ISCI 1001 Lecture Notes - Lecture 13: Ecological Pyramid, Food Chain, Rodent
18 Oct 2015
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Energy flow through a community: passes through trophic hierarchy. Producers (autotrophs), consumers (1 , 2 , 3 ), decomposers, detritivores. From bottom to top: producers, 1 consumer, 2 consumer, 3 consumer. Note: bars can represent energy, biomass, numbers. Real communities food webs are a better picture. General rule: lose about 90% of biomass, numbers, etc. at each upward step in pyramid. Took small area: they removed all sea stars (top predator) for 6 yrs. Beforehand there were 15 species: after 6 yrs -> 8 species. 2 succession -> start from some disturbed community: forest -> farmland -> taken out of farming. Pioneer species: lichens (fungust autotroph) -> grasses -> shrubs -> tree (1) -> tree (2) -> stable . Major regional complex of similar communities: identified by their dominant plant species. T decreases 0. 5 c for each 1 increase in latitude. T decreases 0. 5 c for each 100m increase in altitude.
