unit 4 human influence on the environment 2015
TRANSCRIPT
UNIT 4:
HUMAN INFLUENCES ON THE
ENVIRONMENT
ONLY USE LEARNING GUIDE AND SLIDES TO STUDYREAD PAGES IN TEXTBOOK WHERE INDICATED
INTRODUCTIONHuman impact on the environment
or anthropogenic impact on the environment includes:
Impacts on biophysical environments, biodiversity & other resources.
The term anthropogenic describes an effect or object resulting from human activity.
ENVIRONMENTAL ISSUES IN SA
Many environmental issues affect SA urbanization & acts (LAWS) needed to survive.
Keeping up with developing world + meet high demands of growing population, SA exhausted its many resources severe environmental damage.
Continuous depleting & improper treatment of natural resources SA only harming their environment.
HUMAN ACTIVITIES THAT HAVE AN ENVIRONMETAL IMPACT: Agriculture (FARMING) Fishing Irrigation Meat production Palm oil farming Energy harvesting and consumption Coal mining and burning Manufacturing of products Electricity generation The use of fertilisers may cause
eutrophication
THE EFFECTS OF HUMAN INFLUENCES ON THE ENVIRONMENT Human impact on biodiversity significant. Human impact on coral reefs significant. Coral
reefs are dying around the world. Coral reefs also face high dangers from pollution, diseases, destructive fishing practices and warming oceans
Human impact on nitrogen cycle diverse. Humans destroying habitats & reducing
amount of land available for other organisms by building, quarrying, farming and dumping waste.
Human activities polluting water, air and land.
IMPACT OF POLLUTION ON THE ENVIRONMENT
WATER POLLUTIONWater pollution contamination of
water bodies.Water pollution pollutants are discharged directly/indirectly into water bodies without adequate treatment to remove harmful compounds.
Water pollution affects plants & organisms living in these bodies of water.
WATER POLLUTIONOne of SA biggest issues is the lack of
clean water. Water around Africa unevenly distributed
meaning that 60% of water situated in only 20% of land.
<10% of SA surface water is accessible majority of ground water lay under large rock
formations becomes difficult to access. Climate change & its related effects on
temperature & precipitation may have an additional impact.
WATER POLLUTION – Coal Mining
Coal mining one of SA main energy source: huge negative impact on land’s water, air & soil
quality. Acid mine drainage result of excess coal
mining. Process to neutralize Sulphuric Acid
released from coal mining extremely slow.
Clean, excess water released from rock masses that are broken through mining mixed with sulphuric acid water becomes toxic.
WATER POLLUTION – Coal MiningToxic, contaminated water
kills plants & animals, dissolving aluminium & heavy
minerals found in clean water (increasing toxicity level).
Rocks which contain calcium carbonate able to neutralize acidic water, SA does not have the rocks which
contain these minerals.
2 CATEGORIES OF SOURCES OF SURFACE WATER POLLUTION
Point source water pollution:Contaminants that enter waterway from
single, identifiable source, such as a pipe or drain.
Examples of sources: discharges from sewage treatment plant,
factory, or city storm drain.
POINT SOURCE WATER POLLUTION
Non–point source pollution (NPS):Diffused contamination does not
originate from a single discrete source.
Cumulative effect of small amounts of contaminants gathered from a large area. Common example: leaching out of nitrogen compounds from fertilized agricultural lands.
Nutrient runoff in stormwater from "sheet flow" over an agricultural field / forest examples of NPS pollution.
SHEET FLOW An overland flow / downslope movement
of water taking (thin, continuous film over relatively smooth soil / rock surfaces)
NON-POINT SOURCES
Some of the main contributors to water pollution are: Factories / Refineries Waste treatment facilities Mining Pesticides, herbicides & fertilizers Human sewage Oil spills Failing septic systems Soap (washing car) Oil & antifreeze leaking from cars Household chemicals Animal waste
IMPACT OF WATER POLLUTION ON HUMAN HEALTH Increased incidence (tumours, ulcers) nitrate
pollution. Increased incidence (skin disorders) contact
with pollutants. Increased incidence (constipation, diarrhoea,
infections to intestine. Dangerous effects on growing foetus
pregnant women. Concentration of pollutants bio- accumulative
pesticides through secondary / tertiary food chain in case of non-vegetarians.
Still births, abortions and birth of deformed children.
HOW YOU CAN HELP TO PREVENT WATER POLLUTIONWash car far away from storm water drainsDon’t throw trash, chemicals, solvents into
sewer drains Inspect your septic system every 3-5 yearsAvoid using pesticides & fertilizers that can
run off into water systemsSweep your driveway instead of hosing it
downUse non-toxic cleaning materialsClean up oil / liquid spills with kitty litter &
sweet them upDon’t wash paint brushes in the sink
AIR POLLUTIONWhat are the sources of air pollution?
Automobile emissions Tobacco smoke Combustion of coal Acid rain Noise pollution from cars and construction Power plants Manufacturing buildings Large ships Paint fumes Aerosol sprays Wildfires Nuclear weapons
AIR POLLUTION IN SASA developing region (low-grade fuels are used to meet high demands) for food, energy.
SO2 & CO2 released in air due to deforestation & growing amount of air pollution, air pollutants in the atmosphere are slowly building up.
THE IMPACT OF AIR POLLUTION ON HUMAN HEALTH
Principally affect the body's respiratory system and the cardiovascular system.
The health effects: biochemical and
physiological changes
breathing, wheezing, coughing
aggravation of existing respiratory and cardiac conditions
HOW YOU CAN HELP TO PREVENT AIR POLLUTION
Carpool or join a ride share with friends and co-workers
Don’t smoke Keep your car maintenance up-to-date If you have to drive, do your errands at one time Don’t buy products that come in aerosol spray cans Avoid using lighter fluid when barbecuing outside When you drive accelerate slowly and use cruise
control Always replace your car’s air filter Use a push or electric lawnmower rather than a gas-
powered one Don’t use harsh chemical cleaners that can emit
fumes Inspect your gas appliances and heaters regularly
LAND POLLUTION SELF STUDY KNOW THE SOURCE OF LAND POLLUTION KNOW THE IMPACT LAND POLLUTION HAS ON
HUMAN HEALTH KNOW HOW YOU CAN PREVENT LAND
POLLUTION
LAND POLLUTION Land pollution is the deterioration (destruction)
of the earth’s land surfaces, often directly or indirectly as a result of man’s activities and their misuse of land resources.
It occurs when waste is not disposed off properly, or can occur when humans throw chemicals unto the soil in the form of pesticides, insecticides and fertilizers during agricultural practices. Exploitation of minerals (mining activities) has also contributed to the destruction of the earth’s surface.
GLOBAL ENVIRONMENT
AL ISSUES
•OZONE DEPLETION•GREENHOUSE EFFECT•GLOBAL WARMING
OZONE DEPLETIONLife on Earth is protected from damaging effects of UV radiation by a protective layer of ozone molecules in the atmosphere.
Satellite studies suggest that the ozone layer has been gradually thinning since 1975.
Ozo
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Fig. 55-23
Year
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’95
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’75
’70
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1955
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100
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Destruction of atmospheric ozone probably results from chlorine-releasing pollutants such as CFCs produced by human activity.
The “ozone hole” has increased in size as ozone depletion has increased.
Ozone depletion causes DNA damage in plants & poorer phytoplankton growth
An international agreement signed in 1987 has resulted in a decrease in ozone depletion: The Montreal Protocol on Substances that
Deplete the Ozone Layer (a protocol to the Vienna Convention for the Protection of the Ozone Layer) is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion.
As a result ozone hole in Antarctica is slowly recovering.
Climate projections indicate that the ozone layer will return to 1980 levels between 2050 and 2070.
GREENHOUSE EFFECT AND GLOBAL WARMING
CO2, water vapour & other greenhouse gases reflect infrared radiation back toward Earth; greenhouse effect Important for keeping Earth’s surface at
a habitable temperature.Due to burning of fossil fuels, other
human activities, concentration of atmospheric CO2 has
been steadily increasing.
RISE IN [CO2] AND TEMP
Increased levels of atmospheric CO2 are magnifying the greenhouse effect, which could cause global warming and climatic change.
Increasing concentration of atmospheric CO2 is linked to increasing global temperature.
Northern coniferous forests and tundra show the strongest effects of global warming.
A warming trend would also affect the geographic distribution of precipitation.
Global warming can be slowed by reducing energy needs and converting to renewable sources of energy
Stabilizing CO2 emissions will require an international effort.
Why is Global Warming important?Temperature increases will have significant impacts on human activities, including: where we can live, what food we can grow, how and where we can grow food, and where organisms we consider pests can thrive.
To be prepared for the effects of these potential impacts we need to know :how much the Earth is warming, how long the Earth has been warming, and what has caused the warming.
Answers to these questions provide us with a better basis for making decisions related to issues such as water resources and agricultural planning.
NATIONAL ENVIRONMENTAL ISSSUES
DEFORESTATION OVERGRAZING DESERTIFICATION CROPS COMMERCIAL FORESTS WATER TABLE PROBLEMS MONOCULTURE EFFECTS BIODIVERSITY DEPOSIT OF TOXIC SUBSTANCES INTRODUCTION OF INVASIVE ALIEN SPECIES
INTO SOUTH AFRICA IMPACT ON BIODIVERSITY CONTROL MECHANISMS
DEFORESTATIONDeforestation is the permanent destruction of indigenous forests and woodlands.
The term does not include the removal of industrial forests such as plantations of gums or pines.
Deforestation has resulted in the reduction of indigenous forests.
HOW DOES DEFORESTATION OCCUR?conversion of forests and woodlands
to agricultural land to feed growing numbers of people;
development of cash crops and cattle ranching,
commercial logging destroys trees as well as opening up forests for agriculture;
felling of trees for firewood and building material;
CONSEQUENSES OF DEFORESTATION
1. Alteration of local and global climates through disruption of the carbon and water cycle
2. Soil erosion 3. Silting of water courses, lakes
and dams 4. Extinction of species which
depend on the forest for survival. 5. Desertification
OVERGRAZINGOvergrazing occurs when plants are exposed
to intensive grazing for extended periods of time, or without sufficient recovery periods.
It can be caused by either livestock in poorly managed agricultural applications, or by overpopulations of native or non-native wild animals.
Overgrazing reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion.
Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds.
MONOCULTURE EFFECTS BIODIVERSITYMonoculture is the agricultural
practice of producing or growing a single crop or plant species over a wide area and for a large number of consecutive years.
Monocultures can lead to the quicker spread of diseases, where a uniform crop is susceptible to a pathogen.
Therefore decreasing biodiversity.
DEPOSIT OF TOXIC SUBSTANCES IN THE ENVIRONMENTHumans release many toxic chemicals, into
the environment e.g. Acid mine water In some cases, harmful substances persist
for long periods in an ecosystem .One reason toxins are harmful is that they
become more concentrated in successive trophic levels.
Biological magnification concentrates toxins at higher trophic levels, where biomass is lower.
Pesticides such as DDT are subject to biological magnification in ecosystems.
In the 1960s Rachel Carson brought attention to the biomagnification of DDT in birds in her book Silent Spring
INTRODUCTION OF INVASIVE ALIEN SPECIES INTO SOUTH AFRICAInvasive species, typically introduced to
a new environment by humans, often lack predators or disease.
In total there are 200 species of plants that are declared weeds or invaders in South Africa.
E.G. Eucalyptus species, Port Jackson willow, Black wattle.
PORT JACKSON WILLOWEUCALIPT
US
BLACK WATTLE
LOCAL ENVIRONMENT
AL ISSUES
OVEREXPLOITATION OF LOCAL INDIGENOUS RESOURCES
Overexploitation is human harvesting of wild plants or animals at rates exceeding the ability of populations of those species to rebound
Overexploitation by the fishing industry has greatly reduced populations of some game fish, such as bluefin tuna
DNA analysis can help conservation biologists to identify the source of illegally obtained animal products.
OVEREXPLOITATION OF BLUEFIN TUNA
Population growth, urbanization and the unrestricted collection of medicinal plants from the wild is resulting in an over-exploitation of natural resources in southern Africa.
Therefore, the management of traditional medicinal plant resources has become a matter of urgency.
Problems arising from the exploitation of natural resources Deforestation Desertification Extinction of species Forced migration Soil erosion Oil depletion Ozone depletion Greenhouse gas increase Extreme energy Water pollution Natural hazard/Natural disaster
SUSTAINABILITY OF LOCAL INDIGENOUS RESOURCES IN SOUTH AFRICA
The concept of sustainability helps ecologists establish long-term conservation priorities.
Sustainable development is development that meets the needs of people today without limiting the ability of future generations to meet their needs
Sustainable development requires connections between life sciences, social sciences, economics, and humanities
SOME OF S.A. INDIGENOUS RESOURCES THAT SHOULD BE CONSERVED AND SUSTAINED
Devil’s clawRooibosFynbosAfrican potatoHoodiaPepperbark tree
DEVIL’S CLAWDevil’s claw is an herb. The botanical name, Harpagophytum, means
“hook plant” in Greek. The fruit is covered with hooks meant to
attach onto animals in order to spread the seeds. The roots and tubers of the plant are used to
make medicine.Devil’s claw is used for “hardening of the
arteries" (atherosclerosis), arthritis, gout, muscle pain (myalgia), back pain, tendonitis, chest pain, gastrointestinal (GI) upset or heart burn, fever, and migraine headache.
DEVIL’S CLAW
ROOIBOSRooibos is a member of the legume family of
plants growing in South Africa's fynbos.Traditional medicinal uses of rooibos in South
Africa include alleviating infantile colic, allergies, asthma and dermatological problems.
The plant is used to make a herbal tea called rooibos tea.
Rooibos leaves are dried and used to make tea, though parts of the plant are now used in skin care formulas as well
AFRICAN POTATO (Hypoxis)Africa Potato is rich in vitamins. Boosts energy, improves immune system and
helps to prevent virus infections. Lowers high blood pressure and blood sugar
levels. Older generations drink it as a herbal tea,
creams and tablet are also made from this plant.
HOODIAUsed as an appetite suppressant and
for treating indigestion and small infections
Hoodia is a leafless spiny succulent plant with medicinal properties.
It grows naturally in South Africa and Namibia.
The flowers smell like rotten meat and are pollinated mainly by flies.
PEPPERBARK AND FYNBOS
SELF STUDY FIND OUT MORE ABOUT THE MEDICINAL
VALUE OF THESE TWO PLANTS.