Chapter 3. Ecosystems: What Are They and How Do They Work? The Nature of Ecology

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1 Chapter 3 Ecosystems: What Are They and How Do They Work? The Nature of Ecology Ecosystem organization Organisms Populations Communities Ecosystems Biosphere Fig. 3-2 Populations Genetic diversity In most natural populations individuals vary slightly in their genetic makeup. Figure 3-5

2 BIODIVERSITY Figure 3-15 Biodiversity Loss and Species Extinction: Remember HIPPO H for habitat destruction and degradation I for invasive species P for pollution P for human population growth O for overexploitation Extinction rates are 100 to 10,000 times higher than the world s natural rate of extinction. Core Case Study: Have You Thanked the Insects Today? Many plant species depend on insects for pollination. Insect can control other pest insects by eating them Figure 3-1

3 Ecosystem Boundaries: Ecotones Land zone Transition zone Aquatic zone Number of species Species in land zone Species in aquatic zone Species in transition zone only The Biotic Components of Ecosystems Producers (autotrophs) Photosynthesis Consumers (heterotrophs) Aerobic respiration Decomposers Decomposers (bacteria, fungus) Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Consumers (herbivores, Carnivores,omnivores) Producers (plants) Solar energy Fig. 3.4 Producers: Basic Source of All Food Most producers capture sunlight to produce carbohydrates by photosynthesis:

4 Aerobic and Anaerobic Respiration: Getting Energy for Survival Organisms break down carbohydrates and other organic compounds in their cells to obtain the energy they need. This is usually done through aerobic respiration. The opposite of photosynthesis Connections: Food Chains and Energy Flow in Ecosystems Fig Crabeater seal Humans Blue whale Killer whale Sperm whale Elephant seal Food web Leopard seal Emperor penguin Adélie penguins Petrel Fish Carnivorous plankton Squid Fig 3-18 Krill Herbivorous zooplankton Phytoplankton

5 Ecological Pyramids 10% Pyramid of energy flow Ecological efficiency Pyramid of biomass Ecological efficiency here? ,000 10,000 Usable energy Available at Each tropic level (in kilocalories) Primary consumers (zooplankton) Tertiary consumers (human) Secondary consumers (perch) Producers (phytoplankton) Decomposers Fig Sun Photosynthesis Gross primary production Respiration Growth and reproduction Energy lost and unavailable to consumers Net primary production (energy available to consumers) Fig. 3-21, p. 66 What are nature s three most productive and three least productive systems? Figure 3-22

6 Principles of Ecological Factors Abiotic factors Biotic factors Lower limit of tolerance Law of tolerance Limiting factors Upper limit of tolerance No organisms Few organisms Abundance of organisms Few organisms No organisms Population size Zone of Zone of intolerance physiological stress Optimum range Zone of Zone of physiological stress intolerance Low Temperature High Fig The Earth s Life-Support Systems Atmosphere Atmosphere Vegetation and animals Soil Rock Biosphere Crust Hydrosphere core Lithosphere Biosphere Lithosphere Crust Mantle Hydrosphere Lithosphere (water) (crust, top of upper mantle) Crust (soil and rock) Biosphere (Living and dead organisms) Atmosphere (air) Fig. 3-6 Solar radiation Energy in = Energy out UV radiation Absorbed by ozone Visible Light Absorbed by the earth Reflected by atmosphere (34% ) Lower Stratosphere (ozone layer) Troposphere Greenhouse effect Radiated by atmosphere as heat (66%) radiated by the earth Fig. 3-8, p. 55

7 Hydrologic (Water) Cycle Clearing vegetation Use Use large amounts of of water Fig The Carbon Cycle (Terrestrial) Atmosphere (mainly carbon dioxide) volcanic action Terrestrial rocks photosynthesis aerobic respiration combustion of wood (for clearing land; or for fuel Soil water (dissolved carbon) leaching runoff weathering Interactivity- #11 Land food webs producers, consumers, decomposers, detritivores Global warmingcarbon dioxide death, burial, compaction over geologic time sedimentation Peat, fossil fuels Fig The Carbon Cycle (Aquatic) diffusion between atmosphere and ocean Carbon dioxide dissolved in ocean water combustion of fossil fuels photosynthesis aerobic respiration Marine food webs producers, consumers, decomposers, detritivores incorporation into sediments death, sedimentation Marine sediments, including formations with fossil fuels uplifting over geologic time sedimentation Fig. 3.27

8 The Sulfur Cycle Acid Acid Rain: Rain: Makes Makes plants plants and and animals animals vulnerable vulnerable to to drought drought and and pests. pests. Coal Coal and and industry industry sources sources Fig Biomes Desert Tundra Deciduous Forest Coniferous Forest Tropical Rainforest Mid-latitude Grasslands Tropical Savanna Chaparrel, Information on biomes Information on biomes Chapter 5 has maps( shows you where your biomes are located Fig 5-9 and discusses biomes. My handout The web- Search for pictures and more information Goodwill magazines- Redondo and Anaheim Poster board one per group and other supplies- Target or bookstore. Scissors, glue, markers, poster board. Worth 20 points. 15 points poster, 10 points notes on other biomes Extra credit available

9 Evelyn Hutchinson The Earth s thin film of living matter is sustained by grand scale cycles of energy and chemical elements End chapter 3