1. Succession/Population DynamicsBy
Diana Bivens

2. Why do organisms live where they do?
Limiting factors: anything living or not that restricts the number of a particular organism in an area
How might a cold climate be a limiting factor?
Dry climate?
Salt water?

3. Why do organisms live where they do?
Tolerance range: the ability of an organism to adjust to environmental fluctuations
-Catfish need little oxygen and can live in warmer water
-Bass/Trout need more oxygen and need much colder water

4. Changes in an ecosystem
Changes in the environment can affect organisms that live there
Succession: orderly natural changes that take place over time and occur in stages

5. Primary Succession
Primary succession: the colonization of new areas by organisms
-pioneer species: the first organisms to colonize an area (usually mosses and lichens)
The decay of pioneer species produces soil
With soil comes the ability to sustain larger species

6. Primary Succession

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USFS Controlled Burn Forest Fire, Flathead National Forest, Montana
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Succession
Secondary succession: the community changes that occur after it has been destroyed by a natural disaster or human activity
The land already contains soil
The pioneer species will differ from that in primary succession

8. Primary vs. Secondary Succession

9. Succession
Climax community: a mature, stable community in which little or no succession occurs
-will the climax community be the same in all areas? Why or why not?

10. Population Dynamics
Population: a group of the same species that interbreed and live in the same area at the same time

11. Population Dynamics Density: the number of individuals per area
Dispersion: arrangement of individuals within a given space
Even
Clumped
Random

12. Calculating Growth Equation:
(births- deaths ) + (immigration-emigration) = growth

13. r-strategists vs. K-strategists
Population Dynamics
r-strategists vs. K-strategists
mosquito elephant
short life span long life span
many offspring few offspring
little/ no parental care greater parental care

14. J curve Population Dynamics
Populations grow exponentially when resources are unlimited
J curve

15. S curve Population Dynamics
A population will eventually reach its carrying capacity
Carrying capacity: the number of one species an area can support
S curve

16. What limits population size?
Resource limits
Carrying capacity is reached when the consumption of a resource matches the production of that resource
Competition
Members compete for limited resources
Members compete for territories

17. Population Regulation
Density dependent deaths: rapid deaths that occur within dense populations
Disease, predation, limited resources
Density independent deaths: deaths that occur regardless of a populations density
Natural disasters, severe weather

18. Competition and Populations
When populations are low, resources are plentiful
When populations increase, resources become scarce-

19. Predation and Populations
Predator-prey relationships help maintain population numbers
As prey numbers fluctuate, predator numbers follow

21. Human Population Growth

22. Human Population Growth
Demography: the study of human population growth
Growth rate: the difference between births and deaths
Which country would you expect to see the highest growth rate?
United States or Zimbabwe?

23. Human Population Growth
Developed countries are seeing a leveling off of population levels.
Growth rates
U.S. : 0.6%
Germany: -1.5%
Zimbabwe: 2.5%

24. Human Population Growth
Other factors affecting growth
Age structure
of a population
Immigration and emigration

25. Calculating growth rates
Equation:
(births- deaths )+(immigrants-emigrants)=growth