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

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

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)

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

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

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

Outcome Day 20: $100 person = $2000 ($100) Day 20: Penny person = $10,486 ($5243) Day 50: 11.259 trillion dollars Day 20: $100 person = $2000 ($100)

Change = ~100,166,000 W o r l d P p u a t i n ( e s . ) , - 1 2 3 Now 2 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

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

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

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 (1950-2010) Source: United Nations Population Division ( http://esa.un.org/unpp/index.asp ) North America Latin America Africa Europe 1 & 2 3 & 4 1 2 4 3

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 (1950-2010) Source: United Nations Population Division ( http://esa.un.org/unpp/index.asp ) 1 2 4 3

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

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

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

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

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

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

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

Impact is a trophic cascade! http://www.forestry.oregonstate.edu/aspen/

Visuals YES W.J. Ripple photographs, OSU YES

Impact is a trophic cascade!

Zion National Park, Utah YES

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

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

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)