This document provides a summary of key concepts from a lecture on ecology and the principles of ecology. It covers 5 main topics: (1) how ecologists study relationships between organisms and their environment, (2) biotic and abiotic factors in an ecosystem, (3) energy flow through ecosystems, (4) food chains and food webs, and (5) the cycling of matter like water, carbon, nitrogen, and phosphorus through ecosystems. The summary defines important ecological terms and concepts like producers, consumers, trophic levels, and biogeochemical cycles.

1. A D A P T E D F R O M C H R I S T I N A M I G G E ’ S O R I G I N A L
P O W E R P O I N T L E C T U R E S A T T E S O R O H I G H
S C H O O L A N D C O N T A I N S O N L Y A P O R T I O N O F
T H E E N T I R E P R E S E N T A T I O N ( L E C T U R E N O T E S
T H A T A C C O M P A N Y T H I S W E R E M A D E B Y
M Y S E L F A N D A R E I N T E N D E D F O R T H E E N T I R E
C H A P T E R )
DIGITAL UNIT PLAN
SHANNON O’MALLEY

2. UNIT 5
Chapter 13
The Principles of Ecology

4. UNIT 5: ECOLOGY
Chapter 13: The Principles of Ecology
I. Ecologists Study Relationships (13.1)
A. Ecologists study environments at different
levels of organization
1. Ecology- study of the interactions
among living things and their
surroundings. From Greek
“oikos” meaning house.
In simpler terms: Ecology is the study of an
organism and how it interacts with it’s environment.

5. II. Biotic and Abiotic Factors (13.2)
A. An ecosystem includes both biotic and abiotic
factors
1. Biotic- includes living things

6. 2. Abiotic- includes nonliving things such as
moisture, temperature, wind, sunlight, and soil

7. B. Changing one factor in an ecosystem can affect
many other factors
a. amount
depends on
many factors
b. tropical
rainforests
have large
biodiversity
1. Biodiversity- the assortment, or variety, of
living things in an ecosystem

8. 2. Keystone species- a species that has an
unusually large effect on its ecosystem
a. loss of this species may cause ripple effect
felt across entire ecosystem

9. b. Example- beaver changes habitat for many other
species by creating ponds
Question:
What do you
think would
happen if the
beavers went
extinct?

10. Wolves at Yellowstone

11. III. Energy in Ecosystems (13.3)
A. Producers provide energy for other
organisms in an ecosystem
1. Producer (autotroph)-
get their energy from
nonliving resources (make
their own food).
2. Consumer (heterotroph)-
Get their energy by eating other
living things such as plants
and animals.

12. B. Almost all producers obtain energy from sunlight

13. 1. Most producers on Earth use sunlight as energy
source using photosynthesis.
2. photosynthesis converts light energy (sunlight)
into chemical energy (carbohydrates)

14. C. Chemosynthesis- organisms make
carbohydrates using chemicals instead of sunlight
1. Found in deep-
sea thermal vents
and sulfur-rich
marsh flats and
hydrothermal pools
2. can be basis for
thriving ecosystems

16. IV. Food Chains and Food Webs (13.4)
A. Food chain- sequence that links species by
their feeding relationships.
1. only follows connections between one
producer and single chain of consumers
2. simplest way to look at energy flow in
an ecosystem

17. CIRCLE OF LIFE

18. B. Types of consumers
1. Herbivores- eat only plants
2. Carnivores- eat only animals
3. Omnivores- eat both plant
and animals

19. CAN YOU NAME SOME OTHER
HERBIVORES? CARNIVORES? HOW
ABOUT A WELL KNOWN OMNIVORE?

20. 4. Detritivores- organisms that eat detritus (dead
organic matter)

21. 5. Decomposers- break down organic matter into
simpler compounds
a. Fungi and bacteria
b. Important to stability of
ecosystem by returning
nutrients back into the
environment

22. 6. Organism may focus on single organism to feed
(specialist), or have varying diet (generalist)

23. Specialists or generalist?

24. C. Trophic levels- level in a food chain
1. Producers always first
level
2. Primary consumers
next level (herbivore)
3. Secondary consumer-
eat herbivores (carnivore)
4. Tertiary consumer-
carnivores that eat
secondary consumers.

25. D. A food web shows a complex network of feeding
relationships
1. Food web- organism may have multiple
feeding relationships.
2. Stability of food web depends on presence of
producers (forms base of food web)

27. V. Cycling of Matter (13.5)
A. Water cycles through the environment
1. Hydrologic cycle (water cycle)-
circular pathway of water on Earth
2. Flows from
atmosphere to the
surface, below ground
and back and involves
humans and other
organisms.

28. B. Elements essential for life also cycle through
ecosystems
1. biogeochemical cycles- movement of a
particular chemical through biological and
geological parts of an ecosystem
a. Oxygen cycle- cycle
of photosynthesis and
cellular respiration

29. b. Carbon cycle-flow of carbon through environment
1). Carbon essential for organic
compounds (carbohydrates, proteins, fats,
etc.)

30. 2). Simplest transfer occurs between plants and
animals (photosynthesis and cellular respiration)

31. c. Nitrogen cycle- conversion of nitrogen gas (N2) in
atmosphere into compounds that living things can
utilize.

32. 1). Nitrogen fixation- converting gaseous nitrogen
(N2) into ammonia (NH3) (used by certain bacteria)
2). Denitrifying bacteria- convert nitrogen
compounds back to nitrogen gas.

33. d. Phosphorus cycle- returns phosphorus to
environment (phosphorus is limiting factor for plant
growth)