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能量的单向流动教师在讲述生态系统中能量的流动时,都要强调:能量的流动是单向的;物质的流动是循环的,属于生物地球化学循环.我认为,能量的单向流动应从以下几个方面理解. (一)能量在生态系统中沿食物链与食物网流动的过程中,很大一部分因生物的呼吸转化成热能散失掉了,根据热力学第二定律:一切与热现象有关的实际宏观过程都是不可逆的.(见热学教科书)它只能向自由能(在生态系统中就是贮藏在有机物中的化学能)减少的方向进行而不能逆转. (二)能量是伴随着食物沿食物链与食物
The one-way flow of energy teachers have to emphasize the flow of energy in the ecosystem: the flow of energy is one-way; the flow of matter is cyclic and belongs to the biogeochemical cycle. I believe that the one-way flow of energy should be The following aspects are understood: (1) During the process of energy flowing along the food chain and food web in the ecosystem, a large part of the energy is lost through the conversion of biological respiration into heat energy. According to the second law of thermodynamics, everything is related to thermal phenomena. The actual macroscopic processes are irreversible. (See thermal science textbooks.) It can only proceed in the direction of the reduction of free energy (the chemical energy stored in organic matter in the ecosystem) and cannot be reversed. (B) Energy is accompanied by food along the Food chain and food