Submitted By
Submitted To
MASUD RANA
DR. SHAFIUL ALAM
ID1810556190
Associate Professor
Geography & Environmental
Studies
Geography & Environmental
Studies
UNIVERSITY OF RAJSHAHI
UNIVERSITY OF RAJSHAHI
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GEOGRAPHY & ENVIRONMENTAL0
STUDIES
Ecology and Ecosystem:
Ecology and ecosystem describe the relationship between biotic and abiotic
factors in an environmental system. Ecology is the study of ecosystems.
Ecosystem describes the relationship of the mass of living organisms, which
belong to same or different communities. This is the main difference between
ecology and ecosystem. Organisms maintain relationships and interactions
between each other as well as the external environment for the purpose of
obtaining basic life requirements like food, nutrients, water, and residence.
Ecology
All living organism, whether plant or animal or human being is surrounded
by the environment, on which it derive its needs for its survival. Each living
component interacts with non–living components for their basic
requirements from different ecosystem.
Ecology is the study of interactions among organism or group of organisms
with their environment. The environment consists of both biotic components
(living organisms) and abiotic components (non – living organisms).
Ecology is the study of ecosystems.
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Ecosystem
The term Ecosystem was first proposed by A.G. Tansley in 1935. he defined it
as “the system resulting from the interaction of all the living and non-living
factors of the Environment. An ecosystem consists of the biological
community that occurs in some locale, and the physical and chemical factors
that make up its non-living or abiotic environment. There are many examples
of ecosystems - a pond, a forest, an estuary, a grassland.
Ecosystem is the basic functional unit of ecology. The term ecosystem is
coined from a Greek word meaning study of home.
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Types of Ecosystem
1. Natural Ecosystems: These operate under natural conditions without
any major interference by man. Based on habitat types, it can be further
classified into three types.
1. Terrestrial ecosystem
This ecosystem is related to land.
Example: Grassland ecosystem, forest ecosystem, desert ecosystem, etc.
2. Aquatic ecosystem: This ecosystem is related to water. It is further
sub classified into two types based on salt content.
• Fresh water ecosystem
(i) Running/Fresh water ecosystems.
Examples:
(a) Rivers, Streams
(b) Standing water ecosystems
Examples: Pond, lake
(ii) Marine ecosystem
Example: Seas and sea shores
2. Artificial (Man Made) Ecosystems: These are maintained artificially
by man where by addition of energy and planned manipulation, natural
balance is disturbed regularly e.g., crop land ecosystem.
Example: Croplands, gardens
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Structure of an Ecosystem
The term structure refers to the various components. So, the structure of an
ecosystem explains the relationship between the abiotic (non-living) and the
biotic (living) components. Every ecosystem has two components, namely,
biotic components and abiotic components. Biotic components refer to all
living organisms in an ecology while abiotically refers to the non-living things.
These biotic and abiotic interactions maintain the equilibrium in the
environment.
An ecosystem has two major components
→ Biotic (living) Components: The living components of an
ecosystem are called the biotic components. Some of these factors
include plants, animals, as well as fungi and bacteria. These biotic
components can be further classified, based on the energy requirement
source. Producers, consumers, and decomposers are the three broad
categories of biotic components. All the living things that directly or
indirectly affect the ecosystem biotic factors interact with other living
organisms and the physical environment can also be Limiting Factors
ex. disease (bacteria), predators, food resources. Made up of biological
components consisting of living and dead plants, animals and
microorganisms.
Examples
Plants (producers), animals (consumers), and microorganisms
(decomposers).
The members of biotic components of an ecosystem are grouped in to
three based on how they get food.
a. Producer (plants)
b. Consumer (Animals)
c. Decomposers (Micro-organisms)
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Producers are the plants in the ecosystem, which can generate their
own energy requirement through photosynthesis, in the presence
of sunlight and chlorophyll. All other living beings are dependent on
plants for their energy requirement of food as well as oxygen.
– Make their own food from compounds that are obtained from their
environment.
– Are the source of all food in an ecosystem.
– On land most producers are green plants.
– In freshwater and marine ecosystems, algae and plants are the major
producers near shorelines.
– In open water, the dominant producers are phytoplankton (most of
them microscopic) that float or drift in the water.
– Most producers capture sunlight to make carbohydrates (such as
glucose) by photosynthesis.
Consumers include herbivores, carnivores, and omnivores. The
herbivores are the living organisms that feed on plants. Carnivores
eat other living organisms. Omnivores are animals that can eat
both plant and animal tissue.
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Get their energy and nutrients by feeding on other organisms or their
remains. Consumers are further classified as:
i.
ii.
iii.
iv.
v.
Primary consumers: Are those that eat producers (plants) as
a source of food. They are also known as herbivores.
Examples;
Insects, rat, goat, deer, cow, horse, etc.
Secondary consumers or carnivores: Secondary consumers
are primary carnivores, they feed on primary consumers.
They directly depend on the herbivores for their food. Eat other
animals.
Example;
Frog, cat, snakes, foxes, etc.
Tertiary Consumers: Large Carnivores which feed on
secondary consumers. Tertiary consumers are secondary
carnivores, they feed on secondary consumers. They depend on
the primary carnivores for their food.
Examples;
Tigers, lions, etc.
Quaternary Consumers: Largest Carnivores that feed on
tertiary consumers. They are not eaten by any animals.
Quaternary consumers are often top predators within the
environment, and they eat the tertiary consumers.
Examples;
wolves, polar bears, humans, and hawks etc.
Omnivores: Have mixed diet that include both plants and
animals. An omnivore is an animal that has the ability to eat
and survive on both plant and animal matter. Obtaining energy
and nutrients from plant and animal matter, omnivores digest
carbohydrates, protein, fat, and fiber, and metabolize the
nutrients and energy of the sources absorbed.
Examples;
Pigs, Dogs, Bears, Coatis, Hedgehogs, Opossum,
Chimpanzees etc.
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Decomposers are the fungi and bacteria, which are the
saprophytes. They feed on the decaying organic matter and convert
this matter into nitrogen and carbon dioxide. The saprophytes play a
vital role in recycling the nutrients so that the producers i.e. plants
can use them once again.
• Mostly certain types of bacteria and fungi are specialized consumers
that recycle organic matter in ecosystems.
• They do this by breaking down (biodegrading) dead organic material
to get nutrients and releasing the resulting simpler inorganic
compounds into the soil and water, where they can be taken up as
nutrients by producers.
Examples
Microorganisms like bacteria and fungi. Decomposers attack the
dead bodies of producers and consumers and decompose them into
simpler compounds. During the decomposition inorganic nutrients
are released. The inorganic nutrients together with other organic
substances are then utilized by the procedures for the synthesis of
their own food.
→ Abiotic (non-living) Components: The non-living components
(physical and chemical) of ecosystem collectively form a community
called abiotic components (or) abiotic community.
Abiotic components are the physical and/or the chemical factors that act
on the living organisms at any part of their life. These are also called as the
ecological factors. The physical and chemical factors are characteristic of
the environment. Light, air, soil, and nutrients, etc. form the abiotic
components of an ecosystem.
• Consists of Non-living chemical & physical components such as water,
air, nutrients in the soil or water & Solar Energy.
• Physical & chemical factors that influence living organisms in land
(terrestrial) ecosystem & aquatic life zones.
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• Abiotic factors can act as LIMITING FACTORS that keep a population
at a certain level.
1. Physical components
They include the energy, climate, raw materials and living space
that the biological community needs. They are useful for the growth and
maintenance of its member.
Example
Air, water, soil, sunlight, etc.
2. Chemical Components
They are the sources of essential nutrients.
Examples
• Organic substances: Protein, lipids, carbohydrates, etc., (ii) Inorganic
substances:
•
All micro (Al, Co, Zu, Cu) and macro elements (C, H, O, P, N, P, K) and
few other elements.
In other sense Abiotic Components are mainly of two types:
1) Climatic Factors: which include rain, temperature, light, wind, etc.
2) Edaphic Factors: which include soil, pH, Topography, Minerals, etc.
FUNCTION OF AN ECOSYSTEM
To understand clearly the nature of ecosystem its functioning should be
thoroughly understood. The function of an ecosystem is to allow flow of
energy and cycling of nutrients.
The functions of the ecosystem are as follows:
1. It regulates the essential ecological processes, supports life systems
and renders stability.
2. It is also responsible for the cycling of nutrients between biotic and
abiotic components.
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3. It maintains a balance among the various trophic levels in the
ecosystem.
4. It cycles the minerals through the biosphere.
5. The abiotic components help in the synthesis of organic components
that involves the exchange of energy.
Functions of an ecosystem are of three types:
1. Primary function: The primary function of all ecosystem is
manufacture of starch (photosynthesis).
2. Secondary function: The secondary function of all ecosystem is
distribution energy in the form of food to all consumers.
3. Tertiary Function: All living systems diet at a particular stage. These
dead systems are decomposed to initiate third function of ecosystems
namely “cycling”.
The functioning of an ecosystems may be understood studying the
following terms:
o Energy and material flow.
o Food chains
o Food webs
o Food pyramids
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