Question

How are plate tectonics and continental drift similar?

Answer 1

They are basically the same theory. Continental drift the older theory and plate tectonics the more modern theory

Explanation:

Continental Drift as proposed by Alfred Wegener was theory that all of the continents had once been connected as part of a super continent he called Pangea. Then some ( at the time ) unknown force spilt the super continent into pieces forming the presently observed continents.

Wegener had sufficient evidence from glaciers, fossils, matching coast lines, and geological strata to prove his point. However his theory contradicted the prevailing theories of biological evolutions timeline and geological column, the geosyncline mountain, and sedimentary layer formation, uniform processes in geology, (uniformtarism) His theory postulated a recent rapid separation of the continents. His theory lacked a mechanism or force that could account for the rapid movement of the massive continents.

Plate tectonics is Wegener theory of continental drift reworked. The force needed to move the continents is proposed to be convection currents in the mantle. Geologist have a much better understanding the structure of the earth, in terms of the crust, and mantle than was available in Wegener's time. The rate of expansion of the continents has been modified to not offend the idea of slow uniform processes. The evolutionary timeline and geological record has been modified also to better correlate with the geological evidence of the separation of the continents. The continents are seen as part of large plates of crust that are moved by the convection currents in the mantle.

During World War II submarine warfare revealed the existence of the mid ocean ridges, The symmetric magnetic bands radiating from the mid ocean ridges gave further evidence for the idea of Continental Drift. Subsequent studies of rift valleys gave proof that the crust in the rift valleys was separating and spreading apart. Given the new evidence scientists had to reexamine Wegener's Theory. The examination of the evidence gave birth to the theory of plate tectonics in place of Wegener's theory of Continental Drift.
Even so some evolutionary scientists like Gaylord Simpson continued to oppose the theory of plate tectonics, into the 1970s as being contradictory to the theory of Darwinian Evolution.