LO: Investigate seed dispersal
This week you will need:
- Stopwatch (e.g. on a mobile phone or watch)
- weights – e.g. paperclips or sticky tack
Use these key words to describe the lifecycle of a flowering plant:
fertilisation, germination, photosynthesis, pollination, seed dispersal
Check your ideas with this video:
Watch this video on seed dispersal
Why is it important for plants to spread their seeds as far as they can?
Go for a walk and look for a variety of seeds.
Classify them according to how the seeds are dispersed.
What clues help you to decide?
Poppers have stalks that hold the seed to the plant and when the plant is moved the stalk snaps ("pops") and sends the seed flying. Example: grasses.
Droppers don't have any actual dispersal method; they in fact just drop their seeds to the ground. Example: Conkers.
Fliers have wing-like structures that help the fruit "fly away" when it falls off. Example: Maple trees.
Floaters have light fluffy strands that help the seed float away on the breeze. Examples: Dandelions
Grabbers catch and hold on as you or an animal as it passes by. Example: Beech seeds
Passers are edible fruit that are eaten by animals and deposited elsewhere with ‘free’ fertiliser. Example: apples
Dandelion seeds are dispersed by the wind. Watch this video:
To travel a long distance, the seed needs to stay in the air as long as possible.
- Roll a paper rectangle into a tube and stick it shut.
- Drop it from as high as possible and time how long it takes to fall
- Now make several vertical cuts to half way down and fold out the cuts.
- Predict how long this will take to fall and test.
You can now plan your own investigation to find the best dandelion parachute. Will you change:
- the number of cuts
- the length of the cuts
- the angle of the folds
- the mass of the parachutes (e.g. using paperclips or lumps of sticky tack)