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. Sub cellular Organelles Molecules Atoms Realm of Ecology
Universe
Galaxies
Planets
Earth
Biosphere
Landscapes
Ecosystems
Communities
Species
Populations
Individual Organisms
Organ Systems
Organs
Tissues
Cells
Sub cellular Organelles
Molecules
Atoms
Biosphere
Ecosystems
Communities
Populations
Organisms
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. Types of Ecosystems Terrestrial Fresh Water Marine
Coastal Chaparral and Scrub
Coniferous Forest
Desert
Prairie Grassland
Deciduous Forest
Fresh Water
Lakes
Rivers
Streams
Marine
Estuaries
Coastlines
Coral Reefs
Deep Ocean

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

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%)
UV radiation
Absorbed
by ozone
by the earth
Visible
light
Lower Stratosphere
(ozone layer)
Troposphere
Heat
Greenhouse
effect
Radiated by
atmosphere
as heat (66%)
Earth
Heat radiated

15. One Way Flow of Energy
First law
Second law
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. Heat in the environment
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.
Biosphere
Carbon
cycle
Phosphorus
Nitrogen
Water
Oxygen
Heat in the environment
Heat

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

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

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

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

22. Net Primary Production (measure of produced energy)
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)

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

27. Select Key Factors Affecting Ecosystems
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

28. What is Ecosystem Structure?

29. What is Ecosystem Function?

30. Local Issues You Should Understand Assignment 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. Scientific Method Observation Hypothesis Experiment Conclusion Theory
What is the question?
Designed to answer the question?
Correct interpretation?

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…..