2. Succession
• PRIMARY succession
– Development of a community in an area that has
not supported life before.
• Requires the building of soil by PIONEER PLANTS
– Small fast-growing & fast-reproducing plants
– Lichen, moss, crabgrass, plankton
3. Primary succession
• Seral stages
– Developmental stages of an environment
– Ecological communities that succeed one
another in the biotic development of an area
– Species will eventually be replaced by
successive species based on conditions such as
Soil quantity Sunlight
Soil type Water
4. Seral stages
• Can be determined by an index species
• Index species Definition
– Species that are used as a reference point to
indicate relative placement in an ecosystem
5. Primary succession
• Climax Community
– Will be established eventually
– Community will prevail unless the area is
disturbed again
– Hardwood trees (maple, beech, birch)
6. Examples of Primary Succession
• Bare Rock Succession
• Sand Dune Succession
• Pond/Lake Succession
7. Bare rock succession
• Pioneer Plants:
– Lichens
Help break down rocks
Adds humus for
new soil building
What’s humus?
Substance that provides nutrients
Increases the ability of soil to retain H2O
8. Bare rock succession
• Seral stages:
– Mosses/fern
– Grasses/weeds
– Bushes
– Softwood trees
• Each stage paves the way for the next stage
9. Bare rock succession
• Climax community
– Hardwood trees
• Species of plant remain constant for a long
period of time until a disturbance occurs
10. Lichen
Hardwood
Softwood
trees
Bushes trees
Mosses, Grasses,
ferns weeds
Bare rocks
11.
12. Sand dune succession
• Pioneer plants:
– Beach grass
• Roots stabilize the sand
• Humus is added
to the foredune
– An area directly
behind the beach
13. Sand dune succession
• Seral stages
– Cottonwood
– Pines
– Oaks
• Continue to add
humus and shade
to the soil
17. Pond/lake succession
• Pioneer plants/organisms
– Microscopic plants and animals
• Phytoplankton - producers
• Zooplankton - consumers
• Found in
open water
• Humus is added
and soil develops
18. Pond/lake succession –
Seral stages
• Rooted submerged zone
– Closer to the shore
– Light penetrates all the way to the bottom so
young plants can grow
– Algae/Kelp
19. Pond/lake succession –
Seral stages
• Rooted floating zone
– Rooted in the bottom and leaves float on the
surface
– Water lilies
• Emergent zone
– Very shallow water
– Rooted in the bottom and
extend through the surface
– Cattails
22. Process of lake/pond succession
• As the plants die and as sediment washes in
from the surrounding land the lake (pond)
fills-in
• First the open water zone disappear
• Then the rooted submerged zone,
• Then the rooted floating zone,
• Then the emergent zone
23. Process of lake/pond succession
• Succession of an open field now takes place
(grasses and weeds, bushes, softwood trees,
finally hardwood trees)
• Climax community will depend on the biome
the lake (pond) was in.
32. Energy Flow
• Producers have the most energy.
• As an organism eats the next, available energy
decreases.
• Only 10% is passed on to the next trophic
level. (Ten Percent Law)
• What happens to the other 90%?
– Transferred as heat to the environment
33.
34. Pyramid of Energy
• A measure of the
amount of energy
available in each
trophic level
35. Ecosystem Recycling
• All molecules are recycled naturally in the
environment through a biogeochemical cycle.
• Biogeochemical cycle
– Movement of elements through various
compartments (at least one being biological).
– Water cycle
– Carbon/oxygen cycle
– Nitrogen cycle
36. Water Cycle
• Movement of water through various reservoirs
• Precipitation
– Water falling from the atmosphere to the ground
• Transpiration
– Water entering the atmosphere from plants
• Respiration
– Water entering the atmosphere from animals
• Evaporation
– Water entering the atmosphere through a phase change
(liquid to gas)
37. Water Cycle
• Absorption
– Water taken in by a plant
• Urination
– Water added to the ground by an animal
• Runoff/Seepage
– Excess water entering land or another body of water
• Aquifer/Groundwater
– Underground water stored in porous rocks
41. Carbon/Oxygen Cycle
• Movement of organic compounds through
various reservoirs.
• Based on concepts of photosynthesis and
cellular respiration
• Photosynthesis
– Autotrophs used CO2 found in the atmosphere
and convert it into an organic compound C6H12O6
42. Carbon/Oxygen Cycle
• Respiration
– Hetertrophs consume the glucose and release carbon
compounds in the form of CO2 wastes
• Decomposition
– When detritivores feed off of the remains of dead
organisms
• Fossil fuel
– Formed from years of high temperature and pressure of
decaying, organic matter
• Combustion
– The burning of organic matter
45. Nitrogen Cycle
• Movement of nitrogen-containing compounds
(proteins, nucleic acids, atmospheric
nitrogen, urine, ammonia, nitrates and nitrites.)
• Cycle could not exist if it wasn’t for BACTERIA
• Ammonification
– Decomposition
– When detritivores feed off the remains of dead
organisms and convert protein and nucleic acids into
ammonia
46. Nitrogen Cycle
• Nitrification
– When bacteria convert ammonia into nitrates (NO3) and
nitrites (NO2)
• Absorption
– When plants take up nitrates and form amino acids which
consumers will acquire as protein
• Denitrification
– When bacteria break down nitrates and produce nitrogen
gas
47. Nitrogen Cycle
• Nitrogen Fixation
– When bacteria found on special plants
(legumes – beans, peas, alfalfa) converts
atmospheric nitrogen into ammonia.
– Lightning can also perform this process.
48. Atmospheric
Nitrogen
Nitrogen
Fixation
Lightning
Feeding
NO3- Ammonification
Absorption NH4
Nitrates (NO3-)and Atmospheric Nitrogen (N2) used by plants
