Download Ecosystem Ecology

Ecosystem Ecology
the movement of materials and
energy through an ecosystem
Section 22-1
Pages 415-419
Producers
• Manufacture their own food
• Capture energy and use it to make organic
molecules
• There are two types:
– Photosynthetic = use energy from light
– Chemosynthetic = use energy from inorganic
chemicals
• Examples = plants, protists, and bacteria
Gross Primary
Productivity
- is the rate at which producers
in an ecosystem capture
energy
Biomass
- is the organic material in an
ecosystem
Standing Crop Biomass
Net Primary
Productivity
= gross primary productivity – rate
of respiration in producers
- is the rate at which biomass
accumulates
- is expressed as:
energy/area/year (kcal/m2/y)
mass/area/year (g/m2/y)
Primary Productivity of
Different Ecosystems
Consumers
• obtain energy by ingesting or consuming
organic molecules made by other organisms
• grouped according to the food they eat
– Herbivores = eat producers
– Carnivores = eat consumers
– Omnivores = eat both producers and
consumers
– Detritivores = eat garbage
– Decomposers = break down dead tissues
and waste into smaller molecules
Movement of Stuff Through Ecosystems
Trophic Levels
• an organism’s position in the
sequence of energy transfers
• most ecosystems contain only
three or four trophic levels
st
Producers = 1 level
Herbivores = 2nd level
rd
Carnivores = 3 level +
Movement of Energy
Food Chain
• a pathway of feeding
relationships
Food Chains
Grazing Food Chain
Food Web
Energy Movement & Nutrient Cycling
Pyramid of Net Production
Ecological Efficiency
Why is energy transfer so low?
• Energy is reflected.
• Energy is lost when some parts
cannot be digested.
• Energy is lost as waste.
• Energy is lost in cellular respiration.
• Energy is lost as heat.
• Organisms die without being eaten.
Ecological Efficiency
100 * 6 / 67 = 9%
100 * 67 / 1478 = 4.5%
100 * 3,368 / 20,810 = 17%
Pyramid Shape
• A diagram of trophic level
relationships
• Width of bar correlates with the
number
• Three primary types of diagrams
–Energy
–Biomass
–Population numbers
Biomass Pyramids
Pyramid of Numbers
Ecological Biomagnification