This 3-credit course on fundamentals of ecology covers key topics including definitions of ecology, historical background, classifications of ecology based on nature of study and type of environment, levels of ecological organization, feeding interactions like energy flow and trophic levels, and ecological interactions between organisms such as competition, niche, predation, and symbiosis. The course is taught in the 4th semester of the BS in Environmental Science program at NFC Institute of Engineering & Technology in Multan, Pakistan.

1. Course 19
Fundamentals of Ecology
Credit hour: 3(3-0)
BS Environmental Science
Semester : 4
Arbaz Madni
Lecture 1-2
NFC Institute of Engineering & Technology, Multan

2. Course Outlines:
 Introduction (Definition , Historical background)
 Classification of Ecology (Branches, Comparison)
 Level of Organization
 Feeding Interactions (Energy Flow, Food Chain,
Food Web, Trophic Level)
 Ecological Interactions between organism
(Competition, Niche, Predation, Symbiosis)

3. Background:
The word ‘ecology’ has a greek origin. ‘Oikos’ means home,
‘logos’ means to study. Thus ecology is concerned with
organisms in their environment
Ernst Haeckel coined the term ‘ecology’ in 1869. The term
‘environment’ refers to the surrounding of the organism
Ecology—the scientific study of interactions between different
organisms and between organisms and their environment or
surroundings
In a simple term ecology may be defined as that science which
studies, interrelationships between abiotic and biotic
components of the biospheric ecosystem on one hand, and
among biotic components on the other hand

4. Biotic—living factors that influence an ecosystem
Abiotic—non-living factors that influence an ecosystem

5. Ecology is a basic division of biology and forms an integral part
of all the taxonomic divisions.
Ecological studies are based on three basic principles: Habitat,
Taxonomic group and levels of organizations.
Depending upon the consideration of ecological unit as either
individual or group of organisms, the levels of organization is
divided into auto ecology and synecology.

6. Classification of Ecology:
1. On the basis of nature of study ecology can be subdivided as:
a. Autecology: Autecology deals with the study of the individual
organism or an individual species and its population. Here, the
focus on life-histories and behavior, as means of adaptation to the
environment, is made. Autecology is also called “species ecology.”
For Example: the influence of the change in temperature of the
surrounding can highly influence the life cycle and developmental
stages of individual. In brief, lizards, crocodiles and several other
reptiles can hatch their eggs and sex of the baby is determined by the
temperature at the time of hatching.
b. Synecology: Synecology deals with the study of groups of organisms
which are associated together as a unit. In other words it is study of
communities, their composition, their behaviour and relation to the
environment.
Synecology is also called “Ecology of communities.”

7. An example of synecology is side effects of acid rain to a pond
ecosystem. As the acid rain falls in a pond, rich in flora and
fauna (mainly with fish diversity), it directly and indirectly
affects the health of population or community or total biome or
pond ecosystem.

9. Synecology is further sub divided into:
(i) Population ecology: It relates the organism with various groups of
organisms and their inter-relationship.
(ii) Gene ecology: It deals with the genetic make-up of species in
relation to the environment.
(iii)Taxonomic ecology: It includes ecology of taxonomic groups as
microbial ecology. Vertebrate or invertebrate ecology.
For e.g., if a study is carried out of the relation of a Neem tree with
the environment, then the approach is said to be autecological in
nature. But if the study is carried out of the forest (of which Neem tree
is a part), then the approach is said to be synecological in nature.

10. 2. On the basis of the kind of environment or habitat, ecology has been
sub divided into the following branches:
3. With advancing trends in the fields of ecology present day ecologists
decide ecology into the following branches:

11. Population Ecology
Study of how populations grow
Conservation Ecology
Study of how to preserve
And create a healthy,
Lasting biosphere
Community Ecology
Study of how populations interact
with each other
Ecosystem Ecology
Study of how populations
interact with their
physical environment

12. Population
Communit
y
Biome
Biosphere
Ecosystem
Organism A single living thing
A group of organisms of the same species that
live together.
A group of Populations that live together
Communities and their physical environments
A group of ecosystems that have the same climate.
All the biomes on Earth. Thus, all the living areas
of the planet.
Ecological Organization

13. Feeding Interactions
A. Energy flows through an ecosystem in one
direction—from the sun or inorganic compounds
to autotrophs (producers) and then to
heterotrophs (consumers)
One of the ways in which energy flows through an
Ecosystem is by feeding. Different living organisms eat
each other, and the food is energy moving from one
organism to the next.

14. Energy Flow
Ecosystem
Level of ecological study that includes all
organisms in a given area along with the
factors with which they interact.
A community and its physical environment.
Most ecosystems
are driven
by energy
from
sunlight
Energy flow and chemical cycling are two interrelated processes that occur
by transfer of substances through the feeding levels of ecosystems.

15. Producers
Sunlight is the main energy source for life
on earth
Also called autotrophs
Use light or chemical energy to make food
1. Plants
2. plant-like protists (algae)
3. Bacteria

16. Photosynthesis—use light energy to convert carbon
dioxide and water into oxygen and
carbohydrates
(Remember: 6CO2 + 6H2O 6O2 + C6H12O6)
Chemosynthesis—performed by bacteria, use
chemical energy to produce carbohydrates
Light
Energy

17. Consumers
Organisms that rely on other organisms
for their energy and food supply
Also called heterotrophs

18. Herbivores—obtain energy
by
eating only plants
Carnivores—eat only
animals

19. Omnivores—eat both plants and
animals
Decomposers—breaks down dead organic
matter

20. B. Food Chain—series of steps in which organisms
transfer energy by eating and being eaten
1. Arrows go in the direction of how energy is
transferred
2. Start with producer and end with top consumer
or carnivore
grass cricket frog raccoon

21. C. Food Web—network of food chains within an
ecosystem
Which of the organisms above is the producer?
Which of the organisms above is the top consumer?
Hawks
Weasels Raccoons
Mice
Grass

22. D. Trophic Levels—each step in a food chain or food
web
1. Level 1—Producers (autotrophs)
2. Level 2—Primary Consumers (herbivores)
3. Level 3—Secondary Consumers
(carnivores or omnivores)
4. Level 4—Tertiary Consumers
(carnivore—usually top carnivore)

23. Hawks
Weasels Raccoons
Mice
Grass
Food Webs

24. Ecological Interactions between organisms
A. Competition—when two organisms of the same
or different species attempt to use an ecological
resource in the same place at the same time.
Ex: food, water, shelter

25. Monkeys compete
with each other and
other animals for
food.
Rams compete with
each other for
mates.

26. Until Americans introduced gray squirrels into parts of England in the
early 20th century, red squirrels had been the only species of squirrel in
the country. The gray squirrels were larger and bred faster and
successfully competed for resources. Within a couple years of overlap in
an area, the red squirrels disappeared.

27. B. Niche—the ecological niche involves both the
place where an organism lives and
the roles that an organism has in its habitat.
Example: The ecological niche of a sunflower growing in
the backyard includes absorbing light, water and
nutrients (for photosynthesis), providing shelter
and food for other organisms (e.g. bees, ants,
etc.), and giving off oxygen into the atmosphere.

28. The ecological niche of an organism depends not
only on where it lives but also on what it does. By
analogy, it may be said that the habitat is the
organism’s “address”, and the niche is its
“profession”, biologically speaking.
Worm’s
Niche
“Address”—Soil, Ground,
etc.
“Profession”– Mix-up
soil

29. C. Predation—one organism captures and feeds on
another organism
1. Predator—one that does the killing
2. Prey—one that is the food

31. D. Symbiosis—any relationship in which two
species live closely together
1. Mutualism—both species benefit (WIN-
WIN)
a. Ex: insects and flowers
Can you think of any other examples that we’ve talked about
in class?

32. 2. Commensalism—one member of the
association benefits and the
other is neither helped nor
harmed.
(WIN-0)
Example: barnacles on a
whale

33. Commensalism
The Remora fish attaches
to the shark and gets a
free ride.
Birds build nests in trees.

34. 3. Parasitism—one organisms lives on or
inside another organism (host) and harms
it.
The parasite obtains all or part of its
nutritional needs from the host. (WIN-
LOSE)
Example: fleas on a dog

35. Parasitism
Wasp eggs on back
of caterpillar.
Mosquito biting a
human.
Sea lampreys feed
on fluids of other
fish.