A type of small snail is very widespread in japan, and colonies of the snails that are genetically similar have been found very far apart. scientists wondered how the snails could travel such long distances. a recent study1 provides the answer. biologist shinichiro wada fed live snails to birds and found that of the snails were excreted live out the other end. the snails apparently are able to seal their shells shut to keep the digestive fluids from getting in.

The images show two species of tree frogs in a particular region. the gray tree frogs are adapted to the trees of the woodlands, while the green tree frogs can survive in woodlands or grasslands. the gray frog was abundant in the woodlands. because of climatic changes, most of the trees in the region died, and the woodlands changed to grasslands. in such a case, the . the gray tree frog is closely related to the green tree frog genetically, but they have different mating calls. this suggests that speciation occurred because of .