Wallace Line facts for kids
The Wallace Line is an invisible boundary that separates the types of plants and animals found in Asia from those found in Australasia. It's like a natural fence that most species don't cross. The area around this line, where the two types of life meet, is sometimes called Wallacea.
To the north-west of the line, you'll find plants and animals that are similar to those in Asia. To the south-east, you'll mostly see species like those in Australia, though some Asian species are also present.
The line is named after Alfred Russel Wallace. He was a scientist who traveled through the Malay Archipelago (a group of islands in Southeast Asia) in the 1800s. He noticed this clear dividing line for himself.
The Wallace Line goes through Indonesia. It passes between the islands of Borneo and Sulawesi. It also runs through the Lombok Strait, which is a narrow stretch of water between Bali (to the west) and Lombok (to the east).
Even though Bali and Lombok are only about 35 kilometers apart, many bird species don't cross this gap. This is because many birds don't like to fly over even small areas of open ocean. Some bats can cross the line, but most other mammals stay on one side or the other. An exception is the Crab-eating Macaque. Different groups of plants and animals show slightly different patterns, but the overall separation is very clear.
The name 'Wallace's Line' was first used by another scientist, Thomas Henry Huxley, in 1868.
Contents
Why Animals and Plants Are Different
The main reason for the Wallace Line goes back millions of years. Long ago, there was a huge supercontinent called Gondwana. It broke apart, and the land that became Australia and its nearby islands separated from other parts of the world.
Because Australia was isolated, its animals and plants developed differently from those in Southeast Asia. The Wallace Line shows where the land that was once part of Gondwana meets the land that was part of another ancient continent called Laurasia.
How Ice Ages Affected the Line
During past ice ages, the ocean levels were much lower, sometimes up to 120 meters lower than today. When this happened, Asia and Australia were connected to their nearby islands by dry land.
However, the deep water between these two large land areas stayed a barrier for over 50 million years. This barrier kept the plants and animals of Australia separate from those of Asia. The islands in the Wallacea region were never connected to either continent by dry land. So, only animals and plants that could cross the water between islands were able to reach them.
There is another line called 'Weber's Line' that runs through the Wallacea area. It marks the point where you start to see more Australian species than Asian species.
Related Topics
Images for kids
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The original drawing of the Wallace Line from Alfred Russel Wallace's paper.
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The Wallacea region, located between the Wallace Line and the Lydekker Line.
See also
In Spanish: Línea de Wallace para niños
