4.1 and 7.2 m. Hence given these size mismatches, the decaying Euphorbias cannot induce such observed FCs in the two regions. Spatial patterns of E. damarana and FCs in the two regions Giribes and Brandberg, as well as of E. gummifera and FCs near Garub, showed a strong mismatch within the same habitat: in four out of five plots the patterns differed significantly. FCs were regularly distributed while Euphorbias were predominantly clustered.

We reject the Euphorbia hypothesis based on the fact that grass growth was not prevented under decaying shrubs, the size of dead Euphorbias cannot explain the size of observed FCs and the spatial distribution of Euphorbias cannot cause the specific pattern signature of FCs.

But, an alternative explanation for these rings was provided by a international team who showed in 2016 that a similar pattern of rings found in Western Australia is due to a self-organizing system of interaction between biomass and water resource in an arid environment. In their explanation of its significance, that team said:
Pattern-formation theory predicts that vegetation gap patterns, such as the fairy circles of Namibia, emerge through the action of pattern-forming biomass–water feedbacks and that such patterns should be found elsewhere in water-limited systems around the world. We report here the exciting discovery of fairy-circle patterns in the remote outback of Australia. Using fieldwork, remote sensing, spatial pattern analysis, mathematical modeling, and pattern-formation theory we show that the Australian gap patterns share with their Namibian counterparts the same characteristics but are driven by a different biomass–water feedback. These observations are in line with a central universality principle of pattern-formation theory and support the applicability of this theory to wider contexts of spatial self-organization in ecology.
In other words, supernatural explanation are not required to account for these structural organizations out of the chaos of plant growth, water availability and soil conditions because, in the right conditions, order spontaneously emerges from chaos. The task of science is to explain how this occurs naturally and without magic.

So, what has this got to do with Creationism and Creationists?

As I said at the time of the 2016 study:
The two sacred chants of the creation industry are, "You can't get order from chaos, so order implies design!" and "Design needs a designer!" They are careful always to avoid saying 'biblical god' instead of 'designer' because they still like to pretend people don't know this is fundamentalist biblical creationism masquerading as science, of course.
In this example then we have a vindication of the scientific method as the best way to discover the truth, together with a refutation of one of Creationism's sacred dogmas. Order is not only possible from chaos but inevitable in the right conditions due to the operations of basic laws of chemistry and physics.

And you can be sure that Creationist frauds will ignore the evidence and continue to fool their credulous victims with this falsehood. You can also be sure that Creationist dupes will continue to cooperate wirh their own deception by ignoring the same evidence and failing to fact check their cult leaders' lies.

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