Ecology moodle part 2
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Transcript of Ecology moodle part 2
Succession
The gradual, sequential regrowth of a species in an area due to changing
conditions
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
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 quantitySoil type
SunlightWater
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
Primary succession
• Climax Community– Will be established eventually– Community will prevail unless the area is
disturbed again– Hardwood trees (maple, beech, birch)
Examples of Primary Succession
• Bare Rock Succession• Sand Dune Succession• Pond/Lake Succession
Bare rock succession
• Pioneer Plants: – Lichens
Help break down rocks Adds humus for
new soil building What’s humus?
Substance that provides nutrientsIncreases the ability of soil to retain H2O
Bare rock succession
• Seral stages: – Mosses/fern– Grasses/weeds– Bushes– Softwood trees
• Each stage paves the way for the next stage
Bare rock succession
• Climax community– Hardwood trees
• Species of plant remain constant for a long period of time until a disturbance occurs
Bare rocks
Mosses, ferns
Grasses, weeds
Bushes
Hardwood treesSoftwood
trees
Lichen
Sand dune succession
• Pioneer plants:– Beach grass
• Roots stabilize the sand• Humus is added
to the foredune– An area directly
behind the beach
Sand dune succession
• Seral stages– Cottonwood– Pines– Oaks
• Continue to add humus and shade to the soil
Sand dune succession
• Climax community– Beech or maple
succession
Pond/lake succession
• Pioneer plants/organisms– Microscopic plants and animals
• Phytoplankton - producers • Zooplankton - consumers
• Found in open water
• Humus is added and soil develops
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
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
Pond/lake succession
• Climax community– Land
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
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.
Secondary succession
• Sequential replacement of species that follows the disruption of an EXISTING community
Secondary succession
• Pioneer species– Grasses– Weeds– Plants must be adapted to hot, dry conditions
Secondary succession
• Seral stages– Bushes– Softwood trees– Adds humus & moisture to the soil– Then later, replaced by a larger species
Secondary succession
• Climax community– Hardwood trees
Ecosystem
A system formed by the interaction of a community of organisms with
their environment
Ecological Relationships
• Trophic Level– Any class of organisms that occupy the same
position in a food chain– Examples
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
Pyramid of Energy
• A measure of theamount of energyavailable in eachtrophic level
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
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)
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
Respiration
Transpiration
Absorption
UrinationRun-off
Precipitation
Evaporation
Aquifer
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
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
Carbon dioxide
Photosynthesis
Glucose
DecompositionFossil Fuels
Combustion
Respiration
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
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
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.
Atmospheric Nitrogen
Nitrogen Fixation
Lightning
Feeding
NH4
AmmonificationNO3-
Absorption
Nitrates (NO3-)and Atmospheric Nitrogen (N2) used by plants