as human environment

Classifications of ecosystems

Major components of ecosystems

Life on the earth depends on solar energy

- Flow of energy from the sun through the

biosphere

- The cycling of crucial elements

Human is a component of ecosystems

Terrestrial (land): Rain forest, coniferous

forest, savanna, desert

Aquatic:- Marine : sea. oceans

- Fresh water : lakes, rivers

Transition from land to aquatic (Wet land): Swamp, mangrove

Natural ecosystems:

changes naturally without human interferences

Man-made ecosystems:

require human interferences to manage and to add an energy or matter for maintaining a balance ecosystems (city, village, crop land etc.)

Tropical forest City

Abiotic (non-living/physical and chemical factors): water, air, nutrient and solar energy

Biotic (living): plants, animals (including humans) , and microorganisms

physical and chemical factors

Law of tolerance:

The existence, abundance, and distribution of a species in a

ecosystems are determined by whether the level of one or more

physical or chemical factors fall within the range tolerated by that species

Different from other organisms, human could enhance the range of their tolerance due to the ability to think, to develop technology and to modify the nature

Flow of energy from the sun through the biosphere

The cycling of crucial elements

Gravity, which keeps atmospheric gases from escaping into space and draws chemicals downward in the matter cycles

Biomass is the mass of all the organisms and organic material in an area.

There is more biomass at the trophic level of producers and fewer at the trophic level of tertiary consumers. (There are more plants on Earth than there are animals.)

Bio=life Mass=weight

Bio + Mass = Weight of living things within an ecosystem.

At least 27% of the earth’s total net primary productivity have been destroyed and altered by human activities

Nutrients are cycled continuously from the nonliving environment (air, water, soil, rock) to living organisms and then back again~biogeochemical cycles

Biogeochemical cycles include:

- 4 main types of nutrient cycle :1. Carbon cycle

2. Nitrogen cycle

3. Phosphorus cycle

4. Sulfur cycle

- Hydrologic (water) cycle

Carbon is the basic building block of molecules necessary for life (carbohydrate, fats, proteins, DNA and RNA)

How are human activities affecting the C cycle? CO2 + other gases Atmosphere green house effects global warming: - select fit organism, affect food production

and wildlife habitats

- raise the average sea level

Nitrogen is an essential nutrient for making proteins, DNA, and RNA

How are human activities affecting the N cycle?

Adding large amount of NO when burning any fuel:

N2 + O2 2NO

NO + O2 NO2

NO2 + H2O HNO3

HNO3 in rain or snow acid deposition (acid rain)

P is the limiting factor for plant growth and producers in many freshwater and lakes

How are human activities affecting the P cycle?

-Reducing the available phosphate in tropical forests by removing trees causes P and other soil nutrients are washed away by heavy rains, and the land become unproductive

-Adding excess phosphate to aquatic ecosystems causes explosive growth of cyanobacteria, algae, and aquatic plants. When these plants die and are decomposed they use up dissolved oxygen and finally disrupt aquatic ecosystems

S is stored underground in rocks and minerals, including SO4

2- salt

S enters the atmosphere from active volcanoes,

S is released by the breakdown of organic matter in swamps, bogs, and tidal flats by decomposers

How are human activities affecting the S cycle?

burning sulfur containing coal and fossil fuels release SO2 into atmosphere

In the atmosphere,

SO2 + O2SO3

SO3 + H2O H2SO4 fall to the earth as acid rain

Water Cycle: collects, purifies and distributes the earth’s fixed supply of water

The main processes in water cycle: evaporation, transpiration, condensation, precipitation, infiltration, percolation, runoff

Water cycle is powered by energy from the sun

How are human activities affecting the water cycle?

- withdrawing large quantities of fresh water in heavily

populated areas lead to depletion of underground water

supplies

- clearing vegetation from land for agriculture, mining, and

building construction lead to increase runoff, reduces

infiltration, increase the risk of flooding

Large-scale changes in the ecosystems (biosphere) threaten us as well as other species

How are human considering the earth ?

Gaia concept (Lovelock): Biosfer adalah suatu kesatuan yang mengatur diri sendiri (self-regulating) dan mampu mempertahankan kondisi Bumi dengan mengendalikan lingkungan kimiawi dan fisis. Hadi, Bumi adalah suatu super-ekosistem dimana banyak proses dan umpan balik saling berinteraksi untuk menjaga kondisi kimiawi dan fisis di Bumi. Dalam hal ini, makhluk hidup memiliki peran penting peran terpenting dalam menjaga keseimbangan (homeostatis).

The earth as a aerospace aircraft (Odum 1989) : Bumi dapat dianalogikan dengan suatu pesawat ruang angkasa yang sangat besar karena merupakan suatu benda/kesatuan yang ‘melayang’ di angkasa luar, dengan sistem pendukung kehidupannya sendiri (dalam bentuk udara, air, makanan, energi). Dengan adanya tekanan penduduk, pencemaran, dan pengelolaan yang buruk, maka sistem pendukung kehidupan ini menjadi terancam:ibarat berkurangnya persediaan oksigen bagi astronot dalam suatu pesawat ruang angkasa.