Concept of Ecosystem
Intended
Learning Outcomes
At the end of this Lecture,
students will be able to
• Explain concept of an ecosystem
• Understand ecosystems
• Discuss ecosystem degradation
• Describe resource utilisation
Content
• Concept of an ecosystem
• Understanding ecosystems
• Ecosystem degradation
• Resource utilisation
Concept of
Ecosystem
• An ‘Ecosystem’ is a region with a specific and
recognizable landscape form such as forest, grassland, desert, wetland or
coastal area
• Nature of the ecosystem is based on its geographical
features such as hills, mountains, plains, rivers, lakes, coastal areas or
islands
• It is also controlled by climatic conditions such as the
amount of sunlight, the temperature and the rainfall in the region
• The geographical, climatic and soil characteristics form its
non-living (abiotic) component
• The living part of the ecosystem is referred to as its
biotic component
• Ecosystems are divided into terrestrial or landbased ecosystems
and aquatic ecosystems in water
• Ecosystems have been formed on land and in the sea by
evolution that has created species to live together in a specific region
• Thus ecosystems have both non-living and living components
• Some ecosystems are fairly robust and are less affected by
a certain level of human disturbance. Others are highly fragile and are quickly
destroyed by human activities
• Mountain ecosystems are extremely fragile as degradation
of forest cover leads to severe erosion of soil and changes in river courses
• Island ecosystems are easily affected by any form of human
activity which can lead to the rapid extinction of several of their unique
species of plants and animals
• Evergreen forests and coral reefs are also examples of
species rich fragile ecosystems which must be protected against a variety of
human activities that lead to their degradation
• River and wetland ecosystems can be seriously affected by
pollution and changes in surrounding land use
Understanding
ecosystems
• Natural ecosystems include the forests, grasslands,
deserts and aquatic ecosystems such as ponds, rivers, lakes, and sea
• Man modified ecosystems include agricultural land and
urban or industrial land use patterns
• Each ecosystem has a set of common features that can be
observed in the field:
• ‘What does the ecosystem look like?’ One should be able to
describe specific features of the different ecosystems in one’s own
surroundings
• What is its structure?
Is it a forest, a grassland, a water body, an agricultural area, a
grazing area, an urban area, an industrial area, etc.?
• What you should see are its different characteristics. A
forest has layers from the ground to the canopy. A pond has different types of
vegetation from the periphery to its center. The vegetation on a mountain changes
from its base to its summit
• What is the composition of its plant and animal species?
List the well- known plants and animals you can see. In fact there are so many
that they cannot be easily counted
• ‘How does the ecosystem work’? The ecosystem functions
through several biogeochemical cycles and energy transfer mechanisms
Ecosystem degradation
• Ecosystems are the basis of life itself
• Natural ecosystems in the wilderness provide a variety of
products and are regions in which a number of vital ecological processes are
present, without which human civilization would not be able to exist
• Ecosystems are however frequently disrupted by human
actions which lead to the extinction of species of plants and animals that can
live only in the different natural ecosystems
• Some species if eliminated seriously affect the ecosystem.
These are called ‘keystone’ species
• Extinction occurs due to changes in land use. Forests are
deforested for timber, wetlands are drained to create more agricultural land
and semi-arid grasslands that are used as pastures are changed into irrigated
fields
• Pollution from industry and waste from urban settings can
also lead to extinction of several species
• The reason for the depletion of natural resources is
twofold – our rapidly exploding population that needs to sustain itself on
resources and the growth of affluent societies, which consume and waste a very
large proportion of resources and energy
• If one thinks before wasting resources such as water,
reusing and recycling paper, using less plastics that are non-degradable,
ultimately this can have positive implications on the integrity of our natural
resource base and conserve the resources that nature provides
• Every region of our earth has different ecosystems based
on its climatic conditions and geographical feature
Resource utilisation
• Most traditional societies used their environment
sustainably
• In recent times the proportion of ‘rich’ people in affluent
societies, grew rapidly
• Inequality thus became a serious problem
• Whereas in the past many resources such as timber and fuel
wood from the forest were extracted sustainably, this pattern has drastically
changed during the last century
• Economically better off sections began to use greater
amounts of forest products, while those people who lived in the forest became
increasingly poor
• Similarly the building of large irrigation projects led to
wealth in those areas that had canals, while those who hand to remain dependent
on a constant supply of water from the river itself, found it difficult to
survive.
• The key to this issue is the need for an ‘equitable’
distribution of all types of natural resources
• A more even sharing of resources within the community can
reduce these pressures on the natural ecosystems
Summary
• An ‘Ecosystem’ is a region with a specific and
recognizable landscape form such as forest, grassland, desert, wetland or
coastal area
• Natural ecosystems include the forests, grasslands, deserts
and aquatic ecosystems such as ponds, rivers, lakes, and sea
• Natural ecosystems in the wilderness provide a variety of
products and are regions in which a number of vital ecological processes are
present, without which human civilization would not be able to exist
• Most traditional societies used their environment
sustainably