2. It all started with a little known conversation amongst predators
Did you hear?
No! What?
This is unbelievable.
Great news for my best friend!

3. Course Context Social & Ethical foundation Population I. = P.A.T.
(# people)
Affluence
(GDP/person)
Technology
(tons CO2/GDP)
Air Resources
Water Resources
Biodiversity/Cons Biol
Ecosystem Goods &
Services
Other (Non- Renewable)
Resources
e.g., oil
Future Weeks
Earth Systems
• Biosphere
• Hydrosphere
• Lithosphere
• Atmosphere
Biophysical foundation

4. Top Carnivore - Friend, Foe, or Other
Explore: Top Carnivore: Friend, Foe, or Other
Population Biology
Food chains
Food Webs
Bioaccumulation
Competitor or friend of conservation
Readings: Trophic Cascade
Lecture on Conservation
Concept of Shifting Baselines (reinforce Friday’s
Lecture, web viewing)

5. Population Growth
• What is the difference between linear and exponential growth?
• Lessons & foundations from biological systems (energy & carrying capacity)
• Food chains and food webs
• Bioaccumulation
• Perils of being a top carnivore
• Positives derived from top carnivores

6. Thomas Malthus
Carrying Capacity
Population (Number)
Time (days to millennia)

7. Pick an option for your summer job (50 days)
$0.01, $0.02, $0.04, $0.08, etc.
$100.00, $100.00, $100.00, $100.00

8. Outcome Day 20: $100 person = $2000 ($100)
Day 20: Penny person = $10,486 ($5243)
Day 50: trillion dollars
Day 20: $100 person = $2000 ($100)

9. Change = ~100,166,000 W o r l d P p u a t i n ( e s . ) , - 1 2 3 Now2 3 4 5 6 7 8 9
Billions
Change = ~100,166,000
Now 2 1 9 7 5
1968: Garrett Hardin freaks out
This looks a lot like exponential growth! 1 9 5

10. Illustration/Reference
Growth/Time 1 2 3 4 5 6 7 8 9 10
Linear 12 14 16 18 20 22
Exponential 32 64
128
256
512
1024
2048
With each time interval:
Linear: increases by 2 (+ 2)
Exponential: doubles (*2)
Population Growth: Has been exponential
Population Growth is a function of a number of parameters

11. Linear vs. exponential growth (or decay)
Exponential Growth: Nt = Noekt
No - initial quantity
t - time
Nt - quantity after time to
k - constant
e - exponential function (e is the base of the natural log)
Exponential Decay: Nt = Noe-kt
Linear: Nt = N0*t

12. North America Latin America Africa Europe 1 & 2 3 & 4
Question: Between 1950 and 2009, which of the following regions exhibited linear population growth?
Regional Population Trends ( )
Source: United Nations Population Division ( )
North America
Latin America
Africa
Europe
1 & 2
3 & 4 1 2 4 3

13. North America Latin America Africa Europe 1 & 2 3 & 4
Question: Between 1950 and 2009, which of the following regions exhibited exponential population growth?
North America
Latin America
Africa
Europe
1 & 2
3 & 4
Regional Population Trends ( )
Source: United Nations Population Division ( ) 1 2 4 3

14. Food Chains, Food Webs, Trophic Levels, Bioaccumulation
Obey 1st & 2nd laws of Thermodynamics
Energy cannot be created or destroyed; only its form can change.
Conversion of energy is inefficient (!!)
Main source of energy is the sun.
Key involvement of biogeochemical cycles.

15. Trophic Pyramid Key Messages Energy comes from the sun
Green stuff determines the rest
Quantity (~number) of organisms up the food chain
Humans share the top two places
• Food security
• Eating lower on the food chain
Energy path
Top Carnivores
Detritus or
Decomposition
Chain
Bioaccumulation path
Omnivores
Herbivores
Compounds from
Biogeochemical
cycles
Producers
1 - 5%
Very simple diagram
10% rule
Connections between levels: chain or web

16. Food Web Example
Complexity
Many organisms have relatively short life-cycles.
Top carnivores have much longer life cycles
Role of chemicals and climate change on different organisms

17. Bioaccumulation
Another
optimistic
economist!
As a consequence of energy flow through a food chain (i.e., you must eat a lot!), certain compounds can accumulate.
Examples
Fat soluble compounds
DDT
Tetra-ethyl lead
Methyl mercury
Dioxin
PCBs
Take-home lessons
Being at the top of the food chain has risks
Pollutants are distributed globally
Diet impacts certain population groups more than others.
160 19 10 8
.00001

18. Friend Foe Other • Shared place • Role in conservation • Fear
• Competition
• Food
• Space
• Eg: sea lions
• Role in conservation

19. Top Carnivores: Friend or Foe
“Killing sea lions will not save Columbia River salmon”
By John Balzar
Special to The Times
February 7, 2008
Foe
Other
• Reading for Today
• Wolves in Yellowstone
• Grizzly or wolf as an umbrella species

20. Question: Which picture is before wolves were re-introduced?
Top
Bottom?

21. Impact is a trophic cascade!

22. Visuals
YES
W.J. Ripple photographs, OSU
YES

23. Impact is a trophic cascade!

24. Zion National Park, Utah
YES

25. Shifting Baselines: Forest Example
Old-growth forest 1998
Old-growth forest 2028
Old-growth forest 1928

26. Practice Exam Question: The parable of the lily pond: If lilies growing in a pond double every day, and on the 100th day they cover the whole pond, on what day do they cover half of the pond? 50 67 75 99 5
Correct answer: 99

27. Summary: Top Carnivores
Intro to Population Growth
Food chains, webs, bioaccumulation
Energy from the sun
Rules
Biogeochemical Cycles
Trophic cascades
Foundation for Conservation Biology
Fundamental changes in how we think!
No matter how you cut it, more people = fewer top carnivores
Separate of humans from nature
Aboriginal people
Role of carnivores (competitors)