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7.5 Gaseous exchange in animals and plants 1 Gaseous exchange in animals and plants 7.57.57.57.5.

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Presentation on theme: "7.5 Gaseous exchange in animals and plants 1 Gaseous exchange in animals and plants 7.57.57.57.5."— Presentation transcript:

1 7.5 Gaseous exchange in animals and plants 1 Gaseous exchange in animals and plants

2 7.5 Gaseous exchange in animals and plants 2 Respiration Unbreathed air nitrogen (78%) oxygen (21%) carbon dioxide (0.03%)

3 7.5 Gaseous exchange in animals and plants 3 Respiration Breathed air nitrogen (78%) oxygen (21%) carbon dioxide (0.03%)

4 7.5 Gaseous exchange in animals and plants 4 Respiration Breathed airUnbreathed air less oxygen more carbon dioxide

5 7.5 Gaseous exchange in animals and plants 5 Respiration living cell oxygen break down food energy support body activities

6 7.5 Gaseous exchange in animals and plants 6 food + oxygen carbon dioxide + water + energy Respiration Word equation of respiration:

7 7.5 Gaseous exchange in animals and plants 7 Gaseous exchange in animals gaseous exchange ( 氣體交換 ) oxygen in air carbon dioxide in air taken in remove carbon dioxide from the body

8 7.5 Gaseous exchange in animals and plants 8 Gaseous exchange in mealworms 7.15 Experiment video 1 mealworm wire gauze soda lime capillary tube colour marker A B

9 7.5 Gaseous exchange in animals and plants aIn what way is tube B different from tube A? There is no mealworm in tube B. A B

10 7.5 Gaseous exchange in animals and plants bWhat is the purpose of setting up tube B? B A To eliminate the changes in the set-ups caused by changes in environmental factors, such as air temperature and pressure.

11 7.5 Gaseous exchange in animals and plants 11 2 A B Measure this distance 7.15

12 7.5 Gaseous exchange in animals and plants 12 2 Tube Distance between the colour marker and the stopper (cm) At the beginning20 minutes later A B 7.15

13 7.5 Gaseous exchange in animals and plants 13 Discussion 1Which tube contains less gas at the end of the experiment? Tube A. 7.15

14 7.5 Gaseous exchange in animals and plants 14 The mealworms take in ________ and give out ______________. The ______________ is absorbed by soda lime. oxygen 2Try to explain the result in tube A. carbon dioxide carbon dioxide 7.15

15 7.5 Gaseous exchange in animals and plants The gas pressure inside tube A therefore ___________ and becomes ___________ than the atmospheric pressure. 15 decreases lower 7.15 As a result, the colour marker _____________________________ is pushed towards the boiling tube.

16 7.5 Gaseous exchange in animals and plants 16 3We 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. 7.15

17 7.5 Gaseous exchange in animals and plants 17 The human respiratory system Humans and most animals have a respiratory system ( 呼吸系統 ) for gaseous exchange.

18 7.5 Gaseous exchange in animals and plants 18 Major parts of our respiratory system D model Identify the major parts of the respiratory system. Label the diagram.

19 7.5 Gaseous exchange in animals and plants 19 nasal cavity trachea bronchus bronchiole 7.16

20 7.5 Gaseous exchange in animals and plants 20 air sac intercostal muscle rib lung diaphragm 7.16

21 7.5 Gaseous exchange in animals and plants 21 The human respiratory system nostrils air nasal cavity trachea

22 7.5 Gaseous exchange in animals and plants 22 The human respiratory system bronchi air bronchioles air sacs

23 7.5 Gaseous exchange in animals and plants 23 The human respiratory system lungs are protected by the rib cage ( 肋骨籃 )

24 7.5 Gaseous exchange in animals and plants 24 The human respiratory system backbone rib chest bone

25 7.5 Gaseous exchange in animals and plants 25 The human respiratory system diaphragm intercostal muscles

26 7.5 Gaseous exchange in animals and plants 26 Gaseous exchange in the air sac 3D animation

27 7.5 Gaseous exchange in animals and plants 27 Gaseous exchange in the air sac oxygen carbon dioxide direction of blood flow capillary air sac

28 7.5 Gaseous exchange in animals and plants 28 The breathing mechanism Do you know how breathing is brought about?

29 7.5 Gaseous exchange in animals and plants Feeling your breath Take a deep breath. Feel the movement of your ribs.

30 7.5 Gaseous exchange in animals and plants They move upwards and outwards. aWhich way do your ribs move when you breathe in?

31 7.5 Gaseous exchange in animals and plants bWhich way do your ribs move when you breathe out? They move downwards and inwards.

32 7.5 Gaseous exchange in animals and plants 32 The breathing mechanism Movements are brought by the actions of … intercostal muscles diaphragm

33 7.5 Gaseous exchange in animals and plants 33 aBreathing in intercostal muscles diaphragm lung rib

34 7.5 Gaseous exchange in animals and plants 34 aBreathing in 1aIntercostal muscles contract. Ribs move upwards and outwards. 1bDiaphragm flattens.

35 7.5 Gaseous exchange in animals and plants 35 aBreathing in Gas pressure inside it decreases. 2Volume of chest cavity increases.

36 7.5 Gaseous exchange in animals and plants 36 aBreathing in 3Air is drawn in.

37 7.5 Gaseous exchange in animals and plants 37 bBreathing out 1aIntercostal muscles relax. Ribs move downwards and inwards.

38 7.5 Gaseous exchange in animals and plants 38 bBreathing out 1bDiaphragm returns to dome shape.

39 7.5 Gaseous exchange in animals and plants 39 bBreathing out Gas pressure inside it increases. 2Volume of chest cavity decreases.

40 7.5 Gaseous exchange in animals and plants 40 bBreathing out 3Air is forced out.

41 7.5 Gaseous exchange in animals and plants 41 Using a model to show the action of the intercostal muscles during breathing 7.17 Animation rib cage model ( 肋骨籃模型 ) rubber band A B C B 1

42 7.5 Gaseous exchange in animals and plants 42 A B C B Each part represents… ribs chest bone backbone intercostal muscles

43 7.5 Gaseous exchange in animals and plants 43 2 F G D H E Position X I measure this length 7.17

44 7.5 Gaseous exchange in animals and plants 44 3 L MJ N K O measure this length Position Y 7.17

45 7.5 Gaseous exchange in animals and plants 45 4Which rubber band, HI or NO, is shorter in length? NO. H I N O 7.17

46 7.5 Gaseous exchange in animals and plants 46 5In which case, position X or Y, are the intercostal muscles contracting? Position X Position Y 7.17

47 7.5 Gaseous exchange in animals and plants 47 6Which parallelogram, DEFG or JKLM, is larger in area? F G D E L M J K 7.17

48 7.5 Gaseous exchange in animals and plants 48 7In which case, position X or Y, is the chest volume greater? Position X Position Y 7.17

49 7.5 Gaseous exchange in animals and plants 8When the model is set from position X to position Y, the rubber band becomes ___________. This represents the intercostal muscles are ___________. 49 shortened contracting 7.17

50 7.5 Gaseous exchange in animals and plants The ribs, move __________ and the chest volume __________. This is similar to the situation when we are breathing __________. 50 in 7.17 upwards increases

51 7.5 Gaseous exchange in animals and plants 51 Using a model to show the action of the diaphragm during breathing 7.18 Animation balloon-bell jar model ( 氣球及鐘形罩模型 ) 1glass tube Y-piece balloons rubber sheet

52 7.5 Gaseous exchange in animals and plants Each part represents… 52 1 trachea bronchi lungs diaphragm 7.18

53 7.5 Gaseous exchange in animals and plants

54 7.5 Gaseous exchange in animals and plants

55 7.5 Gaseous exchange in animals and plants 55 3What happens to the balloons when the rubber sheet is pulled down? The balloons become _______. bigger 7.18

56 7.5 Gaseous exchange in animals and plants When the rubber sheet is pulled down, the volume of the bell jar __________ and the gas pressure inside the bell jar becomes __________. 56 increases lower

57 7.5 Gaseous exchange in animals and plants Therefore air flows ________ the balloons. This is similar to the situation when we are breathing ________. 57 in into

58 7.5 Gaseous exchange in animals and plants 58 4What happens to the balloons when the rubber sheet is pushed up? The balloons become ________. smaller 7.18

59 7.5 Gaseous exchange in animals and plants 59 4 When the rubber sheet is pushed up, _____________________________ _____________________________ _____________________________ _____________________________ the volume of the bell jar decreases and the gas pressure inside the bell jar becomes higher. Therefore air flows out of the balloons. 7.18

60 7.5 Gaseous exchange in animals and plants This is similar to the situation when we are _____________ breathing out 7.18

61 7.5 Gaseous exchange in animals and plants 61 In humans, gaseous exchange takes place in the ________. Gaseous exchange in animals air sacs

62 7.5 Gaseous exchange in animals and plants 62 Gaseous exchange in animals In humans, breathing is brought about by the actions of the _________________ between the ribs, and the ___________ that is located below the rib cage. intercostal muscles diaphragm

63 7.5 Gaseous exchange in animals and plants At the same time, the diaphragm becomes _________. 1When we breathe in, the intercostal muscles _________. The ribs move _________ and __________. 635 upwards contract outwards flattened

64 7.5 Gaseous exchange in animals and plants These movements cause the volume of the chest cavity to _________ and therefore the gas pressure inside it ___________. Air is then drawn into the lungs increase decreases

65 7.5 Gaseous exchange in animals and plants lung 2Which photo, A or B, was taken when the man was breathing out? Why? 655 AB rib heart diaphragm diaphragm is dome- shaped Well done!

66 7.5 Gaseous exchange in animals and plants 66 Gaseous exchange in plants Green plants oxygen carbon dioxide Photosynthesis take in give out

67 7.5 Gaseous exchange in animals and plants 67 Gaseous exchange in plants Green plants Respiration oxygen carbon dioxide take in give outtake in give out

68 7.5 Gaseous exchange in animals and plants 68 Gaseous exchange in plants Green plants oxygen and carbon dioxide: uptake or release? In a day…

69 7.5 Gaseous exchange in animals and plants 69 Gaseous exchange in plants Green plants Depends on the rates of photosynthesis and respiration

70 7.5 Gaseous exchange in animals and plants 70 When do green plants take in and give out carbon dioxide? 7.19 Experiment video hydrogencarbonate indicator

71 7.5 Gaseous exchange in animals and plants Concentration of carbon dioxide > 0.03% ~ 0.03% (normal level in air) < 0.03% Colour of hydrogen- carbonate indicator YellowRedPurple

72 7.5 Gaseous exchange in animals and plants green leaves aluminium foil each tube contains 3 cm 3 of hydrogencarbonate indicator ABCD

73 7.5 Gaseous exchange in animals and plants 73 aWhat is the purpose of setting up tube B? ABCD To make sure that the result in tube A is caused by the presence of the green leaf. 7.19

74 7.5 Gaseous exchange in animals and plants 74 bWhat is the purpose of setting up tube D? ABCD To make sure that the result in tube C is caused by the presence of the green leaf. 7.19

75 7.5 Gaseous exchange in animals and plants 75 2 ABCD leave for one hour 7.19

76 7.5 Gaseous exchange in animals and plants 76 2 ABCD represent in the daytime represent at night 7.19

77 7.5 Gaseous exchange in animals and plants 77 Tube Colour of the hydrogencarbonate indicator At the beginningAfter one hour ARed B C D 3 Purple Red Yellow Red 7.19

78 7.5 Gaseous exchange in animals and plants 78 4aCompare the results in tube A and tube B. What does the difference show? Tube ATube B 7.19

79 7.5 Gaseous exchange in animals and plants 79 4aCompare the results in tube A and tube B. What does the difference show? Tube ATube B The green leaf takes in carbon dioxide from the air in the presence of light. 7.19

80 7.5 Gaseous exchange in animals and plants 80 bCompare the results in tube C and tube D. What does the difference show? Tube CTube D 7.19

81 7.5 Gaseous exchange in animals and plants 81 bCompare the results in tube C and tube D. What does the difference show? Tube CTube D The green leaf gives out carbon dioxide in the dark. 7.19

82 7.5 Gaseous exchange in animals and plants 82 Gaseous exchange in plants In the daytime rate of photosynthesis rate of respiration higher than net uptake of carbon dioxide net release of oxygen

83 7.5 Gaseous exchange in animals and plants 83 Gaseous exchange in plants At night photosynthesis stops respiration continues net release of carbon dioxide net uptake of oxygen

84 7.5 Gaseous exchange in animals and plants 84 In the daytime, there is a net release of oxygen and a net uptake of carbon dioxide in green plants. Gaseous exchange in plants

85 7.5 Gaseous exchange in animals and plants 85 Gaseous exchange in plants At night, green plants take in oxygen and give out carbon dioxide.

86 7.5 Gaseous exchange in animals and plants 86 The balance of oxygen and carbon dioxide in nature oxygen in air carbon dioxide in air photosynthesis of green plants respiration of animals and plants taken up during releases oxygen releases carbon dioxide taken up during

87 7.5 Gaseous exchange in animals and plants 87 Living things carry out respiration. Green plants carry out photosynthesis. The balance of oxygen and carbon dioxide in nature

88 7.5 Gaseous exchange in animals and plants 88 The balance of oxygen and carbon dioxide in nature The two processes help keep a balance of oxygen and carbon dioxide in nature.

89 7.5 Gaseous exchange in animals and plants 89 The effect of the increasing amount of carbon dioxide in the atmosphere on us atmosphere Earth Sun Animation

90 7.5 Gaseous exchange in animals and plants 90 The greenhouse effect 1Sunlight passes through the atmosphere and reaches the Earth. 1

91 7.5 Gaseous exchange in animals and plants 91 The greenhouse effect 2Heat energy is reflected back from the Earth’s surface. 2

92 7.5 Gaseous exchange in animals and plants 92 The greenhouse effect 3aSome heat energy is lost to space. 3a

93 7.5 Gaseous exchange in animals and plants 93 The greenhouse effect 3bSome heat energy is absorbed by some gases in the atmosphere, leading to greenhouse effect. 3b

94 7.5 Gaseous exchange in animals and plants 94 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 95 The effect of the increasing amount of carbon dioxide in the atmosphere on us amount of carbon dioxide absorbed during photosynthesis drops large areas of forests are cleared

96 7.5 Gaseous exchange in animals and plants 96 amount of carbon dioxide in the atmosphere increases

97 7.5 Gaseous exchange in animals and plants 97 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 98 amount of carbon dioxide in the atmosphere increases traps more heat and enhances greenhouse effect average temperatures of the Earth keep increasing global warming ( 全球增温 )

99 7.5 Gaseous exchange in animals and plants 99 Global warming speeds up the melting of ice at polar regions

100 7.5 Gaseous exchange in animals and plants 100 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 101 Global warming speeds up the melting of ice at polar regions sea level rises flooding of low- lying areas

102 7.5 Gaseous exchange in animals and plants 102 Global warming causes climate changes more frequent droughts and storms

103 7.5 Gaseous exchange in animals and plants 103 The increasing amount of carbon dioxide in the atmosphere enhances the greenhouse effect. The effect of the increasing amount of carbon dioxide in the atmosphere on us

104 7.5 Gaseous exchange in animals and plants 104 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 1Which of the following leads to global warming? 105 AThe atmospheric temperature rises continuously. DThe amount of carbon dioxide in the atmosphere increases. CThe amount of carbon dioxide in the atmosphere decreases. BThe amount of oxygen in the atmosphere decreases. 6

106 7.5 Gaseous exchange in animals and plants 1066 AAn increase in the amount of oxygen in the atmosphere DFlooding of low-lying areas CClimate change BMelting of ice caps Excellent! 2Which of the following is not likely to be caused by global warming?


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