TLDR: The Wallace Line in Indonesia: A Mysterious Biogeographic Divide Revealed by Alfred Russel Wallace, Showcasing Distinct Asian and Australian Fauna.
This article is a summary of a You Tube video “The Invisible Barrier Keeping Two Worlds Apart” by PBS Eons
Key Takeaways:
- Invisible Biogeographic Boundary: The Wallace Line, an invisible line between Bali and Lombok in Indonesia, represents a sharp biogeographic boundary.
- Distinct Wildlife on Either Side: To the west of the line, wildlife is typically Asian (rhinos, elephants), while to the east, it’s distinctively different (marsupials, Komodo dragons).
- Alfred Russel Wallace’s Discovery: The line was discovered by Alfred Russel Wallace, a British naturalist and co-discoverer of natural selection.
- Observational Basis: Wallace’s observation was based on the stark difference in animal life between closely situated islands.
- Not Just Proximity: The line’s placement is not solely based on island proximity but also on geological and historical factors.
- Role of Geology: Geological history, including plate tectonics, played a significant role in shaping the current distribution of species.
- Sunda and Sahul Paleocontinents: The Wallace Line divides the former paleocontinents of Sunda (west) and Sahul (east).
- Impact of Plate Tectonics: The concept of plate tectonics, accepted after Wallace’s time, explains the formation of the line and the distribution of species.
- Wallacea Region Formation: The area known as Wallacea, formed due to plate tectonics, contains a mix of species from both sides of the line.
- Wallace’s Legacy in Biogeography: Wallace is recognized for his contribution to understanding the geographical distribution of species.
