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