B17

Question 1

biomass

Answer 1

photosynthetic organisms are the producers of biomass for life on Earth

Question 2

feeding relationships

Answer 2

• represented by food chains
• chains begin with a producer which synthesises new molecules
• usually a green plant that makes glucose by photosynthesis

Question 3

producers

Answer 3

• eaten by primary consumers
• primary consumers are eaten by secondary consumers
• secondary consumers eaten by tertiary consumers

Question 4

consumers

Answer 4

• eat other animals
• often predators that eat prey
• in stable communities no. of predators to prey rise and fall in cycles

Question 5

cycle

Answer 5

• prey eat the plenty food available a reproduce successfully, so no. increase
• plenty prey available for predators so reproduce successfully and no. increase
• prey decrease
• less prey so less food for predators so no. fall
• food supply regrows as less consumers
• cycle repeats

Question 6

recycles material

Answer 6

material is recycled to provide building blocks for future organisms

Question 7

decay

Answer 7

decay of dead animals and plants by microorganisms return carbon to atmosphere as carbon dioxide and mineral ions to the soil

Question 8

carbon dioxide

Answer 8

in the atmosphere is used by plants in photosynthesis

Question 9

water cycle

Answer 9

• provides fresh water for plants and animals on land before draining into the seas
• water is contiguously evaporated condensed and precipitated

Question 10

carbon cycle

Answer 10

returns carbon from organisms to the atmosphere as carbon dioxide to be used by plants in photosynthesis

Question 11

respiration

Answer 11

-living organisms produce carbon dioxide and water as a waste product
- carbons returned to the atmosphere

Question 12

combustion

Answer 12

-when wood or fossil fuels are burned carbon dioxide is produced
- carbons returned to atmosphere

Question 13

the future

Answer 13

more burning of fossil fuels means more carbon dioxide in the atmosphere , so more global warming

Question 14

conditions for decay

Answer 14

• temperature - chemical reaction faster with warmth, slow/stop in cold
• moisture - microorganisms grow faster with moisture
• oxygen - respire aerobically need oxygen to break down food and transfer energy

Question 15

farmers

Answer 15

• try provide optimum conditions for the rapid decay of waste organic matter
• The compost produced is used as a natural fertiliser

Question 16

anaerobic decay

Answer 16

• produces methane gas
• biogas generators can be used o produce methane gas as a fuel