Alfred Wegener is the scientist known for the concept of continental drift in geology. In the early 20th century, he proposed that continents were once part of a single landmass, which he called Pangaea, that gradually drifted apart over millions of years. His ideas, published in his 1912 work "The Origin of Continents and Oceans," challenged existing geological theories. Although initially met with skepticism, Wegener's theory laid the groundwork for modern plate tectonics, profoundly influencing geological and geographical sciences.