Ecology: Ecosystems

Ecosystem Resources  Energy:  Energy: one way flow from sun to organisms and loss as heat (yellow, red arrows)  Nutrients:  Nutrients: move in cycles involving organisms and the environment (purple arrows)

Consumers Gain Energy as Organic Molecules from Producers Herbivore Eats Producers Carnivore Eats Primary Consumers Carnivore Eats Secondary Consumers Food Chains

Food Web ShowsShows interconnected food chains TrophicTrophic Levels 1) producer 2) primary consumer 3) secondary consumer 4) tertiary consumer

Energy Transfer and Loss Heat Heat Producer Primary Consumer Secondary Consumer Detritus Feeders Heat Chemicals

Efficiency of Energy Transfer ~10% of calories to next trophic level

Concentration of Contaminants at Higher Levels of Food Chains ppm DDT ppm DDT 0.01 ppm DDT 10 ppm DDT

Detritus Feeders and Decomposers Release Nutrients for Reuse detritus feeders and decomposers Animals and Protists that feed on plant and animal remains Fungi and Bacteria that break down decaying material

The Nitrogen Cycle Plants and animals die and begin to decay Soil bacteria release nitrogen from decaying matter Nitrate is broken down to produce N 2 gas Ammonia is converted to nitrites or nitrates Plants are eaten by animals N 2 gas becomes ammonia or ammonium Nitrate is taken up by plants and converted to ammonium Ammonium is converted to nucleic acids and proteins Animal cells produce proteins and nucleic acids Ammonification Nitrification Assimilation Denitrification Nitrogen Fixation

Nitrogen in Atmosphere Reservoir The Nitrogen Cycle Electrical storms produce nitrate Ammonia & nitrate Nitrogen-fixing bacteria in legume roots and soil Ammonia & nitrate Uptake by plants Producers Consumers Wastes, Dead bodies Soil bacteria and detritus feeders Ammonia & nitrate Dentitrifying bacteria Nitrogen in Atmosphere Reservoir Reservoirs Processes/ Locations Trophic Levels/ Organisms

The Water Cycle Evaporation from land & transpiration from plants Precipitation over land Water vapor in atmosphere Water in ocean (reservoir) Evaporation from ocean Water vapor in atmosphere Water in ocean (reservoir) Groundwater seepage Surface runoff Water in ocean (reservoir) Precipitation over ocean Reservoirs Processes/ Locations Alternates between Evaporation and Precipitation

Water Carrying Industrial Pollutants Can Become Acid Rain