1. Population Dynamics (4.1)
SB4C. Relate environmental conditions to successional changes in ecosystems.

2. Population Ecology HOMEWORK:Chapter 4 4.1 textbook - read/notes
Population Ecology CC Ecology #2 – watch/notes

3. The number of organisms per unit area
Chapter 4
Population Ecology
Population Characteristics (AKA Demographics)
3 Main ways to describe populations:
1. Population Density
The number of organisms per unit area
2. Spatial Distribution
Dispersion is the pattern of spacing of a population.
3. Growth Rate

4. WHY & How Are Populations Measured?
DO THIS!
Density: measurement of population per unit area or unit volume
Pop. Density = # of individuals ÷ unit of space
What is the population density of humans in this classroom? (11m x 11m)
Population density = number of individuals in a given area or volume
Count all the individuals in a population
Estimate by sampling
Mark-Recapture Method

5. A C B

6. Dispersion is the pattern of spacing of a population.
Population Ecology
2. 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

7. Population Dispersion

8. Population Range
A species might not be able to expand its population range because it cannot survive the abiotic conditions found in the expanded region.
Common dolphin
Pupfish

9. density-independent factors density-dependent factors.
Population Ecology
Population-Limiting Factors
There are two categories of limiting factors —
density-independent factors
density-dependent factors.

10. Density-Independent Factors (generally abiotic)
Population Ecology
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

11. Would you want to be in an area with high population density or low population density during the Zombie Apocalypse?
Side note/thought…Is cell phone use a population density independent or density dependent factor?
*We seem to use our phones more when there are more people….WHY? Are we afraid someone might talk to us? Is it as contagious as a yawn?

12. Density-Dependent Factors
Population Ecology
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
Competition
Parasites

13. Growth Rate is affected by…
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)

14. Factors That Affect Future Population GrowthIN
Immigration + + -
Population
Mortality
Natality
A population stops increasing when natality is less than mortality or when emigration exceeds immigration. -
EXIT
Emigration

15. Exponential Growth Model
Population Growth Rate Cont’d
Population Ecology
Exponential Growth Model
Graph shows a
J-shaped Curve!
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.

16. Exponential Growth Curve
Figure 35.3A

17. Population Growth Rate Cont’d
Population Ecology
Logistic Growth Model
The population’s growth slows or stops following exponential growth, at the environment’s carrying capacity (k).
Carrying capacity (k) is the largest # of individuals an environment can support.
Graph shows an
S-shaped Curve!
Carrying capacity is limited by the energy, water, oxygen, nutrients, & space, as well as other limiting factors.

18. Logistic Growth Curve

19. Population Ecology
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.

20. Population Ecology
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
EXAMPLES ???

21. Reproductive Strategies
R Strategists
Short life span
Small body size
Reproduce quickly
Have many young
Little parental care
Ex: cockroaches, weeds, bacteria

22. Population Ecology
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
EXAMPLES ???

23. Reproductive Strategies
K Strategists
Long life span
Large body size
Reproduce slowly
Have few young
Provides parental care
Ex: humans, elephants

24. “Booms” and “Busts”

25. Rabbit/Lynx LAB
Rabbit Hunting!

27. A&P Exam – Post Exam Review

28. If you want to get all people human focused…
Demography – the study of human population size, density, distribution, movement, and birth/death rates.
HUMAN POPULATION GROWTH

29. AGE/SEX Demographics
Distribution of males and females in each age group of a population
Used to predict future population growth

30. Human Population Growth
J curve growth
Grows at a rate of about 80 million yearly
r =1.3%
Why doesn’t environmental resistance take effect?
Altering their environment
Technological advances
The cultural revolution
The agricultural revolution
The industrial-medical revolution

31. History of the Human Population

32. The Human Population Doubled three times in the last three centuries
About 6.1 billion and may reach 9.3 billion by the year 2050
Improved health and technology have lowered death rates

33. A more personal story…
Overpopulation a MYTH?

34. SmartStarter
Take a GUESS:

35. 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

36. 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

37. 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

38. 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

39. 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

40. 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

41. 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

42. 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

43. 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

44. 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

45. 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