Download - Chapter 9 endangered eosystem Form 4 Biology
Chapter 9Endangered Ecosystem
Ong Yee Sing
2017
Chapter index
• 9.1 Human activities that endanger an ecosystem
• 9.2 The greenhouse effect and the thinning of the ozone layer
• 9.3 The importance of proper management of development activities and the ecosystem
9.1 Human Activities that Endanger an EcosystemEdited from
https://www.slideshare.net/NurulHudaKasim/biology-chapter-9
Human activities which threaten the ecosystem• development and industrialisation.
• increase in the number of motor vehicles.
• increase the usage of pesticides and chemical fertilisers in the agriculture sector.
• uncontrolled deforestation.• Rainforest are the oldest ecosystem on
Earth• Diversity of flora and fauna that provide
food, medicine• Regulating word climate – ‘carbon sink’• Water catchment climate
These satellite images show the impact of deforestation. What begins in 1984 as fine lines expands to a fish skeleton shape in 1993 and eventually to land spotted with forest fragments.
The impact of deforestation
• soil erosion.
• flash flood.
• landslide.
• eutrophication.
• water, air, thermal and noise pollution.
• global warming.
• depletion or thinning of the ozone layer.
• climatic change.
• extinction of living things.
POLLUTIONundesirable change in the physical chemical or
abiotic characteristic of the natural
environment, brought about by human
activities
Air
Pollution
Water
PollutionThermal
PollutionNoise
Pollution
Air Pollution
• Caused by the presence of pollutants in the air which are harmful to life and the environment.
• Sources of pollution:• Open burning rubbish, deforestation,
solid waste.• Burning of fossil fuel electrical power
stations, combustion engines of vehicles• Release of toxic gas and waste factories
and industries
• Type of pollutants includes soot, lead, carbon monoxide, oxide of nitrogen, hydrocarbon, carbon dioxide, smog, haze, sulphur dioxide.
Effects of air pollution• Effects:
• Cause respiratory diseases such as lung cancer.
• Dust that cover the plant will block the stomata.
• Soot and dust will blackens the buildings.
• Form haze which is harmful to humans.
• Reduces agricultural productivity.
• Acid rain from nitric acid and sulphuricacid is corrosive to buildings.
Water Pollution
• Caused by domestic wastes, industrial wastes, soil erosion and agriculture waste, oil spillage that are discharged directly into waters.
• Type of pollutants includes heavy metals, radioactive waste, fertilizers.
• Effects:• Causes death to all life forms in the sea.
• Pollutes the beaches.
• Cause cancers and leukaemia.
• Eutrophication.
Eutrophication
• Excessive amount of nutrient in the water
• Occurs when inorganic nutrients and organic material enter a river or a lake.
• Effects:• Encourages photosynthesising
organisms in the water, particularly algae to grow rapidly.
• Light intensity in the water is greatly reduced.
• Decomposition of dead plants and algae by bacteria lead to depletion of oxygen.
• Causing the death of aerobic organisms when depletion of oxygen in the water occurs.
Biochemical Oxygen Demand (B.O.D.)
• The amount of oxygen taken up by the microorganism that decompose organic waste matter in water.
• The use up of oxygen supply by the bacteria will increase the biochemical oxygen demand (B.O.D.).
• The uses of B.O.D.:• As a measure of certain types of
organic pollutants in water.• Measure the level of water pollution.• Indicates the presence of a
microorganisms which suggest a level of pollution.
Thermal Pollution
• The release of excessive heat into the environment.
• Sources of pollution:• Discharged of hot water from factories,
nuclear reactors and electric power stations.
• Glass buildings.• Effects:
• Cause instant death to some species.• Disrupt the entire ecosystem.• Encourages rapid growth for algae, leading
to higher BOD value.
Noise Pollution
• The occurrence of excessive noise in the environment that disturbs the tranquility of life.
• Sources of pollution:• Trains and cars.• Construction sites.• Machines and equipment in factories.
• Effects:• Hearing problems.(≥ 80db
deafness)• Stress related problems
• High blood pressure and coronary disease.
• Emotional and mental disturbances.• Ulcers • headaches
Noise map.
9.2 The greenhouse effect and the thinning of the ozone layer
Greenhouse effect
• Greenhouse gases trapped heat in the atmosphere and radiate infrared radiation.
• Type of greenhouse gases includes carbon dioxide, chlorofluorocarbon (CFCs), methane, nitrous oxide and ozone.
• Effects:• Global warming
• Disturbed ecosystem• Death • Melting of polar ice
Thinning of ozone layer
• Thinning of ozone layer (O3) in the atmosphere that shields the Earth from the Sun's ultraviolet (UV) radiation.
• Source of pollutants is chlorofluorocarbons (CFCs).• Coolants in air conditioners and refrigerators• Propellants in aerosol cans• Foaming agents in Styrofoam making
• Effects:• Deteriorate human health: Skin cancer eye Damage
,damage to Immune system, aging of skin etc.• Growth of amphibians: the growth and
development in the larvae stage, deformities and decreases immunities in some species and to even retinal damage and blindness in some species.
• Damage to leaf cells and chlorophyll, decrease in nutrient content and crop yields
• Change in wind directions, global warming
9.3 The importance of proper management of development activities and the ecosystem
Measurements
• Implementation of law• Environmental Quality Act 1974, 1985• National Forestry Act 1984
• Protecting and preserving forests and wildlifes
• Pesticides Act 1974• Protection of Wildlife Act, 1972• Fisheries Act, 1985
• Use of technology• Recycling• Catalytic converter – reduce amount of
nitrogen oxide• Unleaded petrol
• Education
• Preservation and conservation
• Biological control
• Renewable energy• Solar energy
• Wave energy
• Wind energy
• Hydroelectric
• Geothermic energy
• Biomass energy
• Efficient use of energy