Transcript Ecology Notes

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 Cycles
Carbon Cycle:
http://www.biology.ualberta.ca/facilities/multime
dia/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 factors
Examples:
Population pressure
Biodiversity
Abiotic factors
affecting cycles
Carrying 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 Succession
Newest species to enter and
begin an ecosystem. Abiotic
transformed into Biotic or
new species entering.
Climax Succession
Largest supported
organisms