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46.1: Ekolojia ya Mazingira

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    Ujuzi wa Kuendeleza

    • Eleza aina ya msingi ya mazingira duniani
    • Eleza mbinu ambazo wanaikolojia hutumia kujifunza muundo wa mazingira na mienendo
    • Kutambua njia tofauti za modeling mazingira
    • Tofauti kati ya minyororo ya chakula na webs chakula na kutambua umuhimu wa kila

    Maisha katika mazingira ni mara nyingi kuhusu ushindani wa rasilimali ndogo, tabia ya nadharia ya uteuzi wa asili. Ushindani katika jamii (vitu vyote vilivyo hai ndani ya makazi maalum) huzingatiwa wote ndani ya spishi na kati ya spishi mbalimbali. Rasilimali ambazo viumbe hushindana ni pamoja na nyenzo za kikaboni kutoka kwa viumbe hai au vilivyo hai hapo awali, jua, na virutubisho vya madini, ambavyo hutoa nishati kwa michakato ya maisha na suala la kuunda miundo ya kimwili ya viumbe. Sababu nyingine muhimu zinazoathiri mienendo ya jamii ni vipengele vya mazingira yake ya kimwili na ya kijiografia: latitude ya makazi, kiasi cha mvua, topography (mwinuko), na aina zilizopo. Hizi zote ni vigezo muhimu vya mazingira vinavyoamua ni viumbe gani vinavyoweza kuwepo ndani ya eneo fulani.

    Mazingira ni jamii ya viumbe hai na mwingiliano wao na mazingira yao ya abiotiki (yasiyo ya kuishi). Mazingira yanaweza kuwa madogo, kama vile mabwawa ya mawimbi yanayopatikana karibu na mwambao wa miamba ya bahari nyingi, au kubwa, kama vile msitu wa mvua wa Amazon nchini Brazil (Kielelezo\(\PageIndex{1}\)).

    Picha ya kushoto inaonyesha bwawa la mawimbi yenye mwani na konokono. Picha ya haki inaonyesha msitu wa mvua wa Amazon.
    Kielelezo\(\PageIndex{1}\): A (a) mawimbi pool mazingira katika Matinicus Island katika Maine ni mazingira ndogo, wakati (b) Amazon msitu wa mvua katika Brazil ni mazingira kubwa. (mikopo a: mabadiliko ya kazi na “takomabibelot” /Flickr; mikopo b: mabadiliko ya kazi na Ivan Mlinaric)

    Kuna makundi matatu mapana ya mazingira kulingana na mazingira yao ya jumla: maji safi, maji ya bahari, na duniani. Ndani ya makundi haya mapana ni aina ya mazingira ya mtu binafsi kulingana na viumbe vilivyopo na aina ya mazingira ya mazingira.

    Mazingira ya bahari ni ya kawaida, yenye asilimia 75 ya uso wa Dunia na yenye aina tatu za msingi: bahari duni, maji ya bahari ya kina, na nyuso za kina za bahari (maeneo ya chini ya kina cha bahari ya kina). kina mazingira ya bahari ni pamoja na biodiferse sana mazingira ya matumbawe mwamba, na kina bahari uso inajulikana kwa idadi yake kubwa ya plankton na krill (crustaceans ndogo) kwamba msaada wake. Mazingira haya mawili ni muhimu hasa kwa respirators aerobic duniani kote kama phytoplanktoni hufanya asilimia 40 ya usanisinuru wote duniani. Ingawa si tofauti kama nyingine mbili, mazingira ya bahari ya kina yana aina mbalimbali za viumbe vya baharini. Mazingira hayo yanapo hata chini ya bahari ambako mwanga hauwezi kupenya kupitia maji.

    Mazingira ya maji safi ni rarest, yanayotokea kwenye asilimia 1.8 tu ya uso wa Dunia. Maziwa, mito, mito, na chemchemi hujumuisha mifumo hii; ni tofauti kabisa, na huunga mkono aina mbalimbali za samaki, amfibia, reptilia, wadudu, phytoplankton, fungi, na bakteria.

    Mazingira ya nchi, pia yanajulikana kwa utofauti wao, yanajumuishwa katika makundi makubwa yanayoitwa biomes, kama vile misitu ya mvua ya kitropiki, savannas, jangwa, misitu ya coniferous, misitu ya deciduous, na tundra. Kuunganisha mazingira haya katika makundi machache ya biome huficha utofauti mkubwa wa mazingira ya mtu binafsi ndani yao. Kwa mfano, kuna tofauti kubwa katika mimea ya jangwa: cacti ya saguaro na maisha mengine ya mimea katika Jangwa la Sonoran, nchini Marekani, ni kiasi kikubwa ikilinganishwa na jangwa la mawe la Boa Vista, kisiwa mbali na pwani ya Afrika Magharibi (Kielelezo\(\PageIndex{2}\)).

    Picha (a) inaonyesha saguaro cacti kwamba kuangalia kama miti ya simu na silaha kupanuliwa kutoka kwao. Picha (b) inaonyesha wazi tasa ya udongo nyekundu iliyojaa miamba.
    Kielelezo\(\PageIndex{2}\): mazingira ya jangwa, kama mazingira yote, yanaweza kutofautiana sana. Jangwa katika (a) Hifadhi ya Taifa ya Saguaro, Arizona, ina maisha mengi ya mimea, wakati jangwa la miamba la (b) kisiwa cha Boa Vista, Cape Verde, Afrika, hauna maisha ya mimea. (mikopo a: mabadiliko ya kazi na Jay Galvin; mikopo b: mabadiliko ya kazi na Ingo Wölbern)

    Mazingira ni ngumu na sehemu nyingi zinazoingiliana. Wao ni mara kwa mara wazi kwa misukosuko mbalimbali, au mabadiliko katika mazingira yanayoathiri nyimbo zao: tofauti kila mwaka katika mvua na joto na taratibu polepole ya ukuaji wa mimea, ambayo inaweza kuchukua miaka kadhaa. Mateso mengi haya ni matokeo ya michakato ya asili. Kwa mfano, wakati umeme unasababisha moto wa misitu na kuharibu sehemu ya mazingira ya misitu, ardhi hatimaye inaishi na nyasi, halafu kwa misitu na vichaka, na baadaye kwa miti ya kukomaa, kurejesha msitu kwa hali yake ya zamani. Athari za usumbufu wa mazingira unaosababishwa na shughuli za binadamu ni muhimu kama mabadiliko yaliyofanywa na michakato ya asili. Mazoea ya kilimo ya binadamu, uchafuzi wa hewa, mvua ya asidi, ukataji miti wa kimataifa, uvuvi mkubwa, eutrophication, kumwagika mafuta, na kutupwa kinyume cha sheria kwenye ardhi na ndani ya bahari ni masuala yote ya wasiwasi kwa wahifadhi wa mazingira.

    Msawazo ni hali thabiti ya mazingira ambapo viumbe vyote vina usawa na mazingira yao na kwa kila mmoja. Katika ikolojia, vigezo viwili hutumiwa kupima mabadiliko katika mazingira: upinzani na ustahimilivu. Uwezo wa mazingira kubaki katika usawa licha ya mvuruko huitwa upinzani. Kasi ambayo mazingira yanapona usawa baada ya kusumbuliwa, inayoitwa ujasiri wake. Upinzani wa mazingira na ustahimilivu ni muhimu hasa wakati wa kuzingatia athari za binadamu. Hali ya mazingira inaweza kubadilika kwa kiwango kwamba inaweza kupoteza ustahimilivu wake kabisa. Utaratibu huu unaweza kusababisha uharibifu kamili au mabadiliko yasiyotumiwa ya mazingira.

    Chakula Chakula na Webs Chakula

    Neno “mlolongo wa chakula” wakati mwingine hutumiwa metaphorically kuelezea hali ya kijamii ya binadamu. Kwa maana hii, minyororo ya chakula hufikiriwa kama ushindani wa kuishi, kama vile “nani anakula nani?” Mtu anakula na mtu huliwa. Kwa hiyo, haishangazi kwamba katika jamii yetu ya ushindani “mbwa-kula mbwa”, watu ambao wanaonekana kuwa na mafanikio wanaonekana kuwa juu ya mlolongo wa chakula, wakitumia wengine wote kwa manufaa yao, wakati wasio na mafanikio huonekana kuwa chini.

    Uelewa wa kisayansi wa mlolongo wa chakula ni sahihi zaidi kuliko katika matumizi yake ya kila siku. Katika ikolojia, mlolongo wa chakula ni mlolongo wa mstari wa viumbe kwa njia ambayo virutubisho na nishati hupita: wazalishaji wa msingi, watumiaji wa msingi, na watumiaji wa ngazi ya juu hutumiwa kuelezea muundo wa mazingira na mienendo. Kuna njia moja kupitia mnyororo. Kila kiumbe katika mlolongo wa chakula kinachukua kile kinachoitwa ngazi ya trophic. Kulingana na jukumu lao kama wazalishaji au watumiaji, aina au makundi ya aina yanaweza kupewa ngazi mbalimbali za trophic.

    Katika mazingira mengi, chini ya mlolongo wa chakula ina viumbe vya photosynthetic (mimea na/au phytoplankton), ambayo huitwa wazalishaji wa msingi. Viumbe vinavyotumia wazalishaji wa msingi ni herbivores: watumiaji wa msingi. Wateja wa sekondari ni kawaida carnivores ambao hula watumiaji wa msingi. Wateja wa juu ni carnivores ambao hula carnivores nyingine. Wateja wa ngazi ya juu hulisha viwango vya chini vya tropiki, na kadhalika, hadi viumbe vilivyo juu ya mlolongo wa chakula: walaji wa kilele. Katika Ziwa Ontario mlolongo chakula inavyoonekana katika Kielelezo\(\PageIndex{3}\), Chinook samaki ni kilele walaji juu ya mlolongo huu chakula.

    Katika mfano huu ngazi ya chini ya trophic ni mtayarishaji wa msingi, ambayo ni mwani wa kijani. Wateja wa msingi ni mollusks, au konokono. Watumiaji wa sekondari ni samaki wadogo wanaoitwa slimy sculpin. Watumiaji wa juu na wa kilele ni sahani ya Chinook.
    Kielelezo\(\PageIndex{3}\): Hizi ni ngazi trophic ya mlolongo wa chakula katika Ziwa Ontario katika mpaka wa Marekani-Canada. Nishati na virutubisho hutoka kutoka kwa mwani wa kijani wa photosynthetic chini hadi juu ya mlolongo wa chakula: sahani ya Chinook.

    Sababu moja kubwa ambayo hupunguza urefu wa minyororo ya chakula ni nishati. Nishati inapotea kama joto kati ya kila ngazi ya trophic kutokana na sheria ya pili ya thermodynamics. Hivyo, baada ya idadi ndogo ya uhamisho wa nishati ya trophic, kiasi cha nishati iliyobaki katika mlolongo wa chakula inaweza kuwa kubwa ya kutosha kusaidia watu wenye faida katika ngazi ya juu ya trophic.

    Kupoteza nishati kati ya viwango vya trophic inaonyeshwa na masomo ya uanzilishi wa Howard T. Odum katika Silver Springs, Florida, mazingira katika miaka ya 1940 (Kielelezo\(\PageIndex{4}\)). Wazalishaji wa msingi walizalisha 20,819 kcal/m 2 /yr (kilocalories kwa kila mita ya mraba kwa mwaka), watumiaji wa msingi walizalisha 3368 kcal/m 2 /yr, watumiaji wa sekondari yanayotokana 383 kcal/m 2 /yr, na watumiaji wa juu huzalisha tu 21 kcal/m 2 /yr. Hivyo, kuna nishati kidogo iliyobaki kwa kiwango kingine cha watumiaji katika mazingira haya.

    Grafu inaonyesha maudhui ya nishati katika viwango tofauti vya trophic. Maudhui ya nishati ya wazalishaji wa msingi ni zaidi ya kilocalories 20,000 kwa mita ya mraba kwa mwaka. Maudhui ya nishati ya watumiaji wa msingi ni ndogo sana, kuhusu kilocalories 3,400 kwa mita ya mraba kwa mwaka. Maudhui ya nishati ya watumiaji wa sekondari ni kilocalories 383 kwa mita ya mraba kwa mwaka, na maudhui ya nishati ya watumiaji wa juu ni kilocalories 21 tu kwa mita ya mraba kwa mwaka.
    Kielelezo\(\PageIndex{4}\): nishati jamaa katika ngazi trophic katika Silver Springs, Florida, mazingira ni umeonyesha. Kila ngazi ya trophic ina nishati ndogo inapatikana na inasaidia viumbe wachache katika ngazi inayofuata.

    Kuna tatizo moja wakati wa kutumia minyororo ya chakula ili kuelezea kwa usahihi mazingira mengi. Hata kama viumbe vyote vinapowekwa katika viwango vya trophic vinavyofaa, baadhi ya viumbe hawa wanaweza kulisha spishi kutoka ngazi zaidi ya moja ya trophic; vivyo hivyo, baadhi ya viumbe hivi vinaweza kuliwa na spishi kutoka ngazi nyingi za trophic. Kwa maneno mengine, mfano wa mstari wa mazingira, mlolongo wa chakula, hauelezei kabisa muundo wa mazingira. Mfano wa jumla-ambayo akaunti kwa mwingiliano wote kati ya aina tofauti na uhusiano wao tata unaohusiana na kila mmoja na kwa mazingira-ni mfano sahihi zaidi na wa maelezo kwa mazingira. Mtandao wa chakula ni uwakilishi wa graphic wa mtandao wa jumla, usio na mstari wa wazalishaji wa msingi, watumiaji wa msingi, na watumiaji wa ngazi ya juu waliotumiwa kuelezea muundo wa mazingira na mienendo (Kielelezo\(\PageIndex{5}\)).

    Ngazi ya chini ya mfano inaonyesha wazalishaji wa msingi, ambao ni pamoja na diatoms, mwani wa kijani, mwani wa bluu-kijani, flagellates, na rotifers. Ngazi inayofuata ni pamoja na watumiaji wa msingi ambao hula wazalishaji wa msingi. Hizi ni pamoja na calanoids, waterfleas, na cyclopoids, rotifers na amphipods. Shrimp pia hula wazalishaji wa msingi. Wateja wa msingi kwa upande wake huliwa na watumiaji wa sekondari, ambayo ni kawaida samaki wadogo. Samaki wadogo huliwa na samaki kubwa, watumiaji wa juu, au walaji wa kilele. Pembe ya njano, mtumiaji wa sekondari, anakula samaki wadogo ndani ya ngazi yake ya trophic. Samaki wote huliwa na lamprey ya bahari. Hivyo, mtandao wa chakula ni ngumu na tabaka zilizoingiliana.
    Kielelezo\(\PageIndex{5}\): Mtandao huu wa chakula unaonyesha mwingiliano kati ya viumbe katika ngazi za trophic katika mazingira ya Ziwa Ontario. Wazalishaji wa msingi wanaelezewa katika watumiaji wa kijani, wa msingi katika watumiaji wa machungwa, sekondari katika watumiaji wa bluu, na watumiaji wa juu (kilele) katika zambarau. Mishale inaelezea kutoka kwa viumbe vinavyotumiwa kwa viumbe vinavyotumia. Angalia jinsi mistari fulani inavyoelezea kiwango cha zaidi ya moja ya trophic. Kwa mfano, shrimp ya opossum hula wazalishaji wote wa msingi na watumiaji wa msingi. (mikopo: NOAA, GLERL)

    Ulinganisho wa aina mbili za mifano ya mazingira ya miundo inaonyesha nguvu katika wote wawili. Chakula minyororo ni rahisi zaidi kwa ajili ya uchambuzi modeling, ni rahisi kufuata, na ni rahisi kwa majaribio na, ambapo chakula mtandao mifano kwa usahihi kuwakilisha muundo wa mazingira na mienendo, na data inaweza moja kwa moja kutumika kama pembejeo kwa simulation modeling.

    Unganisha na Kujifunza

    Kichwa kwa simulator hii online maingiliano kuchunguza chakula mtandao kazi. Katika sanduku la Interactive Labs, chini ya Chakula cha Mtandao, bofya Hatua ya 1. Soma maelekezo ya kwanza, na kisha bofya Hatua ya 2 kwa maelekezo ya ziada. Unapokuwa tayari kuunda simulation, kwenye kona ya juu ya kulia ya sanduku la Interactive Labs, bofya OPEN SIMULATOR.

    Aina mbili za jumla za utando wa chakula mara nyingi huonyeshwa kuingiliana ndani ya mazingira moja. malisho ya chakula mtandao (kama vile Ziwa Ontario chakula mtandao katika Kielelezo\(\PageIndex{5}\)) has plants or other photosynthetic organisms at its base, followed by herbivores and various carnivores. A detrital food web consists of a base of organisms that feed on decaying organic matter (dead organisms), called decomposers or detritivores. These organisms are usually bacteria or fungi that recycle organic material back into the biotic part of the ecosystem as they themselves are consumed by other organisms. As all ecosystems require a method to recycle material from dead organisms, most grazing food webs have an associated detrital food web. For example, in a meadow ecosystem, plants may support a grazing food web of different organisms, primary and other levels of consumers, while at the same time supporting a detrital food web of bacteria, fungi, and detrivorous invertebrates feeding off dead plants and animals.

    Evolution Connection: Three-spined Stickleback

    It is well established by the theory of natural selection that changes in the environment play a major role in the evolution of species within an ecosystem. However, little is known about how the evolution of species within an ecosystem can alter the ecosystem environment. In 2009, Dr. Luke Harmon, from the University of Idaho in Moscow, published a paper that for the first time showed that the evolution of organisms into subspecies can have direct effects on their ecosystem environment.1

    The three-spines stickleback (Gasterosteus aculeatus) is a freshwater fish that evolved from a saltwater fish to live in freshwater lakes about 10,000 years ago, which is considered a recent development in evolutionary time (Figure \(\PageIndex{6}\)). Over the last 10,000 years, these freshwater fish then became isolated from each other in different lakes. Depending on which lake population was studied, findings showed that these sticklebacks then either remained as one species or evolved into two species. The divergence of species was made possible by their use of different areas of the pond for feeding called micro niches.

    Dr. Harmon and his team created artificial pond microcosms in 250-gallon tanks and added muck from freshwater ponds as a source of zooplankton and other invertebrates to sustain the fish. In different experimental tanks they introduced one species of stickleback from either a single-species or double-species lake.

    Over time, the team observed that some of the tanks bloomed with algae while others did not. This puzzled the scientists, and they decided to measure the water's dissolved organic carbon (DOC), which consists of mostly large molecules of decaying organic matter that give pond-water its slightly brownish color. It turned out that the water from the tanks with two-species fish contained larger particles of DOC (and hence darker water) than water with single-species fish. This increase in DOC blocked the sunlight and prevented algal blooming. Conversely, the water from the single-species tank contained smaller DOC particles, allowing more sunlight penetration to fuel the algal blooms.

    This change in the environment, which is due to the different feeding habits of the stickleback species in each lake type, probably has a great impact on the survival of other species in these ecosystems, especially other photosynthetic organisms. Thus, the study shows that, at least in these ecosystems, the environment and the evolution of populations have reciprocal effects that may now be factored into simulation models.

    Photo shows two small fish swimming above a rocky bottom.
    Figure \(\PageIndex{6}\): The three-spined stickleback evolved from a saltwater fish to freshwater fish. (credit: Barrett Paul, USFWS)

    Research into Ecosystem Dynamics: Ecosystem Experimentation and Modeling

    The study of the changes in ecosystem structure caused by changes in the environment (disturbances) or by internal forces is called ecosystem dynamics. Ecosystems are characterized using a variety of research methodologies. Some ecologists study ecosystems using controlled experimental systems, while some study entire ecosystems in their natural state, and others use both approaches.

    A holistic ecosystem model attempts to quantify the composition, interaction, and dynamics of entire ecosystems; it is the most representative of the ecosystem in its natural state. A food web is an example of a holistic ecosystem model. However, this type of study is limited by time and expense, as well as the fact that it is neither feasible nor ethical to do experiments on large natural ecosystems. To quantify all different species in an ecosystem and the dynamics in their habitat is difficult, especially when studying large habitats such as the Amazon Rainforest, which covers 1.4 billion acres (5.5 million km2) of the Earth’s surface.

    For these reasons, scientists study ecosystems under more controlled conditions. Experimental systems usually involve either partitioning a part of a natural ecosystem that can be used for experiments, termed a mesocosm, or by re-creating an ecosystem entirely in an indoor or outdoor laboratory environment, which is referred to as a microcosm. A major limitation to these approaches is that removing individual organisms from their natural ecosystem or altering a natural ecosystem through partitioning may change the dynamics of the ecosystem. These changes are often due to differences in species numbers and diversity and also to environment alterations caused by partitioning (mesocosm) or re-creating (microcosm) the natural habitat. Thus, these types of experiments are not totally predictive of changes that would occur in the ecosystem from which they were gathered.

    As both of these approaches have their limitations, some ecologists suggest that results from these experimental systems should be used only in conjunction with holistic ecosystem studies to obtain the most representative data about ecosystem structure, function, and dynamics.

    Scientists use the data generated by these experimental studies to develop ecosystem models that demonstrate the structure and dynamics of ecosystems. Three basic types of ecosystem modeling are routinely used in research and ecosystem management: a conceptual model, an analytical model, and a simulation model. A conceptual model is an ecosystem model that consists of flow charts to show interactions of different compartments of the living and nonliving components of the ecosystem. A conceptual model describes ecosystem structure and dynamics and shows how environmental disturbances affect the ecosystem; however, its ability to predict the effects of these disturbances is limited. Analytical and simulation models, in contrast, are mathematical methods of describing ecosystems that are indeed capable of predicting the effects of potential environmental changes without direct experimentation, although with some limitations as to accuracy. An analytical model is an ecosystem model that is created using simple mathematical formulas to predict the effects of environmental disturbances on ecosystem structure and dynamics. A simulation model is an ecosystem model that is created using complex computer algorithms to holistically model ecosystems and to predict the effects of environmental disturbances on ecosystem structure and dynamics. Ideally, these models are accurate enough to determine which components of the ecosystem are particularly sensitive to disturbances, and they can serve as a guide to ecosystem managers (such as conservation ecologists or fisheries biologists) in the practical maintenance of ecosystem health.

    Conceptual Models

    Conceptual models are useful for describing ecosystem structure and dynamics and for demonstrating the relationships between different organisms in a community and their environment. Conceptual models are usually depicted graphically as flow charts. The organisms and their resources are grouped into specific compartments with arrows showing the relationship and transfer of energy or nutrients between them. Thus, these diagrams are sometimes called compartment models.

    To model the cycling of mineral nutrients, organic and inorganic nutrients are subdivided into those that are bioavailable (ready to be incorporated into biological macromolecules) and those that are not. For example, in a terrestrial ecosystem near a deposit of coal, carbon will be available to the plants of this ecosystem as carbon dioxide gas in a short-term period, not from the carbon-rich coal itself. However, over a longer period, microorganisms capable of digesting coal will incorporate its carbon or release it as natural gas (methane, CH4), changing this unavailable organic source into an available one. This conversion is greatly accelerated by the combustion of fossil fuels by humans, which releases large amounts of carbon dioxide into the atmosphere. This is thought to be a major factor in the rise of the atmospheric carbon dioxide levels in the industrial age. The carbon dioxide released from burning fossil fuels is produced faster than photosynthetic organisms can use it. This process is intensified by the reduction of photosynthetic trees because of worldwide deforestation. Most scientists agree that high atmospheric carbon dioxide is a major cause of global climate change.

    Conceptual models are also used to show the flow of energy through particular ecosystems. Figure \(\PageIndex{7}\) is based on Howard T. Odum’s classical study of the Silver Springs, Florida, holistic ecosystem in the mid-twentieth century.2 This study shows the energy content and transfer between various ecosystem compartments.

    Flow chart shows that the ecosystem absorbs 1,700,00 calories per meter squared per year of sunlight. Primary producers have a gross productivity of 20,810 calories per meter squared per year. 13,187 calories per meter squared per year is lost to respiration and heat, so the net productivity of primary producers is 7,618 calories per meter squared per year. 4,250 calories per meter squared per year is passed on to decomposers, and the remaining 3,368 calories per meter squared per year is passed on to primary consumers. Thus, the gross productivity of primary consumers is 3,368 calories per meter squared per year. 2,265 calories per meter squared per year is lost to heat and respiration, resulting in a net productivity for primary consumers of 1,103 calories per meter squared per year. 720 calories per meter squared per year is lost to decomposers, and 383 calories per meter squared per year becomes the gross productivity of secondary consumers. 272 calories per meter squared per year is lost to heat and respiration, so the net productivity for secondary consumers is 111 calories per meter squared per year. 90 calories per meter squared per year is lost to decomposers, and the remaining 21 calories per meter squared per year becomes the gross productivity of tertiary consumers. Sixteen calories per meter squared per year is lost to respiration and heat, so the net productivity of tertiary consumers is 5 calories per meter squared per year. All this energy is lost to decomposers. In total, decomposers use 5,060 calories per meter squared per year of energy, and 20,810 calories per meter squared per year is lost to respiration and heat.
    Figure \(\PageIndex{7}\): This conceptual model shows the flow of energy through a spring ecosystem in Silver Springs, Florida. Notice that the energy decreases with each increase in trophic level.

    Exercise

    Why do you think the value for gross productivity of the primary producers is the same as the value for total heat and respiration (20,810 kcal/m2/yr)?

    Answer

    According to the first law of thermodynamics, energy can neither be created nor destroyed. Eventually, all energy consumed by living systems is lost as heat or used for respiration, and the total energy output of the system must equal the energy that went into it.

    Analytical and Simulation Models

    The major limitation of conceptual models is their inability to predict the consequences of changes in ecosystem species and/or environment. Ecosystems are dynamic entities and subject to a variety of abiotic and biotic disturbances caused by natural forces and/or human activity. Ecosystems altered from their initial equilibrium state can often recover from such disturbances and return to a state of equilibrium. As most ecosystems are subject to periodic disturbances and are often in a state of change, they are usually either moving toward or away from their equilibrium state. There are many of these equilibrium states among the various components of an ecosystem, which affects the ecosystem overall. Furthermore, as humans have the ability to greatly and rapidly alter the species content and habitat of an ecosystem, the need for predictive models that enable understanding of how ecosystems respond to these changes becomes more crucial.

    Analytical models often use simple, linear components of ecosystems, such as food chains, and are known to be complex mathematically; therefore, they require a significant amount of mathematical knowledge and expertise. Although analytical models have great potential, their simplification of complex ecosystems is thought to limit their accuracy. Simulation models that use computer programs are better able to deal with the complexities of ecosystem structure.

    A recent development in simulation modeling uses supercomputers to create and run individual-based simulations, which accounts for the behavior of individual organisms and their effects on the ecosystem as a whole. These simulations are considered to be the most accurate and predictive of the complex responses of ecosystems to disturbances.

    Link to Learning

    Tembelea Mradi wa Darwin ili uone aina mbalimbali za mifano ya mazingira.

    Muhtasari

    Mazingira yanapo kwenye ardhi, baharini, hewa, na chini ya ardhi. Njia tofauti za kuimarisha mazingira ni muhimu kuelewa jinsi matatizo ya mazingira yataathiri muundo wa mazingira na mienendo. Mifano ya dhana ni muhimu kuonyesha mahusiano ya jumla kati ya viumbe na mtiririko wa vifaa au nishati kati yao. Mifano ya uchambuzi hutumiwa kuelezea minyororo ya chakula ya mstari, na mifano ya simulation hufanya kazi bora na utando wa chakula kamili.

    maelezo ya chini

    1. 1 Nature (Vol 458, 1 Aprili 2009)
    2. 2 Howard T. Odum, “Muundo wa Trophic na Uzalishaji wa Silver Springs, Florida,” Monographs ya kiikolojia 27, namba 1 (1957): 47—112.

    faharasa

    mfano wa uchambuzi
    mfano wa mazingira kwamba ni kuundwa kwa formula hisabati kutabiri madhara ya misukosuko ya mazingira juu ya muundo wa mazingira na mienendo
    kilele matumizi
    viumbe juu ya mlolongo wa chakula
    mfano wa dhana
    (pia, compartment mifano) mfano wa mazingira ambayo ina chati za mtiririko zinazoonyesha mwingiliano wa compartments tofauti ya vipengele hai na yasiyo ya kuishi ya mazingira
    mtandao wa chakula cha chakula
    aina ya mtandao wa chakula ambapo watumiaji wa msingi hujumuisha waharibifu; hizi mara nyingi huhusishwa na malisho ya utando wa chakula ndani ya mazingira sawa
    mfumo wa ikolojia
    jamii ya viumbe hai na mwingiliano wao na mazingira yao abiotic
    mienendo ya mazingira
    utafiti wa mabadiliko katika muundo wa mazingira unaosababishwa na mabadiliko katika mazingira au vikosi vya ndani
    usawa
    hali ya kutosha ya mazingira ambapo viumbe vyote vina usawa na mazingira yao na kila mmoja
    mlolongo wa chakula
    uwakilishi wa mstari wa mlolongo wa wazalishaji wa msingi, watumiaji wa msingi, na watumiaji wa ngazi ya juu waliotumiwa kuelezea muundo wa mazingira na mienendo
    mtandao wa chakula
    uwakilishi wa picha ya mtandao wa jumla, usio na mstari wa wazalishaji wa msingi, watumiaji wa msingi, na watumiaji wa ngazi ya juu waliotumiwa kuelezea muundo wa mazingira na mienendo
    malisho ya chakula mtandao
    aina ya mtandao wa chakula ambayo wazalishaji wa msingi ni ama mimea kwenye ardhi au phytoplankton katika maji; mara nyingi huhusishwa na mtandao wa chakula cha detrital ndani ya mazingira sawa
    jumla ya mfumo wa mazingira
    utafiti kwamba majaribio ya kupima muundo, mwingiliano, na mienendo ya mazingira yote; mara nyingi mdogo na matatizo ya kiuchumi na vifaa, kulingana na mazingira
    mesocosm
    sehemu ya mazingira ya asili ya kutumika kwa ajili ya majaribio
    microcosm
    re-viumbe wa mazingira ya asili kabisa katika mazingira ya maabara ya kutumika kwa ajili ya majaribio
    matumizi ya msingi
    trophic ngazi ambayo inapata nishati yake kutoka kwa wazalishaji wa msingi wa mazingira
    mtayarishaji wa msingi
    trophic ngazi ambayo inapata nishati yake kutoka jua, kemikali isokaboni, au wafu na/au kuoza vifaa vya kikaboni
    ujasiri (kiikolojia)
    kasi ambayo mazingira recovers msawazo baada ya kusumbuliwa
    upinzani (kiikolojia)
    uwezo wa mazingira ya kubaki katika usawa licha ya misukosuko
    matumizi ya sekondari
    kawaida carnivore kwamba kula walaji wa msingi
    mfano wa simulation
    mfano wa mazingira ambayo imeundwa na programu za kompyuta kwa ukamilifu mfano wa mazingira na kutabiri madhara ya misukosuko ya mazingira juu ya muundo wa mazingira na mienendo
    matumizi ya juu
    carnivore kwamba kula carnivores nyingine
    ngazi ya trophic
    nafasi ya aina au kundi la aina katika mlolongo wa chakula au mtandao wa chakula