7 5 Gaseous exchange in animals and plants

7. 5 Gaseous exchange in animals and plants 1

7. 5 Gaseous exchange in animals and plants Respiration Unbreathed air nitrogen (78%) oxygen (21%) carbon dioxide (0. 03%) 2

7. 5 Gaseous exchange in animals and plants Respiration Breathed air oxygen (21%) carbon dioxide (0. 03%) nitrogen (78%) 3

7. 5 Gaseous exchange in animals and plants Respiration Unbreathed air Breathed air less oxygen more carbon dioxide 4

5 7. 5 Gaseous exchange in animals and plants Respiration break down food energy oxygen living cell support body activities

7. 5 Gaseous exchange in animals and plants Respiration Word equation of respiration: food + oxygen carbon dioxide + water + energy 6

7 7. 5 Gaseous exchange in animals and plants Gaseous exchange in animals carbon dioxide in air remove carbon dioxide from the body oxygen in air taken in gaseous exchange (氣體交換)

8 7. 5 Gaseous exchange in animals and plants 7. 15 Experiment video Gaseous exchange in mealworms 1 wire soda capillary colour gauze lime tube marker A mealworm B

7. 5 Gaseous exchange in animals and plants 7. 15 a In what way is tube B different from tube A? There is no mealworm in tube B. A B 9

7. 5 Gaseous exchange in animals and plants 7. 15 b What is the purpose of setting up tube B? To eliminate the changes in the set-ups caused by changes in Aenvironmental factors, such as air temperature and pressure. B 10

7. 5 Gaseous exchange in animals and plants 7. 15 2 Measure this distance A B 11

7. 5 Gaseous exchange in animals and plants 7. 15 2 Tube A B Distance between the colour marker and the stopper (cm) At the beginning 20 minutes later 12

7. 5 Gaseous exchange in animals and plants 7. 15 Discussion 1 Which tube contains less gas at the end of the experiment? Tube A. 13

7. 5 Gaseous exchange in animals and plants 7. 15 2 Try to explain the result in tube A. The mealworms take in ____ oxygen and give out _______. carbon dioxide The carbon dioxide _______ is absorbed by soda lime. 14

7. 5 Gaseous exchange in animals and plants 15 7. 15 The gas pressure inside tube A decreases and therefore ______ lower becomes ______ than the atmospheric pressure. As a result, the colour marker _______________ is pushed towards the boiling tube.

7. 5 Gaseous exchange in animals and plants 7. 15 3 We should not hold the boiling tubes with our hands during the experiment. Why? The heat energy from our hands will heat up the air inside the tubes and cause the air to expand. This affects the experimental results. 16

7. 5 Gaseous exchange in animals and plants The human respiratory system Humans and most animals have a respiratory system (呼吸系統) for gaseous exchange. 17

18 7. 5 Gaseous exchange in animals and plants 7. 16 Major parts of our respiratory system Identify the major parts of the respiratory system. Label the diagram. 3 D model

7. 5 Gaseous exchange in animals and plants 7. 16 nasal cavity trachea bronchus bronchiole 19

20 7. 5 Gaseous exchange in animals and plants 7. 16 air sac rib intercostal muscle lung diaphragm

7. 5 Gaseous exchange in animals and plants 21 The human respiratory system air nostrils nasal cavity trachea

7. 5 Gaseous exchange in animals and plants The human respiratory system air bronchioles air sacs 22

7. 5 Gaseous exchange in animals and plants The human respiratory system lungs are protected by the rib cage (肋骨籃) 23

7. 5 Gaseous exchange in animals and plants The human respiratory system backbone rib chest bone 24

7. 5 Gaseous exchange in animals and plants The human respiratory system diaphragm intercostal muscles 25

26 7. 5 Gaseous exchange in animals and plants Gaseous exchange in the air sac 3 D animation

27 7. 5 Gaseous exchange in animals and plants Gaseous exchange in the air sac oxygen direction of blood flow carbon dioxide air sac capillary

7. 5 Gaseous exchange in animals and plants The breathing mechanism Do you know how breathing is brought about? 28

7. 5 Gaseous exchange in animals and plants 7. 4 Feeling your breath Take a deep breath. Feel the movement of your ribs. 29

7. 5 Gaseous exchange in animals and plants 7. 4 a Which way do your ribs move when you breathe in? They move upwards and outwards. 30

7. 5 Gaseous exchange in animals and plants 7. 4 b Which way do your ribs move when you breathe out? They move downwards and inwards. 31

7. 5 Gaseous exchange in animals and plants 32 The breathing mechanism Movements are brought by the actions of … intercostal muscles diaphragm

7. 5 Gaseous exchange in animals and plants a Breathing in rib intercostal muscles diaphragm lung 33

7. 5 Gaseous exchange in animals and plants a Breathing in 1 a Intercostal muscles contract. Ribs move upwards and outwards. 1 b Diaphragm flattens. 34

7. 5 Gaseous exchange in animals and plants a Breathing in 2 Volume of chest cavity increases. Gas pressure inside it decreases. 35

7. 5 Gaseous exchange in animals and plants a Breathing in 3 Air is drawn in. 36

7. 5 Gaseous exchange in animals and plants b Breathing out 1 a Intercostal muscles relax. Ribs move downwards and inwards. 37

7. 5 Gaseous exchange in animals and plants b 38 Breathing out 1 b Diaphragm returns to dome shape.

7. 5 Gaseous exchange in animals and plants b 39 Breathing out 2 Volume of chest cavity decreases. Gas pressure inside it increases.

7. 5 Gaseous exchange in animals and plants b Breathing out 3 Air is forced out. 40

41 7. 5 Gaseous exchange in animals and plants 7. 17 Animation Using a model to show the action of the intercostal muscles during breathing B A 1 rib cage model rubber band C B (肋骨籃模型)

7. 5 Gaseous exchange in animals and plants 7. 17 1 Each part represents… ribs chest bone B C B A intercostal muscles backbone 42

7. 5 Gaseous exchange in animals and plants 7. 17 2 Position X H measure this length F D E G I 43

7. 5 Gaseous exchange in animals and plants 7. 17 3 Position Y N J K O M L measure this length 44

7. 5 Gaseous exchange in animals and plants 7. 17 4 Which rubber band, HI or NO, is shorter in length? NO. N H O I 45

7. 5 Gaseous exchange in animals and plants 46 7. 17 5 In which case, position X or Y, are the intercostal muscles contracting? Position Y Position X

47 7. 5 Gaseous exchange in animals and plants 7. 17 6 Which parallelogram, DEFG or JKLM, is larger in area? D E G J M F K L

7. 5 Gaseous exchange in animals and plants 48 7. 17 7 In which case, position X or Y, is the chest volume greater? Position X Position Y

7. 5 Gaseous exchange in animals and plants 7. 17 8 When the model is set from position X to position Y, the rubber shortened This band becomes ______. represents the intercostal muscles contracting are ______. 49

7. 5 Gaseous exchange in animals and plants 50 7. 17 upwards and the The ribs, move _____ increases This is chest volume _____. similar to the situation when we are in breathing _____.

51 7. 5 Gaseous exchange in animals and plants 7. 18 Animation Using a model to show the action of the diaphragm during breathing 1 glass tube balloon-bell Y-piece jar model balloons (氣球及鐘形罩模型 ) rubber sheet

7. 5 Gaseous exchange in animals and plants 7. 18 1 Each part represents… trachea bronchi lungs diaphragm 52

7. 5 Gaseous exchange in animals and plants 7. 18 2 53

7. 5 Gaseous exchange in animals and plants 7. 18 2 54

7. 5 Gaseous exchange in animals and plants 55 7. 18 3 What happens to the balloons when the rubber sheet is pulled down? bigger The balloons become _______.

7. 5 Gaseous exchange in animals and plants 7. 18 3 When the rubber sheet is pulled down, the volume of the bell jar increases and the gas pressure _____ inside the bell jar becomes lower _____. 56

7. 5 Gaseous exchange in animals and plants 7. 18 3 Therefore air flows ____ the into balloons. This is similar to the situation when we are breathing in ____. 57

7. 5 Gaseous exchange in animals and plants 58 7. 18 4 What happens to the balloons when the rubber sheet is pushed up? smaller The balloons become ____.

7. 5 Gaseous exchange in animals and plants 59 7. 18 4 When the rubber sheet is pushed the volume of the bell jar decreases up, and the gas pressure inside the bell _______________ jar becomes higher. Therefore air _______________ flows out of the balloons. _____________________________

7. 5 Gaseous exchange in animals and plants 7. 18 4 This is similar to the situation when breathing out we are _______. 60

7. 5 Gaseous exchange in animals and plants Gaseous exchange in animals In humans, gaseous exchange air sacs takes place in the ____. 61

7. 5 Gaseous exchange in animals and plants Gaseous exchange in animals In humans, breathing is brought about by the actions of the intercostal muscles between the _________ ribs, and the ______ diaphragm that is located below the rib cage. 62

7. 5 Gaseous exchange in animals and plants 5 1 When we breathe in, the intercostal contract muscles _____. The ribs move _____ upwards and _____. outwards At the same time, the diaphragm becomes _____. flattened 63

7. 5 Gaseous exchange in animals and plants 5 1 These movements cause the volume of the chest cavity to increase and therefore the gas _____ decreases pressure inside it ______. Air is then drawn into the lungs. 64

65 7. 5 Gaseous exchange in animals and plants 5 Well don e! 2 Which photo, A or B, was taken when the man was breathing out? Why? A rib lung heart diaphragm B diaphragm is domeshaped

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants Stomata are tiny holes on leaf surfaces 66

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants Photosynthesis Green plants give out oxygen carbon dioxide take in 67

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants Respiration Green plants give takeout in oxygen carbon dioxide give take out in 68

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants In a day… Green plants oxygen and carbon dioxide: uptake or release? 69

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants Depends on the rates of photosynthesis and respiration Green plants 70

71 7. 5 Gaseous exchange in animals and plants 7. 19 Experiment video When do green plants take in and give out carbon dioxide? hydrogencarbonate indicator

72 7. 5 Gaseous exchange in animals and plants 7. 19 Concentration of carbon dioxide Colour of hydrogencarbonate indicator > 0. 03% ~ 0. 03% (normal level in air) < 0. 03% Yellow Red Purple

7. 5 Gaseous exchange in animals and plants 73 7. 19 1 green leaves aluminium foil A B C D each tube contains 3 cm 3 of hydrogencarbonate indicator

7. 5 Gaseous exchange in animals and plants 7. 19 a What is the purpose of setting up tube B? To make sure that the result in tube A is caused by the presence of the green leaf. A B C D 74

7. 5 Gaseous exchange in animals and plants 7. 19 b What is the purpose of setting up tube D? A B C To make sure that the result in tube C is caused by the presence of the green leaf. D 75

7. 5 Gaseous exchange in animals and plants 7. 19 2 leave for one hour A B C D 76

7. 5 Gaseous exchange in animals and plants 7. 19 2 represent in the daytime A B C represent at night D 77

7. 5 Gaseous exchange in animals and plants 7. 19 3 Tube A B C D Colour of the hydrogencarbonate indicator At the beginning After one hour Red Red Purple Red Yellow Red 78

7. 5 Gaseous exchange in animals and plants 79 7. 19 4 a Compare the results in tube A and tube B. What does the difference show? Tube A Tube B

7. 5 Gaseous exchange in animals and plants 80 7. 19 4 a Compare the results in tube A and tube B. What does the difference show? The green Tube A leaf takes Tube in B carbon dioxide from the air in the presence of light.

7. 5 Gaseous exchange in animals and plants 7. 19 b Compare the results in tube C and tube D. What does the difference show? Tube C Tube D 81

7. 5 Gaseous exchange in animals and plants 7. 19 b Compare the results in tube C and tube D. What does the difference show? The. Tube green. Cleaf gives out. Dcarbon Tube dioxide in the dark. 82

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants In the daytime net release of oxygen net uptake of carbon dioxide rate of photosynthesis higher than rate of respiration 83

84 7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants At night photosynthesis stops respiration continues net release of carbon dioxide net uptake of oxygen

7. 5 Gaseous exchange in animals and plants Gaseous exchange in plants In the daytime, there is a net release of oxygen and a net uptake of carbon dioxide in green plants. 85

7. 5 Gaseous exchange in animals and plants 86 Gaseous exchange in plants At night, green plants take in oxygen and give out carbon dioxide.

7. 5 Gaseous exchange in animals and plants 87 The balance of oxygen and carbon dioxide in nature oxygen in air photosynthesis of green plants releases oxygen taken up during respiration of animals and releases plants carbon dioxide in air

7. 5 Gaseous exchange in animals and plants The balance of oxygen and carbon dioxide in nature Living things carry out respiration. Green plants carry out photosynthesis. 88

7. 5 Gaseous exchange in animals and plants The balance of oxygen and carbon dioxide in nature The two processes help keep a balance of oxygen and carbon dioxide in nature. 89

90 7. 5 Gaseous exchange in animals and plants The effect of the increasing amount of carbon dioxide in the atmosphere on us Animation Sun atmosphere Earth

7. 5 Gaseous exchange in animals and plants The greenhouse effect 1 Sunlight passes through the atmosphere and reaches the Earth. 1 91

7. 5 Gaseous exchange in animals and plants The greenhouse effect 2 Heat energy is reflected back from the Earth’s surface. 2 92

93 7. 5 Gaseous exchange in animals and plants The greenhouse effect 3 a Some heat energy is lost to space. 3 a

94 7. 5 Gaseous exchange in animals and plants The greenhouse effect 3 b. Some heat energy is absorbed by some gases in the atmosphere, leading to greenhouse effect. 3 b

7. 5 Gaseous exchange in animals and plants The effect of the increasing amount of carbon dioxide in the atmosphere on us The burning of fossil fuels releases a lot of carbon dioxide. 95

7. 5 Gaseous exchange in animals and plants 96 The effect of the increasing amount of carbon dioxide in the atmosphere on us large areas of forests are cleared amount of carbon dioxide absorbed during photosynthesis drops

7. 5 Gaseous exchange in animals and plants amount of carbon dioxide in the atmosphere increases 97

7. 5 Gaseous exchange in animals and plants amount of carbon dioxide in the atmosphere increases traps more heat and enhances greenhouse effect average temperatures of the Earth keep increasing 98

7. 5 Gaseous exchange in animals and plants amount of carbon dioxide in the atmosphere increases traps more heat and global warming (全球增温) enhances greenhouse effect average temperatures of the Earth keep increasing 99

7. 5 Gaseous exchange in animals and plants Global warming speeds up the melting of ice at polar regions 100

7. 5 Gaseous exchange in animals and plants Global warming speeds up the melting of ice at polar regions living things at polar regions may lose their habitats 101

7. 5 Gaseous exchange in animals and plants Global warming speeds up the melting of ice at polar regions sea level rises flooding of lowlying areas 102

7. 5 Gaseous exchange in animals and plants Global warming causes climate changes more frequent droughts and storms 103

7. 5 Gaseous exchange in animals and plants The effect of the increasing amount of carbon dioxide in the atmosphere on us The increasing amount of carbon dioxide in the atmosphere enhances the greenhouse effect. 104

7. 5 Gaseous exchange in animals and plants The effect of the increasing amount of carbon dioxide in the atmosphere on us The global temperatures continue to rise. This is known as global warming. 105

7. 5 Gaseous exchange in animals and plants 6 1 Which of the following leads to global warming? A The atmospheric temperature rises continuously. B The amount of oxygen in the atmosphere decreases. C The amount of carbon dioxide in the atmosphere decreases. D The amount of carbon dioxide in the atmosphere increases. 106

107 7. 5 Gaseous exchange in animals and plants 6 2 Which of the following is not likely to be caused by global warming? A An increase in the amount of oxygen in the atmosphere B Melting of ice caps C Climate change D Flooding of low-lying areas Excellen t!