The evolution of snails was in the news last month. Starting then, scientists from the Open University’s Evolution MegaLab project have sought grassroots support in learning how Europe’s banded snail populations have changed.
Garden snails are evolving slower metabolisms.
The snail evolution study this week comes from scientists in South America. Researchers Roberto Nespolo and Paulina Artacho of the Southern University of Chile report in the journal Evolution that they have discovered that garden snails are evolving slower metabolisms.
In the experiment, the researchers first assessed the size and metabolic rate of around 100 specimens of Helix aspersa. Seven months later, they gathered the same specimens (including the empty shells of those that had died) from the enclosures where the snails were kept. While there was no significant correlation between size and survival, the snails that survived had a metabolic rate 20 percent lower than the snails that didn’t make it.
The scientists believe natural selection favors snails with slower metabolic rates because those snails “have more energy to spend on other activities such as growth or reproduction,” reports BBC News. This is the first study in a series of attempts to demonstrate a significant positive correlation between natural selection and lower metabolism.
While this study does demonstrate natural selection in action (presuming the metabolism–survival link is confirmed in other studies), it demonstrates “evolution” only in the sense of “changes in the characteristics of a population over time,” offering no support for molecules-to-man evolution.
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