Chapter 4
Ecosystem Structure Biotic Living, Relationships Abiotic Nonliving, Cycles Levels of Organizations Cells Tissue Organ Organ System Organism Population Community Ecosystem Biosphere
Hierarchy of Levels Organism form of life Species variety among species or distinct types of living organisms found in different habitats Population same species, same location Community interacting populations Ecosystem living and nonliving Biosphere where all living things live
The Earth s Life Support System Troposphere weather Stratosphere ozone Hydrosphere water Lithosphere land Biosphere
Ecosystem Compartments Habitats home Biomes distinct climates Ecotones non-distinct boundary between ecosystems (mixture of species)
Ecotones
Ecosystem Compartments (abiotic) Law of Tolerance: population distribution determined by physical/chemical factors. Limiting Factors: too much/little abiotic factor can limit/prevent population growth
Ecosystem Compartments (biotic) Producers (Autotrophs) Photosynthesis 6CO 2 + 6H 2 O + sunlight C 6 H 12 O 6 + 6O 2 Chemosynthesis Consumers (Heterotophs)
Biotic (Trophic Levels) Consumers (Heterotrophs) Herbivore Primary Consumer Carnivore Secondary & Tertiary Consumer Omnivore Scavenger feed on dead organisms Detritivores feed off of detritus Detritus Feeders extract nutrients from partly decomposed matter Decomposers - bacteria
Biotic Aerobic Respiration C 6 H 12 O6 + 6O 2 6CO 2 + 6H 2 O + energy Anaerobic Respiration(fermentation) no oxygen used
Biotic Food Web or Chain represent trophic levels of interacting species (primary consumers eaten by secondary and so forth) Energy Pyramid like food web but shows energy flow between levels Ecological Efficiency - % usable energy transferred in biomass between trophic levels (Sun Producers Consumers)
Figure 4-20 Page 79 Heat Tertiary consumers (human) Heat Decomposers Heat 10 100 Secondary consumers (perch) Heat 1,000 Primary consumers (zooplankton) Heat 10,000 Usable energy available at each tropic level (in kilocalories) Producers (phytoplankton)
Each level decreases by ~90% which means ~10% is passed on
2004 Brooks/Cole Thomson Learning Estuaries Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Lakes and streams Continental shelf Open ocean Tundra (arctic and alpine) Desert scrub Extreme desert 800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600 Average net primary productivity (kcal/m 2 /yr) Primary Productivity - a measure of energy available to an ecosystem
Hydrologic or Water Cycle 1. Evaporation 2. Transpiration (leaves) 3. Condensation (clouds) 4. Precipitation 5. Infiltration (above ground) 6. Percolation (underground) What drives the Cycle? SUN
Condensation Rain clouds Precipitation to ocean Precipitation Evaporation Transpiration from plants Transpiration Precipitation Evaporation From ocean Surface runoff (rapid) Surface runoff (rapid) Runoff Groundwater movement (slow) Infiltration and percolation Ocean storage Groundwater movement (slow) Figure 4-27 Page 83
Water Cycle (human impact) 1. Withdrawing water 2. Clearing vegetation - Ag 3. Modifying water quality Destroying wetlands, Pollution, Sewage runoff, Power Plants Absolute Humidity: water/kg (air) Relative Humidity: Condensation Nuclei: ash, dust, smoke, sea salts, fossil fuel particulates Warm air holds more water than cold
Caron Cycle - 1. Two main processes Photosynthesis & Respiration
Carbon Cycle Carbon Sinks (reservoirs) Carbon Sinks (reservoirs) 1. Plant Matter 2. Terrestrial Biosphere freshwater, nonliving organic matter, forests (86% of above ground carbon and 73% of the planet s soil carbon) 3. Oceans shells, skeletons, (removing carbon from ocean raises ph making it more basic) 4. Sedimentary Deposits Limestone (largest reservoir in the carbon cycle), fossil fuels, coal
Carbon Cycle Carbon Released by: 1. Cellular Respiration 2. Decay of inorganic material by decomposers 3. Burning of fossil fuels, wood, coal 4. Weatherization of rocks (limestone, marble, chalk) 5. Volcanic eruptions 6. Release of carbon dioxide by warmer ocean waters
Carbon Cycle - Disruptions - Before Industrial Revolution transfer rates were balanced - Now more being released into atmosphere and less being removed ( took millions of years to form, to 100s of years as a major component of Global Warming - Human Activities Disrupting: Clearing plants, Burning Fossil Fuels
Nitrogen Cycle Main reserve = atmosphere Fixation atmospheric nitrogen (N 2 ) to ammonia (NH 3 ) or ammonium (NH 4 + ) ions, accomplished by rhizobium(bacteria) in the roots of legumes, blue green algae Nitrification ammonia oxidized to nitrite (NO 2- ) and nitrate (NO 3- ), the form usable by plants
Nitrogen Cycle Assimilation Nitrates (most commonly assimilated by plants through root hairs) Animals assimilate by consuming plants Ammonification living organism dies or animal excretes returning organic nitrogen back into ammonia (NH 3 ) Denitrification nitrite & nitrates reduced to gaseous nitrogen
Nitrogen Cycle Human Disruptors 1. Burning fossil fuels adds nitrogen dioxide to atmosphere causing smog, acid rain, destroys atmospheric ozone 2. Fertilizer, livestock wastes increase nitrogen contributing to global warming and ozone depletion 3. Removing N from topsoil (harvesting/irrigating/burning) 4. Adding N (agro. runoff, sewage discharge)
Phosphorus Cycle Know Cycle Need for: production of nucleotides (DNA), making of ATP, fats in cell membranes, bones, teeth, and shells Found in sedimentary rocks, does not depend on bacteria Found in the form of a phosphate ion, released from rocks by weathering and acid rain Human Activities Affecting: Mining rock, clear cutting, adding excess to aquatic ecosystems, runoff from feedlots, fertilizers, sewage discharge (increases growth of algae in water)
Phosphorus Cycle - Continued -No Gas Phase, only solid and liquid - Because P is a limiting factor in aquatic systems, it leads to eutrophication - Rainforest Great at recycling P, (of course not when it is destroyed) - Oceans = Greatest Resevoir
Sulfur Cycle Know Cycle Found in underground rocks and deep oceanic deposits Released from seafloor vents, volcanic eruptions Human Activities Affecting: Burning Sulfur coal/oil for power Refining Sulfur petroleum for gas Smelting metallic minerals to form copper, lead, and zinc