Wallace Line: The Invisible Barrier That Divides Flora and Fauna in This Part of the World

Animal evolution, including humans, has been a given fact since the theory of evolution became a pioneer in discussing how different animal species came to be as they are now. Yet, there are still mysterious aspects of evolution that are out there but we may not fully know. For instance, there is a part of this world where an invisible barrier divides flora and fauna: the Wallace Line.

The Wallace Line may not be as popular as Charles Darwin's theory of natural selection or his concept of "survival of the fittest" in the context of evolutionary theory. However, it also depicts the evolution of life relative to its surrounding environments.

Known as an imaginary line between Indonesia and Australia, the Wallace Line or Wallace's Line separates two different worlds of animals and plants. It is an imaginary line that is both tangible and intangible. Mysterious as it seems, geography and other environmental factors may have played a role in the said distinction or separation of species.

Wallace Line

The proponent of the Wallace Line was none other than the British naturalist Alfred Russell Wallace, who independently discovered the theory of evolution, aside from Darwin.

For eight years, Wallace conducted fieldwork in the islands at the edge of Southeast Asia, where he collected data from different species of birds, butterflies, insects, mammals, and reptiles. The English biologist has reportedly drawn the invisible line in 1859.

The Wallace Line is a boundary line that stretches across Indonesia, specifically intersecting the Lombok Strait between Bali and Lombok islands in the south and it extends through the Makassar Strait between Borneo and Sulawesi in the north, according to the University of Washington.

Distinct Animals

On the Southeast Asia or western side of the Wallace Line, the presence of rhinos, tigers, elephants, woodpeckers, and other animals that are endemic in the Asian region. Meanwhile, the eastern side of the line shows a different set of animal groups, ranging from Komodo dragons to cockatoos, and honeyeaters.

In this context, an inquiry emerged as to why the animals from both sides did not cross the narrow line. Experts argue that it is because of the deep and wide ocean that divides the flora and fauna between Southeast Asia and the Australian regions.

Theory of Evolution

As mentioned earlier, Wallace discovered the biological phenomenon of evolution independent of Darwin, who spent his work from 1835 on the other corner of the globe in Galapagos Islands, an archipelago off Ecuador in South America.

Realizing Wallace also has the same findings, Darwin reportedly rushed to publish his work on the theory of evolution and natural selection. Although a competition seemed imminent at that time, both Wallace and Darwin collaborated to share their work together.

More than a century later, the Wallace Line has been proven to contain significant insights to evolutionary biology. Yet, it is still unclear if there are other invisible barriers in other parts of the world waiting to be discovered.