Ecological Succession Stages to Know for AP Biology

Ecological succession describes how ecosystems change over time, starting from barren landscapes to stable communities. Understanding primary and secondary succession, along with key concepts like pioneer species and climax communities, is essential in biology and environmental science.

1. Primary succession

   • Occurs in lifeless areas where soil has not yet formed, such as after a volcanic eruption or glacial retreat.
   • Involves the gradual establishment of a biological community over time.
   • Begins with the colonization of pioneer species, leading to soil development and increased biodiversity.

2. Secondary succession

   • Takes place in areas where a disturbance has destroyed an existing community but left the soil intact, such as after a forest fire or flood.
   • Generally occurs more rapidly than primary succession due to the presence of soil and seed banks.
   • Results in a return to a stable ecosystem, often resembling the original community.

3. Pioneer species

   • The first organisms to colonize barren environments, such as lichens and mosses in primary succession.
   • Help to create soil by breaking down rock and accumulating organic matter.
   • Facilitate the establishment of other species by modifying the environment.

4. Climax community

   • A stable and mature ecological community that undergoes little change in species composition.
   • Represents the final stage of ecological succession, where the ecosystem is in equilibrium.
   • Characterized by a diverse array of species and complex interactions.

5. Sere

   • A series of stages in ecological succession, from pioneer species to climax community.
   • Each stage is characterized by specific species and environmental conditions.
   • Helps to understand the progression and changes in an ecosystem over time.

6. Facilitation

   • A process where early colonizers modify the environment, making it more suitable for subsequent species.
   • Involves positive interactions among species, such as providing shade or nutrients.
   • Plays a crucial role in the progression of succession.

7. Inhibition

   • A process where the presence of certain species hinders the establishment of others.
   • Can occur through competition for resources or allelopathy (chemical inhibition).
   • Influences the composition and dynamics of the community during succession.

8. Tolerance

   • Refers to the ability of certain species to thrive in a range of environmental conditions.
   • Species that are tolerant can establish themselves regardless of the presence of other species.
   • Important in determining which species dominate at different stages of succession.

9. Autogenic succession

   • Succession driven by internal factors within the ecosystem, such as species interactions and changes in community structure.
   • Results from the natural growth and development of the community over time.
   • Reflects the dynamic nature of ecosystems as they evolve.

10. Allogenic succession

    • Succession influenced by external environmental changes, such as climate shifts or natural disasters.
    • Often leads to significant changes in species composition and community structure.
    • Highlights the impact of abiotic factors on ecological dynamics.

11. Nudation

    • The process of creating a bare substrate that is ready for colonization by organisms.
    • Can occur due to disturbances like fire, landslides, or human activities.
    • Marks the beginning of ecological succession.

12. Colonization

    • The arrival and establishment of species in a new or disturbed area.
    • Involves the dispersal of seeds or organisms to the site.
    • Critical for initiating the process of succession.

13. Ecesis

    • The successful establishment and growth of organisms in a new environment.
    • Involves the survival and reproduction of colonizing species.
    • A key step in the progression of ecological succession.

14. Competition

    • The struggle between organisms for limited resources such as light, nutrients, and space.
    • Can influence species diversity and community structure during succession.
    • Affects the survival and success of different species in an ecosystem.

15. Reaction

    • The interactions among species and their environment that lead to changes in community composition.
    • Includes both facilitative and inhibitory effects on species establishment.
    • Plays a significant role in shaping the trajectory of succession.

16. Stabilization

    • The process by which an ecosystem reaches a stable state after succession.
    • Characterized by a balanced community with established species interactions.
    • Indicates the end of significant changes in species composition and structure.