Unit 4

Question 1

What is bioaccumulation?

Answer 1

The build up of pesticides in the fatty tissues of an organism.

Question 2

What is population?

Answer 2

The number of a particular species.

Question 3

How can pests harm crops’ yield?

Answer 3

-Lowering the amount by reducing growth
-affecting the appearance or quality

Question 4

What is an ecosystem?

Answer 4

Community of living organisms together with their non-living environment.

Question 5

What converts nitrate into nitrogen?

Answer 5

Denitrifying bacteria.

Question 6

What does biodiversity mean?

Answer 6

The amount of variation shown by a species in an ecosystem.

Question 7

How are fossil fuels formed?

Answer 7

When a large amount of carbon is trapped underground over millions of years in the form of waste and dead material.

Question 8

What are the effects of deforestation?

Answer 8

-Reduced biodiversity
-Reduced soil quality
-climate change

Question 9

What is the definition of air pollution?

Answer 9

The contamination of the environment by harmful substances that are produced by the activities of humans.

Question 10

What are the effects of global warming on the planet?

Answer 10

-Ice caps would melt and sea levels would rise
-Change in ocean currents
-Changes in rainfall patterns

Question 11

How does carbon enter the carbon cycle?

Answer 11

Through photosynthesis in plants.

Question 12

What are pests?

Answer 12

Organisms that reduce the yield of crops or stock animals.

Question 13

What is a community?

Answer 13

The population of of all the species living in an ecosystem.

Question 14

Nitrate is used to make ______.

Answer 14

Proteins

Question 15

Waste and dead remains are turned into ______ by ______ ______.

Answer 15

ammonia, decomposing bacteria.

Question 16

What converts nitrogen into nitrate?

Answer 16

Nitrogen-fixing bacteria.

Question 17

List some problems with pesticides.

Answer 17

-Slow to decompose
-kill species that are harmless
-Pests may develop resistance
-Build up along food chains

Question 18

Give one example of an organic fertiliser and explain its benefit.

Answer 18

Animal manure, which returns some nitrogen to the soil.

Question 19

Explain why energy is lost through each trophic level.

Answer 19

-Energy is lost through respiration
-Some parts are not eaten
-Energy is excreted as waste
-Energy is lost as heat

Question 20

Explain how the greenhouse effect works.

Answer 20

Short wavelength IR radiation from the sun enters the atmosphere which bounces off the Earth’s surface. Some of these become long wavelength IR radiation which cannot escape the atmosphere and are re-emitted back into the Earth.

Question 21

List some methods of biological control.

Answer 21

-Introducing a natural predator
-Introducing a herbivore
-Introducing a parasite
-Introduce a pathogenic microorganism

Question 22

Explain why biodiversity is a good thing for an ecosystem.

Answer 22

Ecosystem is more stable as it’s not dominated by one organism which relies on it.

Question 23

Give one example of an inorganic fertiliser and explain its benefit.

Answer 23

Potassium nitrate, which can replace lost ions.