Earth's mantle activity played a crucial role in human evolution

A significant geological event occurred between 35 to 20 million years ago, significantly affecting the relationship between Africa and Asia. Researchers investigated how uplift caused by the activity in Earth's mantle allowed the birth of a land bridge connecting these continents. This geologic activity played a pivotal role in the migration of early ancestors of various species, including human ancestors, out of Africa, effectively ending a 75-million-year isolation of the continent. Such events shaped evolutionary pathways and animal distributions across the continents. The study, led by Eivind Straume at the University of Texas, highlighted how these changes in land formations influenced not only animal migratory patterns but also Earth's climate and oceanic systems. The geological changes included the melting of a rock slab in the Earth’s mantle, which created a mantle plume that surfaced around 30 million years post-formation. This uplift was further propelled by the collision of tectonic plates between Africa and Asia. The convergence led to the closure of the ancient Tethys Sea, splitting it into the modern Mediterranean and Arabian Seas. The emergence of the land bridge enabled flora and fauna, including the primate ancestors of humans, to migrate between the continents, facilitating a vital evolutionary shift. The initial movement from Asia to Africa introduced new primate lineages that diversified in Africa, although the original migrants perished in Asia. As the land bridge formed and closed over the following millions of years, early hominids began to leave Africa, which caused a cascade of ecological and climatic changes. The closing of the Tethys Sea altered ocean circulation significantly, resulting in a warmer Indian Ocean and contributing to the changes in climate in Eastern Africa. This climate shift, marked by aridity, played a definitive role in transforming the Sahara into a desert, possibly forcing hominids out of Africa between 10 to 7 million years ago. The researchers posited that without these geological events in the mantle, the evolutionary pathways for species, including humans, could have been vastly different. The increased monsoon activity that resulted from these changes made Southeast Asia a more hospitable environment for migratory species. This research emphasizes the interconnectedness of geological processes and biological evolution, offering insights into the broader question of how tectonic activity relates to life on Earth.