FIELD BIOLOGY & METHODOLOGY
Lecture
Fall 2015 Althoff
Energy in the Ecosystem
05
_________________…defined again
The __________________ of ecology…the
biological and physical parts of nature
together, unified by the dependence of
animals & plants on their physical
surroundings
Feeding Relationships
• Food ______--sequence of feeding
relationships through which energy
passes in ecosystem
• Food _____--various paths which
energy passes in ecosystem
For simplicity…Food Chains:
• Have many links: plant, herbivore, carnivore
•
• Viewed as _____________, leading to a
pyramid of energy (1940’s - Lindeman)
• Less and less energy passed on “___” the
trophic levels
Pyramid of Energy
• (next slide)
• ____________________= reduced each
trophic level (only 5-20%, on average, is
transferred)
• Reduced efficiency corresponds to more
and more assimilated energy spent on
______________
Food Chain Energetics
• ______________ = “self-nourishers”…make
their own food from raw inorganic materials
• ______________ = “nourished by
others”…obtain their energy and most
nutrients from eating plants and/or other
animals
Adding energy flow & nutrient cycling to
the picture…Odum 1953
Important principle: energy passes from
one link in the consumer food chain to
the next, diminished by __________ and
______________.
E.P. Odum’s “universal” model of
Ecological Energy Flow
Ricklefs Fig. 22.2, p466
Net production…
one trophic level to
the next
Odum’s contribution…con’t
• _______________ key component of “flow”
• Carbon, in particular, bears a close
relationship to energy content because of its
intimate association with photosynthesis
Primary Production (PP)
• _________ = capture of light energy =
photosynthesis = primary producer status
• ___________= total energy assimilated
by plants
• ___________= accumulated energy in
plants & available to consumers
Global Patterns of
NET Primary Production (NPP)
• Summarized in Ricklefs (p474, Fig. 22.12)
(next slide)
• Terrestrial vs. Aquatic…what are the
relationships & numbers saying??
A)_______________________
B)______________________
C)______________________
A
B
C
In Summary….
• An ecosystem is the ______________ of
organisms and the physical environment
• An ecosystem is a giant thermodynamic
machine that dissipates energy continuously
in the form of heat…..this energy initially
enters the biological realm of the ecosystem
via photosynthesis (by ____________) , which
provides energy for animals and nonphotosynthetic microorganisms (_____________)
In Summary….con’t
• ____________ is the common currency for
describing ecosystem function and structure
• Gross primary production is the total energy
assimilated by photosynthesis. Net primary
production is the energy accumulated in plant
biomass
• Ecological efficiency (i.e., movement of energy)
is _________ from one trophic level to the next
• Terrestrial ecosystems produce _____ NPP than
aquatic ecosystems. Swamps & marshes #1