Goals of This Course

1. Goals of This Course • Understand ecosystem structure and function • Understand how ecosystems can be disrupted • Understand local ecological issues • Understand the basic methods of experimental design and analysis

2. Ecology and Ecosystems • Ecology – Study of the interactions of living organisms with one another and with their non-living environment of matter and energy. Ecology is basically the study of why we find living organisms where we do!

3. Levels of Ecological Study • Population – distinct group of individuals of a species that live, interbreed, and interact in the same geographic area. • Community – includes all of the populations of organisms that live and interact with one another in a given area at a given time.

4. Levels of Ecological Study • Ecosystem – consists of a self-sustaining, self-regulating community of organisms interacting with the physical (abiotic) environment within a defined geographical environment. • Biosphere – Earth. • Bayousphere – Research Lab, 303 Gouaux Hall

5. Biosphere Biosphere Ecosystems Communities Populations Organisms Universe Galaxies Planets Earth Biosphere Landscapes Ecosystems Communities Species Populations Individual Organisms Organ Systems Organs Tissues Cells Sub cellular Organelles Molecules Atoms Realm of Ecology

6. One of the main goals of this course is to grasp a detailed understanding of what ecosystem function is and what mechanisms affect ecosystem structure and function. Timbalier Island 7/2/2005, photo’s by Gary Lafleur

7. Terrestrial Coastal Chaparral and Scrub Coniferous Forest Desert Prairie Grassland Deciduous Forest Fresh Water Lakes Rivers Streams Marine Estuaries Coastlines Coral Reefs Deep Ocean Types of Ecosystems

8. Ecosystem Boundaries? • It is easy to picture ecosystems as having distinct boundaries. • The area of transition from one ecosystem to another is considered to be an ecotone. • Ecotones have a mixture of species from both ecosystems. • A marsh between a freshwater lake and dry land. • Zone of grasses, shrubs, and scattered small trees between forests and grasslands.

9. Where does one ecosystem end and the other begin? Two examples of ecotones.

10. Land zone Transition zone Aquatic zone Number of species Species in land zone Species in aquatic zone Species in transition zone only Species Overlap in Ecotones

11. Major Components of Ecosystems • Abiotic - nonliving • Energy, nutrients, water and air • Biotic - living • Plants, animals, and microorganisms (biota)

12. Energy Flow in Ecosystems Producers Consumers Decomposers

13. Two Laws of Thermodynamics • First Law: Energy cannot be created or destroyed, but it can be changed from one form to another. • Second Law: Energy cannot be changed from one form to another without loss of usable energy.

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

15. Second law First law One Way Flow of Energy When energy transformations occur, energy is neither created nor destroyed (1st Law) but there is always loss of usable energy, usually as heat (2nd Law).

16. Biosphere Carbon cycle Phosphorus cycle Nitrogen cycle Water cycle Oxygen cycle Heat in the environment Heat Heat Heat While energy has a unidirectional flow through ecosystems, nutrients are cycled. • All nutrients are already here. • They are cycled from one organism to another and may have a long abiotic existence. • Some nutrients are lost from ecosystems due to runoff.

17. How Do Ecosystems Gain Lost Nutrients? • Carbon – Photosynthetic fixation • Nitrogen – nitrogen fixing bacteria and atmosphere • Phosphorous – original deposits on land and shallow ocean sediments (artificial fertilizers) • Oxygen – Photosynthesis • Water – Precipitation

18. Heat Heat Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Solar energy Heat Decomposers (bacteria, fungus) Producers (plants) Consumers (herbivores, carnivores) Heat Heat Biotic Components of Ecosystems: Producers (autotrophs) -photosynthesis Consumers (heterotrophs) -respiration Decomposers

19. Trophic Levels • Producers (autotroph) • Primary Consumer (herbivore) • Secondary Consumer (carnivore) • Tertiary Consumer • Omnivore • Detritivores and Scavengers • Decomposers

20. First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Heat Heat Solar energy Heat Heat Heat Detritvores (decomposers and detritus feeders) Food Webs (chain) and Energy Flow

21. Heat Heat Heat Tertiary consumers (human) Decomposers 10 Secondary consumers (perch) Heat 100 Primary consumers (zooplankton) 1,000 Heat 10,000 Usable energy Available at Each tropic level (in kilocalories) Producers (phytoplankton) Ecological Pyramid Generally, only about 10% of usable energy is passed on to the next trophic level. Biomass follows a similar pattern.

22. Estuaries Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Lakes and streams Continental shelf Open ocean Tundra (arctic and alpine) Desert scrub Extreme desert 800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600 Average net primary productivity (kcal/m2/yr) Net Primary Production (measure of produced energy)

23. What Factors Limit a Species Abundance and/or Distribution?

24. Law of Tolerance – The existence, abundance, and distribution of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the range tolerated by that species Limiting Factor Principle - 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.

25. Tolerance limits – the range of conditions at which a species is able to survive. A particular species may have a wide tolerance for some variables, but a very narrow tolerance for other variables. Highly tolerant species can live in a variety of habitats with widely different conditions.

26. Lower limit of tolerance Upper limit of tolerance No organisms Few organisms Few organisms No organisms Abundance of organisms Population size Optimum range Zone of intolerance Zone of physiological stress Zone of physiological stress Zone of intolerance Low Temperature High Abiotic Limiting Factors • Temperature • Law of Tolerance If temperature is optimum, but dissolved oxygen is too low, there will be no fish!

27. Terrestrial Sunlight Temperature Precipitation Wind Latitude (distance from equator) Altitude (distance above sea level) Fire Frequency Soil Aquatic Light Penetration Water Currents Dissolved Oxygen Salinity Dissolved Nutrient Concentrations (especially N and P) Suspended Solids Select Key Factors Affecting Ecosystems

28. What is Ecosystem Structure ?

29. What is Ecosystem Function ?

30. Local Issues You Should UnderstandAssignment 1 • Subsidence • Global Warming • Sea Level Rise • Wetland Loss • Invasive Species • Eutrophication • Human Population Growth Pick one of these subjects and write a two page (12 pt font double spaced) synopsis that explains how that issue may affect Louisiana.

31. What is the question? Designed to answer the question? Correct interpretation? Scientific Method • Observation • Hypothesis • Experiment • Conclusion • Theory

32. Experimental Design • Will this design answer my question? • Treatment / Control – what is the question? • Randomization – assignment of treatments to experimental units so as to reduce bias • Bias – a unidirectional shift in error • Replication – assigning of more than one experimental unit to a treatment combination • What is the experimental unit?

33. Experimental Unit • The basic unit of study used for replication • Examples…..