Productivity In Ecosystem

Question 1

Give 2 uses of the sugars made in plants.

Answer 1

Respiration

Biomass production

Question 2

Give the units for biomass

Answer 2

grams per cm2 per year

Mass per area per year

Question 3

Name the technique used to estimate biomass.

Answer 3

Calorimetry

Question 4

Give a definition of gross primary productivity (GPP).

Answer 4

Chemical energy stored in plant biomass in a given area/volume in a given time.

Question 5

How is net primary productivity calculated?

Answer 5

Gross primary productivity - respiratory losses.

NPP = GPP - R

Question 6

Which term NNP or GPP represents the amount of energy available to the other tropic levels?

Answer 6

NPP

Question 7

How is net productivity of consumers (N) calculated?

Answer 7

N = I - (F + R)
I = injested, F= faeces R= repsiration

Question 8

Give 3 ways in which farmers can increase productive in crops.

Answer 8

Fertilisers
Reduce competition (eg remove weeds)
Reduce damage by pests (eg use pesticides/ biological control)

Question 9

Give 3 ways in which farmers can reduce respiratory losses in animals.

Answer 9

Reduce space / movement / muscle contraction

Keep animals warm (less food used to maintain body temperature).

Quality / easily accessible nutrients

Maintain health

Question 10

Wheat –> human
Wheat –> chicken –> human

Which food chain is more efficient at transferring energy to humans?

Answer 10

Wheat –> human

Remember energy is lost from food chain at each tropic level.

Question 11

Give 3 biologically important molecules that contain phosphate.

Answer 11

Proteins / amino acids

RNA / DNA

ATP

Phospholipids.

Question 12

Give 3 biologically important molecules that contain nitrogen.

Answer 12

Amino acids / proteins

DNA / RNA

ATP

Question 13

Saprobiotic nutrition - what is it?

Answer 13

Extra cellular digestion by fungi / bacteria causing decomposition

Question 14

What happens during ammonification?

Answer 14

Organic molecules –> ammonia

Eg protein in dead plant/animal converted to ammonia

Question 15

What happens during nitrification?

Answer 15

Ammonia oxidised to nitrites.

Nitrites oxidised to nitrates

Question 16

What happens during nitrogen fixation?

Answer 16

Nitrogen is oxidised to nitrate

Question 17

What happens during denitrification?

Answer 17

Nitrate converted to nitrogen.

Question 18

What are mycorrhizae?

Answer 18

A mutalistic relationship between fungi and plant roots.

Question 19

What is the advantage of mycorrhizae?

Answer 19

Increases uptake of water / inorganic ions by plant roots.

Increases surface area in contact with soil.

Question 20

Why are fertilisers added to soil?

Answer 20

Increases inorganic ions in soil.

Inorganic ions not a factor limiting plant growth.

Prevents deficiency symptoms in plants.

Question 21

Arable farming reduces the amount of inorganic ions in the soil. Why?

Answer 21

Crop/plants removed at harvest.

No decomposition.

Question 22

What happens if fertilisers are added to the soil?

Answer 22

Leaching - fertiliser enter water system.

Algal bloom.

Plants die.

Bacterial populations increases.

Bacterial respiration reduces amount of oxygen in water.

Suffocation of aquatic animals.

Question 23

What is this process called?
Leaching - fertiliser enter water system.
Algal bloom.
Plants die.
Bacterial populations increases.
Bacterial respiration reduces amount of oxygen in water.
Suffocation of aquatic animals.

Answer 23

Eutrophication