Fichas
How humans affect the environment
Fichas del conjunto (25)
- 1Explain how human population growth has occurred.because the birth rate is greater than the death rate
-people not using contraception
-vaccines preventing death - 2Explain why raw materials are rapidly being used up and more waste is being produced.people want and demand a better standard of living
- 3Describe the effects of population growth on land and resources.-producing more industrial waste
-reduce land available for animals/plants
-waterways with sewage, fertiliser & toxic chemicals
-pollute air with gases such as sulfur dioxide - 4Describe how pesticides and herbicides can pollute the land.herbicides & pesticides are sprayed onto crops then get into the soil & food chain; eventually get washed into water
- 5Describe what happens when water is polluted by fertilisers.fish/marine life killed by chemicals, affecting the food chain
drinking water becomes poisonous to drink without filtration - 6Describe how acid rain is formed.-burning fuels can produce sulfur dioxide
-dissolves in water in air, forming acidic solutions
-fall as acid rain, sometimes far from source of gas - 7Describe some of the effects of acid rain on living organisms.-kills organisms
-changes soil pH, damaging roots & possibly releasing toxic minerals (e.g. aluminium ions damaging organisms)
-affects enzymes, which are sensitive to pH - 8Define ‘deforestation’the removal of forests/trees by felling, burning, etc.
- 9Describe ways in which deforestation affects the carbon dioxide levels in the atmosphere.-increased release of CO2 due to burning of trees or decay of wood by microorganisms
-reduced rate of photosynthesis so CO2 removed from atmosphere slower - 10Describe ways in which deforestation affects the methane levels in the atmosphere.increases in cattle and rice fields for food, therefore more methane produced by cattle and growing rice
- 11Describe the impact of deforestation on biodiversity.loss of food and habitats therefore species cannot survive - reduced biodiversity
- 12Explain why the use of peat-free compost should be encouraged.prevents destruction of peat bogs which releases CO2 into atmosphere:
peat removed from bogs & used in compost - this is decayed by microorganisms - 13Describe what is meant by the ‘greenhouse effect’.trapping of infrared radiation from sun as a result of greenhouse gases (e.g. CO2/methane) in Earth's atmosphere
maintains surface of Earth at temp. suitable for life - 14Describe how increasing levels of carbon dioxide and methane contribute to global warming.they trap too much energy in atmosphere, preventing it from reflecting into space, leading to a rise in global temperature
- 15Describe some of the consequences of global warming.-rise in sea levels due to melting of icecaps/glaciers
-changes to migration patterns
-reduced biodiversity
-climate change - 16Describe how yeast can produce ethanol for fuel.FERMENTATION:
-microorganisms respire anaerobically, using sugars from crops as energy source
-glucose (produced by maize starch and carbohydrase) and sugar cane juices are fermented by yeast
-extracted by distillation - 17Describe the advantages and disadvantages of using ethanol-based fuels.+ carbon neutral
+ reduces greenhouse effect
- batch process
- slow - 18Explain how biogas is produced in a generator.-(mainly methane) produced during anaerobic fermentation by bacteria
-dung, farm waste & animal rubbish put in
-maintained at suitable temperature in O2- free conditions
-more methane=better quality biogas - 19Evaluate the advantages and disadvantages of given designs of biogas generator.-buried in ground or have insulating jackets
-large scale: use waste from factories or sewage works)
-small scale: used by a home or farm - 20Explain why reducing the number of stages in a food chain makes food production more efficient.the shorter the chain, the less energy will be wasted, as energy is lost at each trophic level
- 21Describe ways in which energy losses by animals can be reduced.-preventing animal from moving so energy not wasted on movement
-keeping animal in warm shed so not using as much energy to maintain body temp.
-fed food high in energy - 22Explain the need for increased food production.human population is increasing and food resources are at risk of running out
- 23Describe ways in which fish stocks can be maintained.-quota: only remove a strict allocation of fish per year
-must use certain size nets to avoid catching small, young fish - 24Describe the production of mycoprotein.fungus fusarium grown anaerobically on cheap sugar syrup made from waste starch
- 25Features of a fermenter ensure max growth of fusarium:-air supply providing O2 for respiration
-stirrers/gas bubbles to keep temp. even & spread out microorganisms
-water-cooled jacket around outside to maintain temp. as respiring MOs release energy which heats contents
-sensors to monitor pH & temp.