Post on 15-Feb-2016
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“We must consider our planet to be on loan from our children, rather than being a gift from our ancestors”, G.H. Brundtland (former Prime Minister of Norway)
Community EcologyCampbell Chapters 54-55
(Part I)
LE 54-2
Microorganismsand other
detritivores
Tertiaryconsumers
Secondaryconsumers
Detritus Primary consumers
Sun
Primary producers
Heat
Key
Chemical cycling
Energy flow
LE 53-12
Quaternaryconsumers
Tertiaryconsumers
Carnivore
Carnivore
Carnivore
Carnivore
Secondaryconsumers
CarnivoreCarnivore
Primaryconsumers
ZooplanktonHerbivore
Primaryproducers
PhytoplanktonPlant
A terrestrial food chain A marine food chain
Pyramids of Production• This loss of energy with each transfer in a food
chain– Can be represented by a pyramid of net production
Figure 54.11
Tertiaryconsumers
Secondaryconsumers
Primaryconsumers
Primaryproducers
1,000,000 J of sunlight
10 J
100 J
1,000 J
10,000 J
Production Efficiency• When a caterpillar feeds on a plant leaf
– Only about one-sixth of the energy in the leaf is used for secondary production
Figure 54.10
Plant materialeaten by caterpillar
Cellularrespiration
Growth (new biomass)
Feces 100 J33 J
200 J
67 J
Production Efficiency
Food Web: network of feeding relationships
• In biological magnification– Toxins concentrate at higher trophic levels because
at these levels biomass tends to be lower
Figure 54.23
Conc
entr
ation
of P
CBs
Herringgull eggs124 ppm
Zooplankton 0.123 ppm
Phytoplankton 0.025 ppm
Lake trout 4.83 ppm
Smelt 1.04 ppm
Ecological succession in Massachusetts . . .
• Ferns and Grasses• Shrubs• White pine• Hardwoods (maple,
oak, hickory, and some birches)
• Hemlock and Beech
A. insolitususually percheson shady branches.
A. distichus perches on fence posts and
other sunny surfaces.
A. distichus
A. ricordii
A. insolitus
A. christophei
A. cybotesA. etheridgei
A. alinigar
Figure 53.3
Resource Partitioning• Resource partitioning is the differentiation
of niches – no two species can occupy the same niche.
Community Interactions
• Mimicry• Parasitism• Commensalism• Coevolution (Yucca moth
and Yucca plant)• Predator/prey• Mutualism• Symbiosis• Exotic species
• Cryptic coloration, or camouflage– Makes prey difficult to spot
Figure 53.5
• Aposematic coloration– Warns predators to stay away from prey
Figure 53.6
• In Batesian mimicry– A palatable or harmless species mimics an
unpalatable or harmful model
(a) Hawkmoth larva
(b) Green parrot snake
Figure 53.7a, b
• In Müllerian mimicry– Two or more unpalatable species resemble
each other
(a) Cuckoo bee
(b) Yellow jacketFigure 53.8a, b
Parasitism – one species benefits while the other is harmed Braconid wasps parasitizing a tomato horn worm
• In commensalism– One species benefits and the other is not
affected Ex. Bird nests in trees
Mutualism – both species benefit
Keystone Species
• Keystone species– Are not necessarily abundant in a community– Exert strong control on a community by their
ecological roles, or niches
• Field studies of sea stars– Exhibit their role as a keystone species in intertidal
communities
Figure 53.16a,b
(a) The sea star Pisaster ochraceous feeds preferentially on mussels but will consume other invertebrates.
With Pisaster (control)
Without Pisaster (experimental)N
umbe
r of s
peci
es
pres
ent
0
5
10
15
20
1963 ´64 ´65 ´66 ´67 ´68 ´69 ´70 ´71 ´72 ´73
(b) When Pisaster was removed from an intertidal zone, mussels eventually took over the rock face and eliminated most other invertebrates and algae. In a control area from which Pisaster was not removed, there was little change in species diversity.
Invasive species!
Artificial corridors
Biogeochemical Cycles
• The water cycle and the carbon cycle
Figure 54.17
Transportover land
Solar energy
Net movement ofwater vapor by wind
Precipitationover ocean
Evaporationfrom ocean
Evapotranspirationfrom land
Precipitationover land
Percolationthroughsoil
Runoff andgroundwater
CO2 in atmosphere
Photosynthesis
Cellularrespiration
Burning offossil fuelsand wood Higher-level
consumersPrimaryconsumers
DetritusCarbon compounds in water
Decomposition
THE WATER CYCLE THE CARBON CYCLE
• The nitrogen cycle and the phosphorous cycle
Figure 54.17
N2 in atmosphere
Denitrifyingbacteria
Nitrifyingbacteria
Nitrifyingbacteria
Nitrification
Nitrogen-fixingsoil bacteria
Nitrogen-fixingbacteria in rootnodules of legumes Decomposers
Ammonification
Assimilation
NH3 NH4+
NO3
NO2
Rain
Plants
Consumption
Decomposition
Geologicuplift
Weatheringof rocks
Runoff
SedimentationPlant uptakeof PO4
3
Soil
Leaching
THE NITROGEN CYCLE THE PHOSPHORUS CYCLE