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AIM: SWBAT explain when stomata are most likely to be open and why. Please Do Now: Explain how guard cells open and close the stomata in 2-3 sentences. Agenda. Do Now Data Analysis Stomata notes Prep for tomorrow’s lab Lion video. Data Analysis: Stomata opening vs. time of day.
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AIM: SWBAT explain when stomata are most likely to be open and why Please Do Now: Explain how guard cells open and close the stomata in 2-3 sentences
Agenda • Do Now • Data Analysis • Stomata notes • Prep for tomorrow’s lab • Lion video
Data Analysis: Stomata opening vs. time of day • 1. What is on the x axis? • What is on the y- axis? • 3. What is true of all three plants in the chart (A, B, and C)? This says average stomatalaperature (how wide they are open)
Data Analysis: Soil Moisture content vs. %stomata open • 1. What is on the x-axis? • 2. What is on the y axis? • 3. What % of the plants stomata are open when the ground is 75% saturated in the light? What about the dark?
Data Analysis: Average rainfall vs. stomatal density • 1. What units are the average yearly rainfall numbers given in? • 2. Which plant has the lowest density of stomata? • 3. What is the overall trend shown in this graph? (As _____ increases, _________)
Unifying question • Please respond with a short paragraph • If you had to develop rules as to when stomata are open and close, what would they be? Support your answer using references to particular graphs/charts.
Remember • Stomata open and close to allow CO2 in for photosynthesis
When are stomata most likely to be closed? • They are almost always closed at night • When the plant is very dry and there is not enough water in the soil, they will also close, even if it is sunny out (and could do photosynthesis)
When are stomata most likely to be open? • When there is an adequate supply of the things plants need for photosynthesis: light and water • In the morning when it is cool out but the sun is shining • Right after a rainstorm when the clouds have passed
Do all plants have the same number of stomata? • No, the number/density of stomata a plant has is adapted to their particular lifestyle and environment • General trend: more rain = more stomata • General trend: faster growth = more stomata
Graph to show stomatal opening over 24 hours Some plants close stomata during hottest time-saving water 100 Increased light intensity causes more stomata to open stomatal opening/% An adaptation to hot dry environments Stomata close as the sun sets Dawn-stomata begin to open 0 12 2 4 6 8 10 12 2 4 6 8 10 12
Stomata Practice I will now list four scenarios, and you put your thumbs down if you think the stomata will be mostly closed, and thumbs up if they will be open.
Stomata Practice • A sunny morning after a soaking rain
Stomata Practice • The middle of a hot afternoon in the middle of a drought
Stomata Practice • In the middle of the night after a good soaking rain
Stomata Practice • Immediately after a thunderstorm