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Matter Cycles, Energy Flows Producers/Autotrophs Sunlight is the main energy source for life Photosynthesis is the conversion of inorganic molecules to sugars by photoautotrophes Photosynthesis inorganic radiant + energy matter organic (C) matter extra (chemical energy) + atoms [ Chemoautotrophes Some autotrophes rely on energy stored in chemical bonds of inorganic compounds (H2S) found at hydrothermal vents ] Consumers /Heterotrophs Rely on other organisms for food (nutrients, fuel) Primary consumers are herbivores (plant eaters) producer energy & matter transferred primary consumer Respiration Secondary Consumers Carnivores that eat herbivores producer energy & matter transferred primary consumer energy & matter transferred secondary consumer Tertiary consumers Carnivores or omnivores that eat carnivores/omnivores aka top consumers Producers etc energy & matter transferred Detritivores consumers that derive energy from organic waste and dead organisms Bacteria, insects ,fungi aka decomposers Food Web contains many food chains Arrows indicate energy transfer Pyramid Power Shape reflects trophic (feeding) levels Greek: trophos = nutrition Pyramid shape reflects energy use & transfer Only 10% is transferred on average Most energy is transformed (lost) into heat Pyramid shape reflects number of organisms Many producers needed to support a smaller number of consumers Pyramid shape reflects relative biomass Large base supports smaller (less productive) trophic levels Biomagnification/Bioaccumulation Chemicals ingested that cannot be broken down or easily excreted These accumulate in tissues The more one eats, the more toxin that accumulates Organisms higher in the web have more opportunities to ingest the toxin, increasing concentration in their tissues 10,000x 1,000x 100x 10x 1x It’s exponential 13.8ppm 2.07ppm 0.23ppm 0.04ppm The pyramid is inverted Greatest quantity of toxin per individual is in those top consumers Mercury concentrates in fish Brain damage, death Limit your tuna intake: Albacore 1x/2weeks Chunk light 1x/5 days Source: EPA/FDA For a 100# person DDT Weakens bird egg shells PCB’s from electrical, plastics industries Linked to cancer Also immune, reproductive, neurologic, endocrine disorders
