If we compare, for instance, the number of endemic land-shells in Madeira, or of endemic birds in the Galapagos Archipelago, with the number found on any continent, and then compare the area of the island with that of the continent, we shall see that this is true.
Baldin, adibidez, konparatzen badugu Madeira irlako lehorreko molusku endemikoen kopurua, edo Galapagoak artxipelagoko txori endemikoen kopurua, edozein kontintetan topatzen dugun kopuruarekin, eta gero irlako arloa kontinentekoarekin konparatzen badugu, hau egia dela ikusiko dugu.