Kuliah 4 SYSTEM EKOLOGI DAN PRINSIP–PRINSIP DALAM HARMONISASI MANUSIA & ALAM Mustika Anggraeni
KERANGKA DISKUSI DAYA DUKUN G LINGK.
HUKUM TERMODI NAMIKA
ALIRAN ENERGI & DAUR MATERI
PRINSIP HARMONI MANUSIA & ALAM
SYSTEM ECOLOG Y
ECOLOG Y
HOMEO STASIS
FAKTOR PEMBA TAS
ASDL TKW 4206 PWK UB 18/03/09
DAYA LENTIN G LINGK.
Hukum Termodinamika Law of Conservation of Energy • Energy is neither created nor destroyed. When we use energy, it doesn’t disappear. We change it from one form of energy into another. • A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy. Solar cells change radiant energy into electrical energy. Energy changes form, but the total amount of energy in the universe stays the same. Energy Efficiency (Law of Energy Entropy ) Energy efficiency is the amount of useful energy you get from a system. A perfect, energy-efficient machine would change all the energy put in it into useful work—an impossible dream. Converting one form of energy into another form always involves a loss of usable energy (entropy). • Pencemaran selalu terjadi dan tidak dapat dihindari karena adanya entropy • Entropy dapat dikurangi, karena entropy adalah sumber energy dari proses lain ASDL TKW 4206 PWK UB 18/03/09
Aliran Energi dan Daur Materi ECOSYSTEM dapat berfungsi apa bila ada aliran energy dan daur materi. Energy flows in a simple food chain. At each level of the food chain, about 90% of the energy is lost in the form of heat. Therefore, as you move up the food chain, there is less energy available. Food chain adalah suatu sistem kehidupan yang berupa rantai terbuka disusun oleh Konsumen I (produsen yaitu tanaman, konsumen II (herbivore), konsumen III (omnivore/carnivore) s/d konsumen ke–n) Daur materi adalah rantai makanan sistem tertutup dimana merupakan rantai makanan yang disambung oleh mikrobia yang menguraikan bangkai yang sudah mati menjadi mineral yang selanjutnya mineral ini menjadi bagian penyusun dari tumbuhan (produsen)
ASDL TKW 4206 PWK UB 18/03/09
Energy & Material Flow
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Tolerance Limits •
Every living organism has limits to the environmental conditions it can endure. Environmental factors must be within appropriate levels for life to persist – – – – –
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Temperature Moisture levels Nutrient supply Soil and water chemistry Living space
Leibig's Law of Minimum: In 1840, Justus von Liebig proposed that the single factor in shortest supply relative to demand is the critical determinant in the distribution of that species. Sheldford's Law of Tolerance: Victor Shelford later expanded Liebig's principal by stating that each environmental factor has both minimum and maximum levels called tolerance limits beyond which a particular species cannot survive. ASDL TKW 4206 PWK UB 18/03/09
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Hukum minimum Leibig – Pertumbuhan tanaman tergantung akan jumlah bahan makanan yang tersedia dalam jumlah sedikit. Hukum Toleransi Shelford: – organisme mempunyai rentangan batas toleransi yang lebar (eury…) untuk suatu faktor, dan sempit (steno…) untuk faktor yang lain – Organisme dengan rentangan batas toleransi yang lebar, mempunyai penyebaran yang luas. – Bila kondisi tidak optimum untuk suatu spesies mengenai suatu faktor, maka batas toleransi menjadi berkurang – Organisme di alam tidak betul2 hidup dalam kondisi optimal ditinjau dari satu sektor fisik tertentu. – Masa pertumbuhan adalah masa yang palingkritis karena batas toleransi bibit/benih, telur/embryo, dan larva adalah lebih sempit. ASDL TKW 4206 PWK UB 18/03/09
Indikator ekologi Keadaan kehidupan organisme sangat dipengaruhui oleh lingkungan tempat tinggalnya. Di darat, tumbuhan dipakai sbg indikator ekologi, karena peka atas perubahan lingkungan. Di dalam air ikan dapat berubah dari bentuk idealnya karena perbandingan berat dan panjangnya dipengaruhi kualitas air. ASDL TKW 4206 PWK UB 18/03/09
Daya Dukung Lingkungan (Carriying Capacity)
• Arti harfiah : rasio antara organisme biotik dengan keberadaan lingkungan hidup • Arti modern (untuk manusia): – Limits to Growth – Overshoot ASDL TKW 4206 PWK UB 18/03/09
Carrying Capacity Overshoot To overshoot means to grow rapidly beyond the limits of carrying capacity. When this overshoot occurs, it’s due to a limit or barrier exceeded within the system, and the system corrects and begins to slow, stop, or reverse growth. In addition, as the limits of our natural systems are exceeded they are degraded, which results in the overall carrying capacity being diminished. Overshoot leads to a sudden and catastrophe collapse. ASDL TKW 4206 PWK UB 18/03/09
WORLD’S POPULATION
Miller, 1975
Population
YEAR ASDL TKW 4206 PWK UB 18/03/09
20…
7
1998
6
1988
5
1975
4
1960
3
1930
2
1850
1
Population Oscillations • •
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Populations may go through repeated oscillating cycles of exponential growth and catastrophic crashes ASDL TKW 4206 PWK UB 18/03/09
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In the real world, there are limits to growth. Dieback: when the population decreases as fast as, or faster , than it grows Some limiting factor comes into effect. Overshoot: extent to which a population exceeds the carrying capacity of its environment. Malthusian growth: pattern of population explosion followed by a population crash.
“As the environment is degraded, carrying capacity actually shrinks, leaving the environment no longer able to support even the number of people who could formerly have lived in the area on a sustainable basis. No population can live beyond the environment’s carrying capacity for very long” William E. Rees ASDL TKW 4206 PWK UB 18/03/09
Daya Lenting Lingkungan (Resilience Capacity )
• Kemampuan alam, jika diganggu keseimbangannya, untuk kembali ke kondisi semula Æ seperti pendulum • Setelah batas tertentu, tidak lentur lagi – Suaka margasatwa di Afrika perubahan musim hujan mengakibatkan naiknya air laut pasang dan mematikan tanaman di sekitarnya. – Contoh: bencana alam, bencana teknologi dianggap sebagai ‘gangguan’ terhadap alam.
ASDL TKW 4206 PWK UB 18/03/09
Homeostasis All lives seek balance? For what are lives looking? Peace? Stillness? Zero change? Harmony? Symmetry? The study of Homeostasis reveals that balance within living systems is not peaceful, nor quiet, is filled with change, but does harmonize the interior environment with the exterior environment. For what are lives looking? Call it Dynamic equilibrium, a continuous circle dance of adjustment and correction. Maintaining this balance between a living system's internal conditions and fluctuating environmental (external) conditions is called homeostasis. Inside and outside must fit. ASDL TKW 4206 PWK UB 18/03/09
Bagaimana keharmonisan hidup kita dengan makhluk hidup lainnya?
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• Ada sekitar 10 juta spesies lain di bumi ini. Spesies seperti tikus dan virus flu, hidup mutualisma dengan kita. Manusia juga mendorong kelangsungan hidup spesies seperti jagung dan sapi, karena kita memerlukan produknya. Spesies seperti harimau, dan serangga di hutan hujan tropis hampir punah karena perilaku manusia. • Ahli biologi konservasi percaya bahwa dibutuhkan sekitar 30-70% biosfir utk memelihara biodiversity. Saat ini sekitar 3% yg digunakan untuk taman atau suaka margasatwa. Komisi Brundtland, PBB meminta sekitar 12% biosfir digunakan untuk taman dan suaka margasatwa. ASDL TKW 4206 PWK UB 18/03/09
Ending Overshoot •
Individuals and institutions worldwide must begin to recognize ecological limits. We must begin to make ecological limits central to our decisionmaking and use human ingenuity to find new ways to live, within the Earth’s bounds.
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This means investing in technology and infrastructure that will allow us to operate in a resource constrained world. It means taking individual action, and creating the public demand for businesses and policy makers to participate.
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Using tools like the Ecological Footprint to manage our ecological assets is essential for humanity’s survival and success. Knowing how much nature we have, how much we use, and who uses what is the first step, and will allow us to track our progress as we work toward our goal of sustainable, one-planet living. ASDL TKW 4206 PWK UB 18/03/09
Hukum Ekologi (Commoner, 1972): • Everything is connected to everything else - humans and other species are connected/dependant on a number of other species.
• Everything must go somewhere - no matter what you do, and no matter what you use, it has to go somewhere. For example, when you burn wood, it doesn't disappear, it turns into smoke which rises into the air, and ash, which falls back down to the earth.
• Nature knows best - Like it says, nature knows best.
• There is no such thing as a free lunch - Everything you do, must have a reason behind it. This law basically means you have to do something in order to get something in return.
ASDL TKW 4206 PWK UB 18/03/09
ASDL TKW 4206 PWK UB 18/03/09
ASDL TKW 4206 PWK UB 18/03/09
