biology ecosystem chapter 9
DESCRIPTION
Human activities that endanger an Green EcosystemTRANSCRIPT
CHAPTER 9:CHAPTER 9:ENDANGERED ECOSYSTEMENDANGERED ECOSYSTEM
9.1 Human Activities that 9.1 Human Activities that Endanger an EcosystemEndanger an Ecosystem
Human activities that threaten an Human activities that threaten an EcosystemEcosystem
Human activities that threaten an EcosystemHuman activities that threaten an Ecosystem
Human activities that threaten an Human activities that threaten an EcosystemEcosystem• The world’s population has grown to over
6 billion today, so conflicts arise between the need to meet the immediate human demands in the short term and the need to protect and conserve ecosystems from long-term damage
• Most of the problem related to the environment are the results of human activities and human interference with the ecosystem function
Human activities that threaten an Human activities that threaten an EcosystemEcosystem• Human activities, if unplanned and
mismanagement of ecosystems result in various environmental problems; air and water pollution, the greenhouse effect, global warming and the depletion of natural resources
• These problems bring about negative effects that increasingly threaten the economic resources, health and survival of ecosystem
Human activities that threaten an EcosystemHuman activities that threaten an EcosystemHuman activities that have undesirable
effects on the environment
Deforestation Burning of fossil fuels Overuse of fertilisers in intensive farming
Dumping of domestic and industrial waste
Leads to
Leads to
Leads toLeads to
• Soil erosion
• landslides
• flash floods
• climatic changes
• lost of biodiversity
• greenhouse effect
• greenhouse effect
• global warming
• air pollution
• eutrophication
• water pollution
• water pollution
Deforestation Deforestation Important roles of tropical rainforests: The oldest ecosystem on the Earth
and home to almost half of the world’s flora and fauna.
Contain many unique species which provide food, medicine and other resources for human.
Regulate the world climate. Act as a carbon sink of the Earth
because they absorb vast amount of carbon dioxide during photosynthesis and at the same time release oxygen into the atmosphere.
As water catchments areas.
The impacts are: Soil erosion Flash flood Landslides Changes in the
recycling of materials Severe climatic changes The loss of biodiversity
Deforestation
DeforestationDeforestation
Deforestation Deforestation
Loss of habitat Loss of biodiversity
Burning of fossil fuels and its EffectsBurning of fossil fuels and its Effects
Deforestation through slash and burn
Burning activity
Contributes 25% carbon dioxide
75% CO2 comes from burning of fossil fuel
Effect : The carbon dioxide level increases
1. Greenhouse effect2. Global warming
Atmosphere
Intensive Farming and its EffectIntensive Farming and its Effect Continuous cultivation of the same
plot of land.The ploughing of land down the slope
instead of along the slope contours. Overgrazing by livestock that does
not permit the grass to grow back.
The loss of topsoil nutrients. The silting of the bottom of rivers
and lakes with earth sediment
causing flash floods.
Erosions of topsoil by
flowing water when it rains.
Intensive Farming and its EffectIntensive Farming and its EffectInorganic fertilizers - nitrates- phosphates- potassium
Eutrophication Lakes and river
Farmer
Cause
Used
Highly soluble and quickly leached out
Dumping of domestic and industrial Dumping of domestic and industrial waste and its Effectswaste and its Effects
Human population increased rapidly
Increase in 1. domestic waste2. industrial waste
Pollute:-ground- water resources
1. Dumping of waste
2. Discharge of effluents
Caused
Pollution
The impact of human The impact of human activities on the activities on the
ecosystemecosystem
Greenhouse effect
Thinning of ozone layer
Pollution can be defined as any undesirable changes in physical, chemical and
biological characteristics of the natural environment,
brought about when harmful substances or energy are
released by human activities.
WHAT IS POLLUTION ?
Type of Type of pollutionpollution
WateWaterr
ThermalThermal
NoiseNoise
Sources:
- vehicles
- construction sites
- agricultural
- industrial machinery
Sources :
- in many industrial process
- in cooling towers of electrical power station
Sources:
- waste matter from industrial and domestic
- run-off fertilizer from agricultural area
Sources:
- mostly contributed from burning fossil fuels
- industrial plants and factories
AirAir
Air pollution Factories that pump large amounts of carbon monoxide, oxides of
nitrogen and sulphur dioxide into the atmosphere.
Exhaust fumes from vehicles that contains soot, lead, carbon
monoxide, oxides of nitrogen and hydrocarbon.
Electrical power stations that release large amounts of carbon
dioxide into the atmosphere.
Open burnings that release suspended solids and pollutant gases
such as carbon dioxide and carbon monoxide.
Industrial Plants and Factories:Large amount of
carbon monoxide,
oxides of nitrogen
and sulphur dioxide.
Open Burnings:Large amount of
suspended solids.Large amount of
carbon dioxide and
carbon monoxide.
Burning Fossil Fuels: High level of carbon
particles. High level of carbon
monoxide, oxides of
nitrogen and sulphur
dioxide.
POLLUTANTS IN THE AIR DUE TO
DIFFERENT SOURCES
Note:
Please refer to the acid rain handout
Water pollution
Human activities
on land are the main
contribution to water pollution.
Crude oil spills that cover the water surface reduce water dissolved oxygen and water light intensity.
Industrial and domestic activities discharging untreated waste materials that dissolve or suspend in water and deteriorate the water quality.
The run-offs of fertilizers, pesticides and herbicides from agricultural activities into lakes and rivers affect the freshwater ecosystems.
Activity
The Effects of Water PollutionThe Effects of Water Pollution
Eutrophication
Increase BOD
Toxic Materials
EutrophicationEutrophication
Excess of the organic and inorganic wastes that enter a river or a lake enrich the water
with nutrients
Photosynthesizing organisms particularly algae that grow rapidly, result in population
explosion known as algal bloom
High diversity of algae reduces the light intensity hence lead to the death of other
photosynthetic organisms
The decomposition of these dead organisms by aerobic bacteria causes severe depletion
of water dissolved oxygen,
Eutrophication
Eutrophication
The aerobic bacteria use-up oxygen faster then it replenished; BOD increase
Causing the death of other aerobic organisms such as fish, prawns etc.
Increase BODIncrease BOD
The presence of organic materials in water
promotes the rapid growth of micro-organisms, thus
increase use-up of oxygen, leads to the increase of BOD (Biological Oxygen
Demand)
As a result, the dissolved oxygen in water is reduced and the life of the living
aquatic organisms is affected
What is Toxic Materials?What is Toxic Materials?
The illegal dumping of waste and effluent from heavy industries are the main source of toxic pollution, such as heavy metals and radioactive materials that are highly toxic, last for a long time and accumulate in living organisms via food chain
Thermal pollutionThermal pollution
Thermal pollution occurs when excess heat which is released into the environment
harms the living organisms and the environment itself
Effluents of
industrial processes
Electrical power station cooling agent
Reflection of sunlight by mirror
SourcesSources
The death of aquatic organisms that
only survive within a certain
range of temperature.
Increase in BOD value when the
metabolic rate of aquatic organisms
increases
Disturbance of ecosystem balance when migrations of organisms occur.
The effects of the increase in water temperature
Noise PollutionNoise Pollution
Motor vehicle
AeroplanesConstruction side
Agriculture and industrial machinery
SourceSource
Effects of Noise Pollution
Safe noise level is ≤ 50 decibels
(dB) but above 80 dB can cause
deafness
Development and aggravation of stress
related problems such as high blood pressure,
coronary disease, ulcers, depression and
headaches
The Greenhouse EffectThe Greenhouse Effect
What is greenhouse
effect?
Phenomenon to increase
the Earth temperature.
Without it the Earth would
be too cold for the survival of living organisms
The Greenhouse EffectThe Greenhouse Effect• Greenhouse gases are carbon dioxide, CFCs,
methane, nitrous oxide that contribute by the combustion of fossil fuels (coal, petroleum and natural gas) and other human activities such as increased deforestation and industrial production
• As the concentration of greenhouse gases rises, the more heat is trapped in the atmosphere and the Earth temperature is increased. This is known as global warming; overall rise in the average temperature of the atmosphere (cause changes in the global climate)
Carbon Dioxide andGlobal Warming
The effects of global warmingThe effects of global warming
• As the temperature rises, the polar ice caps and glaciers melt
• This causes a rise in sea levels
• Causes low-lying areas to be flooded
• Global warming leads to changes in wind direction and the distribution of rainfall; agricultural activities are affected
• Global warming causes weather patterns to change; affects the distribution of species
• Global warming increases the frequency of drought
• The land becomes dry and infertile
• Lead to a drop in crop yields
• With warmer climates, pests and vectors may spread to new areas
• Lead to an expansion of territories for vectors, resulting in an increase in the outbreaks of diseases
Occurrence of floods Climate changes
Spread of diseasesOccurrence of drought
Solutions to Global WarmingSolutions to Global Warming• Reduce the burning of fossil fuels to
conserve energy• Develops alternative sources of energy
such as wind, solar and geothermal energy
• Reduce deforestation for farming• Replant trees which have been cut down
The Thinning of the Ozone LayerThe Thinning of the Ozone Layer• The ozone layer is a region in the stratosphere between
17 and 25 kilometres above the Earth surface• Ozone layer contains high concentrations of ozone
molecules (O3) that absorb UV radiation and shield organisms from its damaging effect
• The destruction of ozone layer is due to the increasing levels of chlorofluorocarbons (CFCs) in the atmosphere
• CFCs are used as coolants in air conditioners and refrigerators, as propellants in aerosol cans and as foaming agents in the making of Styrofoam packaging
• CFCs are a group of chemical compounds that contain chlorine, fluorine and carbon
Ozone DepletionOzone Depletion
Ozone DepletionOzone Depletion
protects fromUV rays
Ozone DepletionOzone Depletion
Impact of ozone depletion on human Impact of ozone depletion on human and the ecosystemsand the ecosystems
Increase greenhouse effect
Skin Cancer
Cataract
Damaging the photosynthetic mesophyll
layers of plants
Reduce human immune system
Reduce nutrient contents and crop yields of plant
Kill microorganism and phytoplankton that are at the bottom of marine food chain
Ways to Reduce Ozone DepletionWays to Reduce Ozone Depletion• Reduce or stop the use of CFCs• Replace chlorofluorocarbons with
hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). This gases break down in the atmosphere and return to earth in the form of rainwater