The Lesser Sunda Islands are different from the large islands of Java or Sumatra because it is made of many small islands. These small islands are sometimes divided by deep oceanic trenches. Because flora and fauna cannot move between the islands easily, there are many localised species like the Komodo dragon because of evolution. 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. In this imaginary line between Bali and Lombok, even when sea levels were lower, the sea stopped flora and fauna from moving between islands. The islands east of the Lombok Strait are part of Wallacea, and have wildlife of Asian and Australasian origin in this region. In the Lesser Sundas, there are many plants and animals that come from Asia, because Weber's Line, which separates the parts of Wallacea that have both Asian and Australasian species, is east of the Lesser Sundas. These islands have the driest climate in Indonesia.