Humans drive evolution of conch size

Prehistoric fighting conch Strombus puglis (L) and modern shells of the same species (R) show how the shellfish has decreased in size over time. Credit: Smithsonian Tropical Research Institute/Courtesy of Aaron O'Dea

The first humans to pluck a Caribbean fighting conch from the shallow lagoons of Panama's Bocas del Toro were in for a good meal. Smithsonian scientists found that 7,000 years ago, this common marine shellfish contained 66 percent more meat than its descendants do today. Because of persistent harvesting of the largest conchs, it became advantageous for the animal to mature at a smaller size, resulting in evolutionary change.

Human-driven evolution of wild animals, sometimes referred to as "unnatural selection," has only previously been documented under scenarios of high-intensity harvesting, like industrialized fishing. "These are the first evidence that low-intensity harvesting has been sufficient to drive evolution," said lead author Aaron O'Dea of the Smithsonian Tropical Research Institute. "The reason may be because the conch has been subjected to harvesting for a long period of time." Published March 19 in Proceedings of the Royal Society B, the findings are based on a comparison of mature shell sizes prior to human settlement, from shells excavated from human trash heaps representing various points in the last few thousand years and from modern sites.[...] eurekalert.org/


Actualización 20-03-14. Hasta la evolución en el tamaño de las conchas marinas ha sido afectada por los humanos
Hace 7 mil años las conchas marinas tenían 66 por ciento más carne que sus actuales descendientes
¿Qué les pasó? Se convirtieron en alimento favorito de los humanos. Aaron O'Dea, del Smithsonian Tropical Research Institute, determina que debido a la constante extracción de los caracoles más grandes, comenzaron a presentar menor tamaño...