BIOL 121 Lecture Notes - Lecture 10: Food Web, Apex Predator, Primary Production
Document Summary
Two measures of the efficiency of consumers as energy transformers: production efficiency: percentage of energy assimilated by an organism that become incorporated into new biomass; (= net productivity assimilation * 100) Examines energy flow between trophic levels, not just individual species. Low for two reasons: many organisms cannot digest all of their prey o much assimilated energy lost as heat, limits number of trophic level in a food web. P (producer) - c1 (consumer 1 herbivore) - c2 (consumer 2) -c3 (consumer 3) - c4 (top carnivore) Usually less than six trophic levels (can"t get energy transferred beyond that) Pyramid of numbers: number of individuals decreases at each trophic level. Inverted pyramids single producer supports hundreds of herbivores and thousands of predators. Oak tree supports beetles, caterpillars and their predators (use pyramid of biomass) Pyramid of biomass (measured in kg/m3): measure of efficiency in which the organisms at each trophic level are weighed.
