Learning Intentions
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I will have a better understanding of the processes Photosynthesis and
Respiration and how these processes help to balance the gases Carbon Dioxide
and Oxygen in our atmosphere.
I will have the opportunity to make the connection between our activities and
the change in the balance of gases that has taken place in our atmosphere.
I can describe the process of photosynthesis in terms of a word equation
I can state that cells need oxygen to release energy from food during aerobic
respiration.
I can state that carbon dioxide is given off by cells during tissue respiration and
is derived from food.
I can state that the compensation point of a plant is the point at which
photosynthesis equals respiration
I understand that sun and shade plants have different compensation points
because they must survive at different light intensities
I can state some adaptations of shade plants
I understand that our activities may have had a direct effect on the delicate
balance of these life giving gases in our atmosphere
Success Criteria
 I have described the process of photosynthesis in terms of a word equation
 I have describe aerobic respiration in terms of a word equation
 I have used a card sort activity to show my understanding of the raw materials
and products of photosynthesis and respiration
 I can state that oxygen is required to release energy from food
 I can state that carbon dioxide is given off by cells during respiration
 I can state that oxygen is used by cells during respiration
 I have carried out a practical activity to illustrate that plants use carbon dioxide
 I can state that the compensation point of a plant is the point where
photosynthesis equals respiration
 I have used this information to make inferences about plants that live in the shade
and to design a plant that can survive in the shade
 I can state some adaptations of shade plants
 I have used this information and make inferences about out effect on the delicate
balance of gases in the atmosphere
 I have plotted a graph to illustrate the changing concentrations of carbon dioxide
in our atmosphere as population numbers of humans have increased
Competition for Food (Plants)
List the three main things that plants compete
for:
1. Light
2. Water
3. Soil nutrients
What do they need these things for?
• Growth
http://www.youtube.com/watch?v=C1_uez5
WX1o
PHOTOSYNTHESIS
Conversion of carbon dioxide into simple sugars
LIGHT
(chlorophyll)
Carbon Dioxide + Water Glucose+ Oxygen
COW GO
Plants also RESPIRE
Glucose+ Oxygen  Carbon Dioxide+
Water + energy
GO COW
Net photosynthesis = Photosynthesis Respiration
Darkness
O2 in
CO2 out
Little O in
Little CO2 out
Net of loss of food
Compensation point
O2
CO2
O2
CO2
Equal gas exchange
No net gain or loss of food
High level light intensity
O2
CO2
O2
CO2
Much CO2 in
Much O2 out
Net gain of food
Compensation Point
Where photosynthesis = respiration and there
is no net gain of carbohydrate.
Sun and Shade Plants
• Sun and Shade plants have differing
compensation points.
PAR
Sun Plants vs Shade Plants
• Shade plants grow
better in the sun than
in the shade,
• but sun plants grow
faster than shade
plants in direct sun
Shade
plant –
Peru
Balsam
Sun
plant –
Tropical
Kapok
tree
• Shade plants survive
well in either sun or
shade
• Sun plants cannot
tolerate shade
Shade
plant
Sun
plant
Task
• Design a plant that lives in shade. Indicate
on your plant the adaptations that it has in
order to obtain as much light as it needs to
make enough food to grow.
Success Criteria
Process
• all group members take responsibility for part of the challenge
• all group members can answer questions on the subject
•
what you should the teacher see and hear while collaborating /problem solving is to be determined by the
class after discussion with the teacher
Form
•
product should be informative and accurate
• product should be well-written with correct spelling and correct use of scientific vocabulary
Content
• it should contain information on the challenge facing shade plants
• it should contain a design for the shade plant and its leaves
• it should contain information describing the morphological and physiological adaptations that allow the
plant to take advantage of limited light
• all information is accurate
Impact
• Rest of the class engaged and understand the key ideas.
Peer Assessment
Use the two stars and a wish method to assess
the other designs in a carousel.
Most plants have the ability to alter their morphology
(within limits) in response to light conditions.
Sun and shade leaves can exist within the same
tree.
More deeply lobed -->
More rapid heat loss
Sun leaf
• thicker
• more cell
layers
• more
chloroplasts
Shade leaf
• flat
• thin
• larger
surface
area / unit
weight
Sun leaves
Shade leaves
•Leaves at many angles
•High compensation point
•Horizontal leaves, single
layer
•Low compensation point
•High respiration
•Less chlorophyll
•Low respiration
•More chlorophyll
•Light availability limits
photosynthesis rate
Competition for light:
Some plants are adapted to inhabit shade
areas.
List the adaptations of shade plants
Some plants like Ivy will climb up structures
to reach light.
Some leaves have a pattern to ensure
maximum light absorption.
Some plants have more chloroplasts than sun
plants and have a rich supply of light
absorbing pigments that can absorb
wavelengths of light not absorbed by an
overhead canopy.
Photosynthetically Active Pigments
Some shade plants
• Crocus
• Hosta
Fern
Coleus
Ivy
Success Criteria
All pupils should be able to;
• describe the process of photosynthesis in terms of raw materials and
products.
• describe aerobic respiration in terms of a word equation.
• state that cells need oxygen to release energy from food during aerobic
respiration.
• state that carbon dioxide is given off by cells during tissue respiration and
is derived from food.
• State that the compensation point of a plant is the point at which
photosynthesis equals respiration
• Understand that sun and shade plants have different compensation points
because they must survive at different light intensities
• state some adaptations of shade plants to low light intensities
• understand that our activities may have had a direct effect on the delicate
balance of these life giving gases in our atmosphere