succession lqc 6

Question 1

succession

Answer 1

The sequence of changes in {an ecosystem / a community / organisms /species / plants} over a period of time.

Question 2

climax community

Answer 2

The final {stage / sere / community} of succession. It is normally stable, self-sustaining and sometimes has one or two dominant species.

Question 3

pioneer phase- colonisation of primary succession

Answer 3

1. The process starts on newly formed habitats where there have never been a community before i.e. bare rock, volcanic ash, coastal sand or shingle, mining deposits.
2. Pioneer species, such as lichens and algae start to grow.
3. These species can live in the harsh conditions – no soil, little water and minerals, wind exposure, extremes of temperature.
4. They add organic matter (humus), and with the substrate (rock, ash etc), start to produce a thin soil – change in the abiotic conditions.

Question 4

development phase primary succession

Answer 4

1. Mosses can now grow – change in the biotic conditions. They add more organic matter to the soil – the soil can now hold more water and mineral ions.
2. Small, shallow-rooted plants can now grow - further organic material added to soil.
3. As abiotic conditions in the habitat improves, larger, taller plants can grow. These out-compete the shorter plants – they replace the previous community.

Question 5

climax community primary succession

Answer 5

1. A community dominated by trees (normally!) is established.
2. Remains {unchanged / stable} unless abiotic or biotic conditions in the habitat change.
3. It is self-sustaining.
4. Many different types of species and niches (high biodiversity) (however this does still depend on the climatic conditions and species available).

Question 6

when/ where does secondary succession take place

Answer 6

1. On bare soil where an existing community has been cleared.
2. This can be after events such as ploughing, fires, volcanoes, hurricane, flooding or if grazing has been stopped.

Question 7

what is deflected succession

Answer 7

1. A community that remains stable only because human activity prevents succession from running its course.
2. Examples include: grazing sheep, mowing of grassland, pond dredging, managed fires.