Final answer:
Continents can disappear due to subduction, where a tectonic plate moves under another and melts, and due to erosion and sedimentation. Alfred Wegener proposed continental drift supported by the fit of continents, fossil evidence, and paleoclimate data. These principles are now understood through the theory of plate tectonics.
Step-by-step explanation:
The supercontinent Pangaea formed when all the major land masses collided to create a single large landmass, encompassing today's continents. However, through the process of continental drift, sometimes pieces of continents can disappear. This can occur due to several geological processes, including subduction, where one tectonic plate moves under another and is forced into the mantle where it melts. Additionally, erosion and sedimentary processes can wear down landmasses, and changes in sea level can submerge or reveal different parts of continents.
Continental drift was first proposed by Alfred Wegener, which he supported with evidence such as the jigsaw-like fit of continents, the presence of similar fossils and mountain ranges on continents now separated by oceans, and paleoclimate data suggesting past proximities to the poles or the equator. Wegener's idea was eventually expanded into the widely accepted theory of plate tectonics, which explains how continents move and how supercontinents like Pangaea form and break apart.