1. Ecological succession
2. Steps of succession
• Competition and Coreaction
3. Example of Succession
The replacement of one
community by another
until a stable stage is
reached is called
Ecosystems tend to
change with time until a
stable system is formed.
occurs where there
was no previous
community, such as
on bare rock or sand.
begins with pioneer
When a community is
again, it is called
Disruption may be
from fire, farming,
STEPS OF SUCCESSION
Competition and co action
This is development of bare area without any
form of species.
nudation may occur due to-
Invasion is the successful establishment of a
species (Pioneer organisms) in a bare area.
Invasion include the following three steps:
Competition and coaction
Due to aggregation of a large no. of the species
at the limited place, there develops competition
for space and nutrition.
Individuals of a species affect each other’s life
in various way this is called Coaction.
Reaction includes mechanism of the modification
of the environment through the influence of living
organisms on it. Due to this very significant stage,
changes take place in soil, water, light conditions,
temperature, etc., of the environment. As a result of
reaction, the environment is modified and become
unsuitable for the existing community which sooner
or later is replaced by another community (seral
The final stage of succession is called the
The final community is not replaced and is
known as climax community and the stage as