PPT: Functions of an Ecosystem | Environment for UPSC CSE PDF Download

 Page 1


Functions of An 
Ecosystem
Page 2


Functions of An 
Ecosystem
Energy Flow in Ecosystems
1
Solar Energy
Energy flow begins with producers capturing solar energy through 
photosynthesis, converting it to chemical energy in the form of organic 
compounds.
2
Transfer Through Trophic Levels
Energy flows unidirectionally from producers through various 
consumer levels, with each transfer representing a trophic level in the 
ecosystem.
3
Energy Loss
At each trophic level, significant energy is lost as heat through 
metabolic processes, resulting in decreased available energy at higher 
levels.
Page 3


Functions of An 
Ecosystem
Energy Flow in Ecosystems
1
Solar Energy
Energy flow begins with producers capturing solar energy through 
photosynthesis, converting it to chemical energy in the form of organic 
compounds.
2
Transfer Through Trophic Levels
Energy flows unidirectionally from producers through various 
consumer levels, with each transfer representing a trophic level in the 
ecosystem.
3
Energy Loss
At each trophic level, significant energy is lost as heat through 
metabolic processes, resulting in decreased available energy at higher 
levels.
Food Chains in Ecosystems
Grazing Food Chain
This chain begins with green plants as producers and continues 
through herbivores to various levels of carnivores. In terrestrial 
ecosystems, grass might be eaten by caterpillars, which are 
consumed by lizards, which are then eaten by snakes.
In aquatic systems, phytoplankton are consumed by 
zooplankton, which are eaten by fish, which may be consumed 
by larger predators like pelicans.
Detritus Food Chain
Starting with dead organic matter from decaying plants and 
animals, this chain proceeds through detritivores 
(decomposers) to various predators.
For example, leaf litter might be consumed by earthworms, 
which are eaten by chickens, which may then be consumed by 
hawks. The primary distinction between these chains is the 
energy source for first-level consumers.
Page 4


Functions of An 
Ecosystem
Energy Flow in Ecosystems
1
Solar Energy
Energy flow begins with producers capturing solar energy through 
photosynthesis, converting it to chemical energy in the form of organic 
compounds.
2
Transfer Through Trophic Levels
Energy flows unidirectionally from producers through various 
consumer levels, with each transfer representing a trophic level in the 
ecosystem.
3
Energy Loss
At each trophic level, significant energy is lost as heat through 
metabolic processes, resulting in decreased available energy at higher 
levels.
Food Chains in Ecosystems
Grazing Food Chain
This chain begins with green plants as producers and continues 
through herbivores to various levels of carnivores. In terrestrial 
ecosystems, grass might be eaten by caterpillars, which are 
consumed by lizards, which are then eaten by snakes.
In aquatic systems, phytoplankton are consumed by 
zooplankton, which are eaten by fish, which may be consumed 
by larger predators like pelicans.
Detritus Food Chain
Starting with dead organic matter from decaying plants and 
animals, this chain proceeds through detritivores 
(decomposers) to various predators.
For example, leaf litter might be consumed by earthworms, 
which are eaten by chickens, which may then be consumed by 
hawks. The primary distinction between these chains is the 
energy source for first-level consumers.
Food Webs and Ecological Pyramids
1
2
3
4
Food Webs
Interconnected food chains forming 
complex networks of feeding 
relationships among various organisms 
in an ecosystem.
Pyramid of Numbers
Shows the count of individual 
organisms at each trophic level, may be 
upright (grasslands) or inverted 
(forests).
Pyramid of Biomass
Represents the total dry weight of 
organisms at each level, typically 
upright on land but often inverted in 
aquatic systems.
Pyramid of Energy
Always upright, showing the decrease 
in energy available at successive 
trophic levels due to metabolic losses.
Page 5


Functions of An 
Ecosystem
Energy Flow in Ecosystems
1
Solar Energy
Energy flow begins with producers capturing solar energy through 
photosynthesis, converting it to chemical energy in the form of organic 
compounds.
2
Transfer Through Trophic Levels
Energy flows unidirectionally from producers through various 
consumer levels, with each transfer representing a trophic level in the 
ecosystem.
3
Energy Loss
At each trophic level, significant energy is lost as heat through 
metabolic processes, resulting in decreased available energy at higher 
levels.
Food Chains in Ecosystems
Grazing Food Chain
This chain begins with green plants as producers and continues 
through herbivores to various levels of carnivores. In terrestrial 
ecosystems, grass might be eaten by caterpillars, which are 
consumed by lizards, which are then eaten by snakes.
In aquatic systems, phytoplankton are consumed by 
zooplankton, which are eaten by fish, which may be consumed 
by larger predators like pelicans.
Detritus Food Chain
Starting with dead organic matter from decaying plants and 
animals, this chain proceeds through detritivores 
(decomposers) to various predators.
For example, leaf litter might be consumed by earthworms, 
which are eaten by chickens, which may then be consumed by 
hawks. The primary distinction between these chains is the 
energy source for first-level consumers.
Food Webs and Ecological Pyramids
1
2
3
4
Food Webs
Interconnected food chains forming 
complex networks of feeding 
relationships among various organisms 
in an ecosystem.
Pyramid of Numbers
Shows the count of individual 
organisms at each trophic level, may be 
upright (grasslands) or inverted 
(forests).
Pyramid of Biomass
Represents the total dry weight of 
organisms at each level, typically 
upright on land but often inverted in 
aquatic systems.
Pyramid of Energy
Always upright, showing the decrease 
in energy available at successive 
trophic levels due to metabolic losses.
Pollutants and Trophic Levels
Bioaccumulation
The process by which certain substances, 
particularly toxins and pollutants, 
accumulate in an organism's tissues at 
concentrations higher than in the 
environment. This occurs when an 
organism absorbs a substance at a rate 
faster than it can be metabolized or 
excreted.
Biomagnification
The tendency of pollutants to 
concentrate as they move up trophic 
levels. For biomagnification to occur, the 
pollutant must be long-lived, mobile, 
soluble in fats, and biologically active. 
DDT is a classic example of a compound 
that biomagnifies through food chains.
Ecological Impact
These processes can lead to serious 
ecological consequences, particularly 
affecting top predators with pollutant 
concentrations thousands of times higher 
than environmental levels.