Post on 21-Dec-2015
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