Life evolve on Krakatau or Child (Anak) Krakatau
The crack of Krakatau
"Different" hardly does justice to the astonishing volcanic explosion of August, 1883, in Indonesia. Volcano Krakatau's explosion -- 10,000 times as powerful as the bomb that leveled Hiroshima -- was heard at a distance of 4,500 kilometers.
In a awesome proof of the power that's usually concealed by Earth's quiescent surface, Krakatau (sometimes spelled Krakatoa) obliterated two-thirds of the 11-kilometer-long island of Krakatau and deposited 30 to 60 meters of red-hot ash. The explosion lofted 20 cubic kilometers of rock, ash and smoke into the sky. Shifts in the seafloor triggered tsunamis that killed 36,000 and destroyed 160 villages. Remnants of the giant waves reached the English Channel!
Geologically, Krakatau and the many active volcanoes on Sumatra and Java mark where the Indo-Australian plate dives under the Pacific plate. In the geologic basement, the scenario is much like what's found under Mount St. Helens.
The Krakatau explosion was soon recognized as a giant natural experiment in colonization -- the movement of species to new habitat, and Krakatau blossomed into a biologists' bonanza (see "Krakatau: the Destruction..." in the bibliography).
In Krakatau, transportation was the first hurdle: How do species reach and occupy on a sterile island? (This problem also arises on the volcanic islands of Hawaii, which formed thousands of kilometers from terrestrial life).
Natural transport authority
Organisms colonize isolated land via several mechanisms:
Air: by flying, as a bird or insect, or by passive transportation, as a light orchid seed or fern spore.
Sea: by swimming or floating on a log.
Animal: (The hitchhikers' express). By traveling inside or attached to animals that swim or fly, a trick used by plant seeds and animal larvae.
Many plants and animals have evolved to benefit from these techniques. Some mollusks grab moving objects with a sticky goo. Seeds may have adhesives or barbs to grab animals, or have wings that allow them to be lifted by light breezes. Fruit-eating animals can carry seeds in their gut and deposit them on an islands or sterile patches of land.
If the colonization lasts long enough, the rate of local extinction will start to equal the rate of immigration, and the number of species will stabilize