Unit 3.4.7 - Succession

Question 1

What is succession?

Answer 1

The process by which an ecosystem changes over time.

Question 2

Why is succession called succession?

Answer 2

Succession is split into a number of stages. At each stage a species in the area slowly change the abiotic conditions making the conditions more suitable for other species causing one community of organisms to be succeeded by another.

Question 3

What can succession be split into?

Answer 3

Primary and Secondary

Question 4

Where do you find primary succession?

Answer 4

Newly formed or exposed lands

Question 5

Give 2 examples of newly formed or exposed land.

Answer 5

1. Volcano has erupted to form a new rock surface.

2. Sea level has dropped exposing a new area of land.

Question 6

Describe primary succession in 7 steps.

Answer 6

1. Seeds and spores are blown by the wind onto areas of newly formed or exposed land - these are the pioneer species.
2. Only the pioneer species can grow in the hostile abiotic conditions as they are specialised to cope with harsh conditions.
3. The pioneer species change the abiotic conditions making them less hostile.
4. This means new species can begin to colonise and out compete the pioneer species because they are better adapted to the new abiotic conditions.
5. They change the abiotic conditions again and the process is repeated.
6. Plants create habitats for animals so they can move in.
7. The ecosystem becomes more complex and eventually leads to the climax community.

Question 7

Give 5 examples of hostile abiotic conditions.

Answer 7

1. Limited water supply because there is no soil to contain the water.
2. Few minerals and nutrients because there is no soil.
3. High light intensity because there is no shade from the sun.
4. Exposed to wind and rain.
5. Fluctuating temperatures because the area is directly exposed to the sun.

Question 8

How do the pioneer species change the abiotic conditions?

Answer 8

As they die they are decomposed by microorganisms adding more minerals and stabilising the soil.

Question 9

What is a climax community?

Answer 9

When the ecosystem is supporting the largest and complex community of plants and animals and wont change much more as it is stable.

Question 10

How does biodiversity change during succession?

Answer 10

It increases

Question 11

How does biomass change during succession?

Answer 11

It increases

Question 12

How does gross productivity change during succession?

Answer 12

Decreases

Question 13

Why does gross productivity decrease during succession?

Answer 13

There is less light reaching the ground level due to shading and so there is less photosynthesis and so less energy taken into the food chain.

Question 14

Why does a community become more stable during succession?

Answer 14

There is a more complex food chain and the community can withstand fluctuations in the population size of one species.

Question 15

Where does secondary succession occur?

Answer 15

On land that’s been cleared of all plants but where the soil remains.

Question 16

Give 2 examples of where the land has been cleared of all plants but the soil remains.

Answer 16

1. After a forest fire.

2. Or when a forest has been cut down by humans.

Question 17

What is secondary succession?

Answer 17

The same as primary succession but starts at a later stage because there is already soil.

Question 18

What are the pioneer species in secondary succession?

Answer 18

Larger plants like shrubs.

Question 19

What is the climatic climax?

Answer 19

The climax community in a particular climate.

Question 20

What is conservation?

Answer 20

Protection and management of species and habitats.

Question 21

Why do conservation methods need to be adapted?

Answer 21

As there are constant changes that occur in ecosystems.

Question 22

What are 5 pros for conservation?

Answer 22

1. Ecosystem provides humans with the resources they need - drugs, clothes and food.
2. It helps prevent climate change
3. Conserving species and habitats helps prevent the destruction of food chains.
4. Ethically we have a duty of care for future generations.
5. It can make the ecosystem look more attractive bringing in tourists.

Question 23

What are 2 cons for conservation?

Answer 23

1. It costs a lot of money

2. It can be saving species X at the expense of other species in the area.

Question 24

Name 5 conservation methods.

Answer 24

1. Management of succession
2. Seed banks
3. Captive breeding
4. Relocation
5. Creating protected areas

Question 25

What is the aim of managing succession?

Answer 25

Stopping an area from reaching the climax community.

Question 26

What is plagioclimax?

Answer 26

Where succession is stopped artificially before the climax community.

Question 27

Name 3 ways you can manage succession.

Answer 27

1. Mowing grass
2. Allow animals to graze on the land
3. Manage fires

Question 28

How does mowing the grass and allowing animals to graze on the land stop succession?

Answer 28

The area won’t develop any shrubs or trees because their growing points will be cut down.

Question 29

How does lighting managed fires manage succession?

Answer 29

It causes secondary succession to occur, larger plants species will take longer to grow back and so won’t have time to grow back before the land is burnt again.

Question 30

What is a seed bank?

Answer 30

A store of lots of seeds from different plant species.

Question 31

How do seed banks help to conserve species?

Answer 31

They store seeds of endangered plants and they have different seeds from the same species but with different characteristics.

Question 32

Why are seed banks a good way to conserve plant species?

Answer 32

You can store a large number of seeds in a small place.

Question 33

What is captive breeding?

Answer 33

Breeding animals in controlled environments.

Question 34

Why does captive breeding conserve species?

Answer 34

Endangered species can be bred in captivity to help increase their numbers.

Question 35

Why is captive breeding sometimes hard?

Answer 35

It is hard to get the animals to breed in an unnatural environment.

Question 36

What does relocating a species mean?

Answer 36

Moving a population of a species to a new location because they are directly under threat, they are moved to an area with a similar environment where there is no risk.

Question 37

When is relocation often used?

Answer 37

For species that are only exist in one place to prevent the population dying out.

Question 38

Why can relocation sometimes be bad?

Answer 38

When you move animals to a new area the native species in the new area may be out competed by the new species.

Question 39

What does protecting an area involve?

Answer 39

Restricting urban development, industrial development or farming.

Question 40

How is it decided which species and habitats need to be conserved and the best way to conserve them.

Answer 40

Scientists do research.