Introduction to Ecology
Ecology
• The study of all components (abiotic
and biotic) within a defined area.
• Basic organization:
BiosphereBiomesEcosystems
CommunitiesPopulationsIndividuals
6 major terrestrial biomes
• TRF
• Desert
• Tundra
• Deciduous Forest
• Coniferous Forest
• Grasslands
• Temperature
• Water (precipitation)
• Soil
Aquatic Biomes
• Major distinction is whether water is fresh or salt
• Estuaries: any where freshwater meets saltwater.
Marine Zones
A)Intertidal/Neretic – highly photic has
contact with coast
B) Open Sea/Oceanic – photic but no
contact with the coast
C) Open Sea/Pelagic - non-photic no
contact with land
D) Deep sea/Benthic - non-photic, cold
temps and high pressure
Marine Zones are based on
what 2 main traits?• Depth
– Light
– Pressure
– Temperature
• Contact with
coast
Energy
• What governs the type, abundance
and relationship between living and
non-living things?
• The available energy!
• Therefore we can label biotic items in
each ecosystem by their energy
needs.
• Trophic = energy!
Trophic Levels
• Primary producers~ the trophic level
that supports all others; autotrophs
• Primary consumers~ herbivores
• Secondary consumer-carnivores&
omnivores
• Tertiary consumers~ carnivores&
omnivores
Clean up crew!
• Detritivores- (Detritus feeders) aka
scavengers-EX:
– Larger –will be regulated on energy
pyramid (as secondary consumer)
because of size.
• Decomposers- EX:
– Smaller-does not get regulated on energy
pyramid because of size.
• BOTH heterotrophs that feed on non-
living organic matter…..
Relationships (Community)• Trophic structure / levels~ feeding relationships in
an ecosystem as trophic means “nourishment’.
• Food chain~ trophic level food pathway, linear
• Food Web- many food chains
Energy Flow• Ecological efficiency:
% of E transferred from one trophic level to the next (10% gets through, called the 10% Law)-multiplicative loss per level
• We have 3 diagrams to illustrate efficiency and numbers of organisms/energy:
Pyramid of Energy/productivity: shows the
amount of retained and available energy per
trophic level. (Measured in Joules –J)
Pyramid of Biomass: shows actual weight of
what each trophic level contains
Pyramid of Numbers: Shows the actual
number of each type of organism on each
trophic level
Population Growth Models
Exponential model • idealized
• Called “r populations” (J-curve)
Logistic model• realized
• Called “K populations”
(S-curve)
Which one happens most often? Why?
Strategies to increase biotic
potential
• r-selected (opportunistic)
• Short maturation &
lifespan
• Many (smaller)
offspring
• No/little parental care
• High death rate
• EX:?
• K-selected (equilibrial)
• Long maturation &
lifespan
• Few (larger)offspring;
• Extensive parental care
• Low death rate
• EX:?
Population limiting factors-
Environmental resistance!• Density-dependent
factors: • limited food water, shelter •predation • disease
• Density-independent factors •weather/climate
• These factors lead to K*
• (*K=The max number of individuals an area can sustain/Carrying capacity)
• Biotic potential vsEnvironmental resistance! (All life must deal with this)
• Leads to adaptation