B8 - Cycles with Ecosystems

Question 1

A tapeworm is an example

Answer 1

C - parasite

Question 2

Describe how an adaptation of the tapeworm enables it to live in the human intestine

Answer 2

• suckers on the head

- attached to the intestine

Question 3

suggest how humans could avoid becoming infected with tapeworms

Answer 3

• cook meat thoroughly

- do not eat meat (become vegan)

Question 4

explain the relationship between the tube worms and chemosynthesis bacteria

Answer 4

• chemosynthetic live in the gut of the tube worms
• bacteria convert hydrogen sulphide compounds
• into food for the worms
• tube worms provide place for bacteria to live
• this is a mutualistic relationship

Question 5

the name of this stage is

Answer 5

C - nitrification

Question 6

explain how plants use nitrates from the soil

Answer 6

• used to make protein

- for growth

Question 7

describe how the over use of nitrate fertilisers can cause eutrophication

Answer 7

• nitrates flow into the water
• algae grows rapidly
• underwater plants cannot photosynthesise
• lack of photosynthesis causes them to die
• decomposing bacteria break down dead material
• these bacteria use up oxygen during respiration

Question 8

Explain the relationship between this bean plant and the bacteria growing in the root nodules

Answer 8

• bacteria using nitrogen fixing bacteria
• make ammonia for use by plants
• bacteria is protected within the root module
• bacteria can obtain chemical substances from the plant
• this is a mutualistic relationship

Question 9

build up of nutrients in an aquatic environment is known as

Answer 9

B - eutrophication

Question 10

suggest how farming can lead to a build up of nutrients in the lake

Answer 10

• overuse of of phosphate fertilisers
• leaching in the lake
• sewage leakage into the lake

Question 11

state the effect of nitrates on plant growth

Answer 11

• plant growth is increased

Question 12

Explain how soil bacteria produce nitrates

Answer 12

• decompose bacteria
• breakdown dead matter in the soil
• into ammonia
• ammonia converted into nitrates
• by nitrifying bacteria

Question 13

name one type of bacteria that reduce the nitrate content of the soil

Answer 13

• denitrifying bacteria

Question 14

explain the differences in mean width of the leaves from plant a and and plant b

Answer 14

• leaves are larger for plant b because they have a higher concentration of nitrate
• nitrates required for making protein

Question 15

plants use nitrates to make

Answer 15

D - proteins

Question 16

Explain how different types of bacteria act of increase nitrate concentration in the soil

Answer 16

Nitrogen Fixing Bacteria - fox nitrogen gas for the plant

Decomposing Bacteria - decompose animal/plant matter into ammonia

Nitrifying Bacteria - convert ammonia into nitrates

Question 17

name the process by which bacteria release carbon dioxide into the atmosphere

Answer 17

• respiration

Question 18

suggest why concentration of carbon dioxide changes during a year

Answer 18

• seasonal weather changes
• less leaves on trees means less photosynthesis so less Carbon Dioxide removed from atmosphere
• more fossil fuels may be burnt for winter