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level: 19.6 Succession

Questions and Answers List

level questions: 19.6 Succession

QuestionAnswer
Succession- The gradual directional change of a community over time
Two types of succesion- Primary succession - Secondary succession (end of both is climax community)
Primary succession- Starting point is bare ground
Secondary succession- Here a community is damaged and the soil is left plants to colonise (e.g. a woodland has been felled)
Pioneer species- A highly adapted species that is the first to colonise e.g. algae/lichens
Climax community- Stable community - final stage of succession - The community is still determined by abiotic factors
Abiotic conditions that affect primary colonisersClimate: temp, rain and sunlight, can affect the survival and growth of primary colonisers Light: affects the ability to photosynthesise Wind: intensity and direction of wind as it can affect the distribution of seeds and pollen
How marram grass is adapted to the harsh abiotic conditionsRoot system: deep root system that can reach down to the underlying groundwater, allowing it to access water even in dry conditions Leaf structure: narrow and stiff, reducing water loss through transpiration Wind resistance: strong stems and leaves that can withstand high winds
How marram grass or any other species colonisation changes the abiotic conditionsSoil moisture: stabilise the sand dunes by binding the sand particles together with its roots. This increases the soil moisture, as the sand is less likely to be blown away and water is better retained in the soil. Microclimate: They can also modify the microclimate of the sand dune ecosystem, creating a cooler and more humid environment that is better suited to the growth of other plants.
Explain how succession leads to a climax community (1)- Succession either occurs in areas with no prior vegetation e.g. on sand dunes, or in areas where a community has been disrupted e.g. after a fire or a flood.
Explain how succession leads to a climax community (2)- This creates an abiotic environment that is hostile so only highly adapted species are able to colonise - pioneer species
Explain how succession leads to a climax community (3)- In the pioneer community the species diversity is low as there are few niches, they will compete, some will die and decomposes and release nutrients and produce ‘soil’.
Explain how succession leads to a climax community (4)- This allows new species e.g. grasses to colonise, the grasses then outcompete the pioneer species, increasing diversity.
Explain how succession leads to a climax community (5)- The abiotic conditions have changed due to the biotic environment, this process continues over many years until there is climax community where the diversity is high, there are lots of niches, the abiotic conditions are stable.