Ecosystems consist of living organisms interacting with each other and their non-living environment. Energy from the sun flows through producers, such as plants, which are eaten by consumers and decomposed by detritivores, recycling nutrients and matter back into the environment. Populations of different species living together form communities within ecosystems.

1. Chapter 3 Ecosystems: Connections in Nature

2. Chapter Overview Questions What is ecology? What basic processes keep us and other organisms alive? What are the major components of an ecosystem? What happens to energy in an ecosystem? What are soils and how are they formed? What happens to matter in an ecosystem? How do scientists study ecosystems?

3. 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

4. Core Case Study: Have You Thanked the Insects Today? … if all insects disappeared, humanity probably could not last more than a few months [E.O. Wilson, Biodiversity expert]. Insect ’s role in nature is part of the larger biological community in which they live.

5. THE NATURE OF ECOLOGY Ecology is a study of connections in nature. How organisms interact with one another and with their nonliving environment.

6. Communities Subatomic Particles Atoms Molecules Protoplasm Cells Tissues Organs Organ systems Organisms Populations Populations Communities Ecosystems Biosphere Earth Planets Solar systems Galaxies Universe Organisms Realm of ecology Ecosystems Biosphere

7. Animation: Levels of Organization PLAY ANIMATION

8. Organisms and Species Organisms, the different forms of life on earth, can be classified into different species based on certain characteristics.

9. Insects 751,000 Other animals 281,000 Fungi 69,000 Prokaryotes 4,800 Plants 248,400 Protists 57,700 Known species 1,412,000

10. Case Study: Which Species Run the World? Multitudes of tiny microbes such as bacteria, protozoa, fungi, and yeast help keep us alive. Harmful microbes are the minority. Soil bacteria convert nitrogen gas to a usable form for plants. They help produce foods (bread, cheese, yogurt, beer, wine). 90% of all living mass. Helps purify water, provide oxygen, breakdown waste. Lives beneficially in your body (intestines, nose).

11. Populations, Communities, and Ecosystems Members of a species interact in groups called populations. Populations of different species living and interacting in an area form a community. A community interacting with its physical environment of matter and energy is an ecosystem.

12. Populations A population is a group of interacting individuals of the same species occupying a specific area. The space an individual or population normally occupies is its habitat.

13. Populations Genetic diversity In most natural populations individuals vary slightly in their genetic makeup.

14. THE EARTH ’S LIFE SUPPORT SYSTEMS The biosphere consists of several physical layers that contain: Air Water Soil Minerals Life

15. Biosphere Atmosphere Membrane of air around the planet. Stratosphere Lower portion contains ozone to filter out most of the sun ’s harmful UV radiation. Hydrosphere All the earth ’s water: liquid, ice, water vapor Lithosphere The earth ’s crust and upper mantle.

16. Lithosphere (crust, top of upper mantle) Rock Soil Vegetation and animals Atmosphere Oceanic Crust Continental Crust Lithosphere Upper mantle Asthenosphere Lower mantle Mantle Core Biosphere Crust Crust (soil and rock) Biosphere (living and dead organisms) Hydrosphere (water) Atmosphere (air)

17. What Sustains Life on Earth? Solar energy, the cycling of matter, and gravity sustain the earth ’s life.

18. Nitrogen cycle Biosphere Heat in the environment Heat Heat Heat Phosphorus cycle Carbon cycle Oxygen cycle Water cycle

19. What Happens to Solar Energy Reaching the Earth? Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds and supports plant growth.

20. Absorbed by ozone Visible Light Absorbed by the earth Greenhouse effect UV radiation Solar radiation Energy in = Energy out Reflected by atmosphere (34% ) Radiated by atmosphere as heat (66%) Heat radiated by the earth Heat Troposphere Lower Stratosphere (ozone layer)

21. Animation: Sun to Earth PLAY ANIMATION

22. ECOSYSTEM COMPONENTS Life exists on land systems called biomes and in freshwater and ocean aquatic life zones.

23. 100–125 cm (40–50 in.) Coastal mountain ranges Sierra Nevada Mountains Great American Desert Coastal chaparral and scrub Coniferous forest Desert Coniferous forest Prairie grassland Deciduous forest 1,500 m (5,000 ft.) 3,000 m (10,000 ft.) 4,600 m (15,000 ft.) Average annual precipitation Mississippi River Valley Appalachian Mountains Great Plains Rocky Mountains below 25 cm (0–10 in.) 25–50 cm (10–20 in.) 50–75 cm (20–30 in.) 75–100 cm (30–40 in.)

24. Nonliving and Living Components of Ecosystems Ecosystems consist of nonliving (abiotic) and living (biotic) components.

25. Sun Oxygen (O 2 ) Carbon dioxide (CO 2 ) Secondary consumer (fox) Soil decomposers Primary consumer (rabbit) Precipitation Falling leaves and twigs Producer Producers Soluble mineral nutrients Water

26. Animation: Roles of Organisms in an Ecosystem PLAY ANIMATION

27. Animation: Diet of a Red Fox PLAY ANIMATION

28. Factors That Limit Population Growth Availability of matter and energy resources can limit the number of organisms in a population.

29. Zone of intolerance Optimum range Zone of physiological stress Zone of physiological stress Zone of intolerance Temperature Low High No organisms Few organisms Upper limit of tolerance Population size Abundance of organisms Few organisms No organisms Lower limit of tolerance

30. Factors That Limit Population Growth The physical conditions of the environment can limit the distribution of a species.

31. Sugar Maple

32. Producers: Basic Source of All Food Most producers capture sunlight to produce carbohydrates by photosynthesis:

33. Producers: Basic Source of All Food Chemosynthesis: Some organisms such as deep ocean bacteria draw energy from hydrothermal vents and produce carbohydrates from hydrogen sulfide (H 2 S) gas .

34. Photosynthesis: A Closer Look Chlorophyll molecules in the chloroplasts of plant cells absorb solar energy. This initiates a complex series of chemical reactions in which carbon dioxide and water are converted to sugars and oxygen.

35. Sun Chloroplast in leaf cell Light-dependent Reaction Light-independent reaction Chlorophyll Energy storage and release (ATP/ADP) Glucose H 2 O Sunlight O 2 CO 2 6CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2

36. Consumers: Eating and Recycling to Survive Consumers (heterotrophs) get their food by eating or breaking down all or parts of other organisms or their remains. Herbivores Primary consumers that eat producers Carnivores Primary consumers eat primary consumers Third and higher level consumers: carnivores that eat carnivores. Omnivores Feed on both plant and animals.

37. Decomposers and Detrivores Decomposers: Recycle nutrients in ecosystems. Detrivores: Insects or other scavengers that feed on wastes or dead bodies.

38. Scavengers Powder broken down by decomposers into plant nutrients in soil Bark beetle engraving Decomposers Long-horned beetle holes Carpenter ant galleries Termite and carpenter ant work Dry rot fungus Wood reduced to powder Mushroom Time progression

39. 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

40. Animation: Linked Processes PLAY ANIMATION

41. Aerobic and Anaerobic Respiration: Getting Energy for Survival Anaerobic respiration or fermentation: Some decomposers get energy by breaking down glucose (or other organic compounds) in the absence of oxygen. The end products vary based on the chemical reaction: Methane gas Ethyl alcohol Acetic acid Hydrogen sulfide

42. Two Secrets of Survival: Energy Flow and Matter Recycle An ecosystem survives by a combination of energy flow and matter recycling.

43. Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Heat Heat Heat Heat Heat Solar energy Consumers (herbivores, carnivores) Producers (plants) Decomposers (bacteria, fungi)

44. Animation: Matter Recycling and Energy Flow PLAY ANIMATION

45. BIODIVERSITY

46. 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

47. Why Should We Care About Biodiversity? Biodiversity provides us with: Natural Resources (food water, wood, energy, and medicines) Natural Services (air and water purification, soil fertility, waste disposal, pest control) Aesthetic pleasure

48. Solutions Goals, strategies and tactics for protecting biodiversity.

49. The Ecosystem Approach Protect populations of species in their natural habitats Goal The Species Approach Goal Protect species from premature extinction Preserve sufficient areas of habitats in different biomes and aquatic systems Strategy Tactics Protect habitat areas through private purchase or government action Eliminate or reduce populations of nonnative species from protected areas Manage protected areas to sustain native species Restore degraded ecosystems Tactics Legally protect endangered species Manage habitat Propagate endangered species in captivity Reintroduce species into suitable habitats Strategies Identify endangered species Protect their critical habitats

50. ENERGY FLOW IN ECOSYSTEMS Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem.

51. Heat Heat Heat Heat Heat Heat Heat Heat Detritivores (decomposers and detritus feeders) First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Solar energy Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores)

52. Animation: Energy Flow PLAY ANIMATION

53. Animation: Prairie Trophic Levels PLAY ANIMATION

54. Food Webs Trophic levels are interconnected within a more complicated food web.

55. Humans Blue whale Sperm whale Crabeater seal Elephant seal Killer whale Leopard seal Adelie penguins Emperor penguin Petrel Fish Squid Carnivorous plankton Krill Herbivorous plankton Phytoplankton

56. Animation: Categories of Food Webs PLAY ANIMATION

57. Animation: Rainforest Food Web PLAY ANIMATION

58. Animation: Prairie Food Web PLAY ANIMATION

59. Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs In accordance with the 2 nd law of thermodynamics, there is a decrease in the amount of energy available to each succeeding organism in a food chain or web.

60. Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs Ecological efficiency : percentage of useable energy transferred as biomass from one trophic level to the next.

61. Heat Heat Heat Heat Heat Decomposers Tertiary consumers (human) Producers (phytoplankton) Secondary consumers (perch) Primary consumers (zooplankton) 10 100 1,000 10,000 Usable energy Available at Each tropic level (in kilocalories)

62. Animation: Energy Flow in Silver Springs PLAY ANIMATION

63. Productivity of Producers: The Rate Is Crucial Gross primary production (GPP) Rate at which an ecosystem ’s producers convert solar energy into chemical energy as biomass.

64. Gross primary productivity (grams of carbon per square meter)

65. Net Primary Production (NPP) NPP = GPP – R Rate at which producers use photosynthesis to store energy minus the rate at which they use some of this energy through respiration (R).

66. Photosynthesis Sun Net primary production (energy available to consumers) Growth and reproduction Respiration Energy lost and unavailable to consumers Gross primary production

67. What are nature ’s three most productive and three least productive systems?

68. Average net primary productivity (kcal/m 2 /yr) Open ocean Continental shelf Lakes and streams Estuaries Aquatic Ecosystems Extreme desert Desert scrub Tundra (arctic and alpine) Temperate grassland Woodland and shrubland Agricultural land Savanna North. coniferous forest Temperate forest Terrestrial Ecosystems Tropical rain forest Swamps and marshes

69. SOIL: A RENEWABLE RESOURCE Soil is a slowly renewed resource that provides most of the nutrients needed for plant growth and also helps purify water. Soil formation begins when bedrock is broken down by physical, chemical and biological processes called weathering . Mature soils , or soils that have developed over a long time are arranged in a series of horizontal layers called soil horizons .

70. Fern Mature soil Honey fungus Root system Oak tree Bacteria Lords and ladies Fungus Actinomycetes Nematode Pseudoscorpion Mite Regolith Young soil Immature soil Bedrock Rock fragments Moss and lichen Organic debris builds up Grasses and small shrubs Mole Dog violet Wood sorrel Earthworm Millipede O horizon Leaf litter A horizon Topsoil B horizon Subsoil C horizon Parent material Springtail Red Earth Mite

71. Animation: Soil Profile PLAY ANIMATION

72. Layers in Mature Soils Infiltration: the downward movement of water through soil. Leaching: dissolving of minerals and organic matter in upper layers carrying them to lower layers. The soil type determines the degree of infiltration and leaching.

73. Soil Profiles of the Principal Terrestrial Soil Types

74. Mosaic of closely packed pebbles, boulders Weak humus-mineral mixture Dry, brown to reddish-brown with variable accumulations of clay, calcium and carbonate, and soluble salts Alkaline, dark, and rich in humus Clay, calcium compounds Desert Soil (hot, dry climate) Grassland Soil semiarid climate)

75. Tropical Rain Forest Soil (humid, tropical climate) Acidic light-colored humus Iron and aluminum compounds mixed with clay

76. Deciduous Forest Soil (humid, mild climate) Forest litter leaf mold Humus-mineral mixture Light, grayish-brown, silt loam Dark brown firm clay

77. Coniferous Forest Soil (humid, cold climate) Light-colored and acidic Acid litter and humus Humus and iron and aluminum compounds

78. Some Soil Properties Soils vary in the size of the particles they contain, the amount of space between these particles, and how rapidly water flows through them.

79. 0.05–2 mm diameter High permeability Low permeability Water Water Clay less than 0.002 mm Diameter Silt 0.002–0.05 mm diameter Sand

80. MATTER CYCLING IN ECOSYSTEMS Nutrient Cycles: Global Recycling Global Cycles recycle nutrients through the earth ’s air, land, water, and living organisms. Nutrients are the elements and compounds that organisms need to live, grow, and reproduce. Biogeochemical cycles move these substances through air, water, soil, rock and living organisms.

81. The Water Cycle

82. Precipitation Precipitation Transpiration Condensation Evaporation Ocean storage Transpiration from plants Precipitation to land Groundwater movement (slow) Evaporation from land Evaporation from ocean Precipitation to ocean Infiltration and Percolation Rain clouds Runoff Surface runoff (rapid) Surface runoff (rapid)

83. Animation: Hydrologic Cycle PLAY ANIMATION

84. Water ’ Unique Properties There are strong forces of attraction between molecules of water. Water exists as a liquid over a wide temperature range. Liquid water changes temperature slowly. It takes a large amount of energy for water to evaporate. Liquid water can dissolve a variety of compounds. Water expands when it freezes.

85. Effects of Human Activities on Water Cycle We alter the water cycle by: Withdrawing large amounts of freshwater. Clearing vegetation and eroding soils. Polluting surface and underground water. Contributing to climate change.

86. The Carbon Cycle: Part of Nature ’s Thermostat

88. Animation: Carbon Cycle PLAY ANIMATION

89. Effects of Human Activities on Carbon Cycle We alter the carbon cycle by adding excess CO 2 to the atmosphere through: Burning fossil fuels. Clearing vegetation faster than it is replaced.

90. CO 2 emissions from fossil fuels (billion metric tons of carbon equivalent) Year Low projection High projection

91. The Nitrogen Cycle: Bacteria in Action

92. Gaseous nitrogen (N 2 ) in atmosphere Ammonia, ammonium in soil Nitrogen-rich wastes, remains in soil Nitrate in soil Loss by leaching Loss by leaching Nitrite in soil Nitrification Nitrification Ammonification Uptake by autotrophs Uptake by autotrophs Excretion, death, decomposition Loss by denitrification Food webs on land Fertilizers Nitrogen fixation

93. Animation: Nitrogen Cycle PLAY ANIMATION

94. Effects of Human Activities on the Nitrogen Cycle We alter the nitrogen cycle by: Adding gases that contribute to acid rain. Adding nitrous oxide to the atmosphere through farming practices which can warm the atmosphere and deplete ozone. Contaminating ground water from nitrate ions in inorganic fertilizers. Releasing nitrogen into the troposphere through deforestation.

95. Effects of Human Activities on the Nitrogen Cycle Human activities such as production of fertilizers now fix more nitrogen than all natural sources combined.

96. Nitrogen fixation by natural processes Global nitrogen (N) fixation (trillion grams) Nitrogen fixation by human processes Year

97. The Phosphorous Cycle

98. Dissolved in Ocean Water Marine Sediments Rocks uplifting over geologic time settling out weathering sedimentation Land Food Webs Dissolved in Soil Water, Lakes, Rivers death, decomposition uptake by autotrophs agriculture leaching, runoff uptake by autotrophs excretion death, decomposition mining Fertilizer weathering Guano Marine Food Webs

99. Animation: Phosphorous Cycle PLAY ANIMATION

100. Effects of Human Activities on the Phosphorous Cycle We remove large amounts of phosphate from the earth to make fertilizer. We reduce phosphorous in tropical soils by clearing forests. We add excess phosphates to aquatic systems from runoff of animal wastes and fertilizers.

101. The Sulfur Cycle

102. Hydrogen sulfide Sulfur Sulfate salts Decaying matter Animals Plants Ocean Industries Volcano Hydrogen sulfide Oxygen Dimethyl sulfide Ammonium sulfate Ammonia Acidic fog and precipitation Sulfuric acid Water Sulfur trioxide Sulfur dioxide Metallic sulfide deposits

103. Animation: Sulfur Cycle PLAY ANIMATION

104. Effects of Human Activities on the Sulfur Cycle We add sulfur dioxide to the atmosphere by: Burning coal and oil Refining sulfur containing petroleum. Convert sulfur-containing metallic ores into free metals such as copper, lead, and zinc releasing sulfur dioxide into the environment.

105. The Gaia Hypothesis: Is the Earth Alive? Some have proposed that the earth ’s various forms of life control or at least influence its chemical cycles and other earth-sustaining processes. The strong Gaia hypothesis: life controls the earth ’s life-sustaining processes. The weak Gaia hypothesis: life influences the earth ’s life-sustaining processes.

106. HOW DO ECOLOGISTS LEARN ABOUT ECOSYSTEMS? Ecologist go into ecosystems to observe, but also use remote sensors on aircraft and satellites to collect data and analyze geographic data in large databases. Geographic Information Systems Remote Sensing Ecologists also use controlled indoor and outdoor chambers to study ecosystems

107. Geographic Information Systems (GIS) A GIS organizes, stores, and analyzes complex data collected over broad geographic areas. Allows the simultaneous overlay of many layers of data.

108. Critical nesting site locations USDA Forest Service USDA Forest Service Private owner 1 Private owner 2 Topography Habitat type Lake Wetland Forest Grassland Real world

109. Systems Analysis Ecologists develop mathematical and other models to simulate the behavior of ecosystems.

110. Systems Measurement Define objectives Identify and inventory variables Obtain baseline data on variables Make statistical analysis of relationships among variables Determine significant interactions Objectives Construct mathematical model describing interactions among variables Run the model on a computer, with values entered for different Variables Evaluate best ways to achieve objectives Data Analysis System Modeling System Simulation System Optimization

111. Importance of Baseline Ecological Data We need baseline data on the world ’s ecosystems so we can see how they are changing and develop effective strategies for preventing or slowing their degradation. Scientists have less than half of the basic ecological data needed to evaluate the status of ecosystems in the United Sates (Heinz Foundation 2002; Millennium Assessment 2005).