BISC 102 Lecture Notes - Lecture 18: Ecosystem Ecology, Herbivore, Plant Litter
21 Apr 2016
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Document Summary
Ecosystems: all organisms living in a biotic community/interactions with abiotic factors. Ecosystem ecology emphasizes questions about energy flow (it enters as light and is lost as heat) and nutrient cycling. 4 components: (we will focus on ecosystems with photoautotrophs as primary producers) Primary producers (harvest energy (from nonliving sources) and convert it to chemical energy (photoautotrophs) Consumers (harvest chemical energy from organic molecules (heterotrophs) Decomposers (break down remains from all trophic levels for recycling) Food chains: track the flow of energy nutrients from one trophic level to the next. Food web: complex feeding relationships within an ecosystem. Note that an organism can function at more than one trophic level. Much is absorbed or reflected as heat by nonphotosynthetic surfaces. Only a small % reaches primary producers and even less is converted to chemical. Energy cannot be created or destroyed but only transferred or transformed: energy thermodynamic law.
