Lecture 14 Thursday, October 18, 2007 • Biotic Ecosystem Operations (Function) – Producers, Consumers, and Decomposers • autotrophs and heterotrophs – Examples of Food Chains and (Complex) Food Webs • Difference b/w both? – Efficiency in a Food Web…..pretty low – Energy & Nutrient Pathways – Concentration of Pollution in Food Chains • Physiognomy & Plant Life Forms (Raunkiaer life forms) • Phanerophytes • Perrenating buds on aerial shoots • e.g. trees • tropical wet forest are overwhelmingly (96%) phanerophytes • Chamaephytes • Buds from the ground to about 25 cm up • e.g. small shrubs • Typical of alpine / tundra areas • Hemicryptophytes • Buds at ground surface • e.g. herbs - forbs • Geophytes • Underground structures (bulbs, rhizomes) • e.g. herbs - lilies • Therophytes • Seeds or spores • e.g. herbs - annual grasses • 73% of the plants in deserts are annuals • Ecosystems and Succession I • Stability • Inertia stability and resilience • Equilibrium, and non-equilibrium• Disturbances & Disturbance Regime • Productivity & Biodiversity • Biomass • Biodiversity • Definitions • Species diversity • Ecosystem diversity • Genetic diversity • BioDiversity = richness*abundance*genes*habitat diversity • Distribution • Species-Area Curves • Distribution – Vertebrate biodiversity • Distribution – Vascular plant biodiversity • Distribution – Flowering plant biodiversity • Latitudinal gradients • Biodiversity & Net Primary Productivity • Intermediate disturbance hypothesis • Function • Intrinsic value • Anthropocentric value • Economic benefits • Food / agricultural crops • Current & Future Medicine / biotechnology • Textiles• Clean water & clean air • Biotourism • Future potential • Trends • Current trends: Holocene extinction event • 1-Habitat loss • 2-Species introduction • 3-Over hunting • 4-Climate change • Attempts to address
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