1. Population Dynamics
The study of population characteristics and how they change over time
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.
Population: group of the same species in the same place at the same time.
Demography: the statistical study of populations, make predictions about how a population will change

2. Population
A group of organisms of the same species living in the same area
Three Key Characteristics of Populations
Size
Density
Dispersion
(clumped, even/uniform, random)

3. Size: number of individuals in an area
Three Key Features of Populations
Size: number of individuals in an area
Every population has a carrying capacity or a maximum limit the environment can handle due to Limiting resources.
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

4. Capacity overflow
When the carrying capacity is overshot things like competition, disease, starvation, predation etc… result in a loss of individuals

5. Growth Rates Growth Rate: The change in population size over time
The size of a population depends on the number of organisms entering (birth & immigration) and exiting it (death & emigration)
Migration Types:
Immigration – organisms move into a population
Emigration – organisms move out of a population
Types of growth rates:
Positive Growth Rate
Negative Growth Rate
Zero Growth Rate IN
OUT
Population

6. Analyzing Growth Rates on Graphs
Number of Rabbits Over Time
Zero Growth Rate
Positive
Growth Rate
Negative
Growth Rate

7. Factors That Affect Future Population Growth
Immigration + + -
Population
Mortality
Nativity -
Emigration

8. Graph: Exponential Growth
Population grows exponentially if:
Birth and death rates are constant
More births than deaths
Immigration = Emigration
Creates a
J-Shaped Curve
What is happening?
Growth starts out slowly
Increases rapidly as the number of reproducing individuals increase
Only will occur when there are NO Limiting recourses

9. Graph: Logistic Growth
Usually, there are limits to growth… So….
As the population uses up available resources (nutrients, energy, space, etc.), the overall growth will slow or stop.
Growth will slow or decrease when birth rate decreases or death rate increases.
Eventually the number of births will equal the number of deaths (approaching Zero Growth Rate)
Creates a
S-Shaped Curve

10. Carrying Capacity
Carrying Capacity (K): The number of individuals the environment can support in a given area
Healthy populations will fluctuate around the carrying capacity

11. Limiting Factors
Limiting Factor: Anything that restricts population size
Resources (food, space, water, etc.) are limited
Two main types of limiting factors
Density independent factors
Density dependent factors

12. Density Independent Factors: (does not depend on size of pop)
Abiotic factors in the environment that affect populations regardless of their density
Population size doesn’t matter
Ex: Weather, natural disasters, seasonal cycles

13. Density Dependent Factors: (depends on side of pop)
Biotic factors in the environment that have an increasing effect as population size increases
Ex: Competition, disease, predation
Usually only affects large, dense populations

14. Predation = Density Dependent

15. Limiting Factors will determine the Carrying Capacity of an environment

16. Growth of populations
Carrying capacity: The following data was taken for a fish population in Clark Pond from 2000 to 2010.
DATA TABLE
Year
Fish Population
2000 10
2001 50
2002 75
2003
120
2004
180
2005 60
2006
100
2007
2008
105
2009
115
2010

17. Use the data table from the previous slide: Graph the fish population data. Reminder: independent var goes on X axis, dependent var goes on the Y axis Hint: don’t forget a title for your graph and Label the X and Y axis.

18. Data analysis
Generate a list of at least 4 factors (abiotic and biotic) that could affect the fish population.
Why do you think the size of the population increased starting in 2001?
Why do you think that the population decreased in 2004?
Based on the graph, what do you think the carrying capacity of the pond is? Why?
BONUS: why did growth slow down as time continued?

19. HOW MANY PEOPLE LIVE ON EARTH?
As of
What type of growth rate does this look like?

20. GROWTH RATES REVISITED…
Human CC video?
We will reach a carrying capacity and it will be DISASTROUS

21. ZERO POPULATION GROWTH
In order to achieve zero population growth,
the average couple has just 2 kids

22. AGE STRUCTURE DIAGRAMS
Shows % of people alive at each age group
The U.S. has more _____ 80+ individuals.
What is happening in Mexico’s
older population?
What % of under 5 years
old is male in Sweden?
A little more than 3%

23. POST-REPRODUCTIVE
REPRODUCTIVE
PRE-REPRODUCTIVE

24. Reading age structure diagramsB C D A
Which graph is showing rapid population growth
Which graph is showing no population growth
Which graph is showing negative population growth

25. 2. Density: measurement of population per unit area or unit volume
Three Key Features of Populations
2. Density: measurement of population per unit area or unit volume
Formula: Dp= N
Pop. Density = # of individuals ÷ unit of space
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat. S

27. World Density for Humans

28. 3. Dispersion: describes their spacing relative to each other clumped
Three Key Features of Populations
3. Dispersion: describes their spacing relative to each other
clumped
even or uniform
random
Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

29. Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

30. Population Dispersion
clumped
random
even (uniform)

31. What is the carrying capacity for the WallaWalla Deer

32. Life History Patterns 1. R Strategists short life span small body size
reproduce quickly
have many young
little parental care
Ex: cockroaches, weeds, bacteria

33. Life History Patterns 2. K Strategists long life span large body size
reproduce slowly
have few young
provides parental care
Ex: humans, elephants

34. Life history patterns lead to typical survivorship curves for organisms.
Type I – K Strategists
Most individuals live to old age (high survivorship early and middle years)
Species with few offspring, long period of parental care (humans, large mammals)
Type II – characteristics of both K and R
Constant survivorship across life span
Invertebrates, lizards, rodents, some birds
Type III – R Strategists
Low survivorship early followed by high survivorship in older individuals
Species with large number of offspring, little or no parental care

35. Survivorship curves

36. Check for understanding Questions
Why do you think is it important to study population dynamics?
What are the three main characteristics of a population.
Give an example of a density dependent limiting factor, make sure to explain HOW/WHY it is density dependent.
Give an example of a density independent limiting factor, make sure to explain HOW/WHY it is density independent.
What are limiting factors?
What is a carrying capacity and how does it effect populations?