1. POPULATIONS

2. Ecology Recap: Species, community, populations
Food Webs and Food Chains
Energy flow
Trophic levels
Producers, primary consumers, secondary consumers, tertiary consumers
Autotrophs and heterotrophs
Energy Pyramids
Organism Relationships
Competition
Predation
Symbiosis (mutualism, commensalism, parasitism)
What is the difference between a community and a populations?

3. Population or Community?
Vs.
Individuals of same species
Live in same area
Many different populations that live together in the same defined area.

4. Why would this food web not be possible?
Different habitats

5. Habitats: where an organism lives

6. Niche: an organism’s role in society
Its place in the food web
Range of temperatures that an organism needs to survive
Its food
What eats it

7. Habitat vs. Niche
Species in the same habitat CAN’T have the same niche.
Organisms = siblings/ twins
Habitat = house
Niche = chore of taking out the trash
*both organisms (siblings/ twins) will not be able to do the same chore (niche) if they want to work in the same house.

8. Why can’t they occupy the same niche?
Would be in competition and one species would lose out

9. But different species CAN live in the same habitat
So they will interact
Competition
Predation
Symbiosis
Mutualism
Commensalism
Parasitism

10. Population Notes

11. How would you describe this population?
image
If you were a researcher studying populations what factors would you look at in this map?
What do the colors show you?
Location of the colors?
Growing or decreasing?

12. Terms to Describe Populations:
Range (distribution): a geographic range that is inhabited by a population
Density: number of individuals in an area
Growth rate: how fast or slow a population is growing
Age structure: number of individuals in different age groups

13. Is a Population Growing or Decreasing?
Factors that Determine Population Growth Rate
Factors to look at....
Birth Rate
Death Rate
Immigration: Number that enter area
Emigration: Number that leave area
If you are looking at a growing population would it have more births or deaths?

14. Examples: Low death rate High birth rate High death rate
Low birth rate
Many people leaving the area

15. Example: Penguin Population At the beginning of the year 100 penguins
During the year 50 were born and 20 penguins died and 15 penguins moved away to another population.
Did the population grow or decrease?

16. Exponential Growth
Exponential growth: when the individuals in a population reproduce at a constant rate
A J- shaped Curve
Happens when conditions are ideal

17. Logistical Growth
Logistical Growth: Starts out like an exponential curve, but as the population increases, resources become limited, and growth slows.
A S shaped curve
Happens when resources are limited
Carrying capacity: the number of individuals that a given environment can support

18. Limiting Growth Limiting factors Resources Predation
Parasites and disease

19. Human Populations
How has the size of the human population changed over time?
Why do population growth rates differ in countries throughout the world?

20. Demography
Demography: looks at the characteristics of human populations and attempts to explain how populations will change over time
Researchers look at
Birth rates
Death rates
Age structure of the population

21. Demographic Transition
Slowing of the population growth

22. Analyze a Population
Look at birth and death rates, but you also need to know... age structure

23. Age-Structure Diagrams

24. Societal Impacts?
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