6.5.5 - Succession

• what is succession?

  change in an ecological community over time, from a sparse landscape to a stable community of different plants and animals
• what are the two types of succession?

  primary and secondary
• what is primary succession and give an example

  • primary succession is when an ecological community develops in the absence of soil (e.g - from bare rock).
  • this may happen after a volcanic eruption which results in the formation of a new rock or if the sea level lower and exposes new land
• what is secondary succession and give examples?

  • secondary succession is when an ecological community develops from a barren landscape in which soil is present.
  • may happen after a forest fire
• What are the stages at which succession occurs?

  The stages of succession include the colonization by pioneer species, the formation of humus, and the establishment of a climax community.
• What are pioneer species?

  Pioneer species are the first organisms to colonize an ecosystem, such as moss, lichen, and marram grass.
• Why is there no soil at the beginning of succession?

  There is no soil initially because the ecosystem is newly formed and has not yet developed organic material.
• How are pioneer species adapted to their environment?

  Pioneer species are specially adapted to live in dry, hostile conditions.
• What happens when pioneer species die and decompose?

  When pioneer species die and decompose, they form a basic soil called humus, which improves the environment.
• What is humus?

  Humus is a basic soil formed from the decomposition of pioneer species.
• How does the formation of soil affect the ecosystem?

  The formation of soil allows more plant life to survive as water becomes available.
• What occurs as more plants die and decompose?

  As more plants die and decompose, the soil becomes deeper and thicker, allowing larger plants to survive.
• How does biodiversity change during succession?

  Biodiversity increases as larger plants can survive and more species are introduced into the ecosystem.
• What happens to organisms that are less adapted to the changing ecosystem?

  Organisms that are less adapted will be out-competed and replaced by those that are better adapted.
• What is a climax community?

  A climax community is a stable community of plant and animal life that forms at the end of succession.
• What characterizes a climax community in terms of ecosystem change?

  A climax community is characterized by the ecosystem not changing significantly and supporting the largest and most complex community.