Lecture 1 ns 5 ecology and ecosystem concepts 2010

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Lecture 1 ns 5 ecology and ecosystem concepts 2010

  1. 1. 1INTRODUCTION TO ECOLOGY and ECOSYSTEM CONCEPTS
  2. 2. Case Study: Deformity and Decline in Amphibian Populations •  High incidence of deformities in amphibians •  Declining populations of amphibians worldwide •  ECOLOGISTS’ ROL E IS TO FIND ANSWERS:   Amphibian population declines were recent.   Many declining populations were in pristine or protected areas.   Amphibians are “biological indicators” of environmental problems Figure 1.1 Deformed Leopard Frogs faculty.sxu.edu/~cochran/ecoweb09/ecointro.ppt
  3. 3. HUMANS & ECOLOGY… • Humans have enormous impact on the planet. • Humans are part of global environment. • We must understand how natural systems work. • Ecology is the field of Biological Science that studies the functions of natural systems.
  4. 4. WHAT ECOLOGY IS….AND IS NOT • Ecology is not “Environmentalism” • Ecology is not “Natural History” • Ecology is a Science  “The study of the patterns and processes that determine the distribution and abundance of organisms.”  Based on observations, hypotheses, empirical tests, theory, models and more tests!
  5. 5. ECOLOGISTS VS NATURALIST VS ENVIRONMENTALISTS Example: Consider the •  Naturalist: Observes robins American Robin, Turdus and paints/photographs/ migratorius writes/composes music about robins. Provides valuable “Natural History.” •  Ecologist: Asks, “What causes the robin’s singing behavior? Seeks to explain the Natural History. •  Environmentalist: Seeks action to preserve the habitat of the robin. faculty.sxu.edu/~cochran/ecoweb09/ecointro.ppt
  6. 6. Ecology is the scientific study of interactions between organisms and their environment. Ecology is a branch of biology. Environmental science incorporates concepts from the natural sciences (including ecology) and the social sciences, and focuses on solutions to environmental problems.
  7. 7. Ernst Haeckel (1869) & ECOLOGY •  The scientific study of the interactions between organisms and their environments •  “By ecology we mean the body of knowledge concerning the economy of Nature - the investigation of the total relations of the animal to its inorganic and organic environment.” •  The leading German disciple of Charles Darwin •  Originally used the Greek spelling Oecologie, and defined it as “the science of the relations of living organisms to the external world, their habitat, customs, energies, parasites, etc.” faculty.sxu.edu/~cochran/ecoweb09/ecointro.ppt
  8. 8. FROM OECOLOGIE TO ECOLOGY… • Haeckel derived the new label from the same root found in the older word “economy” (“Oekonomie”):  the Greek oikos, referring originally to the family household and its daily operations and maintenance • The reason was that at that time, people thought that national economic affairs could be understood as an extension of the housekeeper’s budget.  Haeckel thought that the Earth constituted a single economic unit
  9. 9. COINING THE TERM… • Burdon-Sanderson (1890s): Elevated Ecology to one of the three natural divisions of Biology: Physiology - Morphology – Ecology Andrewartha (1961): “The scientific study of the distribution and abundance of organisms.” • Odum (1963): “The structure and function of Nature.”
  10. 10. TO STANDARDIZE OUR DEFINITION… • Charles Krebs. Studies migration and population dynamics in lemmings and other small mammals. • (1972) Ecology is the scientific study of the interactions that determine the distribution and abundance of organisms.
  11. 11. THUS… • the study of the interactions between organisms and their environment • the study of the distribution and abundance of organisms • KEY POINTS: • Interactions - between everyone and everything • Organisms - all taxa are fair game • Environment - includes ABIOTIC and BIOTIC factors outside the organism • Abundance - population sizes • Distribution - where we find organisms?
  12. 12. Official ESA Definition* • Ecology is “The scientific discipline that is concerned with the relationships between organisms and their past, present and future environments, both living and non-living.”  Understanding these relationships will explain the patterns of distribution and abundance * August 2000 Annual Meeting of the Ecological Society of America
  13. 13. WHY STUDY ECOLOGY? •  Curiosity – How does the world around us work? How are we shaped by our surroundings? •  Responsibility – How do our actions change our environment? How do we minimize the detrimental effects of our actions? Overfishing, habitat destruction, loss of biodiversity, climate change. •  Nature as a guide – The living world has been around much longer than we have and has solved many problems with creative solutions. Ecological systems are models for sustainability. How can we feed our growing population? Where will we live? •  Sustainability – a property of human society in which ecosystems (including humans) are managed such that the conditions supporting present day life on earth can continue. •  Ecology helps us understand complex problems.
  14. 14. 1 ECOSYSTEM CONCEPTS
  15. 15. The Earth environment is the home (habitat) of all forms of life including humans. All life forms depend on the proper functioning of our environment!
  16. 16. ECOSYSTEM – basic unit and probably the most important concept in ecology Two Types of System: 1.  Open system – presence of inputs and outputs (matter and energy) 2. Closed system – no exchange of matter and energy (usually artificially made, e.g. terrarium)
  17. 17. ECOSYSTEM • an ecosystem consists of all the organisms and the abiotic pools with which they interact (Chapin) • an ecosystem is the sum of all of the biological and nonbiological parts of an area that interact to cause plants to grow and decay, soil or sediments to form, and the chemistry of water to change (John Aber and Jerry Melillo)
  18. 18. EXAMPLE OF ECOSYSTEMS (CLOSED AND OPEN)
  19. 19. Controls over ecosystem processes: state factors, interactive controls, and feedbacks
  20. 20. STATE FACTORS • State factors set boundary conditions – Hans Jenny (1941)  Climate – broad geographic influence on biome distribution  Parent material – local influence on soil type  Potential biota – what organisms can occupy a site  Topography – microclimate  Time – evolution, weathering
  21. 21. INTERACTIVE FACTORS • Interactive controls: factors that both control and are controlled by ecosystem characteristics.  Resources: energy and materials used to support organisms’ growth and maintenance  Modulators: physical and chemical properties that affect organisms’ activity, but are neither ‘consumed’ nor depleted  Disturbance, Biotic Community, Human Activities
  22. 22. FEEDBACKS •  negative feedbacks – homeostasis – when two components of a system have opposite effects on one another   predator – prey   Thermostat •  positive feedbacks – when two components of a system have the same effect (positive or negative) on each other   runaway greenhouse effect – rising CO2 increases temperature, increasing respiration, increasing CO2   legumes and Rhizobium in nitrogen-fixing mutualisms – each provides key resource to the other •  IN GENERAL:   Negative feedbacks are key to maintaining ecosystems in a given state, because they resist change   Positive feedbacks, if unchecked, have the potential to shift ecosystems from one state to another
  23. 23. BIOTIC COMPONENTS ABIOTIC COMPONENTS   Producers   Climatic Factors   Green Plants   Light   Algae (Phytoplankton)   Temperature   Consumers   Precipitation   Herbivores   Wind   Carnivores   Humidity   Omnivores   Edaphic Factors   Decomposers   Soil Nutrients   Detritivores   Soil Moisture   True decomposers   Soil Ph   Bacteria and fungi   Hydrological Factors   Physicochemical factor
  24. 24. FOUR LAWS OF ECOLOGY 1.  EVERYTHING IS CONNECTED TO EVERYTHING ELSE 2.  EVERYTHING MUST GO SOMEWHERE 3.  NATURE KNOWS BEST 4.  THERE IS NO FREE LUNCH
  25. 25. 1 NEXT MEETING: ENERGY FLOWS IN AN ECOSYSTEM MINI SKIT TIME….

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