IB Biology Topic B3.1.7 Adaptations for Gas Exchange in Leaves Revision Notes (SL/HL)

IB Biology Topic B3.1.7 Adaptations for Gas Exchange in Leaves Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Leaf Adaptations Solve One Problem: Let CO2 In Without Drying Out

A leaf must let carbon dioxide diffuse in and oxygen diffuse out, yet water loss rises every time it does.

Each adaptation below is a compromise that keeps diffusion fast while limiting how much water escapes.
The focus here is why each feature aids gas exchange, not where every tissue sits, which is covered in B3.1.8.

The Waxy Cuticle: A Waterproof Seal That Forces Gases Through the Stomata

The waxy cuticle is a waterproof layer over the epidermis that greatly reduces water loss by evaporation from the leaf surface.
Because it is almost impermeable to gases too, it channels nearly all gas exchange through the stomata instead of straight across the surface.

Note

Cuticle thickness matches the habitat.
Desert plants (xerophytes) have a thick cuticle to cut water loss.
Plants in humid places have a thinner cuticle.

Nice try, unfortunately this paywall isn't as easy to bypass as you think. Want to help devleop the site? Join the team at https://revisiondojo.com/join-us. exercitation voluptate cillum ullamco excepteur sint officia do tempor Lorem irure minim Lorem elit id voluptate reprehenderit voluptate laboris in nostrud qui non Lorem nostrud laborum culpa sit occaecat reprehenderit

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Unlock the rest of this chapter with a free account

Leaf Adaptations Solve One Problem: Let CO2 In Without Drying Out

A leaf must let carbon dioxide diffuse in and oxygen diffuse out, yet water loss rises every time it does.

Each adaptation below is a compromise that keeps diffusion fast while limiting how much water escapes.
The focus here is why each feature aids gas exchange, not where every tissue sits, which is covered in B3.1.8.

The Waxy Cuticle: A Waterproof Seal That Forces Gases Through the Stomata

The waxy cuticle is a waterproof layer over the epidermis that greatly reduces water loss by evaporation from the leaf surface.
Because it is almost impermeable to gases too, it channels nearly all gas exchange through the stomata instead of straight across the surface.

Note

Cuticle thickness matches the habitat.
Desert plants (xerophytes) have a thick cuticle to cut water loss.
Plants in humid places have a thinner cuticle.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic B3.1.7: Adaptations for Gas Exchange in Leaves Notes

Leaf Adaptations Solve One Problem: Let CO2 In Without Drying Out

The Waxy Cuticle: A Waterproof Seal That Forces Gases Through the Stomata

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Leaf Adaptations Solve One Problem: Let CO2 In Without Drying Out

The Waxy Cuticle: A Waterproof Seal That Forces Gases Through the Stomata

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics