Ecological System - Essay Example

Running Head: ECOSYSTEM Ecosystem s Ecological System Summary of Essay In this essay I shall give an over view of the ecological system. The essay shall be dived into three parts. The first will be the introduction in which the definition and background of the Ecological System will be given. Then will come the main body in which there will be clear explanation of the Ecological System along with example. The essay will end with a relevant conclusion. Introduction The term ecosystem is derived from the phrase ecological system, which includes the organisms in a given area. It encompasses the interactions among the organisms, between the organisms, and the nonliving portion of the environment in a specific area under consideration. An ecosystem is an association of animals and plants with their surrounding non-living environment and all the interactions that each organism participates in. The term ecosystem was created in 1935 by Sir Arthur GeorgeTansley, an English ecologist, who said natural systems are constantly changing among their living and nonliving parts (Bennett 1997 p 15). Main body Concept The ecosystem concept is built around the flow of energy and all of its components, which is extremely important to know when dealing with biological community functions. A simple ecosystem works by first receiving energy from the sun that is trapped by the grass during a process known as photosynthesis. The grass is then eaten by a rabbit, which in turn is eaten by a hawk, which eventually dies. The energy originally contained in the photosynthetic products made by the grass goes through various stages where the body molecules of the original rabbit and the hawk become the heat energy lost from the animals and the decaying dead matter. Thats a brief description of how an ecosystem flow of energy is made (Condit etal 1996 p231). The ecosystem concept is very helpful as an organizing principle for the geographic study of the biosphere. There are many different scales at which this concept can be applied and there are endless magnitudes of ecosystems that one can study. Examples of Ecological System The major complexes of ecosystems determined by a particular set of climatic conditions and comprising of a different set of organisms are known as biomes. Biomes are classified in various ways, however the different types are best discussed under seven categories. Although biomes include associated animal life, they go by the name of the dominant vegetation and the physical conditions, since it is these two that influence the characteristic diversity of animal life and smaller plant forms (Biogeogr etal 2007 p 14). The seven major biomes are as follows: Tropical Rain Forests, Savannas, Deserts, Temperate Grasslands, Temperate Deciduous Forests, Taiga and Tundra. But in this report we have to discuss the three examples to understand the concept of Ecosystem. Tropical Rain Forests They are widespread in three major world regions: South America, particularly around the Amazon basin, Central and West Africa and South East Asia. Although they cover only 7% of the land surface, tropical rain forests are the richest biomes in terms of number of animal and plant species (Biogeogr etal 2007 p 19). In just 1km2 one can easily find several hundreds of bird species, beetles, butterflies and thousands of other insect species. common features found between mammals as well as birds and (in reptile and amphibians) consist of adjustments to an arboreal living (a good example of this is the New World monkey’s prehensile tails), dazzling colours along with sharp designs, noisy vocalizations, and fruit based diets. (http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/rainforest/rainfrst.html) In a tropical rain forest there is plenty of water and optimum temperatures; thus there are no limiting factors for photosynthesis. Even the assemblage of these plants and animals is diverse, forming complex food webs. Many of the soils are conditioned by high, constant temperatures and abundant rainfall and are relatively infertile (Stanley etal 1998 p 23). However, tropical rain forests are highly productive, despite the infertile soils that arent even able to support long-term agriculture. Most of the nutrients are tied up in the vegetation and are rapidly recycled when the plant dies, or when parts of the plant, such as leaves, are lost. Tropical rainforests nowadays form about half of the planets forested area but are in the process of being destroyed by human activities, mainly agriculture (Peters 1991 p34). When deforestation occurs, this leaching process accelerates soil erosion, making the fields useless for agriculture within a few numbers of years later, and once cleared they dont recover; instead they turn into desert. Savannas Savannas are transitional regions between evergreen tropical rain forests and deserts. The dry tropical and subtropical regions of Africa, South America and Australia have extensive areas of these perennial grasslands, with scattered broad-leaved and evergreen deciduous trees, occurring either singly or in small clumps. The dominant plants are small trees with a thick bark, seldom more than 15m tall and spiny shrubs, with the Acacia as the common worldwide genus of plants. A tropical damp and dry type of weather predominates in regions that are covered in savannah growth. Average monthly temperatures are at or higher than 64degree F and annual rainfall vary widely according to season, the amount of rain averages between 30 and 50 inches (Stanley etal 1998 p 10). African savannas maintain the worlds best diversity of ungulates i.e. hoofed mammals specially the antelopes, along with other plant eating. The existence of this biome greatly depends on these grazers and browsers as it is these that maintain the savannah (Peters 1991 p 45). If the vegetation is not grazed, browsed or burned, it would typically revert into a dense thorn forest. Deserts Deserts are not just hot, barren biomes filled with sand dunes. They are regions characterised by low moisture levels with infrequent and unpredictable precipitation; most of which being rocky or gravely scrubland (Condit etal 1996 p 240). This lack of moisture necessary to absorb and store heat energy results in wide temperature fluctuations. Desert endurance all relies on water conservation which is only possible by means of structural, behavioural or physiological adjustments (aestivation which the dormancy throughout the summer), the lack of sweat glands, the absorption of urine, contained deposits of fat in tails or humps etc.Vegetation is rather sparse (Biogeogr etal 2007 p 16). Plants, most of them annuals, need a variety of specialisations to conserve water and protect their tissues from predation. Such plants have rapid growth cycles which can be quickly completed when water is available. Xerophytes have a shallow but extensive root systems to absorb rainwater from well beyond the canopy of the shrub whenever it does rain, whilst the phreatophytes have long deep roots that may extend downward 20 to 30 feet, reaching water sources far below the ground (Peters 1991 p 45). Other adaptations involve reducing transpiration rates by having small leaves with waxy cuticles or reduced leaves such as spines and also trichomes, which reduce the air movements against leaf surfaces. Succulents that store large quantities of water in their stems especially, are quite common e.g. the Cactaceae in the Americas. Desert animals such as rodents, ants, lizards and snakes are also well adapted to thrive in these conditions. Taiga The taiga or boreal forest exists as an almost permanent belt of coniferous trees that lengthen over huge areas of Russia, Scandinavia as well as North America. Primarily this type of forest sustains needle leaf coniferous evergreen gymnosperms; except in large areas of north-eastern Siberia, where larches (Larix), which are deciduous conifers, are more dominant (Bennett 1997 p8). Common tree species of the taiga biome include Picea (spruce), Abies (fir), Populus (poplar) as well as Larix (larches). Then there are shrubs like the Salix (willow), Betula (birch) and Ledum (Labrador tea). Herbaceous vegetation is dominated by mosses and lichens. The taiga is characterised by sever winters with most of the rain fall occurring during the summer season (Stanley etal 1998 p 20) . Since most of this biome is underlain by permafrost (permanent ice) and water cannot seep into the soil, the ground is usually moist. Low evaporation rates bring about a humid climate and the common presence of lakes, bogs, and marshes. There are so many benefits of taigas. Some of the most practical are: that taigas are unique to Earth; its self renewing; home to lakes, bogs, marshes, meadows, and rivers; it is the solar powered energy reservoir for the sub-arctic; the ecosystem biodiversity, it makes soil from rock; makes and stores its complex chemical nutrients, its a natural habitat for all sub-arctic animal life; moss and snow provide insulation; and its an object for science and sustainable systems. Temperate Grasslands Temperate grasslands are most often classified as flat, grassy areas that have characteristically rich soil. These areas of earth also are known to have long, cold winters. The climate is semiarid and continental, typically having between 10 and 20 inches of precipitation annually (Bennett 1997 p 18). A great deal of this falls as snow, this serves as tank of moisture for the start of the growing season. Warm to hot summers are take place, the intensity of summers depends on the latitude. One of the largest areas of grassland stretches from north central United States to Canada and is one of the richest agricultural regions on earth. Today, many of the worlds grasslands are used for farming and grazing both wild and domestic animals. Temperate grasslands are subdivided into two types: prairies, characterized by their humid climates and tall grass species that often occur with patches of forest, and steppes that have short grasses usually found scattered in bunches, especially in the driest areas (Peters 1991 p 37). The temperate grassland fauna is very low in diversity but large populations of grazing animals are supported. Conclusion Many scientists are trying to learn all they can about ecosystems by observing healthy, thriving ecosystems in action. Humans, even though their intentions are often good, can upset the fine balance that exists in an ecosystem. References Bennett, K.D. (1997); Evolution and Ecology. The Pace of Life. Cambridge: Cambridge University Press p 8-15 Condit, R., S. P. Hubbell, and R. B. Foster.1996; "Changes in tree species abundance in a Neotropical forest: impact of climate change". Journal of Tropical Ecology 12: 231-256. http://www.runet.edu/~swoodwar/CLASSES/GEOG235/biomes/rainforest/rainfrst.html retrieved on 4 December 2007 J Biogeogr, Gaston KJ, Chown SL, Evans KL (2007); Ecogeographical rules: elements of a synthesis. Journal of Biogeography; p14-20 Peters, R.H. (1991); A Critique for Ecology. Cambridge: Cambridge University Press p 34-45 Stanley I. Dodson, Timothy F. H. Allen, Stephen R. Carpenter, Anthony R. Ives, Robert L. Jeanne, James F. Kitchell, Nancy E. Langston, Monica G. Turner 1998, Ecology , Oxford University Press p 10 -30 Read More