Transcript Primary productivity

Primary Productivity
 Amount
of energy or mass created during
photosynthesis

gC/m2/yr or kcal/m2/yr
 Net
Primary Productivity: biomass for
herbivores

GPP – CR = NPP
 Factors
that contribute to its success
 Nutrients, temperature, sunlight, moisture
Primary Productivity
Factors that contribute to its success
 Nutrients, temperature, sunlight, moisture
 Nutrients as limiting factor
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P = freshwater
N = terrestrial + marine
Ecosystems are stable, resilient, and
resistant
Stable: self perpetuating
Ecosystems are stable, resilient,
and resistant
 Resilient
: repair itself
 If a tree has been damaged it can
regrow using suckers
Ecosystems are stable,
resilient, and resistant
 Resistant:
ability to protect itself
Secondary Succession: soil is
there.
Change is natural
PRIMARY: NO SOIL
SECONDARY: STARTS WITH SOIL
MICROCLIMATE
Lichen
are pioneer species
YELLOWSTONE- 1988
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700,000 aces burn for 2
months
Changed the structure
of the ecosystem.
Stable ecosystems are
resilient to change
DID THE YELLOWSTONE WILDFIRE AFFECT THE
ABUNDANCE OR DIVERSITY OF ORGANISMS? HOW
DOES THE SELECTIVE PRESSURES CHANGE?
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Abundance of shade
tolerant species decrease
Abundance of shade
intolerant species
increased
Diversity remained the
same.
Disturbance adapted
species:
Prairies
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Deep roots
Forests
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Serrotinous cones
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Ecological Succession
 Primary Succession - A community begins to
develop on a site previously unoccupied by
living organisms. Example: A lava flow
creates a new land area that is colonized.
The first colonists are termed pioneer species.
 Secondary Succession - an existing
community is disrupted and a new one
subsequently develops at the site
 Climax community - community that
develops last and remains the longest
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A disturbance is any force that disrupts established
patterns of species diversity and abundance,
community structure, or community properties
e.g. storms, fires, logging.
Disturbance tends to disrupt the superior
competitors the most and allows less competitive
species to persist.
Some landscapes never reach a climax community
because they are characterized by periodic
disturbances (such as wildfires) and are made up
of disturbance-adapted species.