Transcript Concepts In Ecology

Concepts In Ecology
Rocco Cieri
Medford High School
Population Ecology
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Size of population (N)
Density (total number per area)
Dispersion (distribution of individuals)
Age Structure (abundance of individuals at each
age)
Survivorship (mortality of individuals)
r-selected – no parental care, lots of offspring, high
death rate
K-selected – extensive parental care, few offspring,
low death rate
Population Growth
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Exponential
– idealized
population in an
unlimited
environment
Logarithmic
–
maximum population
size that a particular
environment can
support (S-curve)
Limiting Factors to Growth
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Density-dependent factor
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Competition for a shared food resource, water, sunlight,
essential life ingredients, or space
Predation
stress/crowding
waste accumulation
Density-independent factor
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weather/climate (droughts, cold snaps)
periodic disturbances
Human Population Growth
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How many humans can Earth support?
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Consider:
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Increases in food supply
Reduction in disease
Reduction in human wastes (water purification)
Expansion of habitat
There is no consensus among scientists as
to the carrying capacity of Earth.
Community Ecology
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Competitive Exclusion
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Resource Partitioning
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sympatric species tend to diverge in those characteristics that overlap (Darwin’s Finches)
Predation
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sympatric species consume slightly different foods or use other resources in slightly different
ways
Character Displacement (niche shift)
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2 species with similar needs for the same limiting resources cannot coexist in the same place
Kills and eats another animal
Symbiosis
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Two species that live together in close contact during a portion (or all) of their lives.
Mutualism – both species benefit
Commensalism – one species benefits, other is neither helped nor harmed
Parasitism – one benefits, the other is harmed
Ecological Succession
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Ecological succession
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Primary
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transition in species composition over ecological
time
begun in lifeless area; no soil, perhaps volcanic
activity or retreating glacier
Secondary
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an existing community has been cleared by some
disturbance that leaves the soil intact
Coevolution
Cryptic (camouflage) coloration
Aposematic (warning) coloration
Mimicry – a superficial resemblance to another species
– Batesian
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palatable/ harmless species mimics an unpalatable/ harmful
model
Müllerian
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2 or more unpalatable, aposematically colored species
resemble each other
Biogeochemical Cycles
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Biogeochemical cycles are the movements of
matter from one organism to the next and
through the environment.
Water
Carbon
– Nitrogen
– Phosphorus
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Matter Recycles
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Water Cycle
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Transpiration
Evaporation
Precipitation
Carbon
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Biological processes of carbon = respiration,
photosynthesis, decomposition
Geochemical processes of carbon = volcanic activity
and storage within earth's crust
Human activities = burning fossil fuels, cutting and/or
burning wood
Matter Recycles (II)
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Nitrogen
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Nitrogen fixation = when the atmosphere or bacteria take
atmospheric nitrogen and convert it into Ammonia, Nitrates
and Nitrites
Denitrification = when bacteria take nitrates and nitrites and
convert them into atmospheric nitrogen
Phosphorus
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Phosphorus is essential to living organisms becuase it forms
an important part of DNA, RNA, and ATP.
Phosphorus is released through erosion of rocks and
sediments.
Phosphates (useful phosphorus compounds) are taken in by
organisms in water. Usually it is a Limiting Nutrient, when too
much is in water it can be harmful.