Ecosystems: What Are They and How Do They Work?

1. Ecosystems: What Are They and How Do They Work? G. Tyler Miller’s Living in the Environment 14th Edition Chapter 4

2. Essential Questions / Objectives Define ecology. List and distinguish among five levels of organization of matter that are the focus of the realm of ecology List the characteristics of life Distinguish among lithosphere, hydrosphere, atmosphere, and ecosphere. Briefly describe how the sun, gravity, and nutrient cycles sustain life on Earth. Compare the flow of matter and the flow of energy through the biosphere Define soil horizon. Briefly describe 4 soil layers. Using Figure 4-25 on p. 75 in the text, compare soil profiles of five important soil types Describe a fertile soil. In doing so, be sure to refer to soil texture, porosity, loam, and acidity

3. Essential Questions / Objectives Distinguish between an open system and a closed system. Name and describe three types of biogeochemical cycles Define abioticcomponent of an ecosystem. List three important physical factors and three important chemical factors that have large effects on ecosystems Summarize the law of tolerance. Compare limiting factors in terrestrial and aquatic ecosystems Define bioticcomponent of an ecosystem. Distinguish between producers and consumers. List and distinguish four types of consumers. Distinguish among scavengers, detritus feeders and decomposers. Distinguish between photosynthesizers and chemosynthesizers; aerobic respiration and anaerobic respiration

4. Essential Questions / Objectives Distinguish between food chains and food webs; a grazing food web and detrital food web. Apply the second law of energy to food chains and pyramids of energy, which describe energy flow in ecosystems. Explain how there may be exceptions to pyramids of numbers and biomass, but not energy Evaluate which ecosystems show the highest average net primary productivity and which contribute most to global net primary productivity Briefly describe the historical development and distinguishing features of three approaches ecologists use to learn about ecosystems: field research, laboratory research, and systems analysis Define ecosystem service. List five examples of ecosystem services. Distinguish among three types of biodiversity. Briefly state two principles to sustain ecosystems

5. What is Ecology? Ecology is the study of the interactions of living organisms with one another and with their nonliving environment of matter and energy; study of the structure and functions of nature What roles do insects play?

6. Ecosystem Organization Overview Biosphere-Zone of earth where life is found. It consists of parts of the atmosphere (the troposphere), hydrosphere (mostly surface water and groundwater), and lithosphere (mostly soil and surface rocks and sediments on the bottoms of oceans and other bodies of water) where life is found. Sometimes called the ecosphere Ecosystems-Community of different species interacting with one another and with the chemical and physical factors making up its nonliving environment Communities-Populations of all species living and interacting in an area at a particular time Populations- Group of individual organisms of the same species living in a particular area OrganismsAny form of life (species)- group of organisms that resemble one another in appearance, behavior, chemical makeup and processes, and genetic structure. Organisms that reproduce sexually are classified as members of the same species only if they can actually or potentially interbreed with one another and produce fertile offspring

7. What are the Characteristics of Life? • All things living have the following specific properties: • Cellular organization • Metabolism • Homeostasis • Reproduction • Heredity Known species1,412,000 Other animals281,000 Fungi69,000 Insects751,000 Prokaryotes4,800 About 1.4 million species have been identified, but estimates of number of species range from 3.6 million to 100 million Plants248,400 Protists57,700

8. Cells: The Basic Unit of Life Energy Conversion Mitochondria Prokaryotic Cell Nucleus (informationstorage) Eukaryotic Cell Cell membrane (transport of raw materialsand finishedproducts) Protein construction and energy conversion occur without specialized internal structures DNA(information storage, no nucleus) Protein Construction ER Packaging Golgi Body

9. Ecosystem Organization Details Populations- Group of individual organisms of the same species living in a particular area, but not all populations are exactly the same. Characteristics of populations include: Genetic diversity explains why these individuals may not behave nor look exactly alike Habitat is the place where a population or an individual usually lives Distribution (range) is the area over which a species may be found. The genetic diversity among individuals of one species of Caribbean Snail is reflected in the variations in shell color and banding patterns A population of Monarch butterflies. The geographic distribution coincides with that of the milkweed plant on which the larvae feed

10. The Earth’s Life-Support Systems AtmosphereThe whole mass of air surrounding the earth. TroposphereInnermost layer of the atmosphere. It contains about 75% of the mass of earth's air and extends about 17 kilometers (11 miles) above sea level. Stratosphere Second layer of the atmosphere, extending about 17-48 kilometers (11-30 miles) above the earth's surface. It contains small amounts of gaseous ozone (O3), which filters out about 95% of the incoming harmful ultraviolet (UV) radiation emitted by the sun. HydrosphereThe earth's liquid water (oceans, lakes, other bodies of surface water, and underground water), frozen water (polar ice caps, floating ice caps, and ice in soil, known as permafrost), and water vapor in the atmosphere LithosphereOuter shell of the earth, composed of the crust and the rigid, outermost part of the mantle outside the asthenosphere; material found in earth's plates

11. Natural Capital: Sustaining Life of Earth Flow of Energy to and from the Earth From the sun to the Earth One-way flow of energy from Sun Cycling of Crucial Elements Gravity

12. Flow of Energy to and from the Earth The amount of energy received and topography of a region determines climate. Terrestrial parts of the biosphere are classified as biomes, areas such as deserts, forests, and grasslands. Aquatic life zones describe the many different areas found in a water environment, such as freshwater or marine life zones (coral reefs, coastal estuaries, deep ocean). Fig. 4-9 p. 61

13. Major Biomes and the Role of Climate The amount of energy received and topography of a region determines climate. Terrestrial parts of the biosphere are classified as biomes, areas such as deserts, forests, and grasslands. Aquatic life zones describe the many different areas found in a water environment, such as freshwater or marine life zones (coral reefs, coastal estuaries, deep ocean).

14. Biomes of the World Tropic of Cancer Equator Tropic of Capricorn Semidesert, arid grassland Arctic tundra (polar grasslands) Desert Boreal forest (taiga), evergreen coniferous forest (e.g., montane coniferous forest) Tropical rain forest, tropical evergreen forest Mountains (complex zonation) Temperate deciduous forest Tropical deciduous forest Ice Temperate grassland Tropical scrub forest Dry woodlands and shrublands (chaparral) Tropical savanna, thorn forest

15. Aquatic Life Zones-Marine and freshwater portions of the biosphere. Examples include freshwater life zones (such as lakes and streams) and ocean or marine life zones Depth in meters High tide Sun Low tide Coastal Zone Open Sea Sea level 0 50 Euphotic Zone Photosynthesis 100 Estuarine Zone Continental shelf 200 500 Bathyal Zone Twilight 1,000 1,500 2,000 Abyssal Zone 3,000 Marine Life Zones Darkness 4,000 5,000 10,000

16. Ecosystem Components The major components of ecosystems are abiotic (nonliving) water, air, nutrients, solar energy, and biotic (living) plants, animals, and microbes.

17. Ecosystem Factors Ecosystem characteristics include a range of tolerance to physical and chemical environments by the ecosystem's populations Law of tolerance: The distribution of a species in an ecosystem is determined by the levels of one or more physical or chemical factors being within the range tolerated by that species. Aquatic life zones can be limited by the dissolved oxygen (DO) content in the water, temperature, pH or by the salinity Sugar Maple The limiting factor principle states that too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimum range of tolerance. An abiotic factor such as lack of water or poor soil can be understood here

18. Ecosystem Components The major biological components of ecosystems are the producers/autotrophs that are self-feeders and the consumers/heterotrophs. Autotrophsphotosynthesize making their own food from compounds in the environment (organisms such as green plants and algae). A few specialized producers can convert simple compounds to more complex compounds without sunlight, a process called chemosynthesis. Heterotrophs (consumers) feed on other organisms or their remains. Herbivores feed on plants. Carnivores feed on animals. Omnivoresfeed on both plants and animals. Detritivores feed on dead organic matter and break it down into smaller molecules Decomposers (bacteria/fungi) break down organic detritus into simpler inorganic compounds.

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

20. Ecosystem Components Glucose and other organic compounds are broken down and energy released by the process of aerobic respiration, the use of oxygen to convert organic matter back to carbon dioxide and water. This process is a net chemical change to that of photosynthesis. Photosynthesis:CO2 + H2O C6H12O6 + O2 CO2 + H2OC6H12O6 + O2 Aerobic Respiration “Cellular Respiration” Some decomposers are able to break down organic compounds without using oxygen. This process is called anaerobic respiration, or fermentation. The end products are compounds such as methane gas, ethyl alcohol, acetic acid, and hydrogen sulfide. Matter is recycled; there is a one-way flow of energy. Light Glucose sugar Carbon dioxide oxygen water

21. Biological Diversity (Biodiversity) Biodiversity is the amazing variety of earth's genes, species, ecosystems, and ecosystem processes. The kinds of biodiversity are: Genetic diversity: the variety of genetic material with a species or population Species diversity: the number of species present in different habitats Ecological diversity: the variety of terrestrial and aquatic ecosystems found in an area or on the earth Functional diversity: the biological and chemical processes such as energy flow and mater cycling needed for the survival of species, communities, and ecosystems Human cultural diversity is included as part of the earth's biodiversity by some people. Biodiversity keeps us alive and supports our economies. Biodiversity is a renewable resource as long as humans live off the interest, not destroy the capital.

22. Food Chains and Energy Flow in Ecosystems Food chains and food webshelp us understand how eaters, the eaten, and the decomposed are interconnected in an ecosystem. The sequence of organisms as they are eaten is a food chain. Food webs are complex networks of interconnected food chains. They are maps of life's interdependence. Trophic levels are feeding levels for organisms within an ecosystem,(1) Producers belong to the first trophic level. (2) Primary consumers belong to the second trophic level.(3)Secondary consumers belong to the (4) third trophic level.Detritivores and decomposers process detritus from all trophic levels. Energy flow in a food web/chain decreases at each succeeding organism in a chain or web. The dry weight of all organic matter within the organisms of a food chain/web is called biomass.

23. Tropic Levels Humans Ecological efficiency is the term that describes the percentage of usable energy transferred as biomass from one trophic level to another and ranges from 2%-40% with 10% being typical. The greater number of trophic levels in a food chain, the greater loss of usable energy. Blue whale Sperm whale Killer whale Elephant seal Crabeater seal Leopard seal Emperor penguin Adélie penguins Petrel Squid Fish Carnivorous plankton Herbivorous zooplankton Krill Phytoplankton

24. Ecological Pyramids Pyramid of numbers Compares the total number of organism at each trophic level Pyramid of energy flow The pyramid of energy flow visualizes the loss of usable energy through a food chain. The lower levels of the trophic pyramid support more organisms. If people eat at a lower trophic level (fruits, vegetables, grains directly consumed), Earth can support more people. There is a large loss of energy between successive trophic levels. Pyramid of biomass Compares biomass(The dry weight of all organic matter within the organisms of a food chain/web) at each trophic level

25. Primary Productivity of Ecosystems Gross primary productivity (GPP)The rate at which an ecosystem's producers capture and store a given amount of chemical energy as biomass in a given length of time. Net primary productivity (NPP) Rate at which all the plants in an ecosystem produce net useful chemical energy; equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (gross primary productivity) and the rate at which they use some of that energy through cellular respiration. The three most productive systems are swamps and marshes, tropical rain forests, and estuaries. The three least productive are tundra, desert scrub, and extreme desert.

26. Figure4-22 p.71 On land - Dark green highest GPP / Brown or White lowest GPP At Sea: Red, Orange, yellow, green, light blue, dark blue (highest GGP to lowest) The planet's NPP limits the number of consumers who can survive on Earth. The highly productive tropical rain forest cannot support agriculture as practiced in developed countries. Marshes and swamps do not produce food that can be eaten directly by humans; they feed other aquatic species that humans consume (fish, shrimp, clams). Humans are using, wasting, and destroying biomass faster than producers can make it.

27. Soils Importance Soil provides nutrients needed for plant growth; it helps purify water. It is a thin covering that is made of eroded rock, minerals, decaying organic matter, water, air, and billions of living organisms. Mature soils have developed over a long time, are arranged in soil horizons (series of horizontal layers), and have distinct textures and compositions in these layers that vary among different types of soils. Layers of soil, called soil horizons, vary in number, composition, and thickness.

28. Soil Formation and Generalized Soil Profile

29. Horizons The top part/layer is the surface litter layer or O horizon. This layer is brown/black and composed of leaves, twigs, crop wastes, animal waste, fungi, and other organic material. The topsoil layer or A horizon is composed of decomposed organic matter called humus, as well as some inorganic mineral particles. Thick topsoil layers help hold water and nutrients. These two top layers teem with bacteria, fungi, earthworms, and small insects. Air and water fill spaces between soil particles. Plant roots need oxygen for aerobic respiration. The B horizon(subsoil) and the C-horizon (parent material) have most of the soil's inorganic matter—sand, silt, clay, and gravel. The C-horizon rests on bedrock.

30. soil texture Relative amounts of the different types and sizes of mineral particles in a sample of soil. soil permeability Rate at which water and air move from upper to lower soil layers. porosity Percentage of space in rock or soil occupied by voids, whether the voids are isolated or connected. Soil is a complex mixture of inorganic minerals (clay, silt, pebbles, and sand), decaying organic matter, water, air, and living organisms

31. Soil Profiles in Different Biomes Dark-brown/black topsoil is rich in nitrogen and organic matter. Gray, yellow, or red topsoils need nitrogen enrichment. Fig. 4-27, p. 75

32. Leaf Litter Food Web

33. Connections: Matter Cycling in Ecosystems Biogeochemical cycles Hydrologic cycle (H2O) Carbon Cycle Nitrogen Cycle Phosphorous Cycle Sulfur Cycle Back to Essential Questions

34. How Do Ecologists Learn About Ecosystems? Field research -Ecologists do field research, observing and measuring the ecosystem structure and function. Remote sensing -New technologies such as remote sensing and geographic information systems (GISs) gather data that is fed into computers for analysis and manipulation of data. Computerized maps may be made of an area to examine forest cover, water resources, air pollution emissions, coastal changes, and changes in global sea temperatures. Laboratory research -Ecologist use tanks, greenhouses, and controlled indoor and outdoor chambers to study ecosystems(laboratory research). This allows control of light, temperature, CO2, humidity, and other variables. Field and laboratory studies must be coupled together for a more complete picture of an ecosystem.

35. Geographic Information System(GIS) Tracking the 1997-1998 El Niňo Topex / Poseidon http://maps.google.com/maps?ie=UTF-8&hl=en&tab=wl Fig. 4-35 p. 84

36. Systems analysisdevelops mathematical and other models that simulate ecosystems that are large and very complex and can't be adequately studied with field and laboratory research. This allows the analysis of the effectiveness of various alternate solutions to environmental problems and can help anticipate environmental surprises. We need baseline data about components and physical and chemical conditions in order to determine how well the ecosystem is functioning in order to anticipate and determine how best to prevent harmfulenvironmental changes. Define objectives Systems Measurement Identify and inventory variables Obtain baseline data on variables Make statistical analysis of relationships among variables Data Analysis Determine significant interactions Construct mathematical model describing interactions among variables System Modeling Run the model on a computer, with values entered for different variables System Simulation System Optimization Evaluate best ways to achieve objectives