Unit 2

Seed dispersal

How do seeds movefrom place to place?

Seed dispersal: Unit 2

Where do ducks carry seeds?

Seed dispersal: Unit 2

Acorns:• How far do they fall from the

tree

http://www.arkive.org/pedunculate-oak/quercus-robur/video-09b.html

• Mammals and birds bury acorns to eat in the winter. What happens to the ones left in the ground?

http://www.arkive.org/pedunculate-oak/quercus-robur/video-11c.html

Gravity

Darwin’s ways of working: Unit 1Seed dispersal: Unit 2

Dandelion (Taraxacum officinale)

• What helps the seed to move?

“beautifully plumed seed”

Charles Darwin, On the Origin ofSpecies, 1859

http://www.arkive.org/common-dandelion/taraxacum-officinale-agg/video-09.html

• Can you think of other ways that make seeds light enough to be blown on the wind?

Wind

Darwin’s ways of working: Unit 1Seed dispersal: Unit 2

Seed dispersal: Unit 2

Sycamore(Acer pseudoplatanus)

• How tall is a fully grownSycamore tree?

http://www.arkive.org/sycamore/acer-pseudoplatanus/image-A6856.html

• Does each seed fall straightdown?

http://www.arkive.org/sycamore/acer-pseudoplatanus/video-09b.html

Gravity and wind

Seed dispersal: Unit 2

Common Poppy(Papaver rhoeas)

• Where does the seed come out?

• About how tall is a poppy flower?

• What could cause the stalk to sway?

• Why do you think each poppy plant can produce around 17,000 seeds?

Pepper Pot (sways on the stalk)

Blackberry(Rubus fruticosus)

• Which of these berries do you think will be eaten first?

http://www.arkive.org/harvest-mouse/micromys-minutus/video-08a.html

• What happens to the seed after the fruit has been eaten?

Animals - eating

Count the number of blackberries on this branch. Each one will have about 10 sections each with a seed. How many seeds are on this one branch?

Seed dispersal: Unit 2

Cleavers(Galium aparine)

• How do you think the fruits of cleavers move around?http://www.field-studies-council.org/urbaneco/urbaneco/introduction/colonisation.htm

• Which wild animals could do this?

Animals - clinging

Seed dispersal: Unit 2

Marsh marigold(Caltha palustris)

• Where do they live?

• What do you think will happen to the seeds when they fall out of the pod?

http://www.arkive.org/marsh-marigold/caltha-palustris/ image-A16924.html

Water

Seed dispersal: Unit 2

Sweet pea seed(Lathyrus odoratus)

• When will the seed podbe dry enough to suddenly explode and twist?

• Why do the seeds spray away from the Plant?

• How far can these seedstravel?

Explosive - springing apart

Seed dispersal: Unit 2

Squirting cucumber(Ecballium elaterium)

These plants live in hot drycountries. When drops of rain hit the ripe fruit they push off theplant squirting their seedsbehind them.

• Why is rain a helpful trigger?

Explosive - pushing forward

Seed dispersal: Unit 2

Here Darwin collected mud with lots of seeds in it

Keston Ponds

Seed dispersal: Unit 2

A duck inside and outside

Seed dispersal: Unit 2

Seed dispersal: Unit 2