LESSON I.
ECOLOGY:
SCOPE AND MEANING
Ecology is the study of the relationships between the
living organisms and their environment.
No living organism exists in isolation.
Organisms
interact with one another and with the chemical and
physical components of the nonliving environment (Sutton
and Harmon, 1973).
Human ecology is the study of ecosystems as they
affect human beings and vice versa. Human ecology draws
together knowledge and experience from many branches of
learning and considers chemical, economic, political,
social and ethical questions as well as strictly biological
ones (Sutton & Harmon, 1973).
As people’s interactions with the environment become
more drastic, more people have become concerned with human
ecology.
The term “ecology” was first coined by the German
biologist Ernst Haeckel from “oikos” meaning a “house” or
“living place” and “logos” to mean the “study” or “science
of”
(Odum, 1971 and Green et. al. 1984).
Literally,
ecology means the study of the earth’s house.
The study of ecology is of two types. These are
autecology and synecology. Autecology deals with the
relationships between an organism or population and the
environment whereas synecology focuses on the relationships
between communities and their environment. For example,
the study of the ecology of one species of mango (Mangifera
indica) tree is autecology while studying the whole mango
community and its relationships with the environment is
synecology.
Ecology is related with other branches of biology.
This shows that living organisms can be studied at
different levels of organization, each level representing a
type of biological system. In Figure 1, notice that each
level
of
organization
involves
a
biotic
component
interacting with an abiotic component through the exchange
of matter and energy.
Biotic components
interacting
with
Abiotic components
Biological
Systems
Figure 1.
Genetics
Cytology
Cell Biology
Histology
Anatomy
------------------- Ecological ---------------
Concern
Molecular
Biochemistry and Physiology
Biology
genes
 cells

tissues 
organs 
organisms  populations  communities







-----------------------------------------------------------------------------------------------------------------------------------------------------------------matter  energy
----------------------------------------------------------------------------------------------------------------------------------------------------------------
genetic
systems

cell
systems

tissue
systems

organ
systems

organismic
systems
population
systems
ecosystem
Levels of organization spectrum and relationship of ecology to other
branches of biology (Odum, 1971 and Green et.al. 1984)
3
Please look at the diagram. Don’t you notice that
ecology is concerned only with the right side of the
organizational spectrum.
Before we proceed, let us define the following
important terms which you will always read in the modules
that follow. Please try to understand the definitions and
their illustrations. Perhaps you can give better and more
examples. Here they are:

Population is a group of organisms belonging to one kind
of species living in a specific area or habitat. (Sutton
and Harmon, 1973). A typical example is the population of
tilapia living in a pond.

Community is a group of organisms belonging to different
species that exist and interact in a specific area.
(Sutton and Harmon, 1973). For example, the CLSU
community includes all the people, plants, animals and
microorganisms thriving in CLSU.

Ecosystem is a community of organisms and their nonliving
environment interacting as a whole unit (Sutton and
Harmon, 1973). It is simply the interaction of the living
organisms and its non-living organisms. We consider the
CLSU community and its interaction with the soil,
atmosphere, water, sunlight, climate and temperature as
an example of an ecosystem.
However, when we consider all living organisms
around the earth, we are referring to BIOSPHERE.
on
or
Now, are you ready to do Activity 1? This is just to
check what you have picked up from your reading.
4
Activity 1.
Kindly answer the following questions without necessarily
copying the reading text.
1.
What is ecology? _____________________________________
_______________________________________________________
_______________________________________________________
2.
What is human ecology? _______________________________
_______________________________________________________
_______________________________________________________
3.
Differentiate the two types of ecology.
_______________________________________________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
4.
What are the levels of organization that ecologist are
mostly interested to study?
_______________________________________________________
_______________________________________________________
_______________________________________________________
5.
Please fill up the chart below as the first column
requires:
Population
a. organisms
involved
b. Relationship
with non-living
environment
(present or absent)
c. Give an
example
Community
Ecosystem