Kerja Kursus Biology

Topics: Oxygen, Carbon dioxide, Greenhouse gas Pages: 5 (1470 words) Published: March 7, 2011


Name:Muhammad Fakhrullah Syazwan bin Badarulllah
Form:4 Creative
Teacher’S name:Puan



Alhamdulillah, bersyukur ke hadrat Ilahi kerana dengan limpah dan kurnia-Nya dapat saya menyiapkan buku skrap Biologi pada tahun ini tanpa sebarang masalah.
Kesempatan ini,saya ingin mengucapkan ribuan terima kasih yang tidak terhingga kepada Guru Biologi saya, Puan yang telah banyak memberi bimbingan, tunjuk ajar serta panduan.
Akhir sekali, buat rakan-rakan yang telah sama-sama menjalankan kajian ini serta bagi pihak yang terlibat ribuan terima kasih diucapkan. Tanpa mereka semua adalah mustahil bagi saya untuk menyiapkan tugasan ini.

Human Activities that Endangered an Ecosystem

* Deforestation is the permanent removal of trees from the forests. EFFECT OF DEFORESTATION
* Tropical rainforests are the oldest ecosystem on Earth and believed to be home to about half of the world’s flora and fauna species. * Rainforests play an important role in regulating the world’s climate. They are known as the ‘carbon sink’ of the Earth because they absorb vast amounts of carbon dioxide during the photosynthesis and the same time release oxygen into the atmosphere. * Large scale deforestation is thought to have a significant effect on soil erosion,flash flood,severe climatic changes and loss of global biodiversity. * Rainforests also serve as water catchment areas. Without proper planning and development,a land stripped of its vegetation cam rapidly succumb to soil erosion. * The absense of plant root systems makes the soil structure unstable. * When it rains heavily for a long period of time, the top layer of soil disintegrates easily and this leads to landslides esspecially on steep hillsides. * The eroded soil is then carried away by moving water and deposited at the bottom of rivers,which in turn contributes to the sedimentation of the rivers. * Deforestation is the most crucial reason why the loss of biodiversity is occuring at such an alarming rate today. * The loss habitats due to the destruction of millions of hectares of forests has driven countless species of plant and animals to extinction. * Deforestation also disrupts normal weather patterns, creating hotter and drier weather and causing climatic changes globally. * Technique used to clear forests is called slash and burn. The larger trees are removed for sale as timber, but less valueable wood is cut and then burnt. * This practice not only results in air pollution, but also releases more carbon dioxide into atmosphere. * The act of burning after deforestation in the tropic accounts for about 25% of carbon dioxide being added to the atmosphere and the remaining 75% is contributed by the burning fossil. * An increase in the atmospheric carbon dioxide level is closely associated with the greenhouse effect which leads to global warming. * Another example of human activities which has nagetive environmental consequences on the ecosystem is the overuse of land by intensive farming. * When using of the inorganic fertilisers excessive, the highly soluble inorganic nutrients do not remian in the soil for long and the are quickly leached out,ending up in surrounding river and lakes. This will lead to eutrophication. * The rapidly expanding human population also means an increase in domestic and industrial waste. Dumping waste material in landfills pases a great danger to living organisms as toxic substances and other pollutants from the dumpsites are easily absorbed into the ground and eventually end up polluting nearby water sources. AIR POLLUTION

1. Pollutants enter the air from various sourses, but burning of fossil fuels contributes the most to air pollution. 2. Exhaust fumes from vehicles contain soot (tiny carbon particles), lead (from car using unleaded...
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