Transcript We must consider our planet to be on loan from our

“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 Ecology
Campbell Chapters 54-55
(Part I)
LE 54-2
Tertiary
consumers
Microorganisms
and other
detritivores
Detritus
Secondary
consumers
Primary consumers
Primary producers
Heat
Key
Chemical cycling
Energy flow
Sun
LE 53-12
Quaternary
consumers
Carnivore
Carnivore
Tertiary
consumers
Carnivore
Carnivore
Secondary
consumers
Carnivore
Carnivore
Primary
consumers
Herbivore
Zooplankton
Primary
producers
Plant
A terrestrial food chain
Phytoplankton
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
Tertiary
consumers
Secondary
consumers
Primary
consumers
Primary
producers
Figure 54.11
10 J
100 J
1,000 J
10,000 J
1,000,000 J of sunlight
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
Plant material
eaten by caterpillar
200 J
67 J
Feces
Figure 54.10
100 J
33 J
Growth (new biomass)
Cellular
respiration
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
Concentration of PCBs
Herring
gull eggs
124 ppm
Figure 54.23
Lake trout
4.83 ppm
Smelt
1.04 ppm
Zooplankton
0.123 ppm
Phytoplankton
0.025 ppm
Ecological succession in
Massachusetts . . .
•
•
•
•
Ferns and Grasses
Shrubs
White pine
Hardwoods (maple,
oak, hickory, and
some birches)
• Hemlock and Beech
Resource Partitioning
• Resource partitioning is the differentiation
of niches – no two species can occupy the
same niche.
A. insolitus
usually perches
on shady branches.
A. ricordii
A. distichus perches
on fence posts and
other sunny
surfaces.
A. insolitus
A. alinigar
A. distichus
A. christophei
A. cybotes
A. etheridgei
Figure 53.3
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
(b) Green parrot snake
Figure 53.7a, b
(a) Hawkmoth larva
• In Müllerian mimicry
– Two or more unpalatable species resemble
each other
(a) Cuckoo bee
Figure 53.8a, b
(b) Yellow jacket
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
Number of species
present
– Exhibit their role as a keystone species in intertidal
communities
With Pisaster (control)
20
15
10
Without Pisaster (experimental)
5
0
1963 ´64
(a) The sea star Pisaster ochraceous feeds
preferentially on mussels but will
consume other invertebrates.
Figure 53.16a,b
´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 CARBON CYCLE
THE WATER CYCLE
• The water cycle and the carbon cycle
CO2 in atmosphere
Transport
over land
Photosynthesis
Solar energy
Cellular
respiration
Net movement of
water vapor by wind
Precipitation
over ocean
Evaporation
from ocean
Precipitation
over land
Burning of
fossil fuels
and wood
Evapotranspiration
from land
Percolation
through
soil
Runoff and
groundwater
Figure 54.17
Carbon compounds
in water
Higher-level
Primary consumers
consumers
Detritus
Decomposition
THE PHOSPHORUS CYCLE
THE NITROGEN CYCLE
• The nitrogen cycle and the phosphorous cycle
N2 in atmosphere
Rain
Geologic
uplift
Runoff
Assimilation
NO3
Nitrogen-fixing
bacteria in root
nodules of legumes
Decomposers
Ammonification
NH3
Nitrogen-fixing
soil bacteria
Figure 54.17
Denitrifying
bacteria
Consumption
Sedimentation
Nitrifying
bacteria
Nitrification
Plants
Weathering
of rocks
Soil
Plant uptake
of PO43
Leaching
NO2 
NH4+
Nitrifying
bacteria
Decomposition