11/1/2010 1 Geography 1001: Climate & Vegetation Dr. Holly Barnard • Logistics – Writing assignment Due Nov. 30 in lecture - hardcopy – Field trip II this week – weather looks good, but come prepared. – Midterm III – Tuesday, Nov. 16th Photo-synthesis and Respiration The Local Plant Carbon Cycle Autotrophic Respiration of CO2 Heterotrophic Respiration of CO2 Root mortality & exudation Litterfall Photosynthesis11/1/2010 2 Global Carbon and Oxygen Cycles Figure 19.10 Limiting Factors • Def.: One physical or chemical abiotic component that most inhibit biotic operation, through either its lack or excess • Examples – Temps (low at high elevations) – H2O (lack in deserts & excess in bogs) – Changes in topography – Changes in climate Limiting factors – Temperature and Precipitation Figure 19.8 http://msucares.com/crops/fertilizer/index.html11/1/2010 3 Limiting Factors & Microenvironment Limiting Factors & Microenvironment Life Zones Figure 19.10 Can you picture this Life Zone concepts across Latitude? Life Zones & Plant Life Forms11/1/2010 4 Physiognomy Raunkiaer life forms (based on perennating bud) Phanerophytes • Perennating buds on aerial shoots • e.g. trees • Tropical rainforest are dominated overwhelmingly (96%) by phanerophytes Chamaephytes • Buds from the ground to about 25 cm up • e.g. small shrubs • Typical of alpine / tundra areas11/1/2010 5 Hemicryptophytes • Buds at ground surface • e.g. herbs - forbs Therophytes • Seeds or spores • e.g. herbs - annual grasses • 73% of the plants in deserts are annuals Geophytes • Underground structures (bulbs, rhizomes) • e.g. herbs - lilies 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 • Concentration of Pollution in Food Chains11/1/2010 6 Energy, Nutrient, and Food Pathways Figure 19.13 Food Chains Figure 19.14 Food Webs Figure 19.15 Temperate Forest Food Web Figure 19.1611/1/2010 7 Biomass Consumption and Efficiency Figure 19.17 Population Distribution in Two Ecosystems (in 0.25 acres/.1 ha) Figure 19.18 Energy and Nutrient Flows Figure 19.19 • Biological Evolution Delivers Biodiversity • Ecosystem Stability and Diversity • Ecological Succession • Terrestrial Succession • Aquatic Succession Ecosystems, Evolution, and Succession11/1/2010 8 Ecosystems and Succession I • Ecosystem Stability • Ecosystem Diversity or Biodiversity Equilibrium, Stability & Diversity • Stability – Inertia stability and resilience – Disturbances • A discrete & stochastic event that disrupt (any) part(s) or (any) component(s) of a biotic community. • Chronic disturbances – A large changes in ecosystem processes in response to a continuous & directional variation in the environment. Stochastic & Chronic Disturbances Biodiversity • Definitions • Distribution • Function • Threats11/1/2010 9 Definition of biodiversity • Species diversity • Ecosystem diversity • Genetic diversity • BioDiversity = richness*abundance*genes*habitat diversity Distribution – Vascular plant biodiversity Distribution – Flowering plant biodiversity Function of biodiversity Stability and productivity11/1/2010 10 Equilibrium, Stability & Diversity • High species diversity reduces – the risk of large changes in ecosystem processes in response to directional or stochastic disturbances in the environment. – the probability of large changes in ecosystem processes in response to invasions of pathogens and other species. Economic benefits • Food / agricultural crops • Clean water & clean air • Biotourism • Textiles • Current & Future Medicine / biotechnology Function of biodiversity Future potential Top Threats to Biodiversity • Habitat loss • Introduced and invasive species • Over hunting • Climate
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