1. Population Dynamics
SOL BIO 9a

2. BIO SOL: 9a
The student will investigate and understand dynamic equilibria within populations, communities, and ecosystems.
Key concepts include:
interactions within and among populations including carrying capacities, limiting factors, and growth curves;
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.

3. Population Dynamics
Population: all the individuals of a species that live together in an area
Demography: the statistical study of populations, make predictions about how a population will change
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. Population Dynamics Three Key Features of Populations Size Density
Dispersion
(clumped, even/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.

5. Three Key Features of Populations
1. Size: number of individuals in an area
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.

6. Three Key Features of Populations
Growth Rate: Birth Rate (natality) - Death Rate (mortality)
How many individuals are born vs. how many die
Birth rate (b) − death rate (d) = rate of natural increase (r).
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.

7. POST-REPRODUCTIVE
REPRODUCTIVE
PRE-REPRODUCTIVE

8. Population of a Stable Country  

10. You decide!

11. 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

13. 4 Factors that affect density
1. Immigration- movement of individuals into a population
2. Emigration- movement of individuals out of a population

14. 4 Factors that affect density
3. Density-dependent factors- Biotic factors in the environment that have an increasing effect as population size increases
  Ex. disease
competition
parasites

15. 4 Factors that affect density
4. Density-independent factors- Abiotic factors in the environment that affect populations regardless of their density
  Ex. temperature
storms
habitat destruction
drought

16. Factors That Affect Future Population Growth
Immigration + + -
Population
Mortality
Natality -
Emigration

17. 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.

18. Clumped
Clumped Dispersion Is the tendency for populations to be found in tight clusters, dispersed across a large landscape. In between these population hubs, very few to no individuals are usually found. This sort of a dispersion can be caused by a number of factors. Some species cluster together for protection, while others group around natural resources necessary to their survival.

19. Uniform Dispersion
The tendency for populations to be found evenly distributed about their habitat. This is generally caused by a species ability to survive anywhere in their habitat - they use the resources found immediately around them, and spread out as to use all of the available resources.

20. Random Dispersion
the tendency for populations to be found randomly about their habitat. In immobile species, this is usually caused by their ability to live anywhere in a given habitat, except, they are limited to growing wherever they first set root. In motile populations, individuals are able to move about their habitat, so that at any given instance, they can be found anywhere about their environment.

21. clumped even (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.
random

22. Population Dispersion

23. Other factors that affect population growth
Limiting factor- any biotic or abiotic factor that restricts the existence of organisms in a specific environment.
EX.- Amount of water
Amount of food
Temperature

24. Limiting Factor- Zone of Tolerance
Few organisms present
None
Few organisms present
None
Many organisms present
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.

25. Other factors that affect population growth
Carrying Capacity- the maximum population size that can be supported by the available resources
There can only be as many organisms as the environmental resources can support
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.

26. J-shaped curve (exponential growth)
Carrying Capacity Nu m b e r
J-shaped curve (exponential growth)
Carrying Capacity (k)
S-shaped curve (logistic growth)
Ok so
Time

30. R and K strategists
Organisms that live in stable environments tend to make few, "expensive" offspring. Organisms that live in unstable environments tend to make many, "cheap" offspring.

31. R and K Strategists
The two evolutionary "strategies" are termed r-selection, for those species that produce many "cheap" offspring and live in unstable environments and K-selection for those species that produce few "expensive" offspring and live in stable environments.

32. 2 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. 2 Life History Patterns 2. K Strategists long life span
large body size
reproduce slowly
have few young
provides parental care
Ex: humans, elephants

34. Measuring Population Size
There are two main ways to estimate the size of a population:
1. Trap, Mark ,Release, Recapture
2. Random Sampling

35. Trap, Mark, Release, Recapture
One type of estimating method is called “mark and recapture.” Here’s an example showing how mark and recapture works. First, turtles in a bay are caught in a way that does not harm them. Ecologists count the turtles and mark each turtle’s shell with a dot of paint before releasing it

36. Trap, Mark, Release, Recapture
. Two weeks later, the researchers return and capture turtles again. They count how many turtles have marks, showing that they have been recaptured, and how many are unmarked. Using a mathematical formula, the ecologists can estimate the total population of turtles in the bay.

37. Random Sampling
In many cases, it is not even possible to count signs of every member of a population. The population may be very large or spread over a wide area. In such cases, ecologists usually make an estimate. An estimate is an approximation of a number, based on reasonable assumptions.

38. Random Sampling
In random sampling, the number of organisms in a small area (a sample), is counted and then multiply to find the number in a larger area.

39. Random Sampling
To get the most accurate estimate, your sample area should be typical of the larger area. Suppose you count 8 birch trees in 100 square meters of a forest. If the entire forest were 100 times that size, you would multiply your count by 100 to estimate the total population, or 800 birch trees.

40. Human Population Growth

42. Human Population Growth

43. Time unit Births Deaths
Natural increase
Year
130,013,274
56,130,242
73,883,032
Month
10,834,440
4,677,520
6,156,919
Day
356,201
153,781
202,419
Hour
14,842
6,408
8,434
Minute
247
107
141
Second
4.1
1.8
2.3