Gap junctions are tunnel like junctions that can occur anywhere along the lateral membranes of adjacent cells. They allow ions and small molecules to pass to one cell to the next for inter-cellular communication.
They function by allowing the exchange of ions, second messengers, and small metabolites between adjacent cells and are formed by two unrelated protein families, the pannexins and connexins.The protein channels that make up gap junctions consist of two connexons. One connexon resides in the membrane of one cell.
are found along the zigzag line on the periodic table. The only exception is Aluminum. It is considered to be a metal even though it lies along the zigzag.
emigration would theoretically reduce the genetic variation as unique individuals leave, but immigration would bring unique traits into circulation in an ecosystem.
I'm not super great at biogy tho so this might not be right... :)