3.5.3.2 - Energy and Ecosystems (Agricultural Farming)

Question 1

Describe two ways that farming practises can increase the amount of energy available for human consumption.

Answer 1

1. Reduce the energy lost to other organisms e.g pest control.
   Reduce the energy lost through respiration e.g restrict movement, control temp.

Question 2

What are insecticides used for?

Answer 2

To kill insect pests that eat and damage crops.

Question 3

What are herbicides used for?

Answer 3

To kill weeds to remove direct competition for sunlight.

Question 4

How do biological agents increase crop yield?

Answer 4

They reduce the number of pests, so crops lose less energy and biomass.

Question 5

What type of biological agents can be used?

Answer 5

Parasites to either kill the insect or reduce it’s ability to function or
Pathogenic bacteria and viruses

Question 6

What is an integrated system ?

Answer 6

A system of using both chemical and biological methods to reduce pests.

Question 7

What ethical issues might arise from keeping animals in pens?

Answer 7

It may cause animals pain, distress and restrict their natural behaviours.

Question 8

Why are intensively reared animals kept indoors?

Answer 8

To control the environmental temperature so less energy is wasted by generating body heat.

Question 9

Keeping cattle indoors, in barns, leads to a higher efficiency of energy transfer.

Explain why.

Answer 9

Less energy lost as heat / in maintaining body

temperature / in movement

Question 10

Explain 3 advantages for a farmer of removing hedgerows.

Answer 10

1. source of pests / animals, this effect on crop;
2. source of weeds / no longer taking nutrients, hence competition / reduced yield;
3. creation of larger fields / leaving room, hence more efficient use of machinery / grow more crops;

Question 11

Apart from providing a habitat for predators of crop pests, give 3 biological benefits of replanting hedgerows.

Answer 11

1. increases biodiversity;
2. source of food for animals;
3. habitat / nest for animals;

Question 12

Give one reason why not all the light energy falling on the producers is used in photosynthesis.

Answer 12

transmission / reflected / misses chlorophyll / chloroplasts / wrong wavelength;

Question 13

What is meant by the term ecological niche?

Answer 13

An organism’s role / in the ecosystem / community;