Ecosystem ecology Flashcards
Ecosystem ecology
Hoe nutrients and energy move through organisms and different trophic levels
How do nutrients cycle?
In a closed system, cycle and recyce in a circular flow within ecosystems.
How does energy cycle through ecosystems?
Constant energy from the sun is converted to plants and other organisms
Continuous one-way flow
Plants use photosynthesis to convert CO2 to O2 but also use sun energy and other nutrients.
Variations in primary productivity
are proportional to Intensity, water, and temperature
Limiting resources limits productivity.
Summer in the Southern hemisphere has high productivity
Increased rainfall also has a high primary productivity.
What is net primary productivity?
Nor proportional to the biomass of producers
Ecosystems that cover a large area make large contributions even when the productivity is low.
What are primary producers?
Autotrophic photosynthsizing plants.
Why is the EArth green from space?
Chlorophyll
Trophic levels
as we move up the trophic levels more energy can move through the levels but more energy is lost
ONly 10% of energy is transferred to each new trophic level.
Ecological pyramids
lower trophic levels = more number of individuals
energy transfer is proportional to the number to individuals.
Chemicals in lower trophic levels are more concentrated = biological magnification.
Trophic pyramids
One way energy route - photosynthesis
Types:
Wide base + narrow top = 90% energy reduced
Proportional to chemical energy
Small number of predators supported by any ecosystem.
INteractions amoung trophic levels
Trophic cascades = species interacting from different trophic levels
Top down and bottom up effectF
Food chains and webs
Chains = each species is connected to another by a single chain
Webs = Consumers eat multiple food types.
NUtrient cycling
Water
Carbon
Nitrogen
Phosphor
Water cycle
Water enters atm from ocean
Constan recirculisation provides fresh water ecosystems
Transport medium to move nutrients
Disrupted by deforestation:
Rainforests create own rain
when trees are cut down land becomes desert-like and can turn into grasslands. (Madegascar)
Nitrogen cycle
Organisms need nitrogen to make nucleaic acids and biological molecules
Nitrogen moves btwn the atm, soils and water
Little organisms can use N2 - therefore N fixation, ammonification, and Nitrification takes place. Occures via bacteria and fungi
Cycle is disrupted by fossils feusla dn farming.
