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Components Needed to Sustain Life on Earth
There are various specific conditions that are necessary to sustain life on earth such as the availability of water, appropriate temperature range, suitable ambient gases, and light. Water is essential to support life on earth because the constant recycling process of water maintains the ecological balance in the atmosphere and also sustains the hydrological cycle in earth. Temperature helps sustain life by maintaining temporal differences within different time zones, different times of the day and the year. There is an essential need for a certain gas mix in the atmosphere for existence and continuation of life on earth. The main gases which are found in the atmosphere are oxygen (21%) and nitrogen (78%) (Miller & Spoolman, 2011).
Biologigal evolutions: light is important as it enables photosynthesis that utilises solar energy. In this process water and carbon dioxide are converted into oxygen gas and carbohydrates, while nucleic acids, fats and proteins are synthesized along with various other elements, such as phosphorus, sulphur and nitrogen (Botkin, Keller and Rosenthal, 2012).
Identification & Description of a Range of Ecosystems
The ecosystem is a community of animals and plants that are linked to certain specified abiotic (non-living) features and specified climatic conditions. If a broader outlook is considered, then there are only two types of ecosystems in our environment, namely, aquatic (water) and terrestrial (land) ecosystems (Kenneth & Lazier, 2009). Biologigal evolutions: The aquatic ecosystems are further divided into marine ecosystem and freshwater ecosystem. The former include continuously cycling water that is low on salt content such as rivers and streams, while the latter include the oceans and the seas. The fresh water ecosystems at 1.8% of the earth’s surface form the base of food web and help other species in sustaining life. The Ocean or marine ecosystems cover a very huge area of the earth’s surface i.e. 75%. These play a major role in maintaining the environment as almost 40% photosynthesis takes place inside the ocean ecosystems (Newman & Unger, 2002).
The terrestrial ecosystems are further classified into tundra, deserts, grasslands and forests.
Tundra Ecosystems
Biologigal evolutions: These represent the barren land, because they are usually found in severe climatic conditions. Tundra ecosystems are further divided into arctic and alpine categories. Arctic tundra ecosystems are found above the tree line and below the polar ice cap in the northern hemisphere, while the Alpine tundra ecosystem is found above the tree line in high mountains (Newman & Unger, 2002).
Desert Ecosystems
The desert ecosystems comprise of dry arid expanses of land which are characterised by high winds, lesser height above the mean sea level and lack of humidity and moisture. These ecosystems also lack vegetation and water owing to high temperatures and absence of water and rainfalls. Overall, approximately the seventh part of the dry land on earth is constituted by these ecosystems (Tyler Et al., 2006).
Grassland Ecosystems
The grassland ecosystems are normally located in tropical areas and regions with moderate temperature limits. These are covered by wide expanses of wild grass and overall constitute about 1/5th of the dry land on earth (Newman & Unger, 2002).
Forest Ecosystems
Unlike the desert ecosystems, forest ecosystems are characterised by dense vegetation in the form of both trees and shrubs. The principal types of these ecosystems include: North Coniferous or Boreal forests; temperate forests; and tropical rain forests (Tyler Et al., 2006).
Comparison of the Identified Ecosystems
The aforementioned ecosystems enjoy various similarities and differences at almost all levels of classification. These similarities and differences are mainly based upon the biotic and abiotic factors, which are being discussed below.
On a lower level of classification, the terrestrial ecosystems include various smaller ecosystems such as: deserts characterised by flatlands, dunes, dryness and hot temperatures; tropical rainforests characterised by millions of distinct animal and plant species, humidity and hot temperatures; arctic and alpine regions characterised by harsh and cold climates; and also deciduous and coniferous forests (Hoffman Et al., 2002).
As compared to the terrestrial ecosystems, the aquatic ecosystems cover the majority of earth’s surface i.e. 75% and include both fresh water and marine ecosystems. Some other types of the aquatic ecosystems include: littoral ecosystems which are shallow water environments near shores; lentic ecosystems consisting of swamps, ponds and still water bodies; and lotic ecosystems comprising of flowing water bodies such as streams or rivers (Hoffman Et al., 2002).
At the highest level of classification, the similarities amongst the terrestrial and aquatic systems include: stratification or vertical zonation; equilibrium which can be translated as non-existence of change until…
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