Islands are truly a magical environment, where the natural processes of our world are transparent in an unparalleled way. Here ecosystems are simple and unclouded by complex relationships, offering unique insights into evolution, genetics, behavioral biology and many other fascinating sciences.
There are two main island types in the world, continental islands and oceanic islands, such as Galapagos and the Hawaiian Archipelago. Continental islands are pieces of land mass that are located on a continental shelf, close enough to the neighboring mainland to have been connected at times, during the past millennia, through the lowering of sea levels in Ice Ages. They thus start off life with a full compliment of flora and fauna, which biodiversity eventually lessens with the diminished surface area of the landmass. Oceanic islands are the complete opposite. They start life as barren, sterile stubs of black lava, in the case of volcanic archipelagos (they can also be coralline in origin), and are often extremely isolated. The flora and fauna that colonize these areas have to overcome extreme odds to arrive and become established. The arrival process often involves large stretches of open ocean, thus limiting possibilities for certain animal and plant groups, and creating what is termed a “disharmoinc distribution”, where one gets over-representation on certain groups of organisms, and under-representation of others. In Galapagos for example, animals would have had to cross over 600 nautical miles of ocean to arrive, which pretty much eliminates all groups except reptiles and birds. There are in fact only a couple of terrestrial mammals that made it: a rice rat, which holds the world-record for transoceanic crossings and then evolved into different species, and a couple of bats. Once arrived, the organism then had to adapt, an even harder task, as this involves finding a mate or a pollinator, and even food and water. In fact, it is thought that the whole of the Galapagos flora and fauna can be accounted for by just one successful arrival and establishment every 10,000 years! The complete isolation from the parent population that occurred at this stage then led to a great deal of speciation, the main attraction of the Galapagos.
There are two main island types in the world, continental islands and oceanic islands, such as Galapagos and the Hawaiian Archipelago. Continental islands are pieces of land mass that are located on a continental shelf, close enough to the neighboring mainland to have been connected at times, during the past millennia, through the lowering of sea levels in Ice Ages. They thus start off life with a full compliment of flora and fauna, which biodiversity eventually lessens with the diminished surface area of the landmass. Oceanic islands are the complete opposite. They start life as barren, sterile stubs of black lava, in the case of volcanic archipelagos (they can also be coralline in origin), and are often extremely isolated. The flora and fauna that colonize these areas have to overcome extreme odds to arrive and become established. The arrival process often involves large stretches of open ocean, thus limiting possibilities for certain animal and plant groups, and creating what is termed a “disharmoinc distribution”, where one gets over-representation on certain groups of organisms, and under-representation of others. In Galapagos for example, animals would have had to cross over 600 nautical miles of ocean to arrive, which pretty much eliminates all groups except reptiles and birds. There are in fact only a couple of terrestrial mammals that made it: a rice rat, which holds the world-record for transoceanic crossings and then evolved into different species, and a couple of bats. Once arrived, the organism then had to adapt, an even harder task, as this involves finding a mate or a pollinator, and even food and water. In fact, it is thought that the whole of the Galapagos flora and fauna can be accounted for by just one successful arrival and establishment every 10,000 years! The complete isolation from the parent population that occurred at this stage then led to a great deal of speciation, the main attraction of the Galapagos.
