When debates get “heated, “emotions increase and tempers flare. Sometimes these debates go our way, while other times we come to the harsh realization that we – not our opponent – were in the wrong. Each of us presents our side of the argument, usually with the intention of convincing the other person (or people) that our stance is the correct one. Anyone who’s a Star Wars fanboy or general comic geek is well aware of this. Today, inspired by The School of Thought’s awesome Critical Thinking Cards and poster, paranormal investigator Kenny Biddle takes a look at the logical fallacies he runs into when discussing his work. Every day this month we’ll be highlighting skepticism in pop culture and skepticism of pop culture. While the red herring title sells manuscripts well, we suggest being careful with its use, and reserving it only for extreme cases since red herrings may turn pink, as happened to the autumn leaf color co-evolutionary hypothesis.Every February, to help celebrate Darwin Day, the Science section of AIPT cranks up the critical thinking for SKEPTICISM MONTH! Skepticism is an approach to evaluating claims that emphasizes evidence and applies the tools of science. There are cases like the phenomenon of colorful autumn leaves in which hot debates just indicate that the biological situation is so complicated that all sides involved in the argument don't fully understand it or naively think that a specific adaptation in a species or even a group of species they know very well applies to all other species. A red herring tag can be very helpful in promoting better research because it intrigues scientists, but may also sometimes unnecessarily put an end to or block a correct innovative hypothesis for decades. Skepticism is essential for good science, but skeptics should also take their own skeptical ideas with a grain of salt. 29 Again, there was no reason to tag the co-evolutionary hypothesis as a red herring on this unfounded or anecdotal basis.
Sometimes, red leaves in a generally yellow tree reflect dying branches, as in the case of Norway maple Acer plantoides. For instance, in Sorbus aucuparia, branches of an individual may have leaves turning from green to red, while in other branches green leaves turn to yellow and both leaf types may eventually turn brown.
White's 9 statement is simply unfounded as the situation of changing autumn leaf color from green to yellow and later to red is a very rare situation, usually found in individual leaves or individual ornamental trees, and was never well documented even for the rare cases when it happens. 27, 28 White, 9 however, erroneously posited that leaves turn red after they were yellow and his logic argument (based on wrong assumptions) was that when the leaves turn red they have already lost their nitrogen and there is no need for signaling at that late stage of leaf life.
12, 27, 28 Very few species shed green or brown leaves. 27 In a much smaller number of species the leaves change color from green to red. The real facts are that in most species the color of autumn leaves changes from green to yellow. The red-herring tag in White 9 is based on a mistake in understanding the basic facts of autumn leaf coloration. This welcome change (reflecting a decade of scientific effort and progress in this issue) seems to clean the major red-herring tag from this hypothesis. While Schaefer was the most critical figure toward the autumn leaf co-evolution hypothesis, e.g., 8, 21 - 26 recently, as a co-author in the very important book about plant-animal signaling 14 the tone in an elegant review and analysis of the issue in this book is dramatically more moderate. 11 - 14 Following the clear evidence that many aphids are attracted to yellow leaves rather than repelled by them 15 - 19 it is now broadly recognized that yellow and red autumn leaves have a different biology including cuing/signaling to herbivorous insects, and that focusing on the differences between yellow and red autumn leaves may better explain the very complicated and multi-adaptive autumn leaf color phenomenon. 8, 9 While the co-evolutionary hypothesis certainly does not explain all the aspects of the very complicated and taxonomically and geographically diverse phenomenon of red and yellow autumn leaves, e.g., 10, 11 it seems to explain part of this very broad and diverse phenomenon. A recent plant signaling hypothesis of the co-evolution of red and yellow autumn leaves positing that bright autumn leaf colors signal herbivores, especially aphids, about the defensive qualities of the trees 5 - 7 (also known as the “leaf signal theory”) 8 that has been hotly discussed since its publication, was awarded two red herrings.
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