Answer:
The scientist whose observations eventually led to the theory of continental drift is Alfred Wegener. He noticed that the coastlines of Africa and South America seemed to fit together like puzzle pieces, and he also observed similar rock formations and fossil evidence on both continents.
Wegener's observations led him to propose the theory of continental drift in the early 20th century. According to this theory, the continents were once connected in a supercontinent called Pangaea, and over time, they gradually drifted apart to their current positions.
Wegener's theory was met with skepticism initially because he couldn't provide a mechanism for how the continents moved. It wasn't until the 1960s that the theory gained widespread acceptance with the discovery of seafloor spreading and the development of the theory of plate tectonics.
Seafloor spreading refers to the process where new oceanic crust is formed at mid-ocean ridges and spreads outwards, pushing the older crust aside. This discovery provided the mechanism for how continents could move.
The theory of plate tectonics combines the ideas of continental drift and seafloor spreading. It states that the Earth's lithosphere, which consists of several large and small plates, is constantly moving and interacting with each other. These interactions can result in the formation of mountains, earthquakes, and volcanic activity.
In summary, Alfred Wegener's observations of the similarities between continents and the idea of continental drift eventually led to the development of the theory of plate tectonics. This theory explains how the Earth's lithosphere is divided into plates that move and interact with each other, causing various geological phenomena.