The article describes how a strong variation of the snail species "evolved" to a weak, degenerate version of the same species due to lack of predators. Could i

The article describes how a strong variation of the snail species "evolved" to a weak, degenerate version of the same species due to lack of predators. Could it have been lack of food as well? Humans got taller after having wide access to milk etc. How did they control the experiment, given that it was on a rock in the ocean? Could the smaller variation have come from somewhere else? Experiments like this one will not turn skeptics into even micro evolution believers.