OpenStax-CNX module: m20131
1
To understand clearly what an
ecosystem is
∗
Siyavula Uploaders
This work is produced by OpenStax-CNX and licensed under the
†
Creative Commons Attribution License 3.0
1 NATURAL SCIENCES
2 Ecosystems and the environmental balance
3
4 EDUCATOR SECTION
5 Memorandum
(a) A forest is a stretch of land that is covered with dense trees, shrubs, ferns, etc. and animals. These
plants and animals live together in the dense bushes.
Assignment 1:
f) tree (producer)
mouse (primary consumer)
owl (secondary consumer)
jackal (tertiary consumer)
6 LEANER SECTION
6.1 Content
1. Introduction
All living things on earth and the way in which they inuence (or are inuenced by) the environment
form an ecosystem.
The word ecosystem is derived from the Greek word "oikos", which means house or household. Just like
members of a family live together, support and inuence each other and the environment (and are in turn
aected and inuenced by it), so organisms live together, reproduce and are dependent on each other for
food. They have a close relationship with the soil, sun, water and air.
∗ Version
1.1: Mar 11, 2009 1:48 am -0500
† http://creativecommons.org/licenses/by/3.0/
http://cnx.org/content/m20131/1.1/
OpenStax-CNX module: m20131
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6.1.1 ACTIVITY: To understand clearly what an ecosystem is [LO 1.3]
Let's study an example of an ecosystem:
(a) What is a forest?____________________________________________________
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A forest is much more than a large area of land covered with trees. Shrubs, vines, ferns, mosses and
toadstools live in the shade of trees. The forest also swarms with birds, mammals, reptiles, amphibians and
insects. A forest is therefore all these plants and animals living together.
The animals depend on plants for food, while plants use sunlight, carbon dioxide, water and minerals to
make food for themselves and other organisms in the forest.
The living organisms (plants and animals) together with the non-living environment (air, water, sun and
soil) constitute an ecosystem.
(b) Tabulate an example of each of the following found in a forest.
Species
bird
mammal
reptile
insect
amphibian
My example of. . .
__________________________
________________________
________________________
________________________
________________________
Table 1
(c) Now sketch these ve examples in the drawing to complete it!
(d) The Ecosystem concept
The organism-environment interaction leads to the ecosystem concept, elaborating the interaction between matter, energy and organism.
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Figure 1
6.1.1.1 An ecosystem
(e) How big is an ecosystem?
An ecosystem can be of any size, from a puddle of water on the pavement to the entire rain forest in the
Amazon or an even larger area.
A forest with its trees, plants, insects, birds, etc., is an ecosystem of certain kinds of organisms that
occupy a certain environment. On the other hand, a rock in the shade of a forest with its mosses and other
rock plants, insect larvae and centipedes, is also an ecosystem. The system is therefore integrated, with parts
that are intimately related to one another. Anything aecting a part of the system will also aect the rest.
Assignment 1:
(f) Study the sketch of the forest ecosystem below:
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Figure 2
Name the:
producer: _____________________________________________________________
primary consumer: _____________________________________________________
secondary consumer: ___________________________________________________
tertiary consumer: ______________________________________________________
Primary means rst.
Secondary means second or less important.
Tertiary means the third in this case.
2. The ecosystem
is the living organisms together with the ____________________________________
indivisibly linked and mutually interactive.
The living part can be divided into:
(a) food producers - mainly green plants
(b) food consumers - which are macro consumers (animals which eat other organisms)
or
decomposers (bacteria or fungi which break up dead organisms)
7 Assessment
Learning Outcome 1: The learner will be able to act condently on curiosity about natural phenomena,
and to investigate relationships and solve problems in scientic, technological and environmental contexts.
Assessment Standard 1.3: We know this when the learner evaluates data and gives feedback on
ndings.
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