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Ecosystems: What Are They and How Do They Work? Chapter 3 Sections 1-4 Key Concepts What is ecology? Major components of ecosystems Energy flow and matter cycles What are soils and how do they form? Ecosystem studies Importance of Insects Ecological Services Pollination Pest control Important roles in biological community Fig. 3-1, p. 35 Nature of Ecology What is ecology? Study of connections in nature Organisms Cells Species Microbes rule! Benefits Include: Decomposition, nutrient cycling, foods, water purification, digestion, antibiotics Fig. 3-2, p. 37 Nature of Ecology Known species 1,412,000 Other animals 281,000 Insects 751,000 Fungi 69,000 Prokaryotes 4,800 Species Total? Estimated 3.6 - 100 million Protists 57,700 Plants 248,400 Fig. 3-2, p. 37 Animation Levels of organization interaction Levels of Organization of Matter Fig. 2-3, p.23 Genetic Diversity in One Snail Species Fig. 3-4, p. 38 What Sustains Life on Earth? Troposphere: Earth’s surface to 17km up78% N, 21% O2 Stratosphere- 17 - 48 km contains ozone layer Hydrosphere Lithosphere= crust & upper mantle Biosphere = Zone of Earth where life is found (skin of the apple) * All parts are interconnected! Fig. 3-5, p. 38 What Sustains Life on Earth? Oceanic crust Continental crust Atmosphere Vegetation and animals Soil Rock Biosphere Lithosphere Upper mantle Asthenosphere Lower mantle Crust Core Mantle Crust (soil and rock) Biosphere (living and dead organisms) Lithosphere Hydrosphere (crust, top of upper mantle) (water) Atmosphere (air) Fig. 3-5, p. 38 Earth’s Life-Support Systems (3 interconnected factors) One way flow of highquality energy Cycling of matter Gravity- holds atmosphere, enables movement of chemicals thru various spheres “Energy flows, nutrients cycle.” Fig. 3-6, p. 39 Earth’s Life-Support Systems “Energy flows, nutrients cycle.” Biosphere Carbon cycle Phosphorus cycle Nitrogen cycle Water cycle Oxygen cycle Heat in the environment Heat Heat Heat Fig. 3-6, p. 39 Flow of Solar Energy to and from the Earth Greenhouse gases water vapor, CO2 NO, CH4 , O3 Greenhouse effectHeat trapped in the troposphere to warm planet without natural greenhouse effect life would not be possible. Fig. 3-7, p. 40 Flow of Solar Energy to and from the Earth Solar radiation Energy in = Energy out Reflected by atmosphere (34%) UV radiation Radiated by atmosphere as heat (66%) Lower Stratosphere (ozone layer) Absorbed by ozone Visible light Troposphere Greenhouse effect Heat Absorbed by the earth Heat radiated by the earth Fig. 3-7, p. 40 Animation Sun to Earth animation Why is the Earth so Favorable for Life? Liquid water Temperature- Past 3.7 billion years average surface temp. = 50- 68 °F Gravity Atmosphere Major Biomes Average annual precipitation 100–125 cm (40–50 in.) 75–100 cm (30–40 in.) 50–75 cm (20–30 in.) 25–50 cm (10–20 in.) below 25 cm (0–10 in.) 4,600 m (15,000 ft.) 3,000 m (10,000 ft.) 1,500 m (5,000 ft.) Coastal mountain ranges Coastal chaparral and scrub Sierra Nevada Mountains Great American Desert Coniferous forest Rocky Mountains Desert Great Plains Coniferous forest Mississippi River Valley Prairie grassland Appalachian Mountains Deciduous forest Fig. 3-8, p. 41 Major Components of Freshwater Ecosystems Sun Producers (rooted plants) Producers (phytoplankton) Primary consumers (zooplankton) Secondary consumers (fish) Tertiary consumers (turtles) Dissolved chemicals Sediment Decomposers (bacteria and fungi) Fig. 3-9, p. 42 Major Components of a Field Ecosystem Oxygen (O2) Sun Producer Carbon dioxide (CO2) Primary consumer (rabbit) Falling leaves Precipitation and twigs Secondary consumer (fox) Producers Soil decomposers Water Soluble mineral nutrients Fig. 3-10, p. 42 Animation Matter recycling and energy flow animation ABC’s of Ecology (The study of how organisms interact with one another & their non-living environment) •A= Abiotic (Non-living) •B= Biotic (Living) •C= Cultural (Human Interactions) Factors Limiting Population Growth Limiting factor principleToo much or too little of any abiotic factor can limit or prevent growth of population. Limiting factors: Excess water or water shortages for terrestrial organisms Excess or lack of soil nutrients Dissolved oxygen for aquatic organisms Salinity for aquatic organisms Range of Tolerance Lower limit of tolerance Few organisms Abundance of organisms Few organisms No organisms Population Size No organisms Upper limit of tolerance Zone of intolerance Low Zone of physiological stress Optimum range Temperature Zone of Zone of intolerance physiological stress High Fig. 3-11, p. 43 Factors That Limit Population Growth Range of tolerance: range of abiotic conditions required for population to survive Law of tolerance “The existence, abundance and distribution of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the range tolerated by that species.” Consumers: Feeding and Respiration Decomposers (Fungi & Bacteria) - specialized consumers that breakdown detritus (dead stuff) into inorganic nutrients that can be reused by producers Omnivores Detritivores- Decomposers & detritus feeders Aerobic respiration glucose + oxygen = carbon dioxide + water + ENERGY Detritivores Detritus feeders Decomposers Decomposers convert organic chemicals to inorganic chemicals that can be used by producers Long-horned beetle holes Bark beetle engraving Carpenter ant galleries Termite and carpenter ant work Dry rot fungus Wood reduced to powder Time progression Mushroom Powder broken down by decomposers into plant nutrients in soil Fig. 3-12, p. 44 Main Structural Components of an Ecosystem Heat Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Heat Solar energy Heat Producers (plants) Decomposers bacteria, fungi) Heat Consumers (herbivores, carnivores) Heat Fig. 3-13, p. 45 Animation Linked processes animation Animation The role of organisms in an ecosystem Biodiversity (4 Components) Fig. 3-14, p. 45 Examples of Biodiversity Fig. 3-15, p. 46 Model of a Food Chain First Trophic Level Producers (plants) Heat Second Trophic Level Third Trophic Level Fourth Trophic Level Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Solar energy Heat Heat Heat Heat Detritivores decomposers and detritus feeders) Heat Fig. 3-16, p. 47 Food Web in the Antarctic Humans Sperm whale Blue whale Elephant seal Killer whale Crabeater seal Leopard seal Adélie penguins Petrel Emperor penguin Fish Squid Carnivorous plankton Herbivorous zooplankton Krill Phytoplankton Fig. 3-17, p. 48 Energy Flow in an Ecosystem Biomass Ecological efficiency= % of usable energy transferred as biomass from one trophic level to the next (2% - 40%) 10% Rule-assumes 10% ecological efficiency Pyramid of energy flow Ecological Pyramids (3 Types) Heat Heat Tertiary consumers (human) Decomposers Heat 10 Secondary consumers (perch) 100 1,000 10,000 Usable energy available at each tropic level (in kilocalories) Heat Primary consumers (zooplankton) Heat Producers (phytoplankton) Fig. 3-18, p. 49 Biomass Productivity Gross primary productivity (GPP) rate at which producers in an ecosystem convert sun into food Net primary productivity (NPP)= GPP - Respiration NPP and populations NPP limits the number of consumers that can live on earth Differences between GPP and NPP Sun Respiration Gross primary production Growth and reproduction Energy lost and unavailable to consumers Net primary production (energy available to consumers) Fig. 3-19, p. 49 Net Primary Productivity in Major Life Zones and Ecosystems Terrestrial Ecosystems Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Tundra (arctic and alpine) Desert scrub Extreme desert Aquatic Ecosystems Estuaries Lakes and streams Continental shelf Open ocean 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/m2/yr) Fig. 3-20, p. 50