Energy In ecosystems

Question 1

NPP

Answer 1

GPP- respiratory losses
Amount of energy available for growth and reproduction
Available to be passes on to other tropic levels

Question 2

GPP

Answer 2

Chemical energy store in plant bio mass in a given area

Question 3

Measuring biomass

Answer 3

Dry weight
Mass of carbon (50% of dry)
Fresh weight- less accurate as water contents vary

Question 4

Net production of consumers

Answer 4

N= I- (F+R)

Question 5

Boost productivity of livestock

Answer 5

Warm 
Restrict movement 
Antibiotics 
Selective breeding 
Slaughter animals when young

Question 6

Boost productivity of crops

Answer 6

Fertilisers
Herbicides
Pesticides

Question 7

Measure productivity

Answer 7

Energy per area per unit of time
Area- standardises able to compare, size of ecosystem varies
Time- representative seasonal variations

Question 8

Importance of the nitrogen cycle

Answer 8

Nitrogen gas is unreactive, plants cannot take up nitrogen in its gaseous state
Through the cycle nitrates are formed which can be absorbed by plants
Used to produce nucleic acids and proteins
Needed to produce new cells- growth

Question 9

4 stages of the nitrogen cycle

Answer 9

Nitrogen fixation
Nitrification
Denitrification
Ammonification

Question 10

Nitrogen fixation

Answer 10

Gas into nitrogen containing compounds ( ammonium)

Nit fix bacteria free living or mutualistic legumes and root nodules ( bacteria get carbs in return)

Question 11

Ammonification

Answer 11

Nitrogen containing compounds of dead organisms/ waste
Broken down decomposed by saprobionts extra cellular digestion
converted into ammonium
Into ammonium ions soil

Question 12

Denitrification

Answer 12

Nitrates into n gas
Denitrifying bacteria
Anaerobic conditions, low ox conc eg water logged

Question 13

Nitrification

Answer 13

Ammonium ions- nitrites- nitrates
2 stage oxidation reaction
Aerobic conditions
Nitrifying bacteria

Question 14

Nitrates

Answer 14

Absorbed by plant via root hair cells
Active transport
Used to produce proteins, nucleic acids

Question 15

Mycorrhizae

Answer 15

Mutualistic relationship between roots n fungi
Increase sa of roots- faster absorption
Bacteria receive carbs in return

Question 16

Farming to increase nitrogen availability

Answer 16

Aerate soil 
Increase ox conc 
Increase nitrifying bacteria 
Reduce denitrifying bacteria 
More nitrates available to be incorporated into plant biomass
Max growth max yield max profits

Question 17

Natural vs artificial fertilisers

Answer 17

Natural are cheaper and less soluble in water must be decomposed first, less likely to cause eutrophication
Artificial are made of pure chemicals, meaning the extract nutrient levels can be controlled
More soluble in water- lead to more eutrophication
Organic vs inorganic

Question 18

Environmental consequences of use of fertilisers

Answer 18

Eutrophication

Reduce species diversity

Question 19

Why slaughter animals when young?

Answer 19

so more energy is transferred to biomass/ tissues

Question 20

Why feed livestock on a controlled diet?

Answer 20

so proportion of food digested is higher, less lost in faces