Ecology - The Ecosystem PDF

Ecology The Ecosystem Prepared by: Mr. Yves Paul M. Montero Reference: Odum, E. P. and Barrett, G. W. (2005). Fundamentals of Ecology. Brooks/Cole. We are, after all, a species in an ecosystem, exactly adapted to the conditions peculiar to...

Ecology The Ecosystem Prepared by: Mr. Yves Paul M. Montero Reference: Odum, E. P. and Barrett, G. W. (2005). Fundamentals of Ecology. Brooks/Cole. We are, after all, a species in an ecosystem, exactly adapted to the conditions peculiar to the surface of this planet, and subject to the same principles of ecology as all other species. -E. O. Wilson- Topics 1. Concept of ecosystem and ecosystem management 2. Trophic structure of the ecosystem 3. Gradient and ecotones 4. Examples of ecosystems 5. Ecosystem diversity 6. Study of ecosystem  The Concept of the Ecosystem as a System ▪ Biotic– living organisms; abiotic – nonliving environment ▪ Biotic community – all organisms ▪ Ecological system or ecosystem – any unit that includes biotic community in a given area interacting with the physical environment so that a flow of energy leads to clearly defines biotic structures and cycling of materials between living and nonliving components ▪ Ecosystem management ▪ General system theory developed in the mid-20th century by Bertalanffy (1950, 1968) ▪ E.P. Odum (1953), E.C. Evans (1956), Margalef (1958), Watt (1966), Patten (1966, 1971), Van Dyne (1969), and H.T. Odum (1971) ▪ Ecosystem ecology – definitive, quantitative field ▪ Ecosystems are general system and self-organizing ▪ Ecosystems – open systems, things are constantly entering and leaving ▪ General appearance and basic function may remain constant General System Theory Organizational system Inputs Processes or Outputs “throughputs” Outcomes, Resources and products, and information services created needed to or delivered bu supply the the organization organizational The activities within the system organizational system that gets work done Crispy-Chicken House Inputs Processes or Outputs “throughputs” Fried chicken People, served to ingredients, customers, tools, space, profit, electricity, paychecks, water, etc. Mix ingredients for the wastes, etc. coating, slice the chicken, take the orders, fry the chicken, delegate tasks, etc. ▪ Open system ▪ Holism ▪ Interdependence ▪ Feedback ▪ Entropy  Teams Whole organization Major departments Ecosystem Model (external environment) Functional diagram of an ecosystem (internal dynamics) The extent of input and output environment varies: 1. Size of the system (the larger, the less dependent on external environment) 2. Metabolic intensity (the higher the rate, the greater the input and output) 3. Autotrophic-heterotrophic balance (the greater the imbalance, the more externals to balance 4. Stage of development (young systems differ from mature systems) Earth’s climate varies by latitude and season, and is changing rapidly  Climate and Disturbance ▪ Climate - the long-term prevailing weather conditions in an area: temperature, precipitation, sunlight, wind ▪ Macroclimate - global, regional, and landscape level ▪ Microclimate –small, area (community of organisms underneath a fallen log) Global Climate Patterns ▪ determined by solar energy and the planet’s movement in space ▪ causes temperature variations, which drive evaporation and the circulation of air and water ▪ This causes latitudinal variations in climate Latitudinal Variation in Sunlight Intensity What does this mean? Why does it happen? ▪ Rising air masses release water and cause high precipitation, especially in the tropics ▪ Dry, descending air masses create arid climates, especially near 30° ▪ Air flowing close to Earth’s surface creates predictable global wind patterns ▪ Cooling trade winds blow from east to west in the tropics; prevailing westerlies blow from west to east in the temperate zones 66.5°N (Arctic Circle) 60°N Descending 30°N dry air Westerlies absorbs 30°N moisture. Northeast trades Ascending moist air 0° releases moisture. Southeast trades 30°S Westerlies 0° 60°S 66.5°S (Antarctic Circle) Global air circulation and precipitation patterns Regional and Local Effects on Climate ▪Climate is affected by seasonality, large bodies of water, and mountains Seasonality ▪ Seasonal variations of light and temperature increase steadily toward the poles (WHY?) ▪ Belts of wet and dry air straddling the equator shift throughout the year with the changing angle of the sun ▪ Changing wind patterns affect ocean currents Bodies of Water ▪ Oceans, their currents, and large lakes moderate the climate of nearby terrestrial environments ▪ The Gulf Stream carries warm water from the equator to the North Atlantic ▪ Why is there a breeze at the ocean shoreline?  Labrador Current California Current Gulf Stream North Atlantic 30°N North Pacific Subtropical Subtropical Gyre Gyre Equator Indian South Ocean Atlantic Subtropical South Pacific 30°S Subtropical Gyre Subtropical Gyre Gyre Antarctic Circumpolar Current Mountains ▪ Rain shadows- determine where many deserts are found ▪ Mountains affect the amount of sunlight reaching an area ▪ South-facing slope in the Northern Hemisphere receives more sunlight than north- facing slopes and are therefore warmer and drier Leeward side Air flow of mountains Mountain range Ocean Trophic Structure of the Ecosystem Two layers of ecosystem: 1. Autotrophic stratum (upper) ▪ “green belt” of chlorophyll-containing plants ▪ Fixation of light energy ▪ Utilization of simple organic substances ▪ Buildup of complex organic substances 2. Heterotrophic stratum (lower) ▪ “brown belt” of soils and sediments, decaying matter , roots, etc. ▪ Utilization ▪ Rearrangement ▪ Decomposition of complex materials Components constituting an ecosystem 1. Inorganic substances - involved in material cycles; ex. C, N, CO2 and H2O 2. Organic compounds – link biotic and abiotic components; ex. Protein, carbohydrates, lipids and humic substances 3. Air, water and substrate environment, including the climate regime and other physical factors 4. Producers – autotrophic organisms; mostly green plants that can manufacture food from simple inorganic substances 5. Phagotrophs – heterotrophic organisms (animals); ingest other organisms or particulate organic matter 6. Saprotrophs- decomposers (mainly bacteria and fungi); heterotrophic organisms that obtain their energy by breaking down dead tissues or by absorbing DOM from plants and animals; saprophages  Epilimnion Thermocline Hypolimnion Benthic Measuring community metabolism -light-and-dark bottle technique Turnover ▪ the ratio of throughput to content ▪ can be expressed either as a rate of fraction or as a “turnover time” which is the reciprocal of the rate of fraction The Watershed Concept ▪ Eutrophication – ▪ Cultural Eutrophication – a. b. Global Production and Decomposition ▪ Allochthonous Inputs - Organic matter that enters an ecosystem from outside sources ▪ Autochthonous Production - Organic matter produced within an ecosystem, primarily through photosynthesis by primary producers (e.g., plants, algae). Kinds of photosynthesis: Oxygenic Photosynthesis: This is the most common type, performed by plants, algae, and cyanobacteria. It uses water as an electron donor and produces oxygen as a byproduct. The overall equation is: ▪ 6CO₂ + 6H₂O + light energy → C₆H₁₂O₆ + 6O₂ Anoxygenic Photosynthesis: This type is performed by certain bacteria, such as purple sulfur bacteria and green sulfur bacteria. It does not use water as an electron donor and does not produce oxygen. Instead, it uses other electron donors, such as hydrogen sulfide or hydrogen gas. ▪ Oxygen is not released ▪ Photosynthetic bacteria ▪ Cyanobacteria ▪ Obligate anaerobe ▪ Purple Bacteria ▪ Green Bacteria ▪ Facultative anaerobe Ecological Evolution of C3, C4, and CAM Plants ▪ C3 Plants- are the ancestral type ▪ C4 Plants – adaptation to hot and dry climates ▪ CAM - extreme adaptation to arid conditions  Chemosynthetic bacteria Inside Sulfur Springs Park in St. Lucia Types of Decomposition and Decomposers ▪ Type 1. Aerobic Respiration ▪ Type2. Anaerobic respiration ▪ Type 3. Fermentation