5) Sources of Food

Question 1

Why do we need to improve food production?

There are 3 reasons.

Answer 1

1) Humans need food for survival.
2) Growing world’s population means more food is needed.
3) Limited land space for growing food means we need tech to improve food production.

Question 2

What are the factors that affect the photosynthesis and growth of plants?

There are 5 factors.

Answer 2

1) air (carbon dioxide)
2) light
3) water
4) nutrients (from soil)
5) pH of soil

Question 3

Write the equation for photosynthesis of green plants.

Answer 3

chlorophyll + light
carbon dioxide + water ———————————> food + oxygen

Question 4

What is the range of pH values for acidic substances?

Answer 4

0-6

Question 5

What is the range of pH values for alkaline substances?

Answer 5

8-14

Question 6

What is the pH value for neutral substances?

Answer 6

7

Question 7

State 3 methods to improve crops production.

Answer 7

1) use of fertilisers
2) use of pesticides and herbicides
3) slash-and-burn

Question 8

What is the environmental problem associated with the use of excess fertilisers?

Answer 8

Water contanmination which leads to increased algae growth which causes underwater plants to die.
This will eventually cause the fish to also die due to lack of oxygen in water.

Question 9

What is the environmental problem associated with the use of excess pesticides and herbicides?

Answer 9

Soil contamination leads to both pesticides and herbicides moving up the food chain (e.g earthworms eats contaminated soil —–> chickens eat contaminated earthworms —–> humans eat contaminated chickens)
Water contamination is the same as soil contamination (fish is affected instead)

Question 10

What is the environmental problem associated with the slash-and-burn method?

Answer 10

Production of haze leading to breathing difficulties.
Deforestation leading to soil erosion.

Question 11

What is the environmental problem associated with the biological controls?

Answer 11

The introduced predator have no other animals to hunt them to keep their population in control
They grow in huge numbers and feed on other species of animals.

Question 12

GIve 2 examples of how we can improve yields of crops and products by using an improved variety of the anmials or plants

Answer 12

1) Use improved plant variety to produce more food (e.g. corns that gives more food per area grown)
2) Use variety of cows that produced more milk (milk production) and other variety of cows that produced more meat (meat production)

There are more than 2 examples.

Question 13

State 3 methods of intensive farming.

Answer 13

1) vertical farming
2) fish farms instead of kelongs
3) vegetable nursery instead of outdoor growing

Question 14

State 2 uses of plant hormones.

Answer 14

1) kill weeds
2) regulate the growth of the plants and the ripening of fruit