b1b 5.2 adaptation in plants biology 1b evolution and environment gcse core aqa science © nelson...
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AQA Science © Nelson Thornes Ltd 2006 1
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Transpiration
AQA Science © Nelson Thornes Ltd 2006 2
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Learning objectivesKQ: How do plants transpire and what
affects its rate?
Know that• Plants carry out transpiration.Plants carry out transpiration.• Different factors can affect the rate Different factors can affect the rate
at which transpiration is carried out.at which transpiration is carried out.• Know how to read graphs and Know how to read graphs and
measure the rate of transpiration.measure the rate of transpiration.
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Plants take in water through their roots in the soil…
Transpiration
AQA Science © Nelson Thornes Ltd 2006 4
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Transpiration
…it moves up through the plant…
AQA Science © Nelson Thornes Ltd 2006 5
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Transpiration
…..and is lost through the leaves in the transpiration stream.
Corel 178(NT)
AQA Science © Nelson Thornes Ltd 2006 6
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Stomata
There are small openings called stomata in the leaves of a plant.
AQA Science © Nelson Thornes Ltd 2006 7
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
These open to allow gases in and out for photosynthesis and respiration. But at the same time water is lost by evaporation.
Stomata
AQA Science © Nelson Thornes Ltd 2006 8
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Rate of transpiration
When it is hot and dry, photosynthesis andrespiration take place quickly. As a result,
plants also very quickly lose water.
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
The potometer
A potometer can be used to measure the rate of transpiration.
AQA Science © Nelson Thornes Ltd 2006 10
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Rate of transpiration
As the leaf loses water, so the air bubble moves. The distance moved over a time period is measured.
AQA Science © Nelson Thornes Ltd 2006 11
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Transpiration rate
Graph of bubble movement against time.
AQA Science © Nelson Thornes Ltd 2006 12
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Transpiration rate
The steeper the graph, the faster the transpiration rate!
AQA Science © Nelson Thornes Ltd 2006 13
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Which potometer experiment was run in drier air?
Transpiration rate
AQA Science © Nelson Thornes Ltd 2006 14
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
The drier the air, the faster the transpiration rate!
Transpiration rate
AQA Science © Nelson Thornes Ltd 2006 15
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Adaptations for plants growing in a dry environment
• Curled leaves.
• Moist air trapped inside the curl.
• Thick waxy cuticle.
• Stomata on the curled side only.
AQA Science © Nelson Thornes Ltd 2006 16
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Adaptations for plants growing in a dry environment
Marram grass leaves will even uncurl slightly in the wet and curl up more in the dry.
Corel 46(NT)
AQA Science © Nelson Thornes Ltd 2006 17
B1b 5.2 Adaptation in plants
Biology 1b Evolution and EnvironmentBiology 1b Evolution and EnvironmentGCSGCSEE
CORCOREE
Learning objectivesKQ: How do plants transpire and what
affects its rate?
Know that• Plants carry out transpiration.Plants carry out transpiration.• Different factors can affect the rate Different factors can affect the rate
at which transpiration is carried out.at which transpiration is carried out.• Know how to read graphs and Know how to read graphs and
measure the rate of transpiration.measure the rate of transpiration.