Succession Flashcards
1
Q
What is primary succession?
A
- succession starting on bare ground
2
Q
How can colonisation of bare ground occur?
A
- seeds blown by wind
- seeds in water
- birds carrying seeds
- animals bringing seeds in fur
- people with seeds in shoes
3
Q
What is a pioneer?
A
- the first species to colonise the environment
- they are able to survive extreme conditions
4
Q
What is the climax community?
A
- the final community reached
- in Britain this likely to be oak or ash woodland
5
Q
What are the common features of a succession?
A
- increasing plant diversity
- increasing animal diversity
- increasing stability
- increasing productivity
- increasing height of plants
6
Q
What is secondary succession?
A
- occurs when land that has already sustained life is suddenly altered
- this often returns to a climax community much faster than
7
Q
Why is secondary succession faster than primary?
A
- there is already soil and likely to be seeds in the soil too, so succession happens more rapidly than primary succession
8
Q
What is succession?
A
- gradual change in a community over time
9
Q
Succession stage 1
A
- primary succession
- pioneer species
- able to withstand desiccation, extremes of temperature, low levels of nutrients
- penetrate can break up rock so that soil starts to form
- e.g. lichens
10
Q
Stage 2
A
- as pioneers decompose, humus builds up
- abiotic conditions are still extreme
- simple plants like ferns and mosses grow
11
Q
Stage 3
A
- mosses and ferns cast shade and stop lichens from growing
- long roots break up rock
- organic matter increases as humus builds up in soil
- more water retained so grasses, small flowering plants and shrubs can grow
12
Q
Stage 4
A
- growth of larger plants and the animals with inhabit them will cause further changes in soil and light conditions
- shading effect of large plants kills off some smaller ones
13
Q
Stage 5
A
- climax community
- eventually area colonised by dominant plant species
- ash or oak woodland in most of the UK
14
Q
Stages of secondary succession
A
- already seeds and soil so succession happens more rapidly than primary
- wind blown plants that are tolerant to high levels of sun and grow fast will colonise
15
Q
What are human effects on succession?
A
- often a climax community is not reached
- could be because of agriculture
- result of one or more limiting factors in the environment
