Read the following statement. 'A passenger traveling in air plane pops a rivet in seat and takes it to home.' What does it mean according to Rivet popper hypothesis?

Stanford ecologist Paul Ehrlich proposed Rivet Popper Hypothesis. In an airplane (ecosystem) all parts are joined together using thousands of rivets (species). If every passenger traveling in it starts popping a rivet to take home (causing a species to become extinct), it may not affect flight safety (proper functioning of the ecosystem) initially, but as more and more rivets are removed, the plane becomes dangerously weak over a period of time. Furthermore, which rivet is removed may also be critical. Loss of rivets on the wings (key species that drive major ecosystem functions) is obviously a more serious threat to flight safety than loss of a few rivets on the seats or windows inside the plane.

A seat rivet is any species but rivet in wing is key species. Popping a seat rivet may not pose threat to flight safety meaning it is not key species.