20 million years ago, a land bridge emerged in what now comprises the Arabian Peninsula and Anatolia, connecting Africa with Asia and Europe, after a 75 million-year isolation.
This geological event, analyzed in a recent study published in Nature Reviews Earth & Environment, reveals how the processes of the Earth’s mantle drove the migration of ancestors of elephants, giraffes, and humans, altering the course of evolution.
Formation of the land bridge
The origin of this connection dates back to 50-60 million years ago, when a rock plate slid into the Earth’s mantle, creating a flow of hot rocks resembling a conveyor belt.
This activity, along with the collision of tectonic plates, raised the land and led to the closure of the ancient Tethys Sea, giving rise to the Mediterranean Sea and the Arabian Sea, while uniting Asia with Africa.
Impact on the evolution of various species
According to the lead author of the study, Eivind Straume, the appearance of the land bridge was directly related to the evolutionary development of different species, including ancestors of modern humans.
The primate ancestors of humans arrived in Africa from Asia millions of years before the complete formation of the bridge. Although they became extinct in Asia, these primates managed to diversify in Africa and later recolonize Asia once the land connection was fully established.
Climatic and oceanographic consequences
In addition to its impact on animal migration, the uplift of the Arabian Peninsula altered ocean circulation and global climate.
These changes caused:
- Increase in ocean temperatures in nearby areas.
- Greater seasonal variability, intensifying temperature contrasts.
- Increased aridity from northern Africa to central Asia.
- Intensification of monsoons in Asia, increasing humidity in southeast Asia.
- Contribution to the formation of the Sahara Desert.
This geological event, besides altering climate and ecosystems, had a key impact on species evolution and the history of life on Earth.
