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Learning Target: Seed Dispersal 02/24. I Can … Describe different ways that seeds can be dispersed and compare/contrast the advantages/disadvantages of the different methods. I Will … Define seed dispersal List methods of seed dispersal including examples of plants for each method - PowerPoint PPT Presentation
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Learning Target: Seed Dispersal
I Can… Describe different ways that seeds can be dispersed and compare/contrast the advantages/disadvantages of the different methods
I Will… • Define seed dispersal• List methods of seed dispersal including
examples of plants for each method• Discuss advantages/disadvantages of each
method
Seed Dispersal
Dispersal (the process or result of the spreading of organisms from one place to another) is important because:
1.It spreads the progeny (offspring) in order to colonize new environments
2.Reduces competition for resources with parents
3.Reduces chances of predators destroying all of the plant’s yearly seed production
Self Dispersal• Plants disperse their seeds by forceful
ejection• Explosive fruits• Witch Hazel• Squirting Cucumber
http://youtu.be/q5g7EV2fgJw
Self Dispersal
The peanut plant sows (buries) it own seeds
Wind Dispersal• Fruit and seeds may have special
devices for wind dispersal• Plumes catch wind currents• Dandelion
• Trees take advantage of their great heights for wind dispersal• Fruits with wings are used to slow
descent to land• Maple • Ash
Water Dispersal• Fruits and/or seeds use flotation devices to travel by water ( in rivers, oceans, etc…)• Fruit may
have air spaces and corky floats
• Palm Coconuts
Water DispersalLotus Flower
Animal Dispersal
Many plants depend on animals for seed dispersal• Offers nutritional reward• Animals learn to recognize ripened
fruit colors• Fleshy fruit eaten and seeds
dispersed in feces
Animal Dispersal• Some dry fruit attach and cling to
animal’s fur (e.g. Beggar’s ticks)• Some have Velcro-like hooks that
cling to fur (Burdock, Cockleburs)• Others have sticky substances that
adhere to host (e.g. Mistletoe)
Methods of Seed Dispersal
http://youtu.be/6loGKPKDqCw
http://youtu.be/rhp5k5ptSx0?t=23s
How Plants Disperse SeedsTime: 3 mins 30 secs
Seed DispersalTime: 4 mins 17 secs
Seed Dispersal: Things that make you THINK
• What carries the dandelion seed for miles?• What feature of trees gives them a
particular advantage when dispersing seeds by air?
• How does the squirting cucumber disperse its seeds? • What is the advantage of this?
• Although plants use wind and water, what do most plants use as carriers for their seeds?
• Blackberries on a tree do not ripen simultaneously, WHY?