I enjoyed the exhibits at the Burke Museum.

1 2 3 4 5

33%

56%

0%0%

11%

1. Strongly Agree

2. Agree

3. Neutral

4. Disagree

5. Strongly Disagree

THOUGHTS?

Top Carnivore - Friend or FoeReview where we are in the courseExponential vs. linear growthExplore: Top Carnivore: Friend or Foe

Food chainsFood WebsBioaccumulationCompetitor or friend of conservation

Readings: Yellowstone StoryLecture on Conservation

Concept of Shrinking Expectations

A SAND COUNTY ALMANACALDO LEOPOLD

“I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear or its deer.”

Pick an option for your summer job (50 days)

1 2

28%72%

1. $0.01, $0.02, $0.04, $0.08, etc.

2. $100.00, $100.00, $100.00, $100.00

• Day 20: Penny person = $10,486 ($5243)

• Day 50: 11.259 trillion dollars

Outcome

• Day 20: $100 person = $2000 ($100)

World Population (est.), -10,000 to 2300

0

1

2

3

4

5

6

7

8

9

10

-10000 -7500 -5000 -2500 0 2500

Billions

18501900

1800

1950

1975

2000

1968: Garrett Hardin freaks out

Linear vs. exponential growth (or decay)

• Exponential: 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)

• Linear: Nt = N0*t

http://lectureonline.cl.msu.edu/~mmp/applist/decay/decay.htm

Growth/Time 0 1 2 3 4 5 6 7 8 9 10

Linear 2 4 6 8 10 12 14 16 18 20 22

Exponential 2 4 8 16 32 64 128 256 512 1024 2048

Illustration/Reference

http://www.watersfoundation.org/index.cfm?fuseaction=home.main

Population Growth: Has been exponential

Population Growth is a function of a number of parameters

With each time interval:Linear: increases by 2 (+ 2)Exponential: doubles (*2)

Please make your selection...

1 2 3 4

22% 72%0%6%

1. 10th day

2. 25th day

3. 50th day

4. 99th day

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.

• Role of biogeochemical cycles.

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/F/FoodChains.html

Trophic Pyramid

• Very simple diagram

• 10% rule

Herbivores

Omnivores

Top CarnivoresDetritus or DecompositionChain

• Connections between levels: chain or web

Compounds from Biogeochemical

cycles

Producers

Food Web Example

Bioaccumulation• 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

160

19

10

8.00001

Top Carnivores: Friend or Foe

““Killing sea lions will not save Columbia River salmon”Killing sea lions will not save Columbia River salmon”By John BalzarSpecial to The TimesFebruary 7, 2008

Foe

Friend• Reading for Today• Wolves in Yellowstone & Cougars in Zion N Park

Foe

• Shared space• Status• Fear• Competition

• Food• Space

• Example with sea lions

Which of the following statements is false.

0%

5%

89%

0%

5% 1. Wolves were extirpated in 1926

2. Beavers returned after wolves returned

3. Elk browsing increases aspens & willows

4. Rivers became incised with elk browsing

5. Wolves are carnivores & predators

The paper argues top carnivores can be critical in the maintenance of

biodiversity.

1 2

0%

100%1. True

2. False

Impact is a trophic cascade!

http://www.forestry.oregonstate.edu/aspen/

TROPHIC CASCADE

• The progression of indirect effects by predators across successively lower trophic levels

Visuals

W.J. Ripple photographs, OSU

Impact is a trophic cascade!

Zion National Park, Utah

KEYSTONE SPECIES

• Disproportionate effect on its environment relative to its abundance

• Help to determine the type and number of other species

• Verses foundation species and apex predator

Summary: Top Carnivores

• Exponential vs. linear changes

• First and second laws of thermodynamics

• Energy from the sun

• Biogeochemical Cycles

• Food chains, webs, trophic cascades, bioaccumulation

• Foundation for Conservation Biology

• Fundamental changes in how we think!

Concept of Shrinking Expectations

Current Condition or state

Future Condition or state

Historical Condition or state

Russell Jim