Transcript 7. Ecological Succession

7. Ecological
Succession
7.1 Succession
Starter

Match up the key
word to the definition
Ecosystem
An ecological factor that makes
up part of the non-biological
environment
Biotic
More or less self-contained
functional unit in ecology made up
of all the interacting biotic and
abiotic factors in an area
Abiotic
The organisms of all species that
live in the same area
Community
An ecological factor that makes
up part of the living environment
of an organism
Learning Objectives
Describe changes that occur in the variety
of species occupying an area over time
 Define succession and climax community
Success Criteria
 You can describe the order of plant
succession and explain common features
of succession
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Succession

The changes, over time, in the species
that occupy a particular area
Succession of bare rock or barren
land
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Succession happens when an area is first
colonised. What might happen to cause
this?
 A retreating
glacier depositing rock
 Wind or sea piling sand into dunes
 Volcanoes erupting and depositing lava
 Land subsiding and creating lakes or ponds
 Silt and mud being deposited at river
estuaries
Pioneer Species
The first stage of succession involves
pioneer species colonising an
inhospitable environment
 Pioneer species have features that suit
them to colonisation
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Task

In pairs, come up with a list of features
that pioneer species may have, which
would help them to colonise inhospitable
environments
Features of Pioneer Species
Production of a lot of wind-dispersed
seeds to easily reach isolated areas
 Rapid germination of seeds
 The ability to photosynthesise
 The ability to fix nitrogen from the
atmosphere
 Tolerance to extreme conditions

Stages of Plant Succession
Stages of Plant Succession
Colonisers (lichens): when they die, they
release nutrients. This changes the abiotic
environment by creating soil.
 Mosses, then Ferns: rock is continually
eroded, as these die organic matter
increases, building up soil
 Small flowering plants, shrubs then
trees establish
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Climax Community
The organisms that make up the final
stage of ecological succession
 A balanced equilibrium
 In the UK, this is deciduous woodland
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Animal Succession
Animal species present depend on the
plant species found in the area
 For example, mosses and grasses provide
food and habitats for insects and worms.
These can then support secondary
consumers.
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Common features in any
succession
The non-living environment becomes less
hostile
 A greater number and variety of habitats
 Increased biodiversity
 More complex food webs
 Increased biomass
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Land alteration
Succession also occurs when land is
suddenly altered e.g. from a fire
 The area will then undergo succession to
return to a stable, climax community
 This type of succession doesn’t begin with
a pioneer species
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Learning Objectives
Describe changes that occur in the variety
of species occupying an area over time
 Define succession and climax community
Success Criteria
 You can describe the order of plant
succession and explain common features
of succession
