Succession

Question 1

Succession

Answer 1

The change in an ecosystem over time.
Describes the sequential change in species in a community over time.

Question 2

About ecosystems

Answer 2

Ecosystems are affected by changes in the communities within them an environmental disturbances.
Together these factors make ecosystems very dynamic.

Question 3

Primary succession

Answer 3

Takes place on newly exposed or newly formed land.
The land is initially colonised by pioneer species.

Question 4

Stages of primary succession

Answer 4

1) PIONEER SPECIES - the first species to colonise the land and are specialised to live in those conditions.

2) SOIL FORMATION - pioneer species help to break down substances on the exposed land to form soil

3) COLONISATION BY NEW SPECIES - the new soil makes the environment less hostile and a new species colonises this land. When the species die, the matter within the species is released into the soil

4) ALTERING ABIOTIC CONDITIONS - species dying causes the composition of the soil to change which may mean that the pioneer species cannot survive there any longer

Question 5

Secondary succession

Answer 5

When parts of the ecosystem become disturbed.
The land has become damaged in some way e.g., a fire has occurred

Question 6

Stages of succession

Answer 6

1) PIONEER SPECIES - pioneer species colonise the damaged land. The environment is more nutrient rich due to the existing soil layer

2) COLONISATION BY NEW SPECIES - when the pioneer species die the soil becomes more nutrient rich and stable.
The new species colonise the land and the new species outcompete the pioneer species

3) INCREASED COMPLEXITY - the ecosystem becomes more complex as more species colonise the land.
The ecosystem becomes more diverse

4) CLIMAX COMMUNITY - the ecosystem then reaches an equilibrium where the species composition doesn’t change anymore