Our impact on the ecosystem (Ecology) Flashcards
Why the use of natural resources needs to be controlled and regulated
- used everyday
- depletion results in environmental damage
- mostly irreversible
Types of natural resources
- Renewable
- Non-renewable
Renewable natural resources
- can be replaced via natural cycles (as long as not overused)
- e.g. air, water, soil, wildlife
Non-renewable natural resources
- cannot be replaced once used
- e.g. fossil fuel, minerals
Deforestation
- clearing of forests
- makes land available for agricultural, urban development
- wood (raw material)
- usually cleared faster than replaced
Effects of deforestation
- Soil erosion
- Flooding
- Desertification
- Climate changes
Soil erosion (Deforestation)
- forests leafy canopy protects topsoil (most nutrients here) from direct impact of rain
- retain water thru absorption by roots
- w/o, top soil easily washed off by heavy rain
Flooding (Deforestation)
- resultant of soil erosion
- rise in water lvl
- increase chances of flooding
Desertification (Deforestation)
- w/o leafy canopy, sunlight falls directly onto ground
- water evaporate
- create desert-like condition
- unsuitable for plant growth
Climate changes (Deforestation)
- less plants, less CO2 removed frm atmosphere via photosynthesis
- CO2 greenhouse gas, traps heat
- warmer climate
- mosquitoes example
- disrupts water cycle
Uncontrolled fishing practices
- impt food source
- population increase, demand increases
- uncontrolled and unregulated fishing practices leads to reduced aquatic biodiversity
Dredges (uncontrolled fishing practices)
- destroy coral reefs and
- organisms living on sea bed
Drift nets and trawlers
- catch ,marine life indiscriminately
Cyanide fishing
- kills corals and other reef organisms
Effects of uncontrolled fishing practices
- destruction of marine habitat
- decrease and extinction of certain fish populations
Pollution
- process where harmful substances added to environment
Water pollution
- contamination of water bodies
- discharge of untreated sewage into water bodies
- excessive use of fertilisers and insecticides
- dumping of inorganic waste material into water bodies
Sewage
- waste materials frm homes and industries
- untreated sewage may contain disease-causing bacteria, result in epidemic of water bodies
- e.g. cholera outbreaks (caused by bacteria in untreated sewage)
- untreated sewage contain phosphates and nitrates, can lead to eutrophication
Define epidemic
- outbreak of disease
- affects large population of humans in a given period
Chemical fertiliser
- contain phosphates and nitrates
- used to increase crop yield
- excessive use can lead to eutrophication
Eutrophication
- excessive nutrients washed into waterbody
- increase growth of algae, water plants
- form a layer above water
- submerged plants die due to lack of sunlight
- bacteria grow rapidly , use up dissolved O2 as decomposing dead plants
- anoxic environment, other organisms die
Inorganic waste
- include poisonous metals (e.g. mercury)
- pesticides
- harmful to humans
Mercury poisoning (1971 Minamata)
- plastic factory discharged waste water containing mercury in to Minamata Bay
- mercury absorbed by water weeds
- weeds eaten by fish
- fish caught contained high conc of mercury
- villagers ate the contaminated fish, suffered frm mercury poisoning
Insecticides
- DDT
- inorganic compounds, non-biodegradable
- DDT cannot be broken down and excreted, stored in fatty tissues of consumers
- can be passed along food chains
- conc increase along tropic level (biomagnifciation)
- results in bioaccumulation of DDT in top consumers
DDT effect on birds
- insects die, laced with DDT
- birds eat
- shells of egg too thin, cannot hatch eggs
- unable to reproduce enough
Bioaccumulation
- chemicals not excreted, accumulate in bodies of consumers
- within trophic lvl
Biomagnification
- chemicals passed along food chain
- conc in bodies on final consumers
- across trophic lvls
Define conservation
- protection
- preservation
- of natural resources in environment
Define biodiversity
- range of species
- present in particular ecosystem
Reasons for conservation
- Scientific value
- Maintenance of balanced ecosystem
- Maintenance of biodiversity
- Economic importance
- Food source
- Preservation of natural scenery and wildlife
Scientific value (Reasons for conservation)
- study of fossils , diversion of species
- insight on evolution
Maintenance of balanced ecosystem (Reasons for conservation)
- deforestation
- disrupts carbon and water cycle
Maintenance of biodiversity
- discovery of fauna and flora
- medicinal value
- prevent extinction
- maintaining large gene pool
Economic importance
- raw materials for industrial use
- e.g. wood
Food source
- e.g fish
- main human food source
Conservation measures
- Environmental biotech
- Conservation of forests
- Conservation of fishing grounds
Environmental biotechnology
- use of biological sciences
- provide environmentally-friendly solutions (reducing pollution)
- e.g. wastewater treatment process
Wastewater treatment process
- Channelled into water reclamation plants
- Primary settling tank
- Aeration tank
- Final settling tank, treated water discharged into sea
What happens to sludge from primary settling tank
- removed from primary settling tanks
- treated in anaerobic digesters
- dewatered and disposed into soil container
- removed from final settling tanks
Primary settling tank
- heavy solids settle
- bottom of tank
- removed as sludge
Aeration tank
- partially treated wastewater
- mixed with bacteria
- organic pollutants broken down into harmless substances
Final settling tank
- bacteria removed
Conservation of forests
- laws to regulate logging
- reforestation
- designating lands for forests reserves
- research, improve quality and productivity of forests
Conservation of fishing grounds
- banning use of drift nets, trawlers, dredges
- using nets of certain mesh size
- limit no. of ships in fishing ground at certain time
- raising endangered fish in hatcheries b4 releasing into wild
