Chapter 33 - Nutrient Cycles

Question 1

Define a cycle

Answer 1

A cycle occurs when a substance is removed, used, realeased and reused.

Question 2

Name 9 processes involved in the water cycle, in logical order, starting with water rising from oceans and dams.

Answer 2

1. Evaporation
2. Condensation
3. Precipitation
4. Infiltration
5. Absorbtion
6. Transpiration
7. Perspiration
8. Runoff
9. Accumilation

Question 3

Why is Carbon dioxide an essential element in nature?

Answer 3

Carbon is an essential part of organic molecules, all living organisms contain carbon and 0,4% of air consists of carbon dioxide.

Question 4

Name the processes labled a - f

Answer 4

a - Photosynthesis

b - Nutrition

c - Respiration

d - Decomposition

e - Fossilisation

f - Combustion

Question 5

Give to causes of the greenhouse effect

Answer 5

• Combustion of fossil fuels
• Deforestation

Question 6

Describe the greenhouse effect

Answer 6

The greenhouse effect is a natural effect which invovles atmospheric gases, like carbon dioxide, called greenhouse gases, to allow the sun’s heat through in short wavelenghts, but then traps the reflected heat which is in long wavlengths. This process warms the earth to a habitable temperature.

Question 7

Explain global warming

Answer 7

Global warming is the gradual increase in temperature on the earth due to an excess buildup of greenhouse gases in the atmosphere.

Question 8

Name 7 effects of global warming and give one explination of these effects

Answer 8

1. Heat waves - People die of heat stroke each year
2. Violent storms - Extra energy in the atmosphere; Southern Africa experiences increased lightning
3. Melting of the polar ice-caps - sea levels will rise and flood coastal towns
4. Climatic changes - extinction of species, along with diseases and pests
5. Changes in ocean temperatures - extinction of aquatic species
6. Changes in global weather patterns - droughts and floods
7. More evaporation - more deserts

Question 9

Name three ways in which atmospheric nitrogen can be “fixed”

Answer 9

1. Biological Fixation
2. Industrial Fixation
3. Atmospheric Fixation

Question 10

Name the phenomenon that causes atmospheric fixation of nitrogen

Answer 10

Lightning

Question 11

Name the plants involved in biological fixation of nitrogen

Answer 11

Legume Plants

Question 12

Name the process used in industrial fixation of nitrogen

Answer 12

Haber Process

Question 13

Name the bacteria responsible for biological fixation of nitrogen

Answer 13

Rhizobium (Nitrogen Fixing Bacteria)

Question 14

Name the bacteria responsible for converting nitrates to ammonia

Answer 14

Putrifying Bacteria

Question 15

Name the process carried out by nitrifying bacteria

Answer 15

Nitrification

Question 16

Name the process by which nitrogen is returned into the atmosphere

Answer 16

Denitrification

Question 17

Which compound forms when ammonia comes in contact with oxygen?

Answer 17

Nitrites

Question 18

In which form can plants use nitrogen?

Answer 18

Nitrate form

Question 19

How is nitrogen compounds transfered from animals to the soil?

Answer 19

Through excretion and egestion