CIVL3007-EIA-2010-3-Environment & Legislation

CIVL3007-EIA-2010-3-Environment & Legislation -...

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1 Natural and Man-made Environments of Hong Kong CIVL3007-2010 Dr. Zhang T
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2 Natural environment Ecosystem : is a natural unit consisting of all plants, animals and micro-organisms ( biotic factors) in an area functioning together with all of the physical ( abiotic ) factors of the environment. abiotic environment (land = lithosphere, water = hydrosphere, air = atmosphere) + biotic environment (living organisms) interact in ecosystem through exchange of •M a t t e r •E n e r g y Information Two Basic Laws: – unidirectional flow of energy : food chains/ trophic levels/ ecological pyramid – cyclical flow of matter • hydrological cycle (H 2 O) • biogeochemical cycles (C, O, N, P, S, etc.) sum of all ecosystems of the earth = ecosphere or biosphere (nature) aquatic (freshwater/estuarial/marine) terrestrial (grass/wetland/forest) man-made or human environment = anthroposphere or technosphere
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3 Abiotic components Solar energy provides most of the energy for ecosystems. Elements , e.g., carbon, nitrogen, phosphorus, sulfur, etc., cycle in ecosystems. Organic compounds , such as proteins, carbohydrates, lipids, and other complex molecules, form a link between biotic and abiotic components of the system. Biotic components according to their types of carbon sources . producers (autotrophs): Organisms that produce their own body using inorganic carbon, and get energy from the sun or inorganic compounds. – Photoautotroph (use sunlight, dominant) – Chemoautotroph (use chemical energy, less) consumers (heterotrophs): Organisms that consume other organisms as a food source to get carbon and energy. – Herbivores –C a r n i v o r e s – Decomposers – Primary, secondary, tertiary consumers Æ food chain, food web
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4 Flow of Energy The earth receives about one one-billionth of the sun’s energy output. ~ 28% is reflected by atmosphere, ice-cap & sea surface. ~ 71% powers physical processes by heating soil, air, & water. Due to temperature differences, there are wind, ocean currents, evaporation, etc. < 1% is trapped by photosynthesis (available to life). Input to Ecosystem = light Energy via photosynthesis •C O 2 + H 2 O + light = sugar + O 2 Energy (potential) stored in covalent bonds of sugar molecules. Movement (Flow) from organism to organism by feeding in food chain.
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5 Trophic Levels on an Energy Pyramid Producers are found at the base of the pyramid and compromise the first trophic level. Primary consumers make up the second trophic level. Secondary consumers make up the third trophic level. Finally tertiary consumers make up the top trophic level. The greatest amount of energy is found at the base of the pyramid. The least amount of energy is found at top of the pyramid. The producers, consumers, and decomposers of each ecosystem make up a food chain.
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This note was uploaded on 12/01/2010 for the course CIVL 2007 taught by Professor Profchai during the Spring '10 term at HKU.

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CIVL3007-EIA-2010-3-Environment &amp;amp; Legislation -...

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