In this imaginary line between Bali and Lombok, even when sea levels were lower, the sea stopped flora and fauna from moving between islands. In The Malay Archipelago, Alfred Wallace writes about the ' Wallace Line' that passes between Bali and Lombok, along the deep waters of the Lombok Strait. Because flora and fauna cannot move between the islands easily, there are many localised species like the Komodo dragon because of evolution. These small islands are sometimes divided by deep oceanic trenches.

The Lesser Sunda Islands are different from the large islands of Java or Sumatra because it is made of many small islands. ( November 2013) An editor's reason for this is: Not simplified enough from the enwiki article. You can help Wikipedia by reading Wikipedia:How to write Simple English pages, then simplifying the article.

The English used in this section may not be easy for everybody to understand. There are several volcanoes located on the Lesser Sunda Islands. Īt the point where two tectonic plates collide, the Lesser Sunda Islands are some of the most geologically complex and active regions in the world. Ideas of how the islands were formed changed in many ways during the last decades of the 20th century. However, we still do not fully understand how the islands were formed. Since colonial times in Indonesia, people have been studying the geographical history of the islands. They are not volcanic and are probably part of the Australian plate. The southern group of islands include Sumba, Timor and Babar. They formed because of the collision between the Australian and the Asian tectonic plates. The northern group of islands started forming during the Pliocene, about 15 million years ago. However, there are some other volcanoes, such as Kelimutu on Flores, which are extinct. Some of the volcanoes, like Mount Rinjani on Lombok, are still active.

It is made up of Bali, Lombok, Sumbawa, Flores and Wetar. In the Lesser Sunda Islands there are two geologically different groups of islands.

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