2. Population Dynamics (4.1)
State Standard
SB4C. Relate environmental conditions to successional changes in ecosystems.

3. A C B

4. The number of organisms per unit area
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Characteristics (AKA Demographics)
Population Density
The number of organisms per unit area
Spatial Distribution
Dispersion is the pattern of spacing of a population.

5. Demography – the study of human population size, density, distribution, movement, and birth/death rates.

6. The number of organisms per unit area
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Characteristics
Population Density
The number of organisms per unit area
Spatial Distribution
Dispersion is the pattern of spacing of a population.
Uniform – equally dispersed – territorial animals

7. The number of organisms per unit area
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Characteristics
Population Density
The number of organisms per unit area
Spatial Distribution
Dispersion is the pattern of spacing of a population.
Uniform – equally dispersed – territorial animals
Clumped – groups – herding animals

8. The number of organisms per unit area
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Characteristics
Population Density
The number of organisms per unit area
Spatial Distribution
Dispersion is the pattern of spacing of a population.
Uniform – equally dispersed – territorial animals
Clumped – groups – herding animals
Random – no pattern – usually based on resources

9. Chapter 4
Population Ecology
4.1 Population Dynamics
Population Characteristics Cont’d
Population Range
Common dolphin
A species might not be able to expand its population range because it cannot survive the abiotic conditions found in the expanded region.
Pupfish

10. Demography – the study of human population size, density, distribution, movement, and birth/death rates.

11. Chapter 4
Population Ecology
4.1 Population Dynamics
Population-Limiting Factors
There are two categories of limiting factors—density-independent factors and density-dependent factors.

12. Density-Independent Factors (generally abiotic)
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Limiting Factors Cont’d
Density-Independent Factors (generally abiotic)
Any factor in the environment that does not depend on the number of members in a population per unit area is a density-independent factor.
Weather events
Fire
Human alterations of the landscape
Air, land, and water pollution

13. Density-Dependent Factors
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Limiting Factors Cont’d
Density-Dependent Factors
Any factor in the environment that depends on the number of members in a population per unit area is a density-dependent factor.
Biotic factors
Disease
Population Biology
Competition
Parasites

14. Growth Rate is affected by… Limiting Factors
Chapter 4
Population Ecology
Population Growth Rate
The population growth rate (PGR) explains how fast a given population grows.
Growth Rate is affected by…
Limiting Factors

15. Growth Rate is affected by… Limiting Factors Natality (# of births)
Chapter 4
Population Ecology
Population Growth Rate
The population growth rate (PGR) explains how fast a given population grows.
Growth Rate is affected by…
Limiting Factors
Natality (# of births)

16. Growth Rate is affected by… Limiting Factors Natality (# of births)
Chapter 4
Population Ecology
Population Growth Rate
The population growth rate (PGR) explains how fast a given population grows.
Growth Rate is affected by…
Limiting Factors
Natality (# of births)
Mortality (# of deaths)

17. Growth Rate is affected by… Limiting Factors Natality (# of births)
Chapter 4
Population Ecology
Population Growth Rate
The population growth rate (PGR) explains how fast a given population grows.
Growth Rate is affected by…
Limiting Factors
Natality (# of births)
Mortality (# of deaths)
Immigration (# of individuals entering)

18. Growth Rate is affected by… Limiting Factors Natality (# of births)
Chapter 4
Population Ecology
Population Growth Rate
The population growth rate (PGR) explains how fast a given population grows.
Growth Rate is affected by…
Limiting Factors
Natality (# of births)
Mortality (# of deaths)
Immigration (# of individuals entering)
Emigration (# of individuals exiting)

19. Exponential Growth Model
Chapter 4
Population Ecology
4.1 Population Dynamics
Population Growth Rate Cont’d
Graph shows a
J-shaped Curve!
Exponential Growth Model
Exponential growth occurs when the growth rate is proportional to the size of the population.
All populations grow exponentially until
some limiting factor slows the population’s
growth.

20. Chapter 4
Population Ecology
Population Growth Rate Cont’d
Logistic Growth Model
The population’s growth slows or stops following exponential growth, at the environment’s carrying capacity.
Carrying capacity is the largest # of individuals an environment can support.
Graph shows an
S-shaped Curve!

21. Chapter 4
Population Ecology
4.1 Population Dynamics
Population Growth Rate Cont’d
A population stops increasing when natality is less than mortality or when emigration exceeds immigration.
Carrying capacity is limited by the energy, water, oxygen, nutrients, & space, as well as other limiting factors.

22. Chapter 4
Population Ecology

23. Chapter 4
Population Ecology
4.1 Population Dynamics
Reproductive Patterns
Species of organisms vary in the number of births per reproduction cycle, in the age that reproduction begins, and in the life span of the organism.

24. An r-strategist is generally a small organism.
Chapter 4
Population Ecology
4.1 Population Dynamics
Reproductive Patterns Cont’d
The rate strategy, or r-strategy, is an adaptation for living in an environment where fluctuation in biotic or abiotic factors occur.
An r-strategist is generally a small organism.
Short life span
Produces many offspring

25. A k-strategist is generally a larger organism.
Chapter 4
Population Ecology
4.1 Population Dynamics
Reproductive Patterns Cont’d
The carrying-capacity strategy, or k-strategy, is an adaptation for living in stable environments.
A k-strategist is generally a larger organism.
Long life span
Produces few offspring

26. Chapter 4
Population Ecology
Chapter Diagnostic Questions
What term is used to describe the number of individuals moving into a population?
emigration
imitation
immigration
migration A B C D
CDQ 1

27. What is population density?
Chapter 4
Population Ecology
Chapter Diagnostic Questions
What is population density?
pattern of spacing of a population in an area
number of organisms in an area
characteristics of a population
manner in which a population grows A B C D
CDQ 2

28. Which is a density-dependent factor?
Chapter 4
Population Ecology
4.1 Formative Questions
Which is a density-dependent factor?
disease
fire
flooding
weather A B C D
FQ 1

29. Which is a density-independent factor?
Chapter 4
Population Ecology
4.1 Formative Questions
Which is a density-independent factor?
competition
extreme cold
parasites
predation A B C D
FQ 2

30. Which factor can limit the carrying capacity of a population?
Chapter 4
Population Ecology
4.1 Formative Questions
Which factor can limit the carrying capacity of a population?
emigration
predation
available nutrients
extreme temperatures A B C D
FQ 3

31. Which type of population growth model does this graph represent?
Chapter 4
Population Ecology
Chapter Assessment Questions
Which type of population growth model does this graph represent?
exponential
spatial
genetic
logistic A B C D
CAQ 1

32. Use the graph to explain the growth of the mice population.
Chapter 4
Population Ecology
Chapter Assessment Questions
Use the graph to explain the growth of the
mice population.
CAQ 3

33. Chapter 4
Population Ecology
Standardized Test Practice
The ecologist finds that over a 1000m2 plot of tundra, lemmings tend to concentrate in clumps in drier areas. What is the term for this pattern of spacing?
density
dispersion
logistic spacing
spatial distribution A B C D
STP 2

34. It is density-dependent. It is limited by biotic factors.
Chapter 4
Population Ecology
Standardized Test Practice
Brine shrimp are able to survive only in certain lakes that have a very high salt concentration. Which is the correct population characteristic of brine shrimp?
It is density-dependent.
It is limited by biotic factors.
It has a limited spatial distribution.
It is randomly dispersed in the environment. A B C D
STP 3

35. Standardized Test Practice
Chapter 4
Population Ecology
Standardized Test Practice
Why does the population growth level off at 10,000?
Biotic factors have made survival difficult.
The population has reached its carrying capacity.
Density-independent factors have slowed the growth of the population.
Immigration into the population has reached the maximum limit. A B C D
STP 4

36. Which organism is the best example of a k-strategist?
Chapter 4
Population Ecology
Standardized Test Practice
Which organism is the best example of a k-strategist?
wolf
grasshopper
rabbit
whale A B C D
STP 5