1. decline of fisheries worldwide
2. collapse of Chesapeake Bay oyster, blue crab and fish populations
3. Collapse of human societies due to deforestation and other abuses of the environnment (Haiti/Easter Island/Mayans)
4. Flooding and droughts as a result of destruction of wetlands and montane forests
5. fire, logging, and forest health
6. global climate change resulting from deforestation and greenhouse gas emissions.
7. The introduction of exotic species resulting in the disruption of both natural and human dominated ecosystems and the spread of diseases (West Nile Virus)
8. Connected with this are the "dead zones" in the Gulf of Mexico due to pesticide and fertilizer run off along the Mississippi River

Before the oil spill in 2010

• The dead zone is caused by nutrient enrichment from the Mississippi River, particularly nitrogen and phosphorous.
• nitrogen and phosphorous enter the river through upstream runoff of fertilizers, soil erosion, animal wastes and sewage. 
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• The study of the relationships between organisms and their environment. 
• The study of the interactions (both with the physical environment and other organisms) that determine the distribution and abundance of a species 

• the sum total of all physical and biological factors influencing a particular organism.
• The external physical and biological factors that influence growth, survivorship, development, and reproduction of organisms (ultimately, fitness!) 

• Physical Environment: Abiotic Factors
• climate, soil, nutrients, etc. 
• Biological environment: biotic factors
• competitors, predators, parasites, diseases, etc. 

1. Ecological systems function according to the laws of thermodynamics (Ecosystems)
2. The physical environment exerts a controlling influence on the productivity of ecological systems (Ecoystems)
3. The structure and dynamics of ecological communities are regulated by population processes (populations)
4. over generations, organisms respond to change in the environment through evolution within populations (evolution)

Energy can neither be created nor destroyed but may change form. 

important transformations include:

• electromagnetic energy to chemical energy (photosynthesis) and to heat energy (climate).
• chemical energy to kinetic energy (energy of motion) and to heat energy.

• in each energetic transformation, potential energy is reduced, as some energy is lost to the system as heat; or
• entropy increases in a closed system.
• the second law says that energetic transformations are always less than 100% efficient
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because they're not closed systems

-without a constant input of energy, ecoysystems would degrade & life would perish

• tells us that the transfer of energy from one trophic (energy) level (plants to herbivores, for example) to another always involves a dissipation of energy. 

the levels of organization in ecology

what are the units of study?

1. Individual organisms and adaptations to the environment.
2. populations
3. communities
4. ecosystems. 

an environmental unit consisting of biotic & abiotic components related through exchanges of energy and nutrients.

the emphasis in ecosystem ecology is on the movement of energy and nutrients within ecosystems. 

• it is importance to conservation biology in which species are thought to undergo regular local extinctions

• trophic (energy) levels
• heterotrophs
• decomposers

• autotrophs
• can be photosynthetic or chemosynthetic organisms 

• primary carnivores
• secondary carnivores
• tertiary carnivores

animals that feed on primary carnivores (e.g: birds such as chickadees that feed on spiders, for example).

• food chains or food webs.
• based on trophic relationships.
• limited number of trophic links due to Laws of Thermodynamics.
• declining energy in higher trophic levels produces the "Trophic Pyramid"
• Rule of Thumb: approximately 10% of energy transferred to next trophic level. 

Yes, "The Law of unintended consequences."

complex systems create unanticipated or undesireable outcomes with human interference

1. Extinction or near extinction of many native endemic fish species. About half of the 400 species of Tilapia are now extinct. 
2. Loss of phytoplankton eating fish species resulted in.
3. Great increase in algae ("blooms")
• Followed by:
4. Die off of algae; decomposition of algae; anoxia for much of the lake.
5. Further die of fish from lack of oxygen.
6. proliferation on snails due to loss of snail eating fish.
7. Spread of snail borne diseases among the people (Schistosomyosis)
8. Necessity of wood fires to smoke the Nile Perch. Native fish could air dried.
9. Cutting of forest around lake to provide wood for fires to smoke fish.
10. Erosion of land around lake due to tree removal
11. Further Pollution and sedimentation of lake.
12. further loss of fish species.