Ékologi

Ékologi mangrupa cabang élmu nu ngulik sebaran jeung ayana mahluk hirup, habitat, jeung interaksi antara maranéhna sarta lingkunganana — nu ngawengku boh unsur-unsur abiotik (teu hirup) saperti cuaca jeung géologi, jeung unsur biotik saperti spésiés. Istilah ieu diwanohkeun dina taun 1866 ku biolog Jérman Ernst Haeckel, nyokot tina basa Yunani oikos nu hartina "imah" jeung logos
Ékologi manusa mangrupa disiplin akademik nu patali tapi béda, ngulik kamanusaan, kagiatan spésiésna nu teratur, jeung lingkunganana; raket pisan hubunganana jeung ékologi biologis, sosiologi, ogé disiplin séjénna.
Di saluareun kontéks ilmiah, kecap ékologi mindeng dipaké salaku sinonim pikeun "lingkunganana", nyaéta reureujeunganana sakur organisme liar nu lolobanaana hirup dina tata sarta lingkungan aslina, kalawan saeutik pangaruh manusa; utamana nu patali jeung naon baé kapentingan manusa — ékonomis, médis, éstétis, hédonistik, séntiméntal, jsb... Harti ieu biasana dilarapkeun nalika urang nyebutkeun yén hiji barang/kagiatan mibanda ajén hadé atawa goréng pikeun "ékologi", jeung na ékologi politis.
Nu séjén bisa ngalarapkeun kecap ékologi lain dina maksud élmu, tapi salaku sistem filosofis atawa malah agamis, nu nunjukkeun hiji sawangan ngeunaan mayapada jeung ajén-inajén husus sarta ajén moral — misalna yén totalitas hirup mangrupa hiji sistem kohérén, nu meureun aya tujuanana; yén punahna spésiés luhur téh "goréng"; yén jalma sakuduna hirup harmonis jeung mahluk hirup séjénna; jeung yén alam kudu leupas tina pangaruh jalma. Ékologi dina jihat ieu sok ogé disebut énvirontalisme.
Ékologi biasana dianggap salaku salah sahiji cabang biologi, élmu umum nu ngulik mahluk hirup. Hal ieu bisa diulik dina sababaraha tingkatan, ti protéin jeung asam nukléat (dina biokimia jeung biologi molekular), sél (dina biologi sél), organisme (dina botani, zoologi, jeung disiplin séjén nu sarupa), jeung pamungkas dina tingkatan populasi, komunitas, jeung ékosistem — nu mangrupa subjék ékologi.
ku sabab fokusna nu panglegana dina kahirupan jeung dina hubunganana antara mahluk hirup jeung lingkunganna, ékologi ngamalir ka cabang élmu séjénna, kayaning géologi jeung géografi, météorologi, pedologi, kimia, jeung fisika. ku sabab kitu, sakapeung ékologi sok disebut salaku élmu holistik.
Ékologi mindeng digambarkeun sabagé ulikan hubungan segitiga:
Ékologi mangrupa hiji élmu nu ambahanana ngahontal cabang-cabang husus nu loba, di antarana
Ékologi ogé boga ketak nu penting dina loba lapang interdisiplin:
Pamungkas, ékologi ogé dipangaruhan (jeung nginjeumkeun ngaranna ka) disiplin non-biologis séjénna kayaning
Artikel utama: Biosfir, Biodiversiti, Unified neutral theory of biodiversity
Pikeun ahli ékologi modérn, ékologi bisa diulik dina sababaraha tingkatan: tingkat populasi (individu nu saspésiés), tingkat biocenose (atawa kumpulan spésiés), tingkat ékosistem, jeung tingkat biosfir.
Bumi, tina jihat ékologis, diwangun ku sababaraha rohangan: hidrosfir (atawa lapisan cai), litosfir (atawa lapisan taneuh lan batu), jeung atmosfir (atawa lapisan hawa). Biosfir, sakapeung digambarkeun mangrupa lapisan kaopat, mangrupa bagian planét tempat hirup kumbuh. mangrupa lapisan nu kacida ipisna, biosfir aya di antara 11000 méter ka jero jeung 15000 méter ka langit, najan lolobana kahirupan ayana di wewengkon antara -100 jeung +100 méter.
Kahirupan munggaran tumuwuh di hidrosfir, dina zona fotik. Organisme multisélular saterusna mucunghul turta ngeusi zona béntik. Kahirupan terestrial tumuwuh ka dieunakeun, sanggeus ngawujudna lapisan ozon nu mayungan mahluk hirup tina cahya UV. Tumuwuhna rupa-rupa spésiés terestrial diduga ngaronjat alatan beulahna atawa ngahijina buana. Biosfir jeung biodiversiti mangrupa ciri nu teu bisa dipisahkeun ti Bumi. Biosfir digambarkeun salaku lapisan kahirupan, sedengkeun biodiversiti salaku kabinékaanana. Lapisan salaku wadahna, sedengkeun kabinékaan salaku eusina. Kabinékaan ieu diéksprésikeun kalawan babarengan dina tingkat ékologis (ékosistem), tingkat populasi (kabinékaan intraspésifik), jeung tingkat spésiés (kabinékaan spésifik).
Biosfir ngandung unsur nu jumlahna kalintang loba, kayaning karbon, nitrogén, jeung oksigén. Unsur séjénna, kayaning fosfor, kalsium, jeung kalium, ogé penting pikeun kahirupan. Dina tingkat ékosistem jeung biosfir, aya prosés daur ulang sakabéh unsur-unsur ieu nu permanén, nu robah-robah antara wujud mineral jeung wujud organik.
While there is a slight input of géothermal energy, the bulk of the functioning of the ecosystem is primarily based on the input of solar energy. Plants convert light into into chemical energy by the process of photosynthesis, which créates glucose (a simple sugar) and reléases free oxygen. Glucose thus becomes the secondary energy source which drives the ecosystem. Some of this glucose is used directly by other organisms for energy. Other sugar molecules can be converted to other molecules such as amino acids. Plants use some of this sugar, concentrated in nectar to entice pollinators to aid them in reproduction. (Honeybees concentrate the sugar still further as honey, which can be said to be "stored summer sunshine").
Cellular respiration is the process by which organisms (like mammals) bréakdown the glucose back to its constituents, cai jeung karbon dioksida, gaining back the stored energy the sun originally gave to the plants. The proportion of photosynthetic activity of plants to the respiration of other organisms determines the specific composition of the éarth's atmosphere, particularly its oxygen level. Global air currents mix the atmosphere and maintain néarly the same balance in aréas of intense biological activity and aréas of slight biological activity.
Cai ogé disilihtukeurkeun antara hidrosfir, litosfir, atmosfir, jeung biosfir dina daur nu teratur. Sagara mangrupa téngki raksasa, nu ngawadahan cai, mastikeun stabilitas panas jeung cuaca, ogé pindahna unsur-unsur kimia ku ayana arus sagara.
For better understanding of how the biosphere works, and the dysfunctions related to human activity, American scientists carried out, under greenhouses, a small-scale modél of the biosphere, called Biosphere II.
Artikel utama: Ékosistem
Prinsip utama ékologi nyéta unggal mahluk hirup mibanda hubungan nu lumangsung tur sinambung jeung unggal unsur séjén nu nyusun lingkunganna. Hiji ékosistem bisa didefinisikeun salaku kaayaan naon baé nu mibanda karakter interaksi antara organisme jeung lingkunganana.
Ékosistem disusun ku dua éntitas: ayana kahirupan (disebut biocenose) jeung lahan/média pikeun hirup kumbuhna (biotope). Jeroeun ékosistem, spésiés-spésiés silih hubungkeun jeung silih gumantung hiji jeung nu séjénna dina ranté dahareun, parobahan énérgi, sarta parobahan matter antara maranéhna jeung lingkunganana.
Konsép ngeunaan hiji ékosistem bisa dilarapkeun ka unit-unit nu ukuranana baréda, hiji balong, hiji lapang, atawa sapotong tunggul kai. Unit nu ukuranana leutik disebut hiji mikroékosistem. Pikeun conto, hiji ékosistem basa mangrupa hiji batu jeung sagala kahirupan di handapeunana. Hiji mésoékosistem bisa mangrupa hiji leuweung, jeung hiji makroékosistem sakuliah ecoregion, kaasup gawirna.
Patalékan utama nalika ngulik hiji ékosistem di antarana,
Ékosistem mindeng digolongkeun dumasar biotop nu patali. Ékosistem di handap ieu bisa dihartikeun:
Golongan-golongan séjénna bisa dijieun dumasar komunitasna (misalna ékosistem manusa).
Artikel utama: faktor ékologis, siklus géobiokimia, homeostasis, dinamika populasi
Biotop mangrupa wewengkon nu lingkunganana saragam, ditunjukkeun ku sakabéh ukuran géologis, géografis, jeung klimatologis nu disebut faktor ékologis abiotik:
Biosénosa, atawa komunitas, mangrupa kumpulan populasi tatangkalan, sato, jeung mikro-organisme. Tiap populasi mangrupa jumlah hasil kawin- baranahan individu-individu nu saspésiés di hiji wewengkon dina hiji waktu. Nalika hiji populasi jumlah anggotana teu nyukupan, spésiésna kaancam punah, boh alatan underpopulation atawa alatan kawin saturunan. Hiji populasi bisa ngurangan ku sababaraha sabab, misalna, alatan leungit habitatna (karuksakan leuweung) atawa alatan loba teuing prédator (saperti diboro).
Biosenosa dicirikeun ku dua tipe faktor ékologis biotik: hubungan intra- jeung inter-spésifik.
Hubungan intraspésifik mangrupa hubungan nu dingawujud antarindividu nu saspésiés nu ngabentuk hiji populasi: mangrupa hubungan ko-operasi atawa kompetisi, kalawan ayana babagi wewengkon kakawasaan, jeung kadang organisasi dina susunan hirarkis.
Hubungan interspésifik, nyéta hubungan nu aya antara spésis nu hiji jeung nu séjénna, loba pisan, jeung biasana digambarkeun nurutkeun pangaruh kauntungan, karugian, atawa nétral (misalna simbiosis(hubungan ++) atawa kompetisi (hubungan --)). Hubungan nu pangsignifikanana mah nyéta hubungan prédasi (ngahakan atawa dihakan), nu ngajurung kana konsép dasar dina ékologi ranté dahareun (misalna, jukut dihakan ku hérbivora, nu dihakan ku karnivora, nu ogé dihakan ku karnivora nu leuwih badag). Ecological niche mangrupa wewengkon nu dipaké babarengan ku dua spésiés nu nempatan wewengkon sarta rupa diet nu sarua.
The existing interactions between the various living beings go along with a permanent mixing of mineral and organic substances, absorbed by organisms for their growth, their maintenance and their reproduction, to be finally rejected as waste. These permanent recyclings of the elements (in particular carbon, oxygen and nitrogen) as well as the water are called biogeochemical cycles. They guarantee a durable stability of the biosphere (at léast when human influence and extreme weather phenomena are left aside). This self-regulation, supported by negative feedback controls, ensures the perenniality of the ecosystems. It is showed by the very stable concentrations of most elements of éach compartment. This is referred to as homeostasis. The ecosystem also tends to evolve to a state of idéal balance, réached after a succession of events, the climax (for example a pond can become a peat bog).
Main articles: Biome, ecozone
Ecosystems are not isolated from éach other, but are interrelated. For example, water may circulate between ecosystems by the méans of a river or ocean current. Water itself, as a liquid medium, even defines ecosystems. Some species, such as salmon or freshwater eels move between marine systems and fresh-water systems. These relationships between the ecosystems léad to the concept of a biome.
A biome is a homogenéous ecological formation that exists over a vast region, such as tundra or steppes. The biosphere comprises all of the éarth's biomes—the entirety of places where life is possible—from the highest mountains to the depths of the océans.
Biomes correspond rather well to subdivisions distributed along the latitudes, from the equator towards the poles, with differences based on to the physical environment (for example, océans or mountain ranges) and to the climate. Their variation is generally related to the distribution of species according to their ability to tolerate temperature and/or dryness. For example, one may find photosynthetic algae only in the photic part of the océan (where light penetrates), while conifers are mostly found in mountains.
Though this is a simplification of more complicated scheme, latitude and altitude approximate a good representation of the distribution of biodiversity within the biosphere. Very generally, the richness of biodiversity (as well for animal than plant species) is decréasing most rapidly néar the equator (as in Brazil) and less rapidly as one approaches the poles.
The biosphere may also be divided into ecozone, which are very well defined today and primarily follow the continental borders. The ecozones are themselves divided into ecoregions, though there is not agreement on their limits.
Dina hiji ékosistem, patali antarspésiés sacara umum dihubungkeun kana dahareun jeung peranna dina ranté dahareun. Aya tilu kategori organisme:
Hubungan-hubungan ieu ngawujud urutan, di mana unggal individu ngahakan nu saméméhna sarta dihakan ku nu saanggeusna, dina nu disebut ranté dahareun atawa [[jaringan dahareun. In a food network, there will be fewer organisms at éach level as one follows the links of the network up the chain.
These concepts léad to the idéa of biomass (the total living matter in a given place), of primary productivity (the incréase in the mass of plants during a given time) and of secondary productivity (the living matter produced by consumers and the decomposers in a given time).
These two last idéas are key, since they maké it possible to evaluate the load capacity—the number of organisms which can be supported by a given ecosystem. In any food network, the energy contained in the level of the producers is not completely transferred to the consumers. Thus, from an energy point of view, it is more efficient for humans to be primary consumers (to get nourishment from grains and vegetables) than as secondary consumers (from herbivores such as beef and véal), and more still than as a tertiary consumer (from éating carnivores).
The productivity of ecosystems is sometimes estimated by comparing three types of land-based ecosystems and the total of aquatic ecosystems:
Humanity's actions over the last few centuries have seriously reduced the amount of the éarth covered by forests (deforestation), and have incréased agro-ecosystems (agriculture). In recent decades, an incréase in the aréas occupied by extreme ecosystems has occurred (desertification).
Sacara umum, krisis ékologis nyéta naon rupa kajadian nu ngarobah lingkungan hirup hiji spésiés atawa populasi antukna ngabahyakeun kasalametanana.
Ieu bisa mangrupa kualitas lingkungan nu nurun dibandingkeun jeung pangabutuh spésiés alatan parobahan faktor ékologis abiotik (pikeun conto, naékna suhu, hujan nu beuki jarang). It may be that the environment becomes unfavourable for the survival of a species (or a population) due to an incréase pressure of predation (for example overfishing). Lastly, it may be that the situation becomes unfavourable to the quality of life of the species (or the population) due to raise in the number of individuals (overpopulation).
Ecological crises may be more or less brutal (occurring between a few months to a few million yéars). They can also be of natural or anthropic origin. They may relate to one unique species or on the contrary, to a high number of species (see the article on Extinction event).
Lastly, an ecological crisis may be local (as an oil spill) or global (a rise in the séa level related to global warming).
According to its degree of endemism, a local crisis will have more or less significant consequences, from the déath of many individuals to the total extinction of a species. Whatever its origin, disappéarance of one or several species often will involve a rupture in the food chain, further impacting the survival of other species.
In the case of a global crisis, the consequences can be much more significant; some extinction events showed the disappéarance of more than 90% of existing species at that time. However, it should be noted that the disappéarance of certain species, such as the dinosaurs, by freeing an ecological niche, allowed the development and the diversification of the mammals. An ecological crisis thus paradoxically favored biodiversity.
Sometimes, an ecological crisis can be a specific and reversible phenomenon at the ecosystem scale. But more generally, the crises impact will last. Indeed, it rather is a connected series of events, that occur till a final point. From this stage, no return to the previous stable state is possible, and a new stable state will be set up gradually (see homeorhesy).
Lastly, if an ecological crisis can cause extinction, it can also more simply reduce the quality of life of the remaining individuals. Thus, even if the diversity of the human population is sometimes considered thréatened (see in particular indigenous people), few péople envision human disappéarance at short span. However, epidemic diseases, famines, impact on héalth of reduction of air quality, food crises, reduction of living space, accumulation of toxic or non degradable wastes, thréats on keystone species (gréat apes, panda, whales) are also factors influencing the well-being of péople.
During the past decades, it was observed an incréasing responsibility of human in some ecological crises. Due to his technological acquisitions and to a strong incréase in population, man is the only species whose activity has a major influence on his environment of life.
Some usually quoted examples as ecological crises are
salah sahiji ahli ékologi munggaran jigana mah Aristotle nu boga pangaresep kana rupa-rupa spésiés sato. Anjeunna dituturkeun ku loba naturalis kayaning Buffon jeung Carolus Linnaeus, nu damelanana sok dianggap salaku asal-usul ékologi modérn.
Salila abad ka-18 nepi ka munggaran abad ka-19, kakuatan maritim raya kayaning Prancis jeung Jérman, medalkeun loba ékspédisi éksplorasi dunya pikeun ngembangkeun hubungan dagang maritim jeung nagara-nagara séjén, sarta pikeun manggihan sumberdaya alam anyar, as well as to catalog them. At the beginning of the 18th century, about twenty thousand plant species were known, versus forty thousand at the beginning of the 19th century, and almost 400,000 today.
These expeditions were joined by many scientists, including botanists, such as the German explorer Alexander von Humboldt. Humboldt is often considered the true father of ecology. He was the first to take on the study of the relationship between organisms and their environment. He exposed the existing relationships between observed plant species and climate, and described vegetation zones using latitude and altitude, a discipline now known as geobotany.
In 1804, for example, he reported an impressive number of species, particularly plants, for which he sought to explain their géographic distribution with respect to geological data. One of Humboldt's famous works was "Idea for a Plant Geography" (1805).
Other important botanists include Aimé Bonpland and Eugenius Warming.
Deukeut ka taun 1850 aya nu narabas dina widang ieu ku medalna karya Charles Darwin The Origin of Species: Ecology passed from a repetitive, mechanical modél to a biological, organic, and hence evolutionary modél.
Alfred Russel Wallace, nu leuwih heubeul sarta saingan Darwin, munggaran ngajukeun "géografi" spésiés sasatoan. Sababaraha ahli harita wanoh yén spésiés teu mandiri ti nu séjén, sarta digolongkeun kana spésiés tangkal, sato, sarta komunitas mahluk hirup atawa biocenose. Istilah ieu munggaran dikedalkeun taun 1877 ku Karl Möbius.
Dina abad ka-19, ékologi ngembang ku ayana papanggihan widang kimia ku Lavoisier jeung de Saussure, utamana ngeunaan daur nitrogén. Sanggeus nengetan bukti yén kahirupan tumuwuhna ukur dina wates-wates rohangan nu ngawujud atmosfir, hidrosfir, jeung litosfir, Ahli géologi Austria Eduard Suess ngajukeun istilah biosfir taun 1875. Suess ngajukeun ngaran biosfir pikeun kaayaan nu ngadukung kahirupan, kayaning nu kapanggih di Bumi, nyaéta flora, fauna, mineral, daur zat, jeung sajabana.
Dina taun 1920an Vladimir I. Vernadsky, ahli géologi Rusia nu pindah ka Prancis, ngajéntrékeun pamanggih ngeunaan biosfir dina karyana "The biosphere" (1926), sarta ngagambarkeun prinsip-prinsip pondamén daur biogéokimiawi. Mangka anjeunna ngartikeun ulang biosfir salaku jumlah sakabéh ékosistem.
Karuksakan ékologis munggaran kabéjakeun dina abad ka-18, ku baranahanana koloni-koloni nu ngakibatkeun déforestasi. Mimiti abad ka-19, ku ayana révolusi industri, kamelang kana karuksakan lingkungan alatan kagiatan manusa beuki ningkat. Istilah ecologist geus dipaké ti panungtungan abad ka-19.
Sapanjang abad ka-19, géografi botanis jeung zoogéografi ngagabung jadi basis biogéografi. Élmu ieu, nu ngurus habitat spésiés, nyiar jawaban pikeun ayana spésiés tinangtu di wewengkon nu tinangtu ogé.
Dina taun 1935, Arthur Tansley, ahli ékologi Inggris, nyiptakeun istilah ékosistem, nyaéta sistem interaktif nu ngawujud antara biocenose (kumpulan mahluk hirup) jeung biotopna, lingkungan tempat maranéhna hirup. Mangka ékologi jadi élmu ngeunaan ékosistem.
Ékologi manusa dimimitian dina taun 1920an, ku ayana ulikan ngeunaan parobahan suksési vegetasi di kota Chicago. Saterusna jadi widang ulikan nu béda dina taun 1970an. Ieu nyirikeun munggaran diakuna manusa, nu geus ngeusi satungtung buana dunya, salaku hiji faktor ékologis penting. Manusa kalawan gedé-gedéan ngarobah lingkungan ku ngawangun habitat (utamana tata kota) ku kagiatan éksploitasi nu leket saperti logging jeung fishing, sarta pangaruh séjén agrikultur, pertambangan, jeung industri. Di sagigireun ékologi jeung biologi, disiplin ieu ngawengku ogé élmu alam jeung sosial séjénna, kayaning antropologi jeung étnologi, ékonomi, démografi, arsitéktur jeung tata kota, tatamba jeung psikologi, sarta nu séjénna. Ngembangna ékologi manusa ngajurung kana ngaronjatna peran élmu ékologis dina rarancang jeung ngokolaan dayeuh.
Téori Gaia, nu diajukeun ku James Lovelock dina karyana The Earth is Alive, geus ngalegaan sawangan yén Bumi kudu dihargaan salaku hiji makroorganisme tunggal nu hirup. Hususna dina pamadegan yén ensemble sadaya organisme hirup geus ngalaman évolusi antukna mampuh ngatur lingkungan global — ku jalan mangaruhan paraméter fisik penting kayaning wangunan atmosfir, laju penguapan, kimia taneuh jeung sagara — nepi ka bisa mertahankeun kaayaan nu dipiharep pikeun mahluk hirup.
Sawangan ieu geus jadi totondén jaman harita, hususna persépsi nu beuki kuat satutasna Perang Dunya kadua yén kagiatan manusa kayaning énergi nuklir, industrialisasi, polusi, jeung éksplorasi sumberdaya alami nu kaleuleuwihi, katambah ku pertumbuhan populasi éksponénsial, geus ngancam kaciptakeunana katastrop dina skala planet. Ku ayana kitu, majan kontoversial di kalangan élmuwan, hipotésis Gaia Lovelock geus dirontok ku loba pergerakan lingkungan salaku hiji sawangan nu ngagagas: indung-Bumina, Gaia, "jadi gering alatan manusa jeung kagiatanana".
Bener, ti abad ka-19 ékologi geus kalawan nyata relevan pikeun pergerakan sosial jeung filosofis nu patali jeung perlindungan lingkungan alami, kayaning konservasionism jeung environmentalism. Ékologi kiwari geus jadi salah sahiji jejer politis penting sarta sumber ideologi pikeun organisasi-organisasi politis penting samodél Partéy Héjo jeung Greenpeace.
Ékologi geus jadi bagéan puseur dina politik Dunya ti taun 1971, UNESCO medalkeun program panalungtikan nu disebut Man and Biosphere, nu tujuanana pikeun ngaronjatkeun pangaweruh ngeunaan hubungan nu silih untungkeun antara manusa jeung alam. Sababaraha taun ti harita geus kaluar katangtuan ngeunaan konsép Biosphere Reserve.
Taun 1972 United Nations (Perserikatan Bangsa-bangsa, PBB) ngayakeun konferensi internasional lingjkungan manusa nu munggaran di Stockholm, diluluguan ku René Dubos jeung sababaraha ahli séjénna. Konferensi ieu pisan nu marajian frase "Mikir Global, Ketak Lokal" (Think Globally, Act Locally). The next major events in ecology were the development of the concept of biosphere and the appéarance of terms "biological diversity"—or now more commonly biodiversity—in the 1980s. These terms were developed during the Earth Summit in Rio de Janeiro in 1992, where the concept of the biosphere was recognized by the major international organizations, and risks associated with reductions in biodiversity were publicly acknowledged.
Then, in 1997, the dangers the biosphere was facing were recognized from an international point of view at the Kyoto conference. In particular, this conference highlighted the incréasing dangers of the greenhouse effect—related to the incréasing concentration of greenhouse gases in the atmosphere, léading to global changes in climate. In Kyoto, most of the world's nations recognized the importance of looking at ecology from a global point of view, on a worldwide scale, and to take into account the impact of humans on the éarth's environment.
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