Topic B13b - Interdependence, Pollution & Cycles

Question 1

Define producers.

Answer 1

They are organisms which make their own food. (E.g. Green plants use photosynthesis)

Question 2

What are primary consumers?

Answer 2

Animals or organisms which eat plants (eat producers)

Question 3

What are secondary consumers?

Answer 3

Animals or organisms which eat primary consumers

Question 4

What do food chains do?

Answer 4

They show you what eats what

Question 5

What is a tropic level?

Answer 5

Where organisms that feed at the same level in a food chain.

Question 6

Define interdependent

Answer 6

Organisms in an area depending on each other for food

Question 7

Name 2 ways in which animals release energy

Answer 7

Respiration and some transferred into biomass (substance that form tissues).

Question 8

Hat determines the shape of a biomass pyramid

Answer 8

The energy transferred at each tropic level

Question 9

What is parasitism?

Answer 9

A feeding relationship in which 2 organisms live together with one feeding off the other.

Question 10

Name 2 examples of parasites

Answer 10

Headlice and fleas

Question 11

Explain mutualism

Answer 11

Where organisms live in close relationships where both organism benefit.

Question 12

What does nitrogen fixing bacteria do?

Answer 12

Bacteria that can turn nitrogen in the air into nitrogen compounds.

Question 13

What is chemosynthetic bacteria

Answer 13

Are producers that get their energy from chemical substances rather than light.

Question 14

Explain how the increase in population can affect the amount of pollution.

Answer 14

The more people there are, the more water we need and food production. Crops are grown better with fertiliser (which contains nitrates and phosphates)

Question 15

Explain how fossil fuels can add to the pollution in the atmosphere.

Answer 15

When we burn fossil fuels, sulphur dioxide is released from and pollutes the air if the concentration is high

Question 16

How can farmers damage the environment?

Answer 16

If farmers use too much fertiliser, rain washes it away. It can get into the water and raise the natural concentration or nitrates and phosphates. This is called eutrophication.

Question 17

Explain how aquatic animals may die due to farmers.

Answer 17

1) fertiliser is added
2) heavy rain washed fertiliser off and nitrates and phosphates dissolve in water.
3) nitrates and phosphates not taken up by plants and washed into streams and rivers
4) high nitrate and phosphate concentrations in the water encourage plants and algae to grow rapidly
5) surface plants block sunlight so plants underneath die and stop photosynthesis
6) bacteria that break down dead materials increase numbers and use up more oxygen from water
7) oxygen concentration in water decreases
8) animals die due to lack of oxygen

Question 18

Explain how indicator species detects the amount of pollution in an area.

Answer 18

Some organisms are so sensitive to polluting chemicals that when exposed to sulphur dioxide they get killed. This means when they are exposed to sulphur dioxide, the less there are.