A new study led by the University of Kansas might resolve a mystery in the “aging process” in “Red Queen theory” among researchers.
Revisiting the Red Queen Theory
“The Red Queen theory is that species have to keep running just to stay still, like the character in Lewis Carroll’s book ‘Through the Looking-Glass,’” said lead author James Saulsbury, a postdoctoral researcher in the Department of Ecology & Evolutionary Biology at KU. “This idea was turned into a kind of ecological theory in the 1970s in an attempt to explain an observation that extinction risk didn’t seem to change over the lifespan of species.”
Yet the years have not been kind to this theory.
“In the earliest investigations of this phenomenon, species of all ages seemed to go extinct at about the same rate, perhaps just because of the relative crudeness of the evidence available at the time,” Saulsbury said. “This made sense under this Red Queen model, where species are constantly competing with other species that are also adapting alongside them.”
Questioning and Beyond the Red Queen
But as more data was collected and analyzed in more sophisticated ways, scientists increasingly found refutations of Red Queen theory.
“Scientists kept finding instances where young species are especially at risk of extinction,” Saulsbury said. “So we had a theory vacuum – a bunch of anomalous observations and no unified way of understanding them.”
But now, Saulsbury has led research appearing in the Proceedings of the National Academy of Sciences that may resolve this mystery. Saulsbury and his co-authors showed the relationship between a species’ age and its risk of going extinct could be accurately predicted by an ecological model called the “neutral theory of biodiversity.”
Neutral Theory’s Insights
Neutral theory is a simple model of ecologically similar species competing for limited resources, where the outcome for each species is more or less random.
In the theory, “Species either go extinct or expand from small initial population size to become less vulnerable to extinction, but they are always susceptible to being replaced by their competitors,” according to a lay summary of the PNAS paper. By extending this theory to make predictions for the fossil record, Saulsbury and colleagues found that neutral theory “predicts survivorship among fossil zooplankton with surprising DOI: 10.1073/pnas.2307629121