Transcript The Changing Trees of Autumn

The Changing Trees of Autumn
By Meryl Spierenburg
ED 205 (15)
About the
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Let’s Learn About the Leaves!
Where do the colors come from?
Why do the leaves change color?
How does it work?
Why do leaves FALL?
What happens after the leaves fall?
How do we get the best colors?
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Where do the colors come from?
• Leaves have pigments that give them their color.
• There are 3 pigments are involved in the autumn
color.
Chlorophyll
Carotenoids
Anthocyanins
How do they all work together?
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Chlorophyll
• Chlorophyll is the pigment that gives leaves
their basic green color.
• Chlorophyll is necessary for photosynthesis,
the chemical reaction that lets plants use
sunlight to make food.
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Carotenoids
• Carotenoids are the pigments that produce
yellow, orange, and brown colors in the leaves.
• The are also found in things like corn, carrots,
and bananas.
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How do they all work together?
• Chlorophyll and carotenoid are in leaf cells all
the time during the growing season. But the
chlorophyll covers the carotenoid . That's why
summer leaves are green, not yellow.
• Most anthocyanins are produced only in
autumn. Not all trees can make anthocyanins.
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Anthocyanins
• Anthocyanins are the pigments that give
leaves their red color.
• The are also found in cranberries, red apples,
blueberries, cherries, and plums.
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Why do the leaves change color?
• Leaves change color mainly because of the
longer, cooler nights that occur in Autumn.
• As the nights get cooler and longer, a
biochemical process takes place that causes
the leaves to change in color.
• Click here to watch a video about why leaves change color
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How does it work?
• During the spring and summer, chlorophyll is
continually being made, and leaves are green.
• As the nights get longer in the fall, chlorophyll
making slows down and then stops and
eventually all the chlorophyll is gone.
• The carotenoids and anthocyanins that are in
the leaf are then able to show their colors.
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Why do the leaves fall?
• In early autumn, the veins that carry fluids
into and out of the leaf gradually close off.
• These closed veins trap sugars in the leaf and
start the making of anthocyanins.
• When this is complete, the leaf is ready to fall
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What happens after the leaves fall?
• On the ground, fallen leaves are broken down
by bacteria, fungi, earthworms, and other
organisms.
• The broken-down leaves give the soil nutrients
and become part of the layer on the forest
floor that absorb and hold rainfall.
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When do we get the best color?
• The autumn colors are the most vibrant when
there has been:
– A warm and wet spring
– A summer that isn’t too hot or dry
– A fall full of warm days and cool nights.
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About the author
This powerpoint was created by Meryl
Spierenburg. I am a Junior at Grand Valley
State University, majoring in English with a
minor in Elementary Education.
Please, feel free to e-mail me at:
[email protected]
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Concept Map
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Resources
• http://www.jimpetrozzi.com/site_WW/thumbwallpaper/Red%20Leaves.jpg
• http://www.desktoprating.com/wallpapers/nature-wallpaperspictures/fall-of-autumn-leaves-wallpaper.jpg
• http://www.jimpetrozzi.com/site_WW/thumbwallpaper/Red%20Leaves.jpg
• http://riversaredamp.files.wordpress.com/2007/10/yellow-leaves.jpg
• http://www.pewclimate.org/docUploads/images/green%20leaves%20wit
h%20rain%20drops.jpg
• http://www.dnr.state.wi.us/org/caer/ce/eek/veg/trees/treestruecolor.htm
• http://www.na.fs.fed.us/spfo/pubs/misc/leaves/leaves.htm
• http://www.esf.edu/pubprog/brochure/leaves/leaves.htm
• http://farm1.static.flickr.com/113/315997493_35bc95c19c_o.jpg
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