Communities

Question 1

What is succession?

Answer 1

Succession is a directional change in the species composition of a habitat over time, culminating in a climax community.

Question 2

What is a climax community?

Answer 2

The stable end stage of a succession which is in equilibrium with the environment.

Question 3

What are the first plants to grow in an area known as?

Answer 3

Pioneer species e.g. lichens or grasses

Question 4

Name the series of stages that communities develop gradually through.

Answer 4

Seres or seral stages

Question 5

What do the pioneer plants do to the conditions of a region over time?

Answer 5

• change the abiotic conditions
• add nutrients to the soil
• provide cover for new seeds to germinate
• Decaying material adds humus and leads to soil formation 

Question 6

What is the sign of a very ecologically stable system?

Answer 6

A large diversity in the species of vegetation

Question 7

What will you commonly find in the early stages of succession?

Answer 7

A large amount of only one type of species.
At this stage it is the abiotic factors that are controlling the growth of the vegetation ( pH, soil nutrients, water amounts, temperature, wind)

Question 8

If there is a large amount of biodiversity, what is controlling the growth of vegetation?

Answer 8

Biotic factors, for example farming, competition, predation or nests are mainly controlling the growth of vegetation.

Question 9

What is colonisation?

Answer 9

The action by a plant or animal of establishing itself in an area.

Question 10

What is a ‘sere’?

Answer 10

A seral community (sere) is a stage found in an ecological succession in an ecosystem advancing towards its climax community. In many cases more than one seral stage evolves until climax conditions are attained.

Question 11

What is the starting point in primary succession?

Answer 11

The starting point is a bare ecosystem. It has not previously been colonised or nothing has grown there before e.g. following a volcanic eruption or a landslide.
The pioneer species are usually lichen, moss or algae.

Question 12

Why is primary succession a slow process?

Answer 12

Because it always involves the development of a barren or previously uninhabited area.

Question 13

What features do all primary successions have in common?

Answer 13

-they are predictable in pattern
-The abiotic environment becomes less hostile
-The height and biomass of vegetation increases
-communities become more complex
-increased biodiversity
- Communities in the later stages are usually more stable
-Number of food chains increases and more complex food webs develop


Question 14

What is the starting point of secondary succession?

Answer 14

The starting point is bare existing soil e.g. following a fire, flood or human intervention.
The soil is already present and there will be seeds and roots in the soil.

Question 15

Give an example of the process of secondary succession forming an oakland

Answer 15

1. Bare soil is colonised by grasses and pioneer plants.
2. Grasses begin to pre-dominate with time.
3. Shrubs replace grasses.
4. Fast-growing trees appear.
5. Slow-growing oaks create the climax community.

Question 16

Why is secondary succession a faster, predictable and repeatable process?

Answer 16

Because soil is already present and there will be seeds and roots in the soil. Vegetative remains from the previous community are present.

Question 17

What is a climatic climax community?

Answer 17

This is a relatively stable community at the end stage of succession in which the community composition is determined by aspects of the climate.

Question 18

State the process of primary succession forming an oakland.

Answer 18

1. Bare soil is colonised by mosses and lichen.
2. Small plants ferns and grasses take over.
3. Larger plants with deeper roots appear.
4. Shrubs and bushes replace non-woody plants .
5. Fast-growing trees form a dense, low wood
6. Larger slow-growing oak trees create the oak woodland.