The biotic and abiotic structure and function of an ecosystem - Coursework Example

GRASSLAND ECOSYSTEM and Number of Grassland ecosystem is found in all the continents apart from the Antarctica. Grassland vegetation is naturally occurring and is common in most eco-regions of the world. Grassland vegetation varies in height from less than 30 cm to quite longer heights. It is biologically composed of trees and shrubs. Herbaceous non-woody vegetation is also common with grass dominating hence the name grassland (Piperno & Sues, 2005). Biotic features present in grassland compose of various species of shrubs and trees in addition to animals.

Abiotic factors present in grassland include features like different types of soil that support the grass. Other factors such as light, temperature, water, and topography are also inclusive in this type of ecosystem. The grass covers about 32% of the earth. Annual precipitation distinguishes grasslands. For example, temperate grasslands receives about 25-100cm of rainfall annually while tropical grassland may receive about 150cm. Most of the free plains and rolling provide a favorable environment for the growth of the grass.

This plantation depends on water so much for its survival and is usually fresh and lively during raining seasons. Grass receives water in form of precipitation (Courtwright, 2011). Water is absorption is by the roots of plants and later lost in form of vapor through transpiration. This water rises to the atmosphere and cools to form ice, which later falls in term of precipitation. This cycle is continuous and enables the existence of the grassland. However, for the survival of this vegetation, there is need for nitrogen, which is efficient depending on the type of soil.

However, nitrogen the most abundant gas occurs freely as a gas but its availability as a gas makes it unavailable for plants. From the atmosphere, nitrogen gas combines with oxygen to form nitrogen dioxide. This form of gas is unavailable to plants and must be converted by nitrogen fixing bacteria such as nitrobacteria in order to make it available for absorption by roots of the grass (Morford, Houlton, & Dahlgren, 2011). However, nitrogen is also fixed directly to the grass through lightning.

Root nodules found in other leguminous plants growing alongside the grass also perform the function of fixing nitrogen. It is also important to acknowledge the presence of animals in the grassland vegetation, which helps in nitrogen fixation. Animals produce their inorganic wastes, which is in ammonium form, which contains available nitrogen forms for plants. Through nitrification, nitrogen fixation, ammonification, and assimilation nitrogen gas can be converted to available forms for grass. Nitrogen is lost from the grass when animals consume the grass and later release their waste in form of ammonia, which ensures the nitrogen cycle continues.

Alongside the nitrogen cycle there is need to reflect on the importance of the carbon cycle in survival of the grassland vegetation. Grass as any other plants depend on carbon (iv) oxide for photosynthesis. Only 0.003% of this gas is available in the atmosphere. This gas is absorbed directly by grass through the stomata. It is used as a raw material for photosynthesis. It is lost in plants in form of weak carbonic acid through leaching of water (Houghton, 2005). The atmosphere recovers this carbon after microbial decomposition, through fossil fuel, and through respiration and the cycle continues.

Despite the large presence of grassland vegetation, statistical data indicate that this ecosystem is under threat from human activities and natural climatic changes. The worrying trends of global warming and its effect are already evident. Most of the grass is drying from increased atmospheric heat while most of the grass is under threat of flooding mainly due to global warming. Although little research has been done on pests and disease of the grass, it is already evident that global warming has increased viral and fungal infections in the Gramineae family to which the grass belongs.

Human activities have played a significant role in causing disturbance of this ecosystem. Practices of overgrazing, and human encroachment in addition to excessive use of inorganic fertilizers have shifted the equilibrium of this ecosystem. Human activities have affected the hydrological, carbon and nitrogen cycles hence destabilizing the grassland vegetation. Due to global warming grass has lost substantive water to support itself while rising temperatures have led to wilting and consequent death of most grasses.

However, due to resilience and secondary succession, grass has managed to thrive through such tough circumstances. Grass produces many seeds, which ensures that it succeeds to reproduce for the next generation. Its seeds are able to survive for many years in dormant state. The seeds re also able to resist intensive heat and fire hence the reason for their large presence during first week of light showers. The plant does not require nutrients in from of fertilizers in order to grow and most of its species are drought resistance.

Because of its aggressive nature it is able to grow in any open field of land hence increasing its chances of survival. The plant is also known to be resistance to many pests and diseases. References Courtwright, J. (2011). Prairie Fire: A Great Plains History . Kansas: University Press of Kansas. Houghton, R. A. (2005). The contemporary carbon cycle". In William H Schlesinger. Biogeochemistry, 104 (3): 399–417. Morford, S. L., Houlton, B. Z., & Dahlgren, R. A. (2011). Increased forest ecosystem carbon and nitrogen storage from nitrogen rich bedrock.

Nature, 477 (7362): 78–81. Piperno, D. R., & Sues, H. (2005). Dinosaurs Dined on Grass. Science, 310 (5751): 1126–8.