Lesson 17 - Gas Exchange in Leaves

Lesson Objectives

Content Objective: XXX

Students will examine the structural adaptations of leaves that facilitate efficient gas exchange and understand the implications of surface area-to-volume ratio on gas exchange as organisms increase in size. They will also analyze the distribution of tissues in a dicotyledonous leaf and the impact of various factors on the rate of transpiration.

Language Objective:  Students will describe the adaptations and distribution of tissues in leaf structures using appropriate scientific terminology and illustrate these concepts through labeled diagrams. They will also discuss and explain the relationship between organism size, surface area-to-volume ratio, and gas exchange efficiency.

Syllabus Details: 

• B3.1.1—Gas exchange as a vital function in all organisms - "Students should appreciate that the challenges become greater as organisms increase in size because surface area-to-volume ratio decreases with increasing size, and the distance from the centre of an organism to its exterior increases."
  
  

• B3.1.7—Adaptations for gas exchange in leaves - "Leaf structure adaptations should include the waxy cuticle, epidermis, air spaces, spongy mesophyll, stomatal guard cells and veins."
  
  

• B3.1.8—Distribution of tissues in a leaf - "Students should be able to draw and label a plan diagram to show the distribution of tissues in a transverse section of a dicotyledonous leaf."

• B3.1.9—Transpiration as a consequence of gas exchange in a leaf - “Students should be aware of the factors affecting the rate of transpiration.”

Activites

Activity 1  

Activity 2 

Activity 3  

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