EARTHSS 164 Lecture Notes - Lecture 7: Food Web, Nitrogen Fixation, Carbon Fixation

• School: UC-Irvine
• Department: Earth System Science
• Course: EARTHSS 164
• Professor: Professor Allison

Document Summary

Plants are a key part of the organisms state factor. Plant traits influence ecosystem processes (fluxes and changes) Resource availability for herbivores and detritivores (decomposers) Energy transfer from one organism to another though consumption. Linear set of transfers across trophic levels. A group of organisms that have a common feeding strategy. Amount of energy (usually carbon) coming into a trophic level per unit time. Percentage of production transferred from one trophic level to the next. Eating meat is a relatively inefficient way of tapping photosynthetic production. Worldwide agriculture could feed man more people if humans ate only plant material. How much biomass in each trophic level. Usually production (p) declines sharply up the food chain but turnover (k) is similar. Sometimes, p/k can be greater at higher trophic levels = inverted biomass pyramid. Need high trophic efficiencies and low turnover at higher levels. Properties of lower trophic levels affect higher levels. Ex. soil nutrients, abiotic resources, tissue quality.