Ecological succession is a term developed by Botanists to describe the change in structure of a community of different species, or ecosystem.Here we also discuss Energy flow/the transfer of energy from one organism to another in an ecosystem.

1. Ecological succession
And
Enery flow in Ecosystem
Prasanna R Kovath
Assistant Professor
Department of Biotechnology
St.Mary’s College Thrissur

2. * Ecological succession is a term developed by botanists
to describe the change in structure of a community of
different species, or ecosystem
* Species do change spatially within an area at a certain
point in time, this is zonation not succession
* The different types of ecological succession exists during different
phases of an ecosystem, and depend on how developed that
ecosystem is
* Ecosystems advance until they reach a climax community.
In the climax community
* All of the resources are efficiently used and the total mass of
vegetation maxes out
Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege

3. There are four main types of Ecological
Succession:
Pioneer
Establishing
Sustaining
Producing
Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege

4. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
TYPES OF ECOLOGICAL SUCCESSION
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, mossesgrow to hold newly made soil Known as PIONEER
SPECIES
* Soil starts to form as lichensand the forces of weather and erosion
help break down rocks into smaller pieces
When lichens die, they decompose, adding small amounts of organic
matter to the rock to make soil

5. Simple plants like mosses and ferns can grow in the new soil
The simple plants die, adding more organic material (nutrients to the
soil)
The soil layer thickens, and grasses, wildflowers, and other plants begin
to take over
These plants die, and they add more nutrients to the soil
Shrubsand trees can survive now
Insects, small birds, and mammals have begun to move into the area
What was once bare rock, now supports a variety of life
Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege

6. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
SECONDARY SUCCESSION
Begins in a place that already has soil and was once the home of living
organisms
Occurs faster and has different pioneer species than primary succession
Example: After forest fires

7. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
CYCLIC SUCCESSION
Cyclic ecological succession happens within established communities
And is merely a changing of the structure of the ecosystem on a cyclical
basis.
Some plants thrive at certain times of the year, and lay dormant the rest
Examples of Ecological Succession
* Acadia National Park
* Coral Reef Ecological Succession

8. ENERGY FLOW IN ECOSYSTEM
Energy flow is the transfer of energy from one organism to another in an
ecosystem
.
Every organism interacts with its ecosystem in two ways:
1. The organism obtains food energy from the ecosystem
2. The organism contributes energy to the ecosystem
Ecologists use three models to illustrate energy flow and feeding
relationships in an ecosystem:
*Food chains * Food webs * Food pyramids
Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege

9. FOOD CHAINS
*Show the flow of energy from plant to animal and from animal to
animal.
* Each step in a food chain is called a trophic level.
Trophic Level Type of Organism Energy Source Example
1st Primary producer The Sun grass, algae
(plants)
2nd Primary consumer Primary
producers
grasshoppers,
krill (herbivores
3rd Secondary
consumer
Primary
consumers
frogs, crabs
(carnivores
4th Tertiary consumer Secondary
consumers
hawks, sea otters
(top carnivores
Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege

10. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
FOOD WEBS
A food web (or food cycle) is the natural interconnection of food
chains and a graphical representation (usually an image) of what-
eats-what in an ecological community.

11. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
FOOD PYRAMIDS/ECOLOGICAL PYRAMIDS
* A food pyramid is a model that shows the loss of energy from
one trophic level to another.
* When one organism consumes another, the energy stored in the
food organism is transferred to the consumer.
There are different types of ecological pyramids.
1. Pyramid of numbers,
2. Pyramid of biomass (biomass is the weight of living
organisms), and
3. Pyramid of energy.

12. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
* It depicts the numbers of individuals in producers and in
different orders of consumers in an ecosystem.
* The base of pyramid is represented by producers which
are the most abundant.
* In the successive levels of consumers, the number of
organisms goes on decreasing rapidly until there are a few
carnivores.
* Example : Lake Ecosystem
PYRAMID OF NUMBERS

13. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
PYRAMID OF BIOMASS OF ORGANISMS:
* The living weights or biomass of the members of the food chain
present at any one time form the pyramid of biomass of organisms
* The total biomass of secondary consumers will be lesser than that
of herbivores and so on

14. PYRAMID OF ENERGY
* This depicts not only the amount of total energy utilized
by the organisms at each trophic level of food chain but
more important, the actual role of various organisms in
transfer of energy
**At the producer level the total energy will be much greater than
the energy at the successive higher trophic level.
Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege

15. Ecological succession And Enery flow in Ecosystem,Prasanna R Kovath,St.Mary’sCollege
https://www.khanacademy.org/science
https://en.wikipedia.org/wiki/Ecological_succession
https://www.conserve-energy-future.com
http://www.jcdavdasuya.com
https://www.slideshare.net/tangytangling/ecological-pyramids
https://www.tutorialspoint.com/environmental_studies