1. Ecology Unit

2. What is ecology?
Ecology- the scientific study of
interactions between organisms
and their environments,
focusing on energy transfer
• It is a science of relationships

3. What do you mean by environment?
The environment is made up of two
factors:
Biotic factors- all living organisms
inhabiting the Earth
Abiotic factors- nonliving parts of
the environment (i.e. temperature,
soil, light, moisture, air currents)

4. Biosphere
Ecosystem
Community
Population
Organism

5. Organism- any unicellular or
multicellular form exhibiting all of the
characteristics of life, an individual.
•The lowest level of organization

6. Population-a group of organisms of
one species living in the same place
at the same time that interbreed
and compete with each other for
resources (ex. food, mates, shelter)

7. Community- several interacting
populations that inhabit a common
environment and are interdependent
on one another

8. Ecosystem- populations in a
community and the abiotic factors
with which they interact (ex.
marine, terrestrial)

9. Biosphere- life supporting portions
of Earth composed of
air, land, fresh water, and salt
water
•The highest level of organization

10. “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.”
Odum - Fundamentals of Ecology

11. Habitat vs. Niche
Niche - the role a species plays in
a community, i.e.
decomposer, predator, prey, scave
nger, parasite
Habitat- the place in which an
organism lives out its life

12. Niche
An organism‟s niche is
determined by it‟s ability to get
resources from the environment,
avoid limiting factors, and avoid
competition with similar and
neighboring species
Limiting factor- any biotic or
abiotic factor that restricts the
existence of organisms in a
specific environment

13. Limiting Factors
Examples of limiting factors-
•Availability of water
•Availability of food
•Temperature
•Amount of living space
•Competition
•Predation

14. Feeding Relationships
• There are 3 main types of
feeding relationships
1. Producer- Consumer
2. Predator- Prey
3. Parasite- Host

15. Feeding Relationships
Producer- all
autotrophs (plants)
that trap energy
from the sun through
the process of
photosynthesis
• Base of most food
chains

16. Feeding Relationships
Consumer- all heterotrophs that
“eat” other organisms as food for
energy
 Herbivores
 Carnivores
 Omnivores
 Decomposers

17. Feeding Relationships
CONSUMER
Herbivores
– Eat plants
• Primary
consumers
• Tend to be
prey animals

18. Feeding Relationships
CONSUMER
Carnivores - eat
meat
• Secondary, Tertiar
y and Quaternary
consumers
• Predators – hunt
prey animals for
food

19. Feeding Relationships
CONSUMER
Scavengers -feed
on carrion and
other dead
animals
• Feed from many
different levels of the
ecosystem depending on
what animal has died

20. Feeding Relationships
Consumer- Omnivores -eat both plants
and animals

21. Feeding Relationships
CONSUMER
Decomposers
• Breakdown the
complex compounds
of dead and
decaying plants and
animals into simpler
molecules that can
be recycled into the
soil and reabsorbed
by the roots of
plants

22. Trophic Levels
• Each link in a food chain is known as a
trophic level
• When an organism eats food, it is
consuming both energy and matter
(biomass)
• Trophic levels represent a feeding
step in the transfer of energy and
matter in an ecosystem

23. Total Biomass
Biomass- the amount of organic (living)
matter comprising a group of
organisms in a habitat, i.e. literally,
the total weight of all individuals of a
particular type of organism
• As you move up a food chain, both
available energy and biomass decrease
• Energy is transferred through a food
chain but is diminished with each
transfer

24. Trophic Levels
E Tertiary
N consumers- top
E carnivores
R
G Secondary consumers-
Y
small carnivores
T
R
A
Primary consumers- Herbivores
N
S
F
E Producers- Autotrophs
R

27. Trophic Levels
Food chain- simple model that
shows how matter and energy
move through an ecosystem

29. Trophic Levels
Food web- shows all possible
feeding relationships in a
community at each trophic level
• Represents a network of
interconnected food chains

30. Food chain Food web
(1 path of energy) (all possible energy paths)