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2.7 Ecological Succession

3 min readdecember 27, 2022

Joshua Nielsen

Joshua Nielsen

Joshua Nielsen

Joshua Nielsen

Succession Defined

is the process by which an ecosystem or community experiences change. A climax community is found when this ecosystem stops experiencing sporadic change and instead reaches stability. This means that, under the current climate conditions, little to no changes are occurring. Most diagrams depict this as a forest, though the Sahara Desert has remained unchanged for almost five thousand years.

If conditions change, the climax community will change and succession will begin again. Think what would happen if the desert suddenly had more consistent rainfall or the rainforests experienced long term drought. Those conditions then become "unideal" or "unstable" for its residents and it must change (experience succession) again until it reaches another climax community.

Primary Succession

https://cdn.pixabay.com/photo/2017/04/12/23/28/away-2226161_960_720.jpg

Image courtesy of Pixabay

Primary succession occurs after a disaster when only bedrock is in the area. Think about if a parking lot was left alone to reclaim the environment and grow vegetation; the process for plants to overtake cement or rock is a slow and tedious one. Since soil and nutrients in the soil are required to foster plant growth, like are important. These are the first complex organisms involved in succession, and with the help of and , these species will break down rock and create soil from the remains. Since this process is so long and arduous, it will take hundreds (or thousands!) of years for other plants (like grasses) to take root and start growing. As individual organisms die and decompose, this promotes nutrient increase and , which helps succession move faster. More and more complex plants, like shrubs and trees, will start to compete for resources, and forest will eventually form when hardwood trees win the interspecies "competition." This creates, in many years, a pipeline from rock to to much larger, more complex, and ecologically more tolerant plant species.

Secondary Succession

There is little difference between primary and after they start. is only different in that the soil is not wiped out; it remains, and bare bedrock is not exposed. Often, a natural disaster is more tame (such as a wildfire or a flood) and wipes away the living organisms, leaving only soil. Now the will be grasses and ‘weeds’ like dandelions. The rest of the process remains the same, and will eventually foster competition after the ecosystem's entire rebuild.

Fauna: A Part of Succession

Most diagrams of succession, primary or secondary, only show the vegetation (flora) that is changing (replaced) over time. As mentioned before, the plants present become larger or more complex the further along succession processes are. You must also realize that the animals (fauna) will also be changed (replaced). Buffalo are at home in the open grasslands, for example, but would have a hard time navigating the redwood forest.

Keystone Species

https://cdn.pixabay.com/photo/2017/01/19/16/15/wolf-1992716_960_720.jpg

Image courtesy of Pixabay

A is depended upon by other species in the ecosystem such that if it were removed, the ecosystem would undergo dramatic changes. These are disproportionate in size, meaning that they have relatively low population density for how extremely important their effect on their ecosystem is. The wolves of Yellowstone National Park were reintroduced in 1995 after nearly a century of absence. The video link explains some of the changes that the park experienced because of the wolves (including the shape of the rivers). The changes to the park showed that the wolves are an extremely valuable species.  are often undervalued and, as a result of their importance combined with their numbers, are much more prone to going extinct.

Indicator Species

An is one that reflects the health of its ecosystem. If an experiences death or much lower population density, this can indicate that an ecosystem's health is poor or failing. For example, amphibians like frogs experience life both on land and in water, so their health could indicate whether or not both parts of an ecosystem are healthy and functioning properly.

🎥 Watch: AP Environmental Science - Adaptations and Ecological Succession

Key Terms to Review (10)

Ecological succession

: Ecological succession refers to the gradual process of change in species composition and community structure in an ecosystem over time. It occurs as one community replaces another due to natural disturbances or human activities.

Erosion

: Erosion is the process of wearing away or removal of soil, rock, or other materials from the Earth's surface by natural forces such as wind, water, or ice. It can lead to the loss of fertile soil and changes in landscapes.

Indicator Species

: Indicator species are organisms that provide information about the health and condition of an ecosystem. They are sensitive to changes in their environment and can indicate pollution levels or other ecological disturbances.

Interspecies competition

: Interspecies competition is a type of ecological interaction where different species compete for limited resources such as food, water, or territory. It can occur between individuals of the same or different species and can influence population dynamics and community structure.

Keystone species

: Keystone species are organisms that have a disproportionately large impact on their ecosystem relative to their abundance. They play a crucial role in maintaining the structure and function of an ecosystem.

Lichens

: Lichens are unique organisms composed of a symbiotic relationship between fungi and algae or cyanobacteria. They can grow on rocks, trees, and even rooftops, playing important roles in ecological processes such as nitrogen fixation and soil formation.

Pioneer species

: Pioneer species are the first organisms to colonize a barren or disturbed area. They are hardy and can survive in harsh conditions, paving the way for other species to establish themselves.

Secondary Succession

: Secondary succession refers to the process of ecological succession that occurs in an area that has been previously disturbed or disrupted, but still retains its soil. It involves the gradual and predictable changes in plant and animal communities over time.

Soil development

: Soil development refers to the process by which soil forms over time through a combination of weathering, organic matter accumulation, and biological activity. It involves the transformation of rock particles into fertile soil capable of supporting plant growth.

Weathering

: Weathering is the process by which rocks, minerals, and other materials on Earth's surface are broken down into smaller pieces or chemically altered. It can be caused by physical forces like wind and water, as well as chemical reactions.

2.7 Ecological Succession

3 min readdecember 27, 2022

Joshua Nielsen

Joshua Nielsen

Joshua Nielsen

Joshua Nielsen

Succession Defined

is the process by which an ecosystem or community experiences change. A climax community is found when this ecosystem stops experiencing sporadic change and instead reaches stability. This means that, under the current climate conditions, little to no changes are occurring. Most diagrams depict this as a forest, though the Sahara Desert has remained unchanged for almost five thousand years.

If conditions change, the climax community will change and succession will begin again. Think what would happen if the desert suddenly had more consistent rainfall or the rainforests experienced long term drought. Those conditions then become "unideal" or "unstable" for its residents and it must change (experience succession) again until it reaches another climax community.

Primary Succession

https://cdn.pixabay.com/photo/2017/04/12/23/28/away-2226161_960_720.jpg

Image courtesy of Pixabay

Primary succession occurs after a disaster when only bedrock is in the area. Think about if a parking lot was left alone to reclaim the environment and grow vegetation; the process for plants to overtake cement or rock is a slow and tedious one. Since soil and nutrients in the soil are required to foster plant growth, like are important. These are the first complex organisms involved in succession, and with the help of and , these species will break down rock and create soil from the remains. Since this process is so long and arduous, it will take hundreds (or thousands!) of years for other plants (like grasses) to take root and start growing. As individual organisms die and decompose, this promotes nutrient increase and , which helps succession move faster. More and more complex plants, like shrubs and trees, will start to compete for resources, and forest will eventually form when hardwood trees win the interspecies "competition." This creates, in many years, a pipeline from rock to to much larger, more complex, and ecologically more tolerant plant species.

Secondary Succession

There is little difference between primary and after they start. is only different in that the soil is not wiped out; it remains, and bare bedrock is not exposed. Often, a natural disaster is more tame (such as a wildfire or a flood) and wipes away the living organisms, leaving only soil. Now the will be grasses and ‘weeds’ like dandelions. The rest of the process remains the same, and will eventually foster competition after the ecosystem's entire rebuild.

Fauna: A Part of Succession

Most diagrams of succession, primary or secondary, only show the vegetation (flora) that is changing (replaced) over time. As mentioned before, the plants present become larger or more complex the further along succession processes are. You must also realize that the animals (fauna) will also be changed (replaced). Buffalo are at home in the open grasslands, for example, but would have a hard time navigating the redwood forest.

Keystone Species

https://cdn.pixabay.com/photo/2017/01/19/16/15/wolf-1992716_960_720.jpg

Image courtesy of Pixabay

A is depended upon by other species in the ecosystem such that if it were removed, the ecosystem would undergo dramatic changes. These are disproportionate in size, meaning that they have relatively low population density for how extremely important their effect on their ecosystem is. The wolves of Yellowstone National Park were reintroduced in 1995 after nearly a century of absence. The video link explains some of the changes that the park experienced because of the wolves (including the shape of the rivers). The changes to the park showed that the wolves are an extremely valuable species.  are often undervalued and, as a result of their importance combined with their numbers, are much more prone to going extinct.

Indicator Species

An is one that reflects the health of its ecosystem. If an experiences death or much lower population density, this can indicate that an ecosystem's health is poor or failing. For example, amphibians like frogs experience life both on land and in water, so their health could indicate whether or not both parts of an ecosystem are healthy and functioning properly.

🎥 Watch: AP Environmental Science - Adaptations and Ecological Succession

Key Terms to Review (10)

Ecological succession

: Ecological succession refers to the gradual process of change in species composition and community structure in an ecosystem over time. It occurs as one community replaces another due to natural disturbances or human activities.

Erosion

: Erosion is the process of wearing away or removal of soil, rock, or other materials from the Earth's surface by natural forces such as wind, water, or ice. It can lead to the loss of fertile soil and changes in landscapes.

Indicator Species

: Indicator species are organisms that provide information about the health and condition of an ecosystem. They are sensitive to changes in their environment and can indicate pollution levels or other ecological disturbances.

Interspecies competition

: Interspecies competition is a type of ecological interaction where different species compete for limited resources such as food, water, or territory. It can occur between individuals of the same or different species and can influence population dynamics and community structure.

Keystone species

: Keystone species are organisms that have a disproportionately large impact on their ecosystem relative to their abundance. They play a crucial role in maintaining the structure and function of an ecosystem.

Lichens

: Lichens are unique organisms composed of a symbiotic relationship between fungi and algae or cyanobacteria. They can grow on rocks, trees, and even rooftops, playing important roles in ecological processes such as nitrogen fixation and soil formation.

Pioneer species

: Pioneer species are the first organisms to colonize a barren or disturbed area. They are hardy and can survive in harsh conditions, paving the way for other species to establish themselves.

Secondary Succession

: Secondary succession refers to the process of ecological succession that occurs in an area that has been previously disturbed or disrupted, but still retains its soil. It involves the gradual and predictable changes in plant and animal communities over time.

Soil development

: Soil development refers to the process by which soil forms over time through a combination of weathering, organic matter accumulation, and biological activity. It involves the transformation of rock particles into fertile soil capable of supporting plant growth.

Weathering

: Weathering is the process by which rocks, minerals, and other materials on Earth's surface are broken down into smaller pieces or chemically altered. It can be caused by physical forces like wind and water, as well as chemical reactions.


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© 2024 Fiveable Inc. All rights reserved.

AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.