Name: ______________________________ Period: ______ Page: __________
Introduction to Seed Dispersal Screencast Notes
Directions: View the video at: https://www.youtube.com/watch?v=aG5G4VW-1XI (this link is also on my website under “homework” so you don’t have to type it all in)to learn about seed dispersal and complete the following note sheet.
What is seed dispersal?
 Movement of seeds away from parent plant.
Why does it happen?
 To increase the area the plant inhabits and so they don’t have to compete with parent plant for water, sunlight, space and nutrients.
1.
What are the four MAIN methods of seed dispersal? a.
_________________________________ b.
_________________________________ c.
_________________________________ d.
_________________________________
Try it!
2.
The video will show pictures of 9 seeds. Based on the physical characteristics and information on its features decide which type of dispersal the seeds use by checking the appropriate box.
1.
Seed #
Maple
2.
Pond Iris
Animals
Method of Dispersal
Wind Water Explosion
3.
Burdock
4.
Gorse
5.
Ragwort
6.
Blackberry
7.
Red Campion
8.
Oak Tree
9.
Cotton Grass
3.
What is the significance of the Seychelles Palm? _______________________________________
4.
How is its seed dispersed? ___________________________________
5.
Think about it
Birds and other animals wait to eat berries and other fruits until they are ripe. Explain why do you think they do this? _____________________________________________________________
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_______________________________________________________________________________________
_______________________________________________________________________________________
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Directions: read the following on seed dispersal.
Seed Dispersal
Flowering plants reproduce themselves by producing seeds. The seeds also provide the plants with a way to spread out and grow in new places, sometimes a long way from the parent. This is important because if the seeds are not dispersed, many germinating seedlings will grow very close to the parent plant. This results in competition between every one of the seedlings as well as the parent plant. The competition is for light, space, water, and nutrients. All of these are important for the plants to be able to grow. In order for the plants to survive they must find ways of getting their seeds spread out over a large area. Plants have developed four ways to spread their seeds. This process is known as seed dispersal
The first type of seed dispersal is by animals:
Animals- Winter Storage
Some plants produce seeds that entice animals, such as squirrels, to collect them for winter food needs. Some of these seeds are buried, hidden, or hoarded and then not recovered and eaten. These lost seeds are then available for germination in the spring, when the growing conditions are favorable. Examples of this type of seed include acorns, pecans, and other nuts.
Animals- Munching Fruit
Many plants that we know produce fruit in which seeds are incased. These fruits entice animals (such as humans) to eat them and either discard the seeds or expel them after eating. If the seeds are discarded, they can potentially germinate. Some seeds need to pass through the gut of birds or animals, to “etch” the seed coat before they can germinate. Examples of seeds with enticing fruit include cherries, strawberries, cantaloupe, and winter squash.
Animals – Excess Baggage
The outside of a seed can be carefully designed to help disperse the seeds away from the parent plant. One way is to hitch a ride on a passing animal. Velcro was invented by a man who observed hitchhiking seeds.
Many of these types of seeds have hooks which attach to fur or clothing. These will eventually be detached and will germinate away from the parent plant. Examples are: beggar ticks and burdock.
The second type of seed dispersal is wind:
Several types of seeds can travel on wind currents. Hundreds of species of plants have evolved this method of dispersal, but not all look the same. Some seeds resemble parachutes, others helicopters or gliders.
Wind – Parachutes
Some plants take advantage of physical processes to disperse their seeds. One way that they do this is by having a “parachute”. This can be an extension on the seed itself that gets picked up by the wind and carried for some distance before being dropped. Examples are: dandelion, milkweed and thistles.
Wind – Helicopters
Wind can also be used to disperse larger seeds. These seeds have an extension that can be used as a wing.
They will fall from the parent plant and catch the wind; carrying them sometimes great distances. Examples are: Maple seeds and pine samaras.
Wind – Flutters
These are similar to helicopters, but are modified to go longer distances. Examples are: Hopseed and Quipo.
Wind – Cottony
Plants have fluffy seeds that are carried by the wind. Examples are cotton, cattails and willow.
The third type of seed dispersal is water:
Some plants live close to bodies of water and have evolved seeds to easily use it to transport their offspring to new locations. Examples are: coconut and water lilies.
The fourth type of seed dispersal is explosion/popping:
Some plants have evolved a method of dispersing seeds a short distance away from the parent plant. As the seed matures, the pod will dry out and shrink around the seeds. Once it shrinks, it will “pop” and scatter the seeds. Examples are: wisteria and touch-me-nots.