Fruit And Seed Dispersal

Question 1

Define dispersal.

Answer 1

Dispersal is the transfer of a seed or fruit away from the parent plant

Question 2

List the reasons why dispersal is necessary.

4

Answer 2

To avoid large numbers of seeds competing with each other and with the parent plant

To increase the chance of survival for the plant

To find new areas for growth

To increase the numbers of the species

Question 3

List the four main methods of seed dispersal.

Answer 3

Wind dispersal

Water dispersal

Animal dispersal

Self-dispersal

Question 4

Name some plants which are adapted for wind dispersal

3

Answer 4

Orchids

Dandelions, thistles and clematis

Sycamore and ash

Question 5

How are orchids adapted for wind dispersal?

3

Answer 5

Orchids produce small, light seeds

This is an advantage as they are easily dispersed

However, the young plant (embryo) has very little food supply to nourish it in the early days of growth

Question 6

What type of seeds are produced by orchids?

Answer 6

Small, light seeds

Question 7

What is the main advantage of the orchid’s small, light seeds?

Answer 7

They are easily dispersed by wind

Question 8

What is the main disadvantage of the orchid’s small, light seeds?

Answer 8

The young plant (embryo) has very little food supply to nourish it in the early days of growth

Question 9

How are dandelions, thistles and clematis adapted for wind dispersal?

Answer 9

Dandelions, thistles and clematis produce parachute devices that help to disperse the seeds more widely

Question 10

How are sycamore and ash trees adapted for wind dispersal?

2

Answer 10

They produce fruit with wings

These fruits spiral down to the ground and increase the distance over which the seeds may be dispersed

Question 11

What is the advantage of the sycamore and ash tree’s fruit with wings?

Answer 11

These fruits spiral down to the ground and increase the distance over which the seeds may be dispersed

Question 12

Write a note on water dispersal.

2

Answer 12

Coconut trees, alders and water lilies have light, air-filled fruits that float

This allows them to be dispersed by rivers or streams, or even by the sea (as happens with coconuts)

Question 13

Give an example of some plants that are adapted for water dispersal.
(3)

Answer 13

Coconut trees

Alders

Water lilies

Question 14

Write a note on animal dispersal.

4

Answer 14

Animals carry seeds or fruits long distances and tend to live where seeds have a chance of growing

Fruits dispersed by animals have either of two major adaptations

• Sticky fruits
• Edible, fleshy or succulent fruits

Question 15

Explain how having sticky fruits allows for animal dispersal.
(3)

Answer 15

Fruits with hooks (called burrs) may cling to an animal’s hair or fur and be carried away

These seeds are dispersed by attaching to the external surface of the animal

E.g. burdock, goose grass and buttercup

Question 16

What are the hooks found on some fruits called?

Answer 16

Burrs

Question 17

How do burrs allow for animal dispersal?

Answer 17

Fruits with hooks (called burrs) may cling to an animal’s hair or fur and be carried away

Question 18

Give some examples of plants which disperse their sticky fruits by animals.
(3)

Answer 18

Burdock

Goose grass

Buttercup

Question 19

Explain how having edible, fleshy or succulent fruits allows for animal dispersal.
(4)

Answer 19

These fruits attract animals by being brightly coloured with strong scents and plenty of food

The animal eats and digests the fruit by the seeds pass through the intestine unharmed

These seeds are released with the faeces, which even acts as a fertiliser for them

E,g, strawberries, tomatoes, blackberries, acorn and other nuts (which are dispersed when they are accidentally dropped)

Question 20

How do edible, fleshy or succulent fruits attract animals for dispersion of their seeds?

Answer 20

By being brightly coloured with strong scents and plenty of food

Question 21

What happens when an animal eats a fruit containing seeds?

2

Answer 21

The seeds pass though the intestine unharmed

These seeds are released with the faeces which even acts as a fertiliser for them

Question 22

Give some examples of edible, fleshy or succulent fruits which disperse their seeds through animals
(4)

Answer 22

Strawberries

Tomatoes

Blackberries

Acorn and other nuts (dispersed when accidently dropped)

Question 23

Write a note on self-dispersal.

3

Answer 23

Some fruits have explosive mechanisms that catapult the seeds away

These fruits often have pods that dry out and split open (dehisce)

E.g. peas, beans and gorse

Question 24

What is meant by ‘dehisce’?

Answer 24

This is where seed pods dry out and split open

Question 25

Give some examples of fruits which use the self-dispersal method of seed dispersal
(3)

Answer 25

Peas

Beans

Gorse