This document discusses ecological succession, which describes the process of how communities of plants and animals change over time in a particular area. There are two types of succession: primary and secondary. Primary succession occurs in areas not previously inhabited, like after a volcanic eruption, where lichens and mosses first establish, adding soil. Secondary succession takes place in previously inhabited areas affected by a disturbance like fire, where the soil remains. The final stage is a climax community, a stable ecosystem adapted to the area's conditions, until the next disturbance occurs.

1. Ecological Succession
Presented by:
SHER KHAN
M.Sc. II Semester
Deptt. Of Zoology
Shia P.G. College , Lucknow

2. What is Ecological Succession?
• Natural areas are subject to disturbances of
many kinds.
• Humans and natural disturbances such as
storms and fires, hurricane, earthquake etc.,
• Such disturbances have existed so long that
animals and plants have adapted tothem and
benefit from their occurrence

3. If fundamental requirements are available for
life areas on earth without life are soon filled
with living things.
•The Ecosystem undergo series of patterns of
development called ecological succession.
•There are two types of succession
– Primary succession
– Secondary succession

4. Succession
Example:
New land
created by
volcanic
eruption
Example:
An area
destroyed
by fire
Primary Secondary
Restores previous
ecosystem
Creates new
ecosystem

5. Primary Succession
• The establishment and development of an
ecosystem in an area that was previously
uninhabited
Lichens
and
mosses
Grasses
And
small
shrubs
Large
shrubs and
small trees
Large
trees

6. Primary Succession
• Begins in a place without any soil:
»Sides of volcanoes
»Landslides
»Flooding
• First, lichens that do not need soil to
survive grow on rocks
• Next, mosses grow to hold newly made soil
• Known as PIONEER SPECIES

7. Pioneer Species
Lichens break down
rock to form
soil.
Low, growing moss
plants trap moisture
and prevent soil
erosion

8. • Primary succession can be
seen happening on the
sidewalks.
• If left alone, even NYC
would return to a cement
filled woodland.

9. Primary Succession
• Simple plants like mosses and ferns
can grow in the new soil

10. Primary Succession
• The simple plants die, adding more
organic material (nutrients to the soil)
• The soillayer thickens, and grasses, wild
flowers, and other plants begin to take
over.

11. Primary Succession
• These plants die, and they add more
nutrients to the soil
• Shrubs and treescan survive now

12. 6/5/03 M-DCC / PCB 2340C 20
Primary Succession

13. Secondary Succession
• Beginsin aplace that already has soil and
was oncethe home of living organisms
• Occurs faster and has different pioneer
species than primary succession
• Example: after forest fires

15. Secondary Succession
• The recovery of a damaged ecosystem in an
area where the soil was left intact
Sequoia seedlingFireweed

16. The Climax Community
• A climax community is a mature, stable community
that is the final stage of ecological succession. In an
ecosystem with a climax community, the conditions
continue to be suitable for all the members of the
community.
•Any particular region has its own set of climax species,
which are the plants that are best adapted for the area
and will persist after succession has finished, until
another disturbance clears the area.

17. 6/5/03 M-DCC / PC
B
2340C 48
These are Climax Communities

18. Rain6fa/5ll/ M-DCC / PCB 1203-
49 20-30+
• Two main physical factors determine the nature of the
community that develops in an area.
These are temperature and the amount of rainfall.
• If we place the amount of rainfall on a graph’s “x” axis,
from 0-10, 10-20,and 20-30+ inches and the temperature
along the “y” axis from hot, moderate, to cold, the various
types of ecosystems will fit into the graph based on the
conditions that they require.
0-10
Temperature
Cold Moderate Cold desert
Temperate forest
Tundra
Grassland
Taiga
Deciduous forest
Hot Hot desert Savanna Tropical forest

19. Climax Community
• A stable group of plants and animals that is
the end result of the succession process
• Does not always mean big trees
– Grasses in prairies
– Cacti in deserts

20. Thank You