Ecology

Ecosystem• Populations living in a habitat• Different organisms fill niches within the

ecosystem• Biomes are ecosystems or many ecosystems

living within a specific climate ( weather and land)

• All biotic and abiotic are interdependent upon each other for energy or the resources

Biogeochemical Cycles

Nitrogen Cycle (Animation): Input and outputs add Nitrogen to ecosystem build DNA and Proteins (to make cells of everything biotic)•http://vro.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/soilhealth_nitrogen-cycle

• Questions: 1) How is nitrogen (recycled) and connected to ….. ? 2) What three processes are making carbon move among biotic and abiotic things?

Biogeochemical Cycles

Water cycle: http://www.epa.gov/safewater/kids/flash/flash_watercycle.html

Biogeochemical CyclesCarbon Cycle:http://www.biology.ualberta.ca/facilities/multimedia/uploads/alberta/CarbonCycle.html

Adds carbon to all biotic things. Storage and transfer of energy uses carbon in the form of carbohydrates (sugars)Questions: 1) How is oxygen (recycled) and connected to the carbon cycle? 2) What three processes are making carbon move among biotic and abiotic things?

SYSTEMS

• Positive Feedback

• Negative feedback

Greenhouse effect

Positive Feedback --amplifies or increases change; it leads to exponential deviation away from an equilibrium.•An example of this is the possible effect that rising global temperature could have by adding more water vapor to the atmosphere.•Water is a powerful greenhouse molecule trapping heat in the atmosphere.

Greenhouse effect

Water traps heat energy

Biomass differences

Energy transfer

TOXINS and BIOACCUMULATION

• Some bacteria can change mercury to a modified form called methylmercury. Methylmercury is easily absorbed into the bodies of small organisms such as shrimp. Then as fish eat shrimp, methylmercury does not break down easily and can stay in the fish bodies for a long time. The amount of methylmercury increases in concentration at each trophic level. Fish are a major part of the diet humans as well. This process is known as bioaccumulation.

Limiting factorsExamples: Population pressureBiodiversityAbiotic factors affecting cyclesCarrying capacity Population pressure

Negative Feedback: this tends to damp down to maintain equilibrium, and promotes stability.Lynx puts a pressure on the Hare population as more are eaten and their numbers fall. Less food for the Lynx so they start to starve and their numbers fall.

Succession

An ecosystem can remain stable for thousands of years--- unless there is an accidental change that causes a species to go extinct, then succession brings about change over time. Evolution is a series of accidents/ or mutations.

Succession• Pioneer SuccessionNewest species to enter and

begin an ecosystem. Abiotic transformed into Biotic or new species entering.

Climax SuccessionLargest supported organisms