Humans and their environment Flashcards
What happens if waste is not properly handled?
more pollution will be caused
Why is increasingly more waste being produced?
Rapid growth in human population and an increase in the standard of living
How do humans reduce the amount of land available for other animals?
building, quarrying, farming and dumping waste
What may human’s waste pollute?
water with sewage, fertiliser or toxic chemicals.
Air with smoke and gases e.g auld ur dioxide which contributes to acid rain
land with toxic chemicals e.g pesticides and herbicides which may then be washed into waterways
Why is there large scale deforestation in tropical areas?
due to need for timber to provide land for agriculture
What impacts has deforestation had?
increased release of CO2 into atmosphere via burning of the wood and activities of microorganism
reduced rate at which CO2 is removed from the atmosphere (photosynthesis)
and stops trees ‘locking up’ CO2
reduced biodiversity due to loss of food and habitats
Why has deforestation occurred?
Allow crops to be grown to produce ethanol-based biofuels
allow increase in cattle and rice fields to provide food. However methane is produced by these organisms
What happens when peat bogs are destroyed?
CO2 released into atmosphere because peat used as compost which microorganisms decay
What is an environmentally friendly alternative to peat bogs?
Peat free composts
What gas levels are increasing in the atmosphere and what are they contributing to?
Increased levels of CO2 and methane contribute to global warming
What happens if the earths atmosphere increases by only a few degrees Celsius?
climate change rise in sea level reduction of biodiversity changes in migration patterns of animals e.g birds changes in distribution of species
How is CO2 related to oceans, lakes and ponds and why is this important?
CO2 sequestered in oceans, lakes and ponds. Important in removing CO2 from atmosphere
What is a biofuel?
fuel produced from biological material which is renewable and sustainable
Name the process by which ethanol based fuels are produced
fermentation
Describe the process of producing ethanol-based biolfuels
Glucose produced from maize starch by the action of carbohydrase
Glucose and sugar cane juices then fermented by anaerobically respiring yeast
Produced ethanol which is extracted via distillation and used as fuel in motor vehicles
What can ethanol be described as and why?
Carbon neutral as only the CO2 used for photosynthesis by the crops is released into the atmosphere when ethanol is burned
What is biogas?
mainly methane
How is biogas produced?
anaerobic fermentation by bacteria
Describe the process of producing biogas
Plants and waste material containing carbohydrates (e.g cattle dung), broken down by biogas generators
What do generators provide?
ideal conditions for bacteria to reproduce and ferment carbohydrates
What to generators produce in tho process?
slurry which can be used as fertiliser
what can biogas be used for?
cooking, heating or refrigeration
What do large scale generators use?
waste from sugar factories or sugar works
Where can small scale generators be used?
at home or on a farm
How is temperature maintained in biogas generators?
using insulating jackets or being buried underground for insulation
What uses oxygen free conditions?
biogas generators
What happens at each stage of the food chain?
less material and less energy contained in the biomass of the organisms so less stages=more efficient
How can meat be produced more efficiently?
Preventing animal from moving so that no energy wasted on movement
keeping animal warm so no energy lost on maintaining body temp
What is happening to fish stocks?
declining
How are fish stocks maintained?
Fishing quotas - fishermen can only remove a strict allocation per year
Nets with big holes - avoid catching small and young fish which can reproduce
How is mycoprotein produced?
using fusarium (fungus) which is grown aerobically on cheap sugar syrup made from waste starch
mycoprotein then harvested
What do industrial fermenters have?
air supply providing oxygen for respiration
stirrer or gas bubbles used to keep microorganisms spread out and to provide even temp
water-cooked jacket around outside as respiring microorganisms release energy which heats up contents
sensors to monitor pH and temp
