Succession

Question 1

What does an ecosystem being dynamic mean?

Answer 1

They are constantly changing

Question 2

What is succession?

Answer 2

Changes, over time, of the species which occupy a particular area

Question 3

When does primary succession occur?

Answer 3

Occurs when newly formed/exposed land (with no species present) is gradually colonised by an increasing number of species

Question 4

What is an example of primary succession?

Answer 4

Glacier retreating, volcanoes erupting -> magma from erupting volcanoes cools

Question 5

What is a pioneer species?

Answer 5

The first species to colonise the new land

Question 6

What are some characteristics of pioneer species?

Answer 6

1) asexual reproduction
2) vast quantities of wind dispersed seeds/spores
3) rapid germination of seeds (no period of dormancy)
4) ability to photosynthesise- not dependent on others (bottom of food chain)
5) ability to fix nitrogen from the atmosphere
6) tolerance to extreme conditions

Question 7

2nd step?

Answer 7

Lichens/moss die and decompose
This releases sufficient nutrients
Organic matter builds up to form a simple soil
Mosses/small ferns begin to grow
These then die and decompose- make conditions less hostile

Question 8

3rd step?

Answer 8

The topsoil/humus becomes more fertile and enables other species to grow
These plans also die and decompose- leaves organic matter that helps to retain water and provide anchorage for roots
As the small plants/shrubs die and decompose, the new soil becomes deeper and more nutrient rich
The roots of these small plants and shrubs form a network to help the soil in place- prevent from being washed away

Question 9

3rd step after topsoil/hummus becoming more fertile?

Answer 9

Larger plants and shrubs (small trees also) that require deeper, more nutrient-rich soil can now grow
The soil is sufficiently deep, contains enough nutrients and can hold enough water to support the growth of large trees
The final species to colonise the new land becomes the dominant species

Question 10

What is the climax community?

Answer 10

The final community formed

Question 11

What is secondary succession?

Answer 11

From area cleared of organisms, but with soil present e.g. land cleared after a fire

Question 12

What is a plagioclimax community?

Answer 12

A community which will not develop further as humans are influencing it
E.g. parks
Stops a climax community from developing

Question 13

What is conservation?

Answer 13

Protecting and managing ecosystems

Question 14

How can preventing an area from reaching a climax community be a good thing?

Answer 14

Ecosystems at the intermediate stage (small plants) have a distinct diversity of plant species- which may not exist if the climax community was reaches
These diverse plant species also provide food and habitat for a high diversity of animal species- some may be of conservation importance

Question 15

Why do some conservation projects focus on deliberately preventing succession?

Answer 15

in order to preserve an ecosystem in its current stage of succession

Question 16

What are some ways of preventing succession?

Answer 16

Grazing animals- can be introduced temporarily- eat the growing shoots of shrubs and trees
Managed burning- the larger woody plants take longer to grow back

Question 17

What is conservation?

Answer 17

The protection, management and restoration of natural environments and the organisms within them.
Aims to maintain biodiversity, ensure the survival of species and preserve ecosystems for future generations.

Question 18

What are the 2 types of conservation?

Answer 18

Conservation in the natural habitat
Conservation outside the natural habitat

Question 19

What is conservation in the natural habitat?

Answer 19

Protecting species within their natural environment

Question 20

What does conservation in the natural habitat include?

Answer 20

Protected areas e.g. nature reserves
Legal protection of endangered species
Controlling invasive species
Habitat restoration and management

Question 21

Advantages of conservation in the natural habitat?

Answer 21

Maintains natural behaviour and evolution
Preserves whole ecosystems

Question 22

Disadvantages of conservation in the natural habitat?

Answer 22

Limited control over external threats
Habitat may still be degraded
Slow recovery rates
Human conflict
Not always effective for critically endangered species

Question 23

What is conservation outside the natural habitat?

Answer 23

Involves removing organisms from their natural habitat

Question 24

Example of conservation outside the natural habitat?

Answer 24

Captive breeding programmes e.g. zoos
Botanic gardens
Seed banks and gene banks

Question 25

Advantages of conservation outside the natural habitat?

Answer 25

Protects species when the habitat is too damaged or dangerous Allows for controlled breeding and reintroduction

Question 26

Disadvantages of conservation outside the natural habitat?

Answer 26

Captive populations often have reduced genetic diversity Requires significant diversity Organisms may fail to adapt to captive conditions or may lose natural behaviours Difficulty reintroducing captive-bred organisms

Question 27

Why is conservation important?

Answer 27

maintains biodiversity- critical for ecosystem stability and services e.g. pollination Prevents extinction of endangered species Preserves genetic diversity- vital for adaptation to environmental change Supports sustainable human use of natural resources e.g. fisheries, forestry

Question 28

What is sustainable management?

Answer 28

Ensures resources are used without depleting them e.g. fishing quotas means fish populations are not depleted beyond a level from which they cant recover

Question 29

What is an agri-environment scheme?

Answer 29

Encourage farmers to conserve hedgerows, leave field margins and reduce pesticide use