農(nóng)業(yè)生態(tài)學國家精品課程課件第三章

1、第三章 能量流動Chapter 3 Energy flow,2024/3/19,1,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,2,一、能量轉(zhuǎn)移二、農(nóng)業(yè)生態(tài)系統(tǒng)遵守能量流動的基本規(guī)律三、食物是農(nóng)業(yè)生態(tài)系統(tǒng)中的能量載體四、農(nóng)業(yè)生態(tài)系統(tǒng)的能源、能流途徑和能效五、農(nóng)業(yè)生態(tài)系統(tǒng)的能流調(diào)控,主要內(nèi)容,2024/3/19,國家級精品資源共享課,3,（一）能量轉(zhuǎn)移 植物利用太陽能，通過光合作用生產(chǎn)食物能，食

2、物能通過食物鏈和食物網(wǎng)，從一個營養(yǎng)級傳遞到另一個營養(yǎng)級。,,,一、能量轉(zhuǎn)移,食草動物,食肉動物,2024/3/19,4,國家級精品資源共享課,The relationship between matter and energy,Once energy is transformed into heat, it can no longer be used by living organisms to do work or to fuel t

3、he synthesis of biomass, the heat is lost to the atmosphere and can never be recycled. Life on Earth is possible because a fresh supply of solar energy is made available every day. In contrast, nutrients such as carbon c

4、an be reused. Chemical nutrients, the building blocks if biomass, can be used again, and recycling is a critical feature. Unlike the energy in solar radiation, nutrients are not in unalterable supply. If plants, and thei

5、r consumers were not eventually decomposed, the supply of nutrients would become exhausted and life on Earth would cease.,2024/3/19,5,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,6,1.流—生態(tài)系統(tǒng)中能量和物質(zhì)不斷地被吸收、貯存和轉(zhuǎn)移的運動狀態(tài)。能量的轉(zhuǎn)移—能量流。物質(zhì)的轉(zhuǎn)化—物質(zhì)流。

6、流量要多，流速要快 增加流量的方法：提高能量轉(zhuǎn)化效率、減少消耗 增加流速的方法：縮短周轉(zhuǎn)周期、提高周轉(zhuǎn)速率,（二）流、庫、環(huán)的概念及應用,2024/3/19,國家級精品資源共享課,7,2.庫—能量和物質(zhì)在運動過程中暫時被吸收和貯存的單位。庫要大、庫效率要高。（1）植物庫：庫大—土地利用充分、植物產(chǎn)品多；庫效率高—光合效率高（2）動物庫：庫大—種群多數(shù)量大、動物產(chǎn)品多；庫效率高—出欄率高，產(chǎn)肉蛋奶多（3

7、）土壤庫：庫大—土壤肥力高而穩(wěn)庫效率高—養(yǎng)分損失少，利用率高,2024/3/19,國家級精品資源共享課,8,3.環(huán)—各種庫將流連接起來形成的整體。環(huán)結構要合理 環(huán)流庫是相互聯(lián)系的。庫要大、效率高；環(huán)結構要合理；流要多且流暢。,2024/3/19,國家級精品資源共享課,9,（一）熱力學第一定律,二、農(nóng)業(yè)生態(tài)系統(tǒng)遵守能量流動的基本規(guī)律,（二）熱力學第二定律,1.能量傳遞有一定的方向，是不可逆的。2.能量轉(zhuǎn)化過程中存在著衰變現(xiàn)象，必

8、然有能量的耗散。3.為了判斷能量流動的方向和限度，用自由能和熵來描述。,2024/3/19,國家級精品資源共享課,10,The first law of thermodynamics states that energy can neither be created nor destroyed. The second law of thermodynamics states that every transformation resu

9、lts in a reduction of the free energy of the system. Because energy transformation cannot be 100% efficient (from the second law), heterotrophs must have less energy, and must therefore be rarer than the plants they feed

10、 on. The complexity of ecological interactions means that it is not possible to construct predictive mathematical models of living systems based on these laws of thermodynamics.,Ecosystems and the laws of thermodynamics,

11、2024/3/19,國家級精品資源共享課,11,（三）耗散結構理論,€ 普里高津耗散結構理論 Prigogine’s dissipation structure theory 指開放系統(tǒng)在遠離平衡態(tài)的非平衡態(tài)下，系統(tǒng)可能出現(xiàn)的一種穩(wěn)定的有序結構。€ 表明：一個遠離平衡態(tài)的開放系統(tǒng)，通過與外界環(huán)境進行物質(zhì)、能量的不斷交換，就能克服混亂狀態(tài)，維持穩(wěn)定狀態(tài)并且還有可能不斷提高系統(tǒng)的有序性，使系統(tǒng)的商減少。,2024/3/19,國

12、家級精品資源共享課,12,1.根據(jù)熱力學第一定律，可以對農(nóng)業(yè)生態(tài)系統(tǒng)的能量流進行定量研究。2.在農(nóng)業(yè)生態(tài)系統(tǒng)能量流中，只有少部分轉(zhuǎn)化成有機形態(tài)的化學潛能儲存起來，大部分轉(zhuǎn)化成熱能而耗散。3.能量流的流動方向是不可逆的，能量只能稱為轉(zhuǎn)化或轉(zhuǎn)移，而不能是循環(huán)。4.為了維持農(nóng)業(yè)生態(tài)系統(tǒng)的穩(wěn)定，應不斷的向系統(tǒng)輸入能量，減少熵。,(四)熱力學定律在農(nóng)業(yè)生態(tài)系統(tǒng)中的應用,2024/3/19,國家級精品資源共享課,13,（一）食物鏈1.定義：

13、生態(tài)系統(tǒng)中，來源于植物的食物能通過一系列吃與被吃的關系，把生物緊密的聯(lián)系起來，形成以食物營養(yǎng)為中心的鏈索關系即食物鏈。典型的食物鏈：植物→食草動物→一級食肉動物→二級食肉動物→頂級食肉動物,三、食物是農(nóng)業(yè)生態(tài)系統(tǒng)的能量載體,Autotrophic organisms assimilate inorganic resources into packages of organic molecules. There become the r

14、esources for heterotrophs which then become a resource for another consumer. At each link in this food chain we can recognize three pathways to the next trophic level: decomposition, parasitism and predation. Consumers m

15、ay be generalists (polyphagous), taking a wide variety of prey species or may specialize on single species or a range of closely related species (monophagous).,Pathways of nutrient flow,2024/3/19,14,國家級精品資源共享課,食物鏈,2024/3

16、/19,15,國家級精品資源共享課,A characteristic of an ecosystem is the number and nature of the species that occupy its various trophic levels. The relationship between constituents of one trophic level and constituents of adjacent t

17、rophic levels may be described by a food chain. This is a chain of eating and being eaten that connects, for example, carnivorous animals to their ultimate plant food. Many food chains exist in any given ecosystem and ca

18、n be combined into food webs. Ecosystems vary considerably in the pattern of their energy-nutrient webs.,Interactions between trophic levels,2024/3/19,16,國家級精品資源共享課,Top-down or bottom-up?,It has been argued that the eart

19、h is green and vegetated because herbivore numbers are regulated by their predators (top-down control), whilst all other trophic levels are regulated by competition for resources (bottom-up control). This simple model is

20、 attractive but of doubtful value. Herbivore species are highly constrained in the range of plant tissue they can eat, due to plant defences, and hence may be limited by competition even if the world is green. Further, a

21、t a gross level, plants are not energy-limited but space limited, so any space cleared by herbivory opens opportunities for more plants.,2024/3/19,17,國家級精品資源共享課,一個食物鏈的例子“螳螂捕蟬，黃雀在后”,,螳螂捕蟬，黃雀在后！哈！哈！,2024/3/19,18,國家級精品資源共享課

22、,食物鏈的基本類型（四種）,（1）捕食食物鏈，又稱為活食或草食食物鏈 海洋中：浮游植物→浮游動物→蝦→魚 草原上：草→羚羊→老虎 農(nóng)田中：水稻→蝗蟲→青蛙 農(nóng)業(yè)生產(chǎn)中：作物秸稈→?！耍?）腐生食物鏈，又稱碎屑或殘渣食物鏈 農(nóng)業(yè)上用秸稈、糞便生產(chǎn)沼氣 棉籽殼、稻草培育蘑菇,2024/3/19,19,國家級精品資源共享課,（3）寄生食物鏈植物型：大豆→菟絲子動物型：哺乳動物→跳蚤→原生動物→細菌→病毒；馬→蛔

23、蟲（4）混合食物鏈 稻草→牛（牛糞）→蚯蚓→雞（雞糞）→豬（豬糞）→魚；稻→螟→赤眼蜂；菜（溫棚）→雞（雞糞）→沼氣（沼渣）→肥田,2.營養(yǎng)級：生物在食物鏈上所處的位置，即食物鏈上每一個環(huán)節(jié)稱為營養(yǎng)級。,2024/3/19,20,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,21,海洋生態(tài)系統(tǒng)的食物鏈,The Trophic Pyramid:A Model of Consumption,,2024/3/19

24、,22,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,23,海洋與陸地生態(tài)系統(tǒng)的食物鏈,2024/3/19,國家級精品資源共享課,24,（1）同一食物鏈中常含有食性和生活習性極不相同的生物。（2）同一生態(tài)系統(tǒng)中可能有多條食物鏈，各種食物鏈相互聯(lián)系，協(xié)同發(fā)揮作用。（3）自然生態(tài)系統(tǒng)中，營養(yǎng)級的數(shù)目是有限的。（4）不同生態(tài)系統(tǒng)中，各類食物鏈的比重不同。森林生態(tài)系統(tǒng)：腐生食物鏈占生產(chǎn)有機物的90%草原生態(tài)系統(tǒng)：腐生

25、食物鏈占生產(chǎn)有機物的70%農(nóng)田生態(tài)系統(tǒng)：腐生食物鏈占生產(chǎn)有機物的20%~30%,3.食物鏈的基本特征,2024/3/19,國家級精品資源共享課,25,1.食物網(wǎng)和營養(yǎng)結構的概念食物網(wǎng)：生態(tài)系統(tǒng)中，一種生物常常以多種生物為食，同一生物又常常被多種生物取食，于是食物鏈交錯起來，多條食物鏈相互連接、形成的網(wǎng)狀結構。營養(yǎng)結構：以營養(yǎng)為紐帶，把生物與環(huán)境、生物與生物，緊密連接起來的結構。,（二）食物網(wǎng)和生態(tài)系統(tǒng)的營養(yǎng)結構,,Food Web

26、s Illustrate Complex Trophic Relationships,2024/3/19,26,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,27,生態(tài)系統(tǒng)抵抗外界干擾、自動修復的能力稱為生態(tài)系統(tǒng)的穩(wěn)定性。影響穩(wěn)定性的因素有很多，如生物的適應性、外界干擾的程度、營養(yǎng)結構等。 營養(yǎng)結構復雜、食物網(wǎng)復雜的生態(tài)系統(tǒng)，穩(wěn)定性強,2.營養(yǎng)結構與生態(tài)系統(tǒng)的穩(wěn)定性,2024/3/19,國家級精品資源共享課,2

27、8,（一）農(nóng)業(yè)生態(tài)系統(tǒng)的能源1.太陽能是生態(tài)系統(tǒng)的主要能源2.農(nóng)業(yè)生態(tài)系統(tǒng)的輔助能輔助能的類型：自然輔助能、人工輔助能：生物輔助能（有機能）、工業(yè)輔助能（無機能）輔助能的性質(zhì)：不能轉(zhuǎn)化成生物能，對生物能的合成、轉(zhuǎn)化起輔助作用輔助能的作用：促進轉(zhuǎn)化、減少消耗、改善環(huán)境,四、農(nóng)業(yè)生態(tài)系統(tǒng)的能源、能流途徑和能效,2024/3/19,國家級精品資源共享課,29,（二）農(nóng)業(yè)生態(tài)系統(tǒng)的能流途徑,生態(tài)系統(tǒng)中能量流動是指能量由非生物環(huán)境經(jīng)生物

28、有機體，再到外界環(huán)境所進行的一系列傳遞過程。在農(nóng)業(yè)生態(tài)系統(tǒng)中，能量流動的一般途徑包括以下幾個方面：1.太陽輻射的能量進入生態(tài)系統(tǒng)2.以植物有機體儲存的能量，沿食物鏈流動轉(zhuǎn)化3.生態(tài)系統(tǒng)中能量的外界輸入及輸出,生態(tài)系統(tǒng)中的能量流動,輸入生態(tài)系統(tǒng)中的能量（太陽能）總是和生物有機體貯存、轉(zhuǎn)換的能量和釋放的熱量相等。 以熱的形式散失的能量不能再回到生態(tài)系統(tǒng)參與流動和被利用,2024/3/19,30,國家級精品資源共享課,Connect

29、ions: Food Chains and Energy Flow in Ecosystems,,Ecological efficiency=10%Loss?,2024/3/19,31,國家級精品資源共享課,Primaryproducers,100 J,1,000,000 J of sunlight,10 J,1,000 J,10,000 J,Primaryconsumers,Secondaryconsumers,Tertia

30、ryconsumers,2024/3/19,32,國家級精品資源共享課,The dynamics of energy through ecosystems have important implications for the human population.,2024/3/19,33,國家級精品資源共享課,Energy flow through a community,Given that specified values can

31、 be obtained for net primary production and CE, AE and PE, it is possible to predict, using models, the pathway of energy flow at different trophic levels for different communities. From such modeling studies, which are

32、supported by field data, the most significant finding is the overwhelming importance of the decomposer system. Overall, in a steady state community, losses through animal respiration balance NPP so that standing crop bio

33、mass remains the same.,2024/3/19,34,國家級精品資源共享課,太陽輻射能,24%,52%,云層吸收10 %,浮塵15%,,,,,,反射25%,,臭氧層、水蒸氣等9%,24%,地球表面,47%,反射4%,,散射6%,散射17%,散射損失9%,,,,2024/3/19,35,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,36,一個穩(wěn)定生態(tài)系統(tǒng)的能量流,2024/3/19

34、,國家級精品資源共享課,37,2024/3/19,國家級精品資源共享課,38,Ecosystem Energy Flow,生態(tài)系統(tǒng)的能流,能流特征逐級減少單方向性能流路徑,2024/3/19,39,國家級精品資源共享課,Assimilatory:同化的 Dissimilatory：異化的,2024/3/19,40,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,41,1.能量流動過程中損耗的必然性（1）由于不可

35、食或不得食（2）消費者密度低或食物選擇限制 （3）利用后未被同化（4）同化后呼吸消耗掉（5）變?yōu)樯a(chǎn)量又被減少 營養(yǎng)級能量傳遞效率約平均為10%。,（三）農(nóng)業(yè)生態(tài)系統(tǒng)的能效和生態(tài)金字塔規(guī)律,2024/3/19,國家級精品資源共享課,42,2.能量傳遞效率（生態(tài)效率）：通常指食物鏈各環(huán)節(jié)上能量的各種轉(zhuǎn)化效率。肉豬35%、奶牛 20%、蛋雞15%、肉兔13~18%、肉羊11%、肉牛5~8%。,2024/3/19,國家級精品資源共

36、享課,43,新陳代謝、生長和運動是生命的基本功能 物理運動—化學運動—生命運動,2024/3/19,國家級精品資源共享課,44,3.生態(tài)金字塔規(guī)律,生態(tài)金字塔是生態(tài)學研究中用以反映食物鏈各營養(yǎng)級之間生物個體數(shù)量、生物量和能量比例關系的一個圖解模型。類型 數(shù)量金字塔樹木→昆蟲→鳥類（畸形金字塔）生物量金字塔浮游植物→浮游動物→底棲動物（倒置金字塔）能量金字塔,能量金字塔,2024/3/19,45,國家級精品資源共享課,20

37、24/3/19,國家級精品資源共享課,46,Biomass and productivity generally decrease with trophic level,Hence the Trophic Pyramid,2024/3/19,國家級精品資源共享課,47,4.農(nóng)業(yè)生態(tài)系統(tǒng)的輔助能利用率又稱為能量產(chǎn)投比，是指農(nóng)業(yè)生態(tài)系統(tǒng)產(chǎn)出的生物能與人工輔助能的比值。,五、農(nóng)業(yè)生態(tài)系統(tǒng)的能流調(diào)控 1.擴源 2.強庫 3.截流 4.

38、減耗,能量：energy動能：dynamic energy潛能：potential energy食物鏈：food chain食物網(wǎng)：food web捕食食物鏈：predator chain or grazing chain腐食食物鏈：saprophytic food chain or detritus chain 寄生食

39、物鏈：parasitic food chain,2024/3/19,48,國家級精品資源共享課,生態(tài)金字塔：ecological pyramid生態(tài)效率：ecological efficiency人工輔助能：artificial auxiliary energy能值：emergy營養(yǎng)級：trophic level生物地球化學循環(huán)：biogeochemical cycles氣相型循環(huán)：gaseous type cycles

40、沉積型循環(huán)：sedimentary type cycles能量元素：energy elements大量元素：macronutrients微量元素：micronutrients,2024/3/19,49,國家級精品資源共享課,2024/3/19,國家級精品資源共享課,50,Trophic Relationships and Energy & Nutrient Flows,Components of an Agroecosys