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FANTASY LIFE.
Saturday, January 3, 2009
10)Discuss the impact of human activites on our ecosystem, highlighting issues on deforestation, over-fishing, eutrophication and biomagnification.
Human beings are continually using and depleting or reducing the Earth's natural resources and upsetting the balance of nature in many areas by certain activities. The uncontrolled use of the Earth's natural resources, like forests and wildlife, has caused lasting damage to the environment. Such activities are
~Deforestation
~Over-fishing
~Eutrophication
~Biomagnification
Deforestation
With modern technology, forests are being cleared at much faster rate than they can be replace. This leads to loss of habitats which leads to extinction of animals. As trees are removed, topsoil gets washed away or eroded during heavy rain, causing soil erosion. Without the topsoil, the land becomes barren and plants cannot grow in the soil. This causes desertification and leads to habitat loss. Eroded soil may be deposited in rivers or streams. This causes flooding as it blocks the flow of water.
Over-finshing
As human population increases, so does the demand for fish. Some species of fish will have their populations decreased. Some fishing method will destroy marine habitat such as cyanide fishing, cyanide or dynamite is used to stun and catch reef fish, however corals and many other reef organisms are killed in the process.
Eutrophication
Eutrophication is an increase in chemical nutrients in an ecosystem and mean the resultant increase in the ecosystem's primary. As fertilisers are being washed into nearby rivers or lake, it will lead to profuse growth and multiplication of algae and water plants in the lake or river. Submerged algae and plants will die due to lack of sunlight andwill be decomposed by bacteria. Other organisms will die as well as the bacteria rapidly uses the oxygen to decomposes those death plants.
Biomagnification
Also known as bioamplification which is the increase in concentration of a substance sush as pesticide DDT (dichloro-diphenyl-trichloroetheane...so long). DDT is insoluble in water and organisms cannot break down DDT, hence, DDT accumulates in the bodies of consumers. This results in the insecticide being passed along food chains, increasing in concentration in the bodies of organisms along the trophic levels.
Picture of DDT
For e.g. Mercury is only present in small amounts in seawater and is absorbed by algae. Biomagnification result in the buildupin the adipose tissue of successive trophic levels: zooplankton, small fish, larger fish etc. Anything which eats these fish also consumes the higher level of mercury the fish have accumulated.
Picture shows a thousand words!!
-------------------final fantasy--------------- ; {4:27 AM}
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ME
Jin Hao
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Biology Assignment
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