Biologi Endangered Ecosystem

INTRODUCTION Great challenges in today’s world have lead to various development projects. The projects

or human activities, if unplanned and mismanaged, can upset the balance of the natural

environment and damaged the ecosystem.

A new report shows that some 60 per cent of the benefits that the global ecosystem

provides to support life on Earth (such as fresh water, clean air, and a relatively stable climate)

are being degraded or used unsustainably. In the report, scientist working on the Millennium

Ecosystem Assessment (MA) warns that harmful consequences of this degradation to human

health are already being felt and could grow significantly worse over the next 50 years.

So, we as human being have an important responsibility to manage the environment. The

Earth can only be a better place if development activities are planned with a great care.

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ObjectiveLearning outcomes

Identify human activities that threaten the ecosystem.

Explain the impact of human activities on the ecosystem.

Evaluate critically the effect of unplanned development and mismanagement of the

ecosystem.

Describe types of pollution.

Explain the effect of pollution on living thing and the environment

Compare and contras pollutants in the air from different environment.

State the source of air pollution.

Interpret data on the level of air pollution in some cities.

Make an inference on the source of the air pollution in some cities.

Interpret data on the level of water pollution in some rivers.

Predict the level of air and water pollution in a particular location within the next ten

years.

Suggest strategies to solve problem related to in air and water pollution.

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Impact of human activitiesHuman activities which threaten the ecosystem are:

Development

Increase in the number of motor vehicles

Increase in the usage of pesticides and chemical fertilizers in the agriculture sector

Uncontrolled deforestation

The effects of unplanned development and mismanagement of the ecosystem are:

Soil erosion

Flash flood

Landslide

Eutrophication

Water, air, thermal, and noise pollution

Global warming (phenomenon of increase in temperature of the Earth, also known as

the greenhouse effect)

Depletion of the ozone layer

Climatic change

Extinction of living things

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PollutionAir pollution

- Caused by the presence of pollutants in the air which are harmful to life and the environment.

Source of pollution are:

.

Effects of air pollution

Acidic gaseous pollutant cause respiratory diseases such as bronchitis, breathlessness, lung cancer and asthma

These pollutants irritate eye, cause skin diseases and conjunctivitis Increases the acidity in the soil and cause the soil to be infertile. Acid rain reduces the pH level of the lakes and the rivers and threatens the aquatic life Acid rain corrodes metal structure and erodes limestone used for making building

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Water pollution

- Caused by domestic wastes, industrial wastes, and agriculture wastes that are discharged directly into the rivers

Source of water pollution Harmful effectDischarge of untreated sewage and domestic waste into rivers

Encourage growth of bacteria, causing diseases such as cholera

Number of bacteria increases due to increased concentration of nitrates and phosphates in untreated sewage

Cause bad odour and unsightly viewDischarge of industrial wastes Contaminate the water physically

Decomposition of organic wastes reduces the concentration of oxygen in the water

Discharge of agriculture wastes Cause Eutrophication Agrochemicals are poisonous to aquatic

animals and cause cancerOil spillage Cause death to all life forms in the sea

Pollute the beaches

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Eutrophication

Eutrophication occurs when large quantities of nutrients such as nitrates and

phosphates enter an aquatic environment. Sources of these nutrients include animal wastes,

agricultural runoff, and sewage. The ecosystem quickly experiences and increase in

photosynthetic and blue-green algae, as these organisms thrive in the presence of the added

nutrients. An algae bloom occurs as the algae accumulates into dense, visible patches near the

surface of the water, prohibiting light from penetrating deeper areas of the lake or stream.

Some fish are unable to survive without this light, but for them an even more serious problem

arises when the algae begin to die. At this point, oxygen-demanding bacteria take over the

ecosystem, decomposing the algae and using up dissolved oxygen in the process. These

bacteria increase the biological oxygen demand (BOD) of the ecosystem. BOD is the amount of

oxygen required for the decomposition of organic compounds by microorganisms in a given

amount of water. It is usually measured in milligrams of oxygen consumed per litre of water.

Biological oxygen demand is important because it affects the amount of dissolved oxygen

available to all species in an aquatic ecosystem. A higher BOD indicates a lower level of

dissolved oxygen. This lower concentration of oxygen causes many fish suffocate, and as the

die, the number of oxygen-demanding decomposers increases even more.

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Thermal pollution

- The release of excessive heat into the environment.

Effects of thermal pollution:

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Noise pollution

- The occurrence of excessive noise in the environment that disturbs the tranquillity of life such as :

The loudness of sound is measured using the decibel (dB) unit Human ears can only receive sound less than 80 dB

The sources of noise pollution are

Effects of noise pollution include:

Hearing problems (deafness) Ear injury Headaches Emotional and mental disturbances High blood pressure

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Greenhouse effect

The greenhouse effect is the heating of the surface of a planet or moon due to the

presence of an atmosphere containing gases that absorb and emit infrared radiation.

Greenhouse gases, which include water vapour, carbon dioxide, methane, CFC and nitrogen

dioxide, are almost transparent to solar radiation but strongly absorb and emit infrared

radiation. Thus, greenhouse gases trap heat within the surface-troposphere system. This

mechanism is fundamentally different from that of an actual greenhouse, which works by

isolating warm air inside the structure so that heat is not lost by convection. The greenhouse

effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall

in 1858, and first reported quantitatively by Svante Arrhenius in 1896. Greenhouse effect makes

the earth’s temperature rises causing global warming.

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The following human activities can increase the concentration of carbon dioxide in the atmosphere to cause a greenhouse effect are:

Burning of fuels in factories Forest fires Deforestation Open burning of rubbish Coal-fuelled power-stations Use of CFC

The consequences of the greenhouse effect are:

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Thinning of the ozone layer

Ozone is the made up of 3 oxygen atoms. It is located at stratosphere which is 20-50 km

above the earth’s surface. The ozone layer absorbs the harmful ultraviolet rays and prevents

them from reaching the earth’s surface. It was found that the depletion of the ozone layer

occurred over both the Arctic an Antarctic, creating the ozone holes. The ozone hole in the

Antarctic is found to be is big as the USA. The depletion of the ozone is caused by the increasing

use of CFC which can break down and convert ozone molecules into other molecules. Other

pollutants such as halons, chlorine gas, and nitrogen oxides can also destroy the ozone.

Effects of the thinning of the ozone layer which allow excessive ultraviolet radiation to reach the

Earth:

On the environment Increases the temperature of the environment

Changes in the climate and weather patterns

Changes in wind direction

On plants The rate of photosynthesis decrease due to destruction of

stomata and chlorophyll in the leaves

Disturbs the ecological balance by destroying aquatic organisms

such as planktons.

On human health Causes skin cancer (melanoma)

Damage eyesight and causes cataract

Weakens the human immune system

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Impact of the Thinning of the Ozone Layer and Global Warming on the Ecosystem

1. The thinning of the ozone layer allows ultraviolet radiation to reach the Earth surface

and destroy the planktons in the food chains. This problem threatens other marine life.

2. Reduce the number of stomata and amount of chlorophyll in the leaves. The plant

cannot carry out photosynthesis. The plant will die and the biotic component in the

ecosystem threatens.

3. Global warming causes the atmosphere to be very hot, resulting in drought and changes

in the climate. This affects the biotic component in the ecosystem which consequently

affects the distribution and population of the biotic component.

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Steps to maintain a stable environment

Implementation of lawsi. The Environmental Quality Act 1874, 1985 (amendment) :

- Control and prevent pollution of the environment (covering air, water, thermal and noise pollution)

- Coordinate all activities related to waste disposal and fix the maximum light of waste to be disposed

- Control the extent of waste production (amount, type, content, and effect) so as not to threaten the quality of that environment

ii. Factory and Machine Act 1967/1983 to protect the workers from being exposed to noise levels of more than 95 dB for 4 hours continuously.

iii. Pesticides Act 1974 to control the usage of pesticides.iv. National Forestry Act 1984 to protect and preserve forest as well as all wild-life in the

forests Use of technology

i. Install factory chimney that have specific devices to filter fine particles and toxic gases before they are released into the air

ii. Use of oil-disintegration bacteria to clean up oil spillage the seaiii. Recycle wastes made of manufactured materials such as glass, metal, paper and

aluminium cans to protect the environment and conserve natural resources

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Education on the management of resourcesi. The public must be educated on the concept of 4R

Preservation and conservation of the ecosystem

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i. Preservation involves efforts to protect an ecosystemii. Conservation involves efforts to return an affected ecosystem to its natural

equilibrium and keep them good.iii. Preservation is better than conservationiv. The efforts of conservation includes

- Preservations of soil- Preservations of water- Preservations of flora and fauna - Preservations of mangrove swamps

The practice of biological controli. Biological control is the use of natural predators to control the population of pest

species such as:- The use of khaki chambel (a species of ducks) to control the population of gold

snails (siput gondang emas) which feeds on paddy stalks- The use of owls to control the populations of rats in oil palm plantations- The use of hoverfly larvae to control aphids which feed on crop plants

The use of renewable energyi. Renewable energy is energy flow that occurs naturally in the environment and can be

harnessed for the benefit of the humansii. Renewable energy is inexhaustible and does not pollute the air

iii. Examples of renewable energy- Solar energy (generates electricity)- Wind energy (to operate windmills)- Flowing water (generate hydroelectric power) - Wave energy (generates electricity)- Geothermal energy (generates electricity)- Biomass energy (produces biogas as fuel)- Gasohol (converted to ethanol as fuel)- Palm oil (converted to methyl ester as fuel)

The efficient use of energyi. Reduce the burning of coal, petroleum and other fossil fuels

ii. Substitute natural gas for coal at power plantsiii. Improve fuel efficiency in vehicle-use cars that run on energy-efficient enginesiv. Use a cleaner fuel by reducing the content of sulphur in diesel and switching to gasv. Improve energy efficiency in factories

vi. Use more hybrid car which combines electric and gasoline engines

Conclusion

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Management of the ecosystem is the task of maintaining the balance of nature by means of preservations and conservation of natural resources as well as protecting the ecosystem. Improper management of development activities can threaten the ecosystem.

Some activities can upset the balance in ecosystem such as disposal of rubbish freely in all places which includes drains and rivers; open burning of rubbish and disposal of effluent water from factories.

To ensure these activities do not destroy the ecosystem, the following measure can be taken. Some examples are stricter law and closer supervision of responsible particles; educating the public to cultivate an awareness to keep the environment clean and to care for the ecosystem and carrying out programmes to recycle discarded wastes such as paper, glass and aluminium cans.

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