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24.11.07 Bio: trophic levels, competition

Migration

The Bio modules:

  • mod 6 Net Primary Productivity
  • mod 7 trophic levels
  • mod 1 competition

  • mod 8 biodiversity-M&Ms
  • mod 9 ecosystem services
  • mod 10 biogeography

  • mod 11 ecological tolerance
  • mod 12 disruptions
  • mod 13 adaptation
  • mod 14 ecological succession

  • mod 15 population dynamics r, K
  • mod 16 carrying capacity-lynx-hare
  • mod 17 age distribution 
  • mod 18 human population 

Net Primary Productivity: The rate of turning solar energy into organic materials

From last week: photosynthesis (water, CO2 based) or chemosynthesis (sulfur based) turn energy into organic compounds (light+water->sugar)

  • Autotrophs= auto (self) troph (food)
  • also known as Producers in progressthe forfood chain
  • GPP: gross primary productivity = all energy into all food
  • NPP: net primary productivity = gross - energy of respiration
  • Net is usually only 25-50% of gross (not much)
  • Fun fact: your body is only about 33% efficient, the rest goes to heat
  • Same with your gas powered car...
Plants are not very efficient users of solar energy:

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If this were a business, they would charge 20$ for a shirt, that cost them $12, so they only make $8 per shirt. Not good business.

This is most efficient where there is lots of solar radiation, biomass and water:

Look for the richest and the poorest in each ecosystem:

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Net vs. Gross is easy to understand:

  • If your business takes in money, this is your gross income, say 100$
  • If your materials cost 20$, then your net income would be 80$


Ecosystem services: terms
  • Ecosystem services: processes by which clean water, timber, fisheries and ag crops are produced
  • Provisions: goods humans can use: timber, food crops, plants
  • Support systems: pollinators (bees), water filtration (soils)
  • Cultural services: aesthetics (John Muir, Ansel Adams)
  • Monetary value: lumber, fishing, tourism, ecotourism
Island Biogeography: an intro to evolution by location and geography 
Island (physically separate) bio=life, geography=mapping the earth
Important: Size of islands determines number of species on an island: bigger island=more species

Species-area curve: what this means: larger islands have more species

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Dependent on several factors:

  • colonization: how many new species can make it to the island, e.g. is it far from the mainland like Hawaii?
  • extinction: how many species die out, and how fast, from what (disasters, humans)
  • distance from each other: greater separation=fewer species (think of birds migrating across our island chain)
Invasive species are usually generalists, so pose a greater threat to island species (specialists)


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