Download Chapter 8

Population Dynamics, Carrying
Capacity, and Conservation Biology
G. Tyler Miller, Jr.’s
Environmental Science
10th Edition
Chapter 8
Key Concepts
 Environmental factors affecting populations
 Role of predators in controlling populations
 Reproductive patterns and species survival
 Conservation biology
 Human impacts on populations
 Lessons about sustainable living
Sea Otters: Back from the Brink
of Extinction?
Keystone species
Importance of otters
Pollution effects
Orcas
Fig. 8-1, p. 160
Population Dynamics and Carrying
Capacity
 Population
dynamics
 Biotic potential (intrinsic rate of increase [r])
 Environmental resistance
 Carrying capacity (K)
 Minimum viable population (MVP)
 Exponential and logistic population growth
Dispersion Patterns for
Organisms
Fig. 8-2 p. 161
Factors Affecting
Population Size
Fig. 8-3, p. 162
Exponential and Logistic
Population Growth
Fig. 8-4, p. 163
Logistic Growth of Sheep
Population
Number of sheep (millions)
2.0
1.5
1.0
.5
1800
1825
1850
1875
Year
1900
1925
Fig. 8-5, p. 163
When Population Size Exceeds
Carrying Capacity
Overshoots
Reproductive time lag
Diebacks (crashes)
Exponential Growth, Overshoot and
Population Crash of Reindeer
Number of reindeer
2,000
1,500
1,000
500
1910
1920
1930
Year
1940
1950
Fig. 8-6, p. 164
Population Density Effects
Density-independent controls
Density-dependent controls
Natural Population Curves
Fig. 8-7 p. 164
The Role of Predation in Controlling
Population Size
 Predator-prey cycles  Top-down control
 Bottom-up control
Fig. 8-8, p. 165
Reproductive Patterns and Survival
 Asexual reproduction
 Sexual reproduction
 r-selected species
 K-selected species
Fig. 8-10 p. 167
Positions of r-selected and K-selected
Species on Population Growth Curve
Number of individuals
Carrying capacity
K
K species;
experience
K selection
r species;
experience
r selection
Time
Fig. 8-9, p. 166
r-Selected Species
cockroach
dandelion
Many small offspring
Little or no parental care and protection of offspring
Early reproductive age
Most offspring die before reaching reproductive age
Small adults
Adapted to unstable climate and environmental
conditions
High population growth rate (r)
Population size fluctuates wildly above and below
carrying capacity (K)
Generalist niche
Low ability to compete
Early successional species
Fig. 8-10a, p. 167
K-Selected Species
elephant
saguaro
Fewer, larger offspring
High parental care and protection of offspring
Later reproductive age
Most offspring survive to reproductive age
Larger adults
Adapted to stable climate and environmental
conditions
Lower population growth rate (r)
Population size fairly stable and usually close
to carrying capacity (K)
Specialist niche
High ability to compete
Late successional species
Figure 8-10b, p. 167
Survivorship Curves
Age
Fig.8-11, p. 167
Conservation Biology: Sustaining
Wildlife Populations
 What is conservation biology?
 Which species are endangered?
 How are ecosystems functioning?
 How can ecosystems be sustained?
 Principles of conservation biology
 Aldo Leopold’s ethical principles
 Bioinformatics
Human Impacts on Ecosystems
 Habitat degradation and fragmentation
 Ecosystem simplification (monocultures)
 Wasting Earth’s primary productivity
 Genetic resistance
 Eliminating predators
 Introducing nonnative species
 Overharvesting renewable resources
 Interfering with cycling and flows in ecosystems
Human Footprint on Earth’s Land
Surface
Fig. 8-12, p. 169
Learning Sustainability from Nature
 Dependence on nature
 Interdependence
 Unpredictability
 Limited resources
 Recycle wastes
See Connections p. 170
Four Principles of Sustainability
PRINCIPLES
OF
SUSTAINABILITY
Fig. 8-13, p. 170
Principles of Sustainability
How Nature Works
Solutions:
Implications
of the Principles
of Sustainability
Runs on renewable
solar energy.
Recycles nutrients
and wastes.
There is little waste
in nature.
Uses biodiversity
to maintain itself
and adapt to new
environmental
conditions.
Controls a species'
population size
and resource use
by interactions
with its environment
and other species.
Fig. 8-14, p. 171
Lessons for Us
Rely mostly on
renewable solar
energy.
Prevent and reduce
pollution and recycle
and reuse resources.
Preserve biodiversity
by protecting
ecosystem
services and
preventing
premature extinction
of species.
Reduce births and
wasteful resource
use to prevent
environmental
overload and
depletion and
degradation of
resources.