Transcript Document

“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)
Qu ickTime™ and a
TIFF (Uncompressed) decompressor
are need ed to see this picture .
Ecology (Unit 2: Chap 3, 4, 5, and 6)
• Ecology is the study of how living things
interact with their environment - it’s
niche!
What biotic (living) and abiotic (nonliving)
factors does this Cheetah need in order to
survive?
Organismal Ecology - learning
(imprinting, maturation, innate,
habituation, conditioning, etc.)
Population Ecology - cohorts,
fecundity,carrying capacity, density,
generation time
Community Ecology
LE 52-21
120
9
Lynx
80
6
40
3
0
1850
1875
1900
Year
1925
0
Lynx population size
(thousands)
Hare population size
(thousands)
Snowshoe hare
160
Landscape Ecology
Community Ecology
(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
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
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
100 J
33 J
Figure 54.10
Growth (new biomass)
Cellular
respiration
• Density is the result of a dynamic interplay
– Between processes that add individuals to a
population and those that remove individuals
from it
Births and immigration add
individuals to a population.
Births
Immigration
PopuIation
size
Emigration
Deaths
Figure 52.2
Deaths and emigration
remove individuals from a
population.
Population Ecology
• A clumped dispersion
– Is one in which individuals aggregate in
patches
– May be influenced by resource availability
and behavior
(a) Clumped. For many animals, such as these wolves, living
in groups increases the effectiveness of hunting, spreads
the work of protecting and caring for young, and helps
exclude other individuals from their territory.
Figure 52.3a
• A uniform dispersion
– Is one in which individuals are evenly
distributed
– May be influenced by social interactions
such as territoriality
(b) Uniform. Birds nesting on small islands, such as these
king penguins on South Georgia Island in the South
Atlantic Ocean, often exhibit uniform spacing, maintained
by aggressive interactions between neighbors.
Figure 52.3b
• A random dispersion
– Is one in which the position of each
individual is independent of other
individuals
(c) Random. Dandelions grow from windblown seeds that
land at random and later germinate.
Figure 52.3c
• Carrying capacity (K)
– Is the maximum population size the
environment can support
• K-selection, or density-dependent selection
– Selects for life history traits that are sensitive to
population density (large animals - elephants)
• r-selection, or density-independent selection
– Selects for life history traits that maximize
reproduction (small animals - minnows)
• Some populations overshoot K
Number of Daphnia/50 ml
– Before settling down to a relatively stable
density
180
150
120
90
60
30
0
0
20
40
60
80
100 120 140 160
Time (days)
Figure 52.13b
(b) A Daphnia population in the lab. The growth of a
population of Daphnia in a small laboratory culture
(black dots) does not correspond well to the logistic
model (red curve). This population overshoots the
carrying capacity of its artificial environment and then
settles down to an approximately stable population size.
The Global Human Population
• The human population
– Increased relatively slowly until about 1650
and then began to grow exponentially
5
4
3
2
The Plague
1
Figure 52.22
8000
B.C.
4000 3000 2000 1000
B.C. B.C. B.C. B.C.
0
0
1000 2000
A.D. A.D.
Human population
(billions)
6
• Age structure
– Is commonly represented in pyramids
Rapid growth
Afghanistan
Male
Female
8 6 4 2 0 2 4 6 8
Percent of population
Figure 52.25
Age
85
80–84
75–79
70–74
65–69
60–64
55–59
50–54
45–49
40–44
35–39
30–34
25–29
20–24
15–19
10–14
5–9
0–4
Slow growth
United States
Female
Male
8 6 4 2 0 2 4 6 8
Percent of population
Age
85
80–84
75–79
70–74
65–69
60–64
55–59
50–54
45–49
40–44
35–39
30–34
25–29
20–24
15–19
10–14
5–9
0–4
Decrease
Italy
Female
Male
8 6 4 2 0 2 4 6 8
Percent of population
Community Ecology
(Part II)
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
– That enables similar species to coexist in a
community
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
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
• In commensalism
– One species benefits and the other is not
affected
Figure 53.10
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
20
With Pisaster (control)
15
10
Without Pisaster (experimental)
5
0
1963 ´64 ´65 ´66 ´67 ´68 ´69 ´70 ´71 ´72 ´73
(a) The sea star Pisaster ochraceous feeds
preferentially on mussels but will
consume other invertebrates.
Figure 53.16a,b
(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.
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
Denitrifying
bacteria
Consumption
Sedimentation
Decomposers
NH3
Nitrogen-fixing
soil bacteria
Nitrifying
bacteria
Nitrification
Ammonification
Figure 54.17
Plants
Weathering
of rocks
Soil
Plant uptake
of PO43
Leaching
NO2 
NH4+
Nitrifying
bacteria
Decomposition