3b) Humans and Their Environment

Question 0

Why is deforestation done?

Answer 0

Provide timber for building material
Clear more land for farming
Produce paper from wood

Question 1

What is happening to the worlds population?

Answer 1

Rapidly increasing

Exponential growth

Question 2

What problems arise from deforestation?

Answer 2

More methane in the atmosphere
More carbon dioxide in atmosphere
Less carbon dioxide taken in
Less biodiversity

Question 3

What are bogs?

Answer 3

Areas of land that are acidic and waterlogged

Question 4

How do human use land?

Answer 4

Buildings
Farming
Dumping waste
Quarrying for metal ores

Question 5

Where can carbon dioxide be sequestered (stored) ?

Answer 5

Oceans, lakes and ponds
Green plants that remove CO2 from the atmosphere
Peat Bogs

Question 6

How do greenhouse gases cause global warming?

Answer 6

Gases released get trapped in the ozone layer of the atmosphere
Act as an insulating layer
Absorb most of the heat normally radiated out into space
Re-radiate heat back to Earth
Earth is heated up

Question 7

Why does deforestation mean there will be more methane in the atmosphere?

Answer 7

Forests cleared to rear cattle - more cattle means more methane
More decomposers from crops that produce methane

Question 8

Why does deforestation mean there will be more carbon dioxide in the atmosphere?

Answer 8

Carbon dioxide released when trees are burnt to clear land

Microorganisms feed on dead wood can release carbon dioxide when respiring

Question 9

Why don’t plants that live in pray bogs fully decay?

Answer 9

There’s no enough oxygen

Question 10

How does destroying peat bogs add more carbon dioxide to the atmosphere?

Answer 10

When the peat bogs are drained it starts to decompose

Carbon stored in plants are released

Question 11

Why are peat bogs drained?

Answer 11

Are can be used for farmland
Peat is cut up and dried to use as fuel
Peat sold as compost

Question 12

What are some of the problems that global warming will cause?

Answer 12

Melting of ice caps - rising sea levels - flood risks
Changed weather patterns - more extreme weather like hurricanes
Biodiversity reduces - unable to survive in change in climate

Question 13

How can biofuels be made?

Answer 13

Fermentation of natural products

Question 14

What is fermentation?

Answer 14

When bacteria or yeast break down sugars using anaerobic respiration (without oxygen)

Question 15

How is ethanol made?

Answer 15

Yeast using anaerobic respiration to break down sugar

Question 16

What is gasohol?

Answer 16

Mixture of ethanol and petrol

Question 17

Where can we get sugar from to make ethanol?

Answer 17

Sugar cane juices

Glucose can be derbies from maize starch using carbohydrase enzyme

Question 18

How is biogas made?

Answer 18

Anaerobic fermentation of waste martial

Question 19

What is a fermenter used to make biogas called?

Answer 19

Digester

or Generator

Question 20

What are the two types of biogas generators?

Answer 20

Batch generator - small batches, manually loaded, by products cleared away after each session
Continuous generator - waste is continuously fed in, run all the time, biogas produced at a steady rate

Question 21

Why does biogas have to be used straight away?

Answer 21

It can’t be stored as a liquid as if needs to high a pressure

Question 22

Why do biogas generators need to be kept at a constant temperature?

Answer 22

To keep the microorganism respiring

Question 23

Why is biogas better for the environment?

Answer 23

Energy obtained from waste

Otherwise waste would rot naturally and methane would be released

Question 24

What do all biogas generators need to have?

Answer 24

Inlet for waste material Outlet for digested material Outlet do biogas can be piped

Question 25

Explain the disadvantages and disadvantages if each biogas generator

Answer 25

Continuous - more expensive - machine costs, more convenient | Batch - cheaper, less convenient - have to be continually loaded, emptied and cleaned

Question 26

What are some of the advantages of using biogas generators as a whole?

Answer 26

Carbon neutral Doesn't produce sulphur dioxide or nitrogen oxide (no acid rain) Methane isn't released in process Raw materials needed are cheap and easily available Waste disposal system Produces fertiliser to grow crops

Question 27

What happens if the temperature in the biogas generator falls below 35oC?

Answer 27

Production will be slower | Enzymes work slower - need optimum temperature

Question 28

Why should a generator be insulated?

Answer 28

To keep warm Maintain optimum temperature Enzymes work better Faster production

Question 29

Where should biogas generators be placed and why?

Answer 29

Away from homes - smell of waste | Close to a waste source - less transport costs

Question 30

Outline 3 ways that the efficiency of good production can be improved

Answer 30

Reducing number of stages in the food chain Restricting the energy lost by farm animals Developing new food sources like Mycoprotein

Question 31

Why does reducing the number of stages in the food chain make food production more efficient?

Answer 31

Less energy and less biomass every time you move up a stage Less energy lost as less stages Can produce more food

Question 32

Explain the disadvantages and disadvantages if each biogas generator

Answer 32

Continuous - more expensive - machine costs, more convenient | Batch - cheaper, less convenient - have to be continually loaded, emptied and cleaned

Question 33

What are some of the advantages of using biogas generators as a whole?

Answer 33

Carbon neutral Doesn't produce sulphur dioxide or nitrogen oxide (no acid rain) Methane isn't released in process Raw materials needed are cheap and easily available Waste disposal system Produces fertiliser to grow crops

Question 34

What happens if the temperature in the biogas generator falls below 35oC?

Answer 34

Production will be slower | Enzymes work slower - need optimum temperature

Question 35

Why should a generator be insulated?

Answer 35

To keep warm Maintain optimum temperature Enzymes work better Faster production

Question 36

Where should biogas generators be placed and why?

Answer 36

Away from homes - smell of waste | Close to a waste source - less transport costs

Question 37

Outline 3 ways that the efficiency of good production can be improved

Answer 37

Reducing number of stages in the food chain Restricting the energy lost by farm animals Developing new food sources like Mycoprotein

Question 38

Why does reducing the number of stages in the food chain make food production more efficient?

Answer 38

Less energy and less biomass every time you move up a stage Less energy lost as less stages Can produce more food

Question 39

Why should animals be kept close together indoors?

Answer 39

Keep them warm, less movement Saves then wasting energy on movement and heat Transfer of energy from animal feed to animals more efficient Animals grow faster on less food Cheaper - less money spent on feed

Question 40

What is Mycoprotein?

Answer 40

Protein from fungi (mainly Fusarium) | Used to make meat substitutes for vegetarian meals like Quorn

Question 41

How is Mycoprotein made?

Answer 41

Fungus is grown in fermenters using glucose syrup as food (from maize starch) Fungus respires aerobically (oxygen in supplied) Mycoprotein if harvested and purified

Question 42

How are other microorganisms prevented from growing in the fermenter?

Answer 42

Fermenter is sterilised using steam Incoming nutrients are heat sterilised Air supply is filtered

Question 43

Why is Mycoprotein an efficient source of food production?

Answer 43

Microorganisms grown very quickly Don't need much space Can feed on waste material

Question 44

What are some of the problems that arise from efficient food production?

Answer 44

Animal rights Spread of diseases - animals kept in crowded conditions Antibiotics given to animals can promote bacteria developing anti-biotic resistance Fossil fuels burnt to keep animals warm

Question 45

What is sustainable food production?

Answer 45

Having enough food without using resources faster than they can renew themselves

Question 46

How can fish stocks be maintained?

Answer 46

Fishing quotas - limits on number and size of fish caught in certain areas - prevents overfishing Bigger net size - allows unwanted fish and younger fish to escape that are usually accidentally caught

Question 47

Why are fish stocks declining?

Answer 47

Overfishing