IB Environmental systems and societies Topic 2.5B Succession Revision Notes (SL/HL)

IB Environmental systems and societies Topic 2.5B Succession Revision Notes (SL/HL) | RevisionDojo

Written by official IB examiners

Succession: How an Ecosystem Builds Itself Over Time

Definition

Succession

Succession is the gradual process of change in ecosystems, where one community replaces another due to shifts in biotic and abiotic conditions.

Succession is the process by which a community develops and changes over time, from a few pioneer species to a complex, more stable ecosystem with high biodiversity.
It is a temporal change, which is what distinguishes it from zonation, the change in a community across space.
It is driven by the interaction of biotic and abiotic factors, because each community changes the conditions for the next.

Note

Zonation is a spatial pattern; succession is a temporal one.
Mixing up the two is a common exam error, so always ask whether the change is across space or over time.

Seral Stages: From Pioneers to a Climax Community

Definition

Seral community

A seral community (sere) is a stage in the process of succession, where one community modifies the environment, making it more suitable for the next community.

Each stage of succession is a sere (or seral stage), and the community living in it is a seral community.
Each seral community changes the environment, for example by building soil, which paves the way for the one after it.

1. Pioneer stage

The first colonisers are hardy pioneer species such as lichens, mosses, and algae.
They tolerate harsh conditions like temperature extremes, drying out, and low nutrients.
As they weather rock and then die, they add organic matter and build the first thin layer of soil.

Example

Lichens on volcanic rock release weak acids that break down the surface, forming the first soil particles.

2. Intermediate stage

As soil deepens, grasses and small plants take hold, improving water retention and nutrient cycling.
Roots stabilise the soil and microorganisms enrich it with nitrogen and organic matter.
Shrubs and small trees then outcompete the grasses, helped by taller growth and deeper roots.

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Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

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Duis aute irure dolor in reprehenderit

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Note

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Excepteur sint occaecat cupidatat non proident

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Tip

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Succession: How an Ecosystem Builds Itself Over Time

Definition

Succession

Succession is the gradual process of change in ecosystems, where one community replaces another due to shifts in biotic and abiotic conditions.

Succession is the process by which a community develops and changes over time, from a few pioneer species to a complex, more stable ecosystem with high biodiversity.
It is a temporal change, which is what distinguishes it from zonation, the change in a community across space.
It is driven by the interaction of biotic and abiotic factors, because each community changes the conditions for the next.

Note

Zonation is a spatial pattern; succession is a temporal one.
Mixing up the two is a common exam error, so always ask whether the change is across space or over time.

Seral Stages: From Pioneers to a Climax Community

Definition

Seral community

A seral community (sere) is a stage in the process of succession, where one community modifies the environment, making it more suitable for the next community.

Each stage of succession is a sere (or seral stage), and the community living in it is a seral community.
Each seral community changes the environment, for example by building soil, which paves the way for the one after it.

1. Pioneer stage

The first colonisers are hardy pioneer species such as lichens, mosses, and algae.
They tolerate harsh conditions like temperature extremes, drying out, and low nutrients.
As they weather rock and then die, they add organic matter and build the first thin layer of soil.

Example

Lichens on volcanic rock release weak acids that break down the surface, forming the first soil particles.

2. Intermediate stage

As soil deepens, grasses and small plants take hold, improving water retention and nutrient cycling.
Roots stabilise the soil and microorganisms enrich it with nitrogen and organic matter.
Shrubs and small trees then outcompete the grasses, helped by taller growth and deeper roots.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

IB Environmental systems and societies 2.5B Succession Notes

Topic 1: Foundation 3 subtopics

Topic 2: Ecology5 subtopics

Topic 3: Conservation and biodiversity3 subtopics

Topic 4: Water4 subtopics

Topic 5: Land2 subtopics

Topic 6: Atmosphere and climate change4 subtopics

Topic 7: Natural resources3 subtopics

Topic 8: Human populations and urban systems3 subtopics

HL lenses 3 subtopics

Succession: How an Ecosystem Builds Itself Over Time

Seral Stages: From Pioneers to a Climax Community

1. Pioneer stage

2. Intermediate stage

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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Succession: How an Ecosystem Builds Itself Over Time

Seral Stages: From Pioneers to a Climax Community

1. Pioneer stage

2. Intermediate stage

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account