Post on 26-Dec-2015
Ecosystem EcologyEcosystem 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
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)
Prim
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Pro
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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 levelsProducers = 1st levelHerbivores = 2nd level
Carnivores = 3rd level +
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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.
Eco
logi
cal E
ffici
ency
100 * 3,368 / 20,810 = 17%
100 * 67 / 1478 = 4.5%
100 * 6 / 67 = 9%
Pyramid Shape• A diagram of trophic level
relationships• Width of bar correlates with the
number • Three primary types of diagrams
–Energy–Biomass–Population numbers
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