Final answer:
The notion that Earth's continents were separate before Pangea is false. Pangea was a supercontinent that formed by amalgamating earlier landmasses, and its existence is key to understanding the shared geological and biological history of the continents. This understanding comes from the theory of plate tectonics and evidence like fossil distribution.
Step-by-step explanation:
The statement that Earth's continents existed largely as separate land masses prior to the existence of the supercontinent Pangea is false. Pangea was a supercontinent that included almost all of Earth's continental crust and existed from approximately 300 to 200 million years ago (Ma). Before Pangea, the continents were not separate as they are today. In fact, they were previously joined together in other supercontinents such as Rodinia and Gondwana. The concept of Pangea was proposed by Alfred Wegener in 1915, based on evidence from the fit of the continents, matching fossils, mountain ranges, and paleoclimate data, suggesting all continents were once combined into a single landmass.
Wegener's hypothesis of continental drift later evolved into the widely accepted theory of plate tectonics, which explains the movement of Earth's lithospheric plates and the formation and breakup of supercontinents. The presence of similar plants and animals across continents that are now separated by vast oceans, like the Proteaceae family found in Australia, southern Africa, and South America, is indicative of their shared origin on the supercontinent Gondwana, which constituted the southern part of Pangea.
Overall, the creation of Pangea was a significant event in Earth's geological history, leading to extreme temperatures, a dry climate, and significant evolutionary adaptations among plants and animals. The supercontinent eventually broke apart due to the continuous movement of tectonic plates, resulting in the distribution of land masses we recognize today.