I enjoyed the exhibits at the Burke Museum. 1.Strongly Agree 2.Agree 3.Neutral 4.Disagree 5.Strongly Disagree
THOUGHTS?
Top Carnivore - Friend or Foe Review where we are in the course Exponential vs. linear growth Explore: Top Carnivore: Friend or Foe Food chains Food Webs Bioaccumulation Competitor or friend of conservation Readings: Yellowstone Story Lecture on Conservation Concept of Shrinking Expectations
A SAND COUNTY ALMANAC ALDO 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.$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: trillion dollars Outcome Day 20: $100 person = $2000 ($100)
1968: Garrett Hardin freaks out
Linear vs. exponential growth (or decay) Exponential: N t = N o e kt N o - initial quantity t - time N t - quantity after time t o k - constant e - exponential function (e is the base of the natural log) Linear: N t = N 0 *t
Growth/Time Linear Exponential Illustration/Reference 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)
The parable of the lily pond If lilies growing in a pond double every day, and on the 100 th day they cover the whole pond, on what day do they cover half of the pond?
Please make your selection th 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.
Trophic Pyramid Very simple diagram 10% rule Herbivores Omnivores Top Carnivores Detritus or Decomposition Chain 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
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 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. 1.Wolves were extirpated in 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.True 2.False
Impact is a trophic cascade!
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