1. B-6.3: Illustrate the processes of succession in ecosystems.
Ecology: Succession

2. What is Succession?
Ecological succession is the series of changes in an ecosystem when one community is replaced by another as a result of changes in abiotic and biotic factors
There are 2 types of succession:
Primary
secondary

3. Primary Succession Begins in a place without soil, such as:
Volcanic lava flows
Pavement
Bare rock
The first organisms to colonize the bare rock are called pioneer species, which do not need soil to survive
Examples: mosses and lichens

4. Primary Succession
Mosses and lichens among most important pioneer species (first organisms)
The mosses and lichens help to break apart the rocks into smaller pieces, which begins the process of soil formation
Erosion by wind and water also helps to break down the rock
When lichens and mosses die, they decompose and add small amounts of organic matter and nutrients to the newly forming soil

5. Primary Succession
After mosses and lichens, then the other plants like annual grasses, weeds and ferns can grow in the newly formed soil
Continue to break down rock and provide more soil
Soil layer thickens

6. Primary Succession
After the ferns, seeds of other plants and small trees are able to germinate and grow
Over time more species grow and die
Their decomposed bodies add nutrients to the soil and larger plants are able to populate the area

7. Primary Succession
As species of plants change, species of animals that can inhabit area change
Organisms in each stage may alter ecosystem in ways that may hinder their own survival but benefit future organisms
This is how one community replaces another over time

8. Primary Succession
The climax community is the final stage of succession, which is considered stable and permanent (unless a disturbance occurs, such as a forest fire)
The climax community is determined by the limiting factors of the area
Scientists have found that the processes of succession are always changing ecosystems

9. Primary Succession

10. Secondary Succession
Begins in a place that already has soil and once had living organisms
For example, secondary succession would occur after a forest fire
Abandoned farmland, vacant lots, clear-cut forest areas
Because soil is already present, wildflowers, bushes and tree seedlings can quickly grow back
These would be the pioneer species

11. Secondary Succession

12. Secondary Succession
Similar to primary succession in later stages after soil has been formed
Something halts the succession, such as a fire, a hurricane or human activities, and destroys the established community but soil remains intact
When disturbance is over, ecosystem interacts to restore the original condition of the community

13. Where does Succession Happen?
Succession can occur in any environment, such as a forest, grassland, beach, coral reef, desert)
Each biome has a different type of climax community

14. Succession Continual process
Some stages may last for a short period of time, while others may last for hundreds of years
Any disturbance will affect rate of succession. Usually secondary succession occurs faster than primary because it already has soil present
When disturbances are frequent or intense, area has species that are present early on in succession
When disturbances are moderate, area is composed of habitats in different stages of succession

15. What would be the order of the stages of succession?3 1 4 2