The isthmus and the Panama Canal were believed to be the physical barrier that separated groups of snapping shrimps 3 million years ago. In addition, one family of snapping shrimps that got separated is the Alpheidae which produces loud sound when it snaps its pincers.
Symbiotic bacteria are present in nodules of cereal plants such as wheat. Symbiotic bacteria are present in nodules of pod bearing plants such as peas, grams, etc.
