1. UNIT 4 – INTRODUCTION TO ECOLOGY
(pp. 63, 64, )

2. A. Introduction
Ecology is the study of interactions between organisms and their environment
Includes biotic,
or living factors
And abiotic or
non - living factors
Biotic factors and
abiotic factors
determine the health
of an ecosystem and its inhabitants

3. B. Levels of Organization
a. Species
b. Population
c. Community
d. Ecosystem
e. Biome

4. II. ENERGY IN AN ECOSYSTEM (pp. 67-73)
The ultimate source of energy for most life on earth is the sun.
A. Autotrophs –
Self – feeders
also known as producers.
Most producers capture energy from the sun in a process called photosynthesis.

5. B. Heterotrophs Have to obtain food Also known as consumers.
There are several categories of consumers:
1. Herbivores – Eat producers (plants)
2. Carnivores – Eat other consumers (animals)
3. Omnivores – Eat Producers and Consumers
4. Decomposers – Break down organic matter.
Most are found in Kingdom Eubacteria or Fungi.

6. C. Energy in a Cell
All producers and consumers must convert chemical (potential) energy present in glucose into usable energy.
This is known as metabolism.
The end-product is known as ATP.
Most ATP is produced through the process of cellular respiration.
The equation for cellular respiration is
C 6H12O6 + O2 → CO2 + H2O + ATP

7. Use energy from sun to make glucose
III.ENERGYFLOW–A COMPARISON OF PHOTOSYNTHESIS CELLULARRESPIRATION (p. 232)
Process
PHOTOSYNTHESIS
CELLULAR RESPIRATION
Function
Use energy from sun to make glucose
Release energy from glucose to make ATP
Cell
Location
Chloroplasts
Mitochondria
Occurs In
Autotrophs
Heterotrophs AND Autotrophs
Reactants
CO2 + H2O + energy
C6H12O6 + O2
Products
Overall
Reaction
CO2 + H2O + energy → C6H12O6 + O2
C6H12O6 + O2 → CO2 + H2O + energy

8. IV ENERGY FLOW – A COMPARISON OF PHOTOSYNTHESIS & CELLULAR RESPIRATION (p. 232)

9. IV. Energy Flow in an Ecosystem
Energy flows in one direction
CANNOT be recycled
Energy is captured by producers and converted to glucose in photosynthesis, which is then used by the plants or eaten by consumers to make ATP.

10. A. Trophic Levels Step in the pathway of energy
The first trophic level is always a producer.
The 2nd trophic level is known as the primary (1 st)
consumer and may be an herbivore or omnivore.
The last step is always a decomposer.
Energy (sun) → Producer →1 Consumer (herbivore or omnivore)
→ 2 Consumer (carnivore or omnivore) → Decomposer

11. T R O P H I C L E V S

12. B. Tracing Energy Flow 1. Food Chains illustrates how energy is
transferred by showing
feeding relationships.
The arrows show the
direction of energy transfer –
means “is eaten by”
consist of only 3 or 4 trophic
levels

13. Food Chains · Which organism acts as secondary consumer?
·  According to this food chain, which organism could be described as an herbivore?
Which organism is the producer? 
What are two terms that could be used to describe the hawk?

14. 2. Food Webs are more complex than a food chain
Most organisms eat & and are eaten by a variety of organisms
interconnected pathways are shown in a food web

16. Food Web How many different producers are there?
Is the grasshopper a producer, primary, or secondary consumer?
Is the grasshopper an herbivore, carnivore, or omnivore?
What organism(s) acts as the decomposer?
Give an example of an organism in this food web that acts as secondary and tertiary consumer.
If all the squirrels in the community perished, would the hawk be able to survive? Explain.
If the grass was destroyed, which organism would be most directly affected? Explain.

17. 3. Ecological Pyramids
10% of the energy stored in an organism is passed to the next trophic level.
90% of the energy is either used by the organism to maintain homeostasis or lost as heat to the environment
Used to represent amount of energy or matter at each trophic level

18. 3 Types of Ecological Pyramids

19. IV. ECOSYSTEM INTERACTIONS (pp. 90-93)
A. The Niche
The role an organism plays in its __________
comprised of _______ and ______ factors
example:
the type of food it eats
how it obtains its food
the way it is food for other organisms
how & when it reproduces
its physical living requirements to survive
community
biotic
abiotic

20. B. Interactions Within a Community
1. Competition
organisms are attempting to use the same _____________ at the same time
2. Predation
_________ killing and eating _______
3. Symbiosis
A relationship in which two organisms _____________________________
resources
prey
predator
live very closely together

21. 3. Symbiosis 1. Mutualism- Both organisms ________ benefit
example, clown fish (Nemo) & sea anemone
2. Commensalism
one organism benefits, the other organism _______________________
example: barnacles on whales
3. Parasitism
one benefits and the other is ________
example: ____________________________
benefit
in not helped nor harmed
harmed
tapeworms, hookworms, ticks, lice

22. IV. POPULATIONS WITHIN AN ECOSYSTEM (pp. 124-127)
limiting factors
___________- conditions that have an impact on population size
Density-Dependent Limiting Factors
depend on population size
example: ___________ and availability of _________, _________, __________
competition
food, water, and sunlight

23. IV. POPULATIONS WITHIN AN ECOSYSTEM
B. Density-Independent Limiting Factors
affect all populations the same way, regardless of size
Examples: ____________, _____________ and human activities: ____________________________________
C. Climax Community
a ______ community with very little population growth or decline
_______________, a certain number of organisms that can exist _____________
carrying capacity is exceeded, resources become a ____________, and population numbers ________
unusual weather
natural disasters
cutting down trees, damming rivers, etc
stable
carrying capacity
successfully
limiting factor
decline

24. V. NUTRIENTS IN AN ECOSYSTEM (pp. 74-80)
only available to an ecosystem in specific quantities and must be _______
Nutrients may become a ____________ when depleted.
require nutrients to ____________________________________
recycled
limiting factor
build macromolecules, cells, tissues, etc.

25. A. Carbon Cycle proteins
carbohydrates,
lipids
proteins
make __________, ______, ________, and _________________
taken up by ________ and ________ for _____________
_______ is a waste product of cellular respiration
Erosion, burning of ____________, and ______________ recycle carbon
nucleic acids
algae
plants
photosynthesis
CO2
fossil fuels
decomposition

26. A. Carbon Cycle

27. B. Nitrogen Cycle bacteria plants nucleic acids eat plants & algae
proteins
require nitrogen to build ____________ and _____________
_____________ is mostly nitrogen
only _________ can convert nitrogen from the atmosphere to a useable form, known as ______________
absorbed by _______ and used to make ________ & _______________
other organisms ______________________ can re-use the nitrogen to build their own _______ and ______________
______________ return the nitrogen to the soil
nucleic acids
atmosphere
bacteria
nitrogen fixation
plants
proteins
nucleic acids
eat plants & algae
proteins
nucleic acids
decomposers

28. B. Nitrogen Cycle

29. C. Water Cycle
Precipitation
Evaporation
Transpiration
Condensation