Concept of Ecosystem

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