Topic 10.1.2 - Succession Flashcards
What is a community?
A community consists of all the plants and animals that occupy a particular area.
What is primary succession?
the progressive colonisation of bare rock or barren terrain by living organisms.
What is the definition of secondary succession?
the recolonization of an area after an earlier community has been removed or destroyed.
What is the terrain like at the start of primary succession?
Bare rock
Barren terrain
What is the first stage in primary succession?
Pioneer species begin breaking down rock. (Lichens)
They secrete acids that break down rocks into small particles which mix with lichen remains to form soil.
What is the second stage of primary succession?
More complex plants, usually mosses, begin growing when soil is deep enough, after many years.
eventually replace (succeed) lichens.
Tiny organisms such as insects move in, add their remains to soil.
What is the third stage of primary succession?
Larger, more complex plants.
As soil gets thicker ferns succeed mosses.
Grasses and wildflowers may succeed ferns.
When enough soil has developed, shrubs and small trees move into the area.
What is the fourth stage of primary succession?
Forests
Soil may be deep enough after hundreds or thousands of years for pine or hardwood forests.
What is the fifth stage of primary succession?
Climax community
Is very stable and can endure for hundreds of years.
What is climax community?
all the organisms which make up the final stage of ecological succession.
What are the overall features that emerge due to succession?
The abiotic environment becomes less hostile (e.g. soil forms).
More complex food webs.
Increased biomass.
Increased biodiversity – increase in number of species.
Greater number and variety of habitats and niches.
Summary of succession from mark schemes
Pioneer species/mosses/lichens arrive
decomposition increases the soil depth and mineral/nutrient content.
Therefore larger plants can grow.
More herbaceous plants/shrubs/trees are present.
Nitrate content in soil grows as there are more leaves/plants/animals/faeces.
Climax community emerges at end.
What is secondary succession?
Secondary succession takes place in areas where life is already present but has been altered in some way.
The process is usually faster than in primary succession.
There may be a change in species as well.
What are the 3 main causes of secondary succession?
Natural catastrophe
Human destruction
Human management
Examples of a natural catastrophe.
Fires
Blow outs on sand dunes
Volcanic blasts
