Topic: Rapid evolution?

[Nemesis]

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"As a result, individuals on Pod Mrcaru have heads that are longer, wider and taller than those on Pod Kopiste, which translates into a big increase in bite force," observes Irschick. "Because plants are tough and fibrous, high bite forces allow the lizards to crop smaller pieces from plants, which can help them break down the indigestible cell walls."

These lizards' physical changes also included the unexpected presence of a special subset of muscles in the intestines, known as caecal valves. These valves, which slow the movement of food by creating fermenting chambers in the gut, is the most dramatic morphological change shown by these lizards;

In contrast, less than 1% of all lizard species have caecal valves in their intestines.

Intestinal fermenting chambers provide a home for microorganisms that break down cellulose into volatile fatty acids that the lizards can utilize, so these chambers are only present in animals that consume plants. Additionally, the researchers also found that the hindguts of the translocated lizards contained nematodes, whereas they were absent from the hindguts of the parental population.

Evolutionary changes of significance in only 36 years or just 18 generations.