Fish Evolution Accelerated After Adapting to Eat off Hard Surfaces
50 Million Years Ago, A Sudden Burst of Evolution Among Reef and Bottom-Dwelling Fish Led to New and Diverse Species
Why are there so many species of coral reef fish? According to a new study, it’s because about 50 million years ago, some fish figured out how to bite food from hard surfaces.
Evolution doesn’t proceed at an even pace—species evolve in jumps and spurts, followed by lulls. These periods of rapid diversification usually occur after a dramatic environmental change or upheaval, or when a lineage develops a new “innovation” that allows them to use a previously inaccessible resource. For fish, the ability to feed from a hard surface was one such innovation.
In a study published April 13 in Proceedings of the National Academy of Sciences, University of California, Davis researchers show that, after some fish lineages acquired the ability to bite food from hard surfaces, the pace of diversification increased by 1.5-1.7 times for fish living in coral reefs and at the bottom of freshwater lakes and rivers, where there are ample surfaces from which to scrape algae, snails, and shellfish. In contrast, evolution proceeded more steadily for fish living higher in the water column, where there are no hard surfaces to feed from.