Examine critically the Equilibrium Theory of island biogeography. In your answer you are expected to critique its validity and practical usefulness
An Island is undoubtfully an appealing study unit. It is less complex than continents or oceans, a visibly distinct object that can be labelled with a title and its resident populations identified thereby (MacArthur RH, Wilson EO, 1967). From a perspective of biogeographical science, MacArthur and Wilson proceed to state that islands are the first units an individual can discover, investigate and begin to understand. This essay thoroughly discusses the equilibrium theory of island biogeography, and critiques its quality and practical uses
Oceanic islands and other groups are very essential to biologists. A good number of portions of the evolutionary histories occurred on oceanic islands. But the importance of an island hasn’t urged the research in island biogeography. Instead it is the awareness that an island is a typical example for graphic entities ranging in size, from very small resident portions, to continental scale or even global scale. Because islands are evidently apart from other bodies of land, the information of the island contributed to the awareness that most formations of species are due to an occurrence of a geographical barrier. Island isolation is important to ecologists, because it gives them reasons to believe that any species encountered on an island is inhabiting that particular island. As a result, issues in the structure and function of the community are attacked in an island setting; any encountered species is believed to be inhabiting that particular area.
According to Daniel Simberloff, isolation being the most noticeable characteristic of islands ...
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...on less apart and smaller islands.
Curiosity about the assumption of independence between the rate of immigration and that of extinction has brought about modifications within the existing MacArthur-Wilson theory.
Though there is insufficient evidence of the constantly changing equilibrium in continental habitat islands and that the theory fails to give reasons to all other characteristics of islands such as the shape, the MacArthur-Wilson theory has been applied to numerous “islands of habitat” such as plants, caves, lakes, just to name a few and has urged scientist to pay attention to the patchiness in space and the influences of the size of habitat and isolation on ecological and evolutionary processes. Therefore this theory does not provide detailed explanations to the assumptions made by previously mentioned scientists and principles they abide to.
Isle Royal is located fifty-six miles north of Michigan’s Keweenaw Peninsula. It is the largest wilderness area in Michigan (USNPS, 2014). The island is surrounded by Lake Superior, which creates a cooler temperature. This results in arctic plant species growth on the island. There are only eighteen mammal species present on the island because most mammals cannot make the trip across the frozen great lake (USNPS, 2014). The need for an ice bridge is not the only environmental factor that is stopping the migration of animals; there is also the severe cold, and also wind and fog (Vucetich, 2012). Some species such as caribou and coyote have found the island to be too intense and have gone extinct (Vucetich, 2012). Due to the harsh weather and isolation of the island, humans have never regularly lived on the island (Vucetich, 2012). Some of species that are present such as the red squirrel are becoming their own subspecies due to its separation from the mainland (USNPS, 2014). The isolation of Isle Royal is what makes it a great place to conduct research, it has very low human interaction and the species that are on the island will have been and continue to be isolated from the mainland.
Burton, Robert, ed. Nature's Last Strongholds. New York: Oxford UP, 1991. Print.
4) My small island results compared with my large island results came out as like the species number on my small island went down while the changes in species number for my large island went up. I feel that this result could have been predicted by the species-area formula. The reason is because since my big island is a lot bigger than the small island, it can hold up to 2x the animals than the small island could. Another reason is that when the island increases, the extinction rates slow down and try to balance towards a greater biodiversity unlike with the small island where extension rates are going
Biodiversity is influenced by landscape fragmentation at various scales of space and time. The extinction of ecosystem types and component species may cause an increased patchiness of the landscape, resulting in lower population sizes and decreased connectivity. As a result, inhabitants may experience decreased dispersal abilities and lowered gene flows between populations.
The Galapagos Islands, located about 600 miles west of continental Ecuador, contain a rich history of settlement and exploration and represent a living example of evolution that is still relevant today. For centuries, this chain of volcanic islands has been used uniquely by various cultures based off distinct needs. What has remained the same however is the fact that island isolation has forced many animal and plant species to adapt differently from one another based off their island’s environmental conditions, creating a living model of microevolution over time. Today, these models tend to be the primary resources used by biology professors when teaching their students evolutionary topics.
The island rule means that the island does evolve certain animals into its own species, then that species fails and goes extinct. Both island evolution and extinction have been proven, however now they are now connected. The islands cause evolution, the evolution causes the extinction, and thus meaning that the island caused the extinction. Shown by numerous scientist and written books, both are correct, islands cause evolution and extinction.
Roderick Nash. ISLAND CIVILIZATION A VISION FOR HUMAN OCCUPANCY OF EARTH IN THE FOURTH MILLENNIUM. 2001. .
3. Assume in a hypothetical situation there is a certain island that contains 5 types of sea lizards, each occupying a section of the coast with no opportunity for mating amongst species on the other side of the island, but mating occurs with species that are adjacent. What is this an example of?
For example the canopies of kelp provide shelter for many organisms . Because the kelp is able to float, it creates a canopy. This canopy has warm temperatures and slow water currents, providing a home to defenseless young. This is important because the kelp is able to protect many organisms from predators and rough storms (6). Kelp is also the base of the food chain. Since kelp is the base of the food chain many organisms eat kelp and other animals eat them.This is important because without the kelp all the primary consumers would starve having no other food source (5). Finally each part of kelp is home to a different species. Because each part of kelp is home to a different species, many species breed in them. This is important because if the kelp where gone there would be no place for the organisms to breed downsizing their population (4). Overall kelp is providing food and shelter to many
In spite of the overwhelming amount of negative speculation, the practice of de-extinction might potentially produce some positive ramifications. According to Stewart Brand, a writer for National Geographic, humans should bring back extinct species “to preserve biodiversity, to restore diminished ecosystems...and to undo harm that humans have caused in the past.” If humans were to tamper with nature and bring back an extinct animal, desolate ecosystems which previously thrived, such as deserted islands, could be partially restored through their
On the first level, when foreign, but previously non-invasive species is first introduced to a new area, the new species may play a role in a community that was previously unfulfilled; it may fill a vacant niche in the ecosystem. Originally this new species may be seen as a useful contributor to its new surroundings because it has only (temporarily) increased biodiversity in the area (Meinesz, 2003).
of the book. Vol. 24. What is the difference between a'smart' and a'smart'? Berkeley, CA: University of California, 1984.
Natural has its own world in St. Martin. The island is about two kilometres long and the deep blue water all around it is outstanding to watch. Rocks of different sizes and types are all around the beach, some of which are with razor sharp spikes that can cut your foot into pieces if you step on them. Moreover, different coloured sea weeds and live corals can be seen on the rocks which are submerged in the water. St. Martin is the only Island in the world with live corals. There are more than thousands of different types of coral in this island. Scientists say that this island actually grew from this coral by the metamorphosis of different c...
Overall, Robinson Crusoe’s ship crashing on the island forever changes the ecology, and biodiversity. Robinson colonized the island by introducing invasive species, European crops, and enclosing areas of the island. This colonization would lead to the islands decent in, wildlife habitation, and biodiversity. Although, these concerns would change the ecosystem on the fictional island they are the signs of colonization, and improvement in the lives of the inlands inhabits.