Transcript Ecological Succession

April 16, 2012
1. How does energy flow through
an ecosystem?
2. What is a trophic level and give
an example?
3. Explain the difference between
a detritivore and a decomposer.
Ecological Succession
SPI 3210.2.6
SPI 3210.2.7
Essential Question:
How does the process of
ecological succession reshape
an ecosystem?
Ecological Succession
• Ecosystems are constantly
changing in response to natural
and human disturbances.
Primary Succession
• Occurs on surfaces where no soil or
nutrients are present.
– Examples
• land covered with lava rock after a
volcanic eruption.
• Bare rock exposed when glaciers melt.
• Paved areas such as parking lots
• It can take up to 1800 years for an
ecosystem to form through primary
succession.
Primary Succession
• The first species to populate the
area are called pioneer species.
– These are often lichens.
• Made up of fungus and algae that
can grow on bare rock.
Primary Succession
• Next, mosses and grasses will
begin to take root.
• Eventually, tree seedlings and
shrubs sprout among the plant
community.
Which of the following events would
cause primary succession to occur?
A. Forest fire
B. Deforestation
C. Volcanic eruption
D. Flood
Which of the following would be
considered a pioneer species?
A. Grass
B. Shrubs
C. Moss
D. Lichens
How long does it take for an ecosystem
to form from primary succession?
A. Up to 10 years
B. Up to 100 years
C. Up to 500 years
D. Up to 1800 years
Secondary Succession
• Occurs when ecosystems are
changed through natural or
human disturbances leaving the
soil intact.
– Examples:
• Forest fires
• Farming
• Deforestation
Secondary Succession
• Occurs much faster than primary
succession. The ecosystem
usually recovers in 300 years.
Secondary Succession
• Could forest fires sometimes be
beneficial for an ecosystem?
Which of the following would result in
secondary succession?
A. Volcanic eruption
B. Glacier receding
C. Forest fire
D. Paving new roads
How long would it take for an ecosystem to
fully recover via secondary succession?
A. 50 years
B. 15 years
C. 300 years
D. 1500 years
Water Cycle
Carbon Cycle
Nitrogen Cycle
• Largest concentration found in
atmosphere (N2)
• Nitrogen fixation: Capture
and conversion of N2 gas into a
form useable by plants
– Bacteria
• Denitrification: Soil bacteria
convert fixed nitrogen into N2
Nitrogen Cycle
Phosphorus Cycle
• Short-term: phosphates in
solution are cycled from
soilproducersconsumers
– Decomposers return phosphorus to
the soil
• Long-term: weathering or
erosion of rocks containing
phosphorus slowly add to the cycle.
Phosphorus Cycle