Founder’s Briefs: An occasional series where Mongabay’s founder Rhett Ayers Butler shares analysis, perspectives, and story summaries. Elisabeth Vrba did not set out to overturn the way scientists understood evolution. But her relentless inquiry, guided by a keen mathematical mind and a sharp eye for patterns in the fossil record, challenged some of Darwin’s most sacrosanct ideas. In a field where slow, incremental change had long been the reigning orthodoxy, she made the case that evolution moved in bursts — abrupt waves of extinction and speciation triggered by climatic upheaval. Her “Turnover Pulse” hypothesis became one of the most influential, and contentious, contributions to evolutionary biology in the past half-century. Born in Hamburg, she moved to what is now Namibia as a child. The stark landscapes of her new home seemed an apt setting for the questions that would later define her career. She studied zoology and mathematical statistics before turning her focus to fossil antelopes, which provided the raw material for her boldest ideas. Vrba’s great insight was that extinctions and originations of species were not random, nor the result of gradual competition between individuals, as Darwin had proposed. Rather, they were shaped by environmental changes, particularly shifts in climate. She noticed that some lineages remained remarkably stable, while others proliferated in fits and starts. The difference, she argued, was in their ecological flexibility. Generalists, with broad diets and adaptable habits, could ride out environmental changes. Specialists, attuned to narrow ecological niches, were more vulnerable — flourishing in one…This article was originally published on Mongabay
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