Our impact on the ecosystem (Ecology)

Question 1

Why the use of natural resources needs to be controlled and regulated

Answer 1

• used everyday
• depletion results in environmental damage
• mostly irreversible

Question 2

Types of natural resources

Answer 2

• Renewable

- Non-renewable

Question 3

Renewable natural resources

Answer 3

• can be replaced via natural cycles (as long as not overused)
• e.g. air, water, soil, wildlife

Question 4

Non-renewable natural resources

Answer 4

• cannot be replaced once used

- e.g. fossil fuel, minerals

Question 5

Deforestation

Answer 5

• clearing of forests
• makes land available for agricultural, urban development
• wood (raw material)
• usually cleared faster than replaced

Question 6

Effects of deforestation

Answer 6

1. Soil erosion
2. Flooding
3. Desertification
4. Climate changes

Question 7

Soil erosion (Deforestation)

Answer 7

• 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

Question 8

Flooding (Deforestation)

Answer 8

• resultant of soil erosion
• rise in water lvl
• increase chances of flooding

Question 9

Desertification (Deforestation)

Answer 9

• w/o leafy canopy, sunlight falls directly onto ground
• water evaporate
• create desert-like condition
• unsuitable for plant growth

Question 10

Climate changes (Deforestation)

Answer 10

• less plants, less CO2 removed frm atmosphere via photosynthesis
• CO2 greenhouse gas, traps heat
• warmer climate
• mosquitoes example
• disrupts water cycle

Question 11

Uncontrolled fishing practices

Answer 11

• impt food source
• population increase, demand increases
• uncontrolled and unregulated fishing practices leads to reduced aquatic biodiversity

Question 12

Dredges (uncontrolled fishing practices)

Answer 12

• destroy coral reefs and

- organisms living on sea bed

Question 13

Drift nets and trawlers

Answer 13

• catch ,marine life indiscriminately

Question 14

Cyanide fishing

Answer 14

• kills corals and other reef organisms

Question 15

Effects of uncontrolled fishing practices

Answer 15

• destruction of marine habitat

- decrease and extinction of certain fish populations

Question 16

Pollution

Answer 16

• process where harmful substances added to environment

Question 17

Water pollution

Answer 17

• 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

Question 18

Sewage

Answer 18

• 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

Question 19

Define epidemic

Answer 19

• outbreak of disease

- affects large population of humans in a given period

Question 20

Chemical fertiliser

Answer 20

• contain phosphates and nitrates
• used to increase crop yield
• excessive use can lead to eutrophication

Question 21

Eutrophication

Answer 21

• 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

Question 22

Inorganic waste

Answer 22

• include poisonous metals (e.g. mercury)
• pesticides
• harmful to humans

Question 23

Mercury poisoning (1971 Minamata)

Answer 23

• 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

Question 24

Insecticides

Answer 24

• 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

Question 25

DDT effect on birds

Answer 25

- insects die, laced with DDT - birds eat - shells of egg too thin, cannot hatch eggs - unable to reproduce enough

Question 26

Bioaccumulation

Answer 26

- chemicals not excreted, accumulate in bodies of consumers | - within trophic lvl

Question 27

Biomagnification

Answer 27

- chemicals passed along food chain - conc in bodies on final consumers - across trophic lvls

Question 28

Define conservation

Answer 28

- protection - preservation - of natural resources in environment

Question 29

Define biodiversity

Answer 29

- range of species | - present in particular ecosystem

Question 30

Reasons for conservation

Answer 30

1. Scientific value 2. Maintenance of balanced ecosystem 3. Maintenance of biodiversity 4. Economic importance 5. Food source 6. Preservation of natural scenery and wildlife

Question 31

Scientific value (Reasons for conservation)

Answer 31

- study of fossils , diversion of species | - insight on evolution

Question 32

Maintenance of balanced ecosystem (Reasons for conservation)

Answer 32

- deforestation | - disrupts carbon and water cycle

Question 33

Maintenance of biodiversity

Answer 33

- discovery of fauna and flora - medicinal value - prevent extinction - maintaining large gene pool

Question 34

Economic importance

Answer 34

- raw materials for industrial use | - e.g. wood

Question 35

Food source

Answer 35

- e.g fish | - main human food source

Question 36

Conservation measures

Answer 36

1. Environmental biotech 2. Conservation of forests 3. Conservation of fishing grounds

Question 37

Environmental biotechnology

Answer 37

- use of biological sciences - provide environmentally-friendly solutions (reducing pollution) - e.g. wastewater treatment process

Question 38

Wastewater treatment process

Answer 38

1. Channelled into water reclamation plants 2. Primary settling tank 3. Aeration tank 4. Final settling tank, treated water discharged into sea

Question 39

What happens to sludge from primary settling tank

Answer 39

- removed from primary settling tanks - treated in anaerobic digesters - dewatered and disposed into soil container - removed from final settling tanks

Question 40

Primary settling tank

Answer 40

- heavy solids settle - bottom of tank - removed as sludge

Question 41

Aeration tank

Answer 41

- partially treated wastewater - mixed with bacteria - organic pollutants broken down into harmless substances

Question 42

Final settling tank

Answer 42

- bacteria removed

Question 43

Conservation of forests

Answer 43

- laws to regulate logging - reforestation - designating lands for forests reserves - research, improve quality and productivity of forests

Question 44

Conservation of fishing grounds

Answer 44

- 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