Why in the News?

A recent study confirms that Arabia wasn’t always a desert wall but occasionally a green bridge between continents.

About the Green Arabia Hypothesis:

Core Idea: It suggests that the Arabian Peninsula, now one of the driest places on Earth, experienced multiple humid phases over the past 8 million years, turning it into a green corridor for early migrations.
Challenge to Old Views: This theory challenges traditional models that excluded Arabia from early human dispersal routes in the ‘Out of Africa’ narrative.
Fossil Evidence: The discovery of fossils of crocodiles, hippos, and horses, dating up to 74,000 years ago, supports the claim that Arabia was once lush and habitable.

Archaeological Sites: Over 10,000 ancient lakebeds and sites over 500,000 years old were found, confirming Arabia’s role as a migration bridge between Africa and Eurasia.
Speleothem Analysis: 22 speleothem samples (mineral deposits formed within caves) from seven Saudi caves indicated humid phases between 7.44 million and 60,000 years ago.
Dating Techniques: Scientists used uranium-thorium dating to accurately time wet periods, revealing patterns linked to monsoon shifts and glacial cycles.
Environmental Impact: These wet intervals, though brief, supported vegetation, biodiversity, and water bodies, enabling human and animal settlements.

Biogeographic Role: Arabia is now viewed as a climate-sensitive migratory bridge, not a barrier, in human evolution and dispersal.
Climate Dependency: Human movement was influenced not just by geography, but by shifts in rainfall patterns and monsoonal activity.
Key Locations: Sites like Jubbah Oasis provided stone tools and lakebed evidence, validating early human habitation in the region.
Conclusion: Arabia’s periodic greening played a decisive role in early human migration, revising our understanding of ancient dispersal pathways out of Africa.

[UPSC 2014] Which of the following phenomena might have influenced the evolution of organisms?

1. Continental drift

2. Glacial cycles Select the correct answer using the code given below.

Options: (a) 1 only (b) 2 only (c) Both 1 and 2* (d) Neither 1 nor 2