Agriculture

Question 1

Agricultural
practices to
maximise plant
growth

Answer 1

Growing plants under artificial
lighting to maximise light
intensity
heating in greenhouse to
increase temperature
burning fuel to release CO2

Question 2

What is the benefit
of agricultural
practices for plant
growth?

Answer 2

aim to maximise plant growth and
yield e.g.
use of fertilisers to provide essential
minerals (e.g. nitrates, phosphates)
irrigation to maintain water supply
pest and disease control to reduce
damage to crops
These increase plant growth and
therefore yield and profit

Question 3

Farming practices
to increase energy
transfer for crops

Answer 3

Simplifying food webs to reduce
energy/biomass
herbicides kill weeds -> less
competition
fungicides reduce fungal infections
results in more energy available to use
to create biomass
fertilisers such as nitrates to promote
growth

Question 4

Farming practices
to increase energy
transfer for
animals

Answer 4

Reducing respiratory losses
(more energy to make biomass)
restrict movement
keep warm
slaughter animal when young
(most energy used for growth)
selective breeding to produce
breeds with higher growth rates

Question 5

Fertilisers

Answer 5

Replace nutrients (nitrates and
phosphates) lost from an
ecosystem’s nutrient cycle when
crops are harvested
livestock removed
can be natural (manure) or
artificial (inorganic chemicals)

Question 6

Natural
fertilisers
advantages

Answer 6

Cheaper than artificial
fertilisers
often free if farmer has own
animals - recycle manure
organic molecules have to be
broken down first by
saprobionts so leaching less
likely

Question 7

Natural
fertilisers
disadvantages

Answer 7

Exact minerals and proportions
cannot be controlled

Question 8

Artificial
fertilisers
disadvantages

Answer 8

High solubility means larger
quantities can leach away with
rain
risking eutrophication
reduce species diversity as
favour plants with higher
growth rates e.g., nettles

Question 9

Leaching

Answer 9

When water-soluble compounds
are washed away into rivers /
ponds
for nitrogen fertilisers, this can
lead to eutrophication

Question 10

Eutrophication

Answer 10

When nitrates leached from
fields stimulate growth of algae
algal bloom
can lead to death of aquatic
organisms

Question 11

How does
eutrophication lead
to death of aquatic
organisms?

Answer 11

Algal bloom creates blanket
surface of water blocking light
plants cannot photosynthesize
and die
aerobic bacteria feed and
respire on dead plant matter
eventually, aquatic organisms
die due to lack of dissolved
oxygen in water

Question 12

Mutualistic
relationships

Answer 12

A symbiotic relationship where
both species benefit