Problem: Over the past 430 million years the land area on Earth has shifted from: Week 5 questions, below relating to Tectonics and Paleozoic/Mesozoic Biogeography: Over the past 430 million years the land area on Earth has shifted from: being more in the northern hemisphere to more in the southern hemisphere. greater areas east of the prime meridian (0 degree longitude) to more in the western areas. the equatorial regions to both poles and back again being more in the southern hemisphere to more in the northern hemisphere.