CHAPTER-2
ECOSYSTEMS AND BIODIVERSITY
Concepts of an Ecosystem – Structure and Function of an Ecosystem – Producers,
Consumers and Decomposers – Energy Flow in the Ecosystem – Ecological
Succession – Food Chains, Food Webs and Ecological Pyramids – Introduction,
Types, Characteristic Features, Structure and Function of the (A) Forest Ecosystem
(B) Grassland Ecosystem (C) Desert Ecosystem (D) Aquatic Ecosystems (Ponds,
Streams, Lakes, Rivers, Oceans, Estuaries)
BIODIVERSITY Introduction to Biodiversity – Definition: Genetic, Species and
Ecosystem Diversity – Biogeographical Classification of India – Value of
Biodiversity: Consumptive Use, Productive Use, Social, Ethical, Aesthetic and Option
Values – Biodiversity at Global, National and Local Levels – India as a Mega-
Diversity Nation – Hot-Spots of Biodiversity – Threats to Biodiversity: Habitat Loss,
Poaching of Wildlife, Man-Wildlife Conflicts – endangered and Endemic Species of
India – Conservation of Biodiversity: In-Situ and Ex-Situ conservation of
Biodiversity. Field Study of Common Plants, Insects and Birds.
2.1 ECOSYSTEMS
2.1.1INTRODUCTION:
ECOLOGY:
The term was first coined by Hons Reiter and Haekel in 1869.
The term ecology (Okekologie) is originated from two Greek words Oikos (eco) –
means “house” (or) place of living and “ology” means “the science of (or) the study of.
Hence, ecology is the branch of science that deals with the study of the pattern of
relations between the organism and their environment.
(OR)
Ecology is the study of interactions among organisms (or) group of organisms with
their environment.
(OR)
Ecology is the study of ecosystems.
ECO SYSTEM:
In 1935, the British ecologist A.G.Tansley coined the term “eco system”.
Environmental Science 33 AITT & H&S
, The term “eco system” is made up of two Greek words. “Eco” means ecological
sphere (or) house (or) place of living (or) surroundings (or) Environment, w here living
organism does exist while “system” means “group of organisms joined in regular and
interdependent manner. Hence,
A group of organisms interacting among themselves and with environment is known as
ecosystem.
(OR)
A system of interaction of organisms with their surroundings (i.e., environment) is
called as “ecosystem”.
Examples: Pond, lake, ocean, forest and desert…. Etc are some of the examples of the
ecosystems.
2.1.2 FUNDAMENTAL CHARACTERISTICS OF ECOLOGY
STRUCTURE:
Living /Biotic
Non-Living /Abiotitic
PROCESS:
Energy flow
Cycling of matter
CHANGE:
Dynamic (Not static)
Succession etc.
FUNCTION:
Food chain
Food web
Ecological pyramids
Energy Flow
Cycling of matter
2.1.3 CHARACTERISTICS OF ECOSYSTEM
Eco system is the basic functional unit of ecology.
It contains both biotic and abiotic components.
Environmental Science 34 AITT & H&S
, The function of ecosystem is related to the cycling of matter (materials) and flow of
energy.
The amount of energy needed to maintain an ecosystem depends on its structure.
Ecosystem passes from a less complex state to more complex state, which is called as
“ecological succession”.
2.1.4 CLASSIFICATION OF ECOSYSTEM:
The ecosystem can be generally classified into two types:
1. Natural Ecosystem
2. Artificial Eco system
1. NATURAL ECOSYSTEM:
A natural ecosystem is developed and governed by nature.
These are capable of operating and maintaining themselves without any major
interference by man.
The following are the two types of natural ecosystem based on their habitat.
1. Terrestrial Ecosystem.
2. Aquatic Ecosystem.
1) Terrestrial Ecosystem:
This ecosystem is related to land.
Examples: Grassland ecosystem.
Forest ecosystem, and
Desert ecosystem etc.
2) Aquatic Ecosystem:
This ecosystem is related to water, it is further sub divided into two types
based on salt content.
i. Fresh Water Ecosystem:
a. Running Water Ecosystems
Examples: Rivers, streams (small narrow rivers)
b. Standing Water Ecosystems
Examples: Pond, lake & well, etc
ii. Marine Ecosystem:
Examples: seas and sea shores <land along the edges of sea>
Environmental Science 35 AITT & H&S
, 2. MAN MADE (OR) ARTIFICIAL ECOSYSTEM:
An artificial ecosystem is created and maintained by man for his different needs.
Examples: Reservoirs, Artificial lakes and gardens, etc.
2.1.5 STRUCTURE (OR) COMPONENTS OF AN ECOSYSTEM:
The term structure refers to various components. So, the structure of an
ecosystem explains the relationship between the abiotic (non-living) and the
biotic (living) components.
Each and every ecosystem has two major components are:
1. Biotic (living) components.
2. Abiotic (Non-living) components.
Biotic
Components
Eco System
Abiotic
Components
Fig: Components Of Ecosystem
1. Biotic Components: The living component of an ecosystem is called “Biotic
component”.
Examples: Plants (Producers)
Environmental Science 36 AITT & H&S
ECOSYSTEMS AND BIODIVERSITY
Concepts of an Ecosystem – Structure and Function of an Ecosystem – Producers,
Consumers and Decomposers – Energy Flow in the Ecosystem – Ecological
Succession – Food Chains, Food Webs and Ecological Pyramids – Introduction,
Types, Characteristic Features, Structure and Function of the (A) Forest Ecosystem
(B) Grassland Ecosystem (C) Desert Ecosystem (D) Aquatic Ecosystems (Ponds,
Streams, Lakes, Rivers, Oceans, Estuaries)
BIODIVERSITY Introduction to Biodiversity – Definition: Genetic, Species and
Ecosystem Diversity – Biogeographical Classification of India – Value of
Biodiversity: Consumptive Use, Productive Use, Social, Ethical, Aesthetic and Option
Values – Biodiversity at Global, National and Local Levels – India as a Mega-
Diversity Nation – Hot-Spots of Biodiversity – Threats to Biodiversity: Habitat Loss,
Poaching of Wildlife, Man-Wildlife Conflicts – endangered and Endemic Species of
India – Conservation of Biodiversity: In-Situ and Ex-Situ conservation of
Biodiversity. Field Study of Common Plants, Insects and Birds.
2.1 ECOSYSTEMS
2.1.1INTRODUCTION:
ECOLOGY:
The term was first coined by Hons Reiter and Haekel in 1869.
The term ecology (Okekologie) is originated from two Greek words Oikos (eco) –
means “house” (or) place of living and “ology” means “the science of (or) the study of.
Hence, ecology is the branch of science that deals with the study of the pattern of
relations between the organism and their environment.
(OR)
Ecology is the study of interactions among organisms (or) group of organisms with
their environment.
(OR)
Ecology is the study of ecosystems.
ECO SYSTEM:
In 1935, the British ecologist A.G.Tansley coined the term “eco system”.
Environmental Science 33 AITT & H&S
, The term “eco system” is made up of two Greek words. “Eco” means ecological
sphere (or) house (or) place of living (or) surroundings (or) Environment, w here living
organism does exist while “system” means “group of organisms joined in regular and
interdependent manner. Hence,
A group of organisms interacting among themselves and with environment is known as
ecosystem.
(OR)
A system of interaction of organisms with their surroundings (i.e., environment) is
called as “ecosystem”.
Examples: Pond, lake, ocean, forest and desert…. Etc are some of the examples of the
ecosystems.
2.1.2 FUNDAMENTAL CHARACTERISTICS OF ECOLOGY
STRUCTURE:
Living /Biotic
Non-Living /Abiotitic
PROCESS:
Energy flow
Cycling of matter
CHANGE:
Dynamic (Not static)
Succession etc.
FUNCTION:
Food chain
Food web
Ecological pyramids
Energy Flow
Cycling of matter
2.1.3 CHARACTERISTICS OF ECOSYSTEM
Eco system is the basic functional unit of ecology.
It contains both biotic and abiotic components.
Environmental Science 34 AITT & H&S
, The function of ecosystem is related to the cycling of matter (materials) and flow of
energy.
The amount of energy needed to maintain an ecosystem depends on its structure.
Ecosystem passes from a less complex state to more complex state, which is called as
“ecological succession”.
2.1.4 CLASSIFICATION OF ECOSYSTEM:
The ecosystem can be generally classified into two types:
1. Natural Ecosystem
2. Artificial Eco system
1. NATURAL ECOSYSTEM:
A natural ecosystem is developed and governed by nature.
These are capable of operating and maintaining themselves without any major
interference by man.
The following are the two types of natural ecosystem based on their habitat.
1. Terrestrial Ecosystem.
2. Aquatic Ecosystem.
1) Terrestrial Ecosystem:
This ecosystem is related to land.
Examples: Grassland ecosystem.
Forest ecosystem, and
Desert ecosystem etc.
2) Aquatic Ecosystem:
This ecosystem is related to water, it is further sub divided into two types
based on salt content.
i. Fresh Water Ecosystem:
a. Running Water Ecosystems
Examples: Rivers, streams (small narrow rivers)
b. Standing Water Ecosystems
Examples: Pond, lake & well, etc
ii. Marine Ecosystem:
Examples: seas and sea shores <land along the edges of sea>
Environmental Science 35 AITT & H&S
, 2. MAN MADE (OR) ARTIFICIAL ECOSYSTEM:
An artificial ecosystem is created and maintained by man for his different needs.
Examples: Reservoirs, Artificial lakes and gardens, etc.
2.1.5 STRUCTURE (OR) COMPONENTS OF AN ECOSYSTEM:
The term structure refers to various components. So, the structure of an
ecosystem explains the relationship between the abiotic (non-living) and the
biotic (living) components.
Each and every ecosystem has two major components are:
1. Biotic (living) components.
2. Abiotic (Non-living) components.
Biotic
Components
Eco System
Abiotic
Components
Fig: Components Of Ecosystem
1. Biotic Components: The living component of an ecosystem is called “Biotic
component”.
Examples: Plants (Producers)
Environmental Science 36 AITT & H&S
