Island Games For Pc
Mallory Chowansky
An island or isle is a piece of subcontinental land completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been part of a continent. Oceanic islands can be formed from volcanic activity, grow into atolls from coral reefs, and form from sediment along shorelines, creating barrier islands. River islands can also form from sediment and debris in rivers. Artificial islands are those made by humans, including small rocky outcroppings built out of lagoons and large-scale land reclamation projects used for development.
Islands are host to a diverse array of plant and animal life. Oceanic islands have the sea as a natural barrier to the introduction of new species, causing the species that do reach the island to evolve in isolation. Continental islands share animal and plant life with the continent they split from. Depending on how long ago the continental island formed, the life on that island may have diverged greatly from the mainland due to natural selection.
Humans have lived on and traveled between islands for thousands of years at a minimum. Some islands became host to humans due to a land bridge or a continental island splitting from the mainland. Polynesians were the first group of humans to colonize islands at scale, dispersing over the Pacific Ocean starting near New Guinea starting as early as 1100 BC. Today, up to 10% of the world's population lives on islands. Islands are popular targets for tourism due to their perceived natural beauty, isolation, and unique cultures.
Islands became the target of colonization by Europeans, resulting in the majority of islands in the Pacific being put under European control. Decolonization has resulted in some but not all island nations becoming self-governing, with lasting effects related to industrialization, nuclear weapons testing, invasive species, and tourism. Islands and island countries are threatened by climate change. Sea level rise threatens to submerge nations such as Tuvalu and the Marshall Islands completely. Increases in the frequency and intensity of tropical cyclones can cause widespread destruction of infrastructure and animal habitats. Species that live exclusively on islands are some of those most threatened by extinction.
An island is an area of land surrounded by water on all sides that is distinct from a continent.[1] There is no standard of size that distinguishes islands and continents. Continents have an accepted geological definition -- they are the largest landmass of a particular tectonic plate.[2] Islands can occur in any body of water, including rivers, seas, and lakes.[3] Low-tide elevations, areas of land that are not above the surface during a high tide, are generally not considered islands.[4] Islands that have been bridged or otherwise joined to a mainland with land reclamation are sometimes considered "de-islanded", but not in every case.[5]
The spelling of the word was modified in the 15th century because of a false etymology caused by an association with the Old French loanword isle, which itself comes from the Latin word insula.[1][7]
Islands often are found in archipelagos or island chains, which are collections of islands. These chains are thought to form from volcanic hotspots, areas of the lithosphere where the mantle is hotter than the surrounding area.[8][9] These hotspots would give rise to volcanoes whose lava would form the rock the islands are made of.[8] For some islands, the movement of tectonic plates above stationary hotspots would form islands in a linear chain, with the islands further away from the hotspot being progressively older and more eroded, before disappearing under the sea entirely.[10] An example is the Hawaiian Islands,[10] with the oldest island being 25 million years old, and the youngest, Hawaii, still being an active volcano.[9] However, not all island chains are formed this way. Some may be formed all at once by fractures in the tectonic plates themselves simultaneously creating multiple islands. One supporting piece of evidence is that of the Line Islands, which are all estimated to be 8 million years old, rather than being different ages.[9]
Other island chains form due to being separated from existing continents. The Japanese archipelago may have been separated from Eurasia due to seafloor spreading, a phenomenon where new oceanic crust is formed, pushing away older crust.[9] Islands sitting on the continental shelf may be called continental islands.[3] Other islands, like those that make up New Zealand, are what remains of continents that shrank and sunk beneath the sea.[11] It was estimated that Zealandia, the continent-like area of crust that New Zealand sits on, has had 93% of its original surface area submerged.[11]
Some islands are formed when coral reefs grow on volcanic islands that have submerged beneath the surface.[12] When these coral islands encircle a central lagoon, the island is known as an atoll.[13] The formation of reefs and islands related to those reefs is aided by the buildup of sediment in shallow patches of water. In some cases, tectonic movements lifting a reef out of the water by as little as 1 meter can cause sediment to accumulate and an island to form.[12]
Barrier islands are long, sandy bars that form along shorelines due to the deposition of sediment by waves. These islands erode and grow as the wind and waves shift. Barrier islands have the effect of protecting coastal areas from severe weather because they absorb some of the energy of large waves before they can reach the shore.[14]
A fluvial island is an island that forms from the erosion and sedimentation of debris in rivers; almost all rivers have some form of fluvial islands.[15] These islands may only be a few meters high, and are usually temporary. Changes in the flow speed, water level, and sediment content of the river may effect the rate of fluvial island formation and depletion.[15] Permanent river islands also exist, the largest of which (that is completely inland) is Bananal Island in the Tocantins of Brazil, which has a maximum width of 55 kilometers.[16]
The field of insular biogeography studies the ecological processes that take place on islands, with a focus on what factors effect the evolution, extinction, and richness of species. Scientists often study islands as an isolated model of how the process of natural selection takes place.[19][20] Island ecology studies organisms on islands and their environment. It has yielded important insights for its parent field of ecology since the time of Charles Darwin.[20]
In biology, endemism is defined as the phenomenon where species or genus is only found in a certain geographical area. Islands isolate land organisms from others with water, and isolate aquatic organisms living on them with land.[20] Island ecosystems have the highest rates of endemism globally. This means that islands contribute heavily to global biodiversity.[21] Areas with high lives of biodiversity are a priority target of conservation efforts, to prevent the extinction of these species.[22] Despite high levels of endemism, the total species richness, the total number of unique species in a region, is lower on islands than on mainlands.[23] The level of species richness on islands is proportional to the area of that island, a phenomenon known as the species-area relationship. This is because larger areas have more resources and thus can support more organisms. Populations with a higher carrying capacity also have more genetic diversity, which promotes speciation.[20]
Oceanic islands, ones that have never been connected to shore, are only populated by life that can cross the sea. This means that any animals present on the island had to have flown there, in the case of birds or bats, were carried by such animals, or were carried in a sea current in what is known as a "rafting event". This phenomenon is known as oceanic dispersal.[25] Tropical storms have the capacity to transport species over great distances.[26] Animals like tortoises can live for weeks without food or water, and are able to survive floating on debris in the sea.[27] One case study showed that in 1995, fifteen iguanas survived a 300 km journey to Anguilla in the Caribbean, an island which no iguana had lived on previously. They survived floating on a mass of uprooted trees from a storm.[28] Plant species are thought to be able to travel great distances of ocean. New Zealand and Australia share 200 native plant species, despite being separated by 1500 km.[25]
Continental islands, islands that were at one point connected to a continent, are expected to share a common history of plant and animal life up until the point that the island broke away from the continent.[25] For example, the presence of freshwater fish on an island surrounded by ocean would indicate that it once was attached to a continent, since these fish cannot traverse the ocean on their own.[20] Over the course of time, evolution and extinction changes the nature of animal life on a continental island, but only once it splits from the mainland. An example is that of the southern beech, a tree that is present in Australia, New Zealand, parts of South American, and New Guinea, places that today are geographically distant. A possible explanation for this phenomena is that these landmasses were once all part of the continent Gondwana and separated by tectonic drift. However, there are competing theories that suggest this species may have reached faraway places by way of oceanic dispersal.[25]
Species that colonize island archipelagos exhibit a specific property known as adaptive radiation. In this process, a species that arrives on a group of islands rapidly becomes more diverse over time, splitting off into new species or subspecies. A species that reaches an island ecosystem may face little competition for resources, or may find that the resources that they found in their previous habitat are not available. These factors together result in individual evolutionary branches with different means of survival.[29]