1. Do now activity #4 What is commensalism? Give an example.
What is mutualism? Give an example.
What is parasitism? Give an example.
What is a symbiotic relationship?

2. Section 8-2: Populations
Essential Question:
How do characteristics of a population shape the population over time?
Learning Target
Explain how environmental factors affect carrying capacity of a population.
Analyze population data and explain how age structure, growth rate, and population density will impact the population over time.
Section 8-2: Populations

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4. overview Population: a group of the same species in the same area
cyclins
Population: a group of the same species in the same area

5. overview
cyclins
Density, age groups, and growth rates are used to describe populations.

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7. Population Density is the number of individuals in an area.

8. Population density
Geographic distribution (range) describes the size of the area an organism lives in.

9. Population density
This can vary in size from a few cm3 to millions of km2.

10. Population density Population density is calculated by this formula:
number of individuals in the area
Geographic distribution
Example:
100 antelope inhabiting 1 km2 area of land would be:
100 antelope
1 km2

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12. The ages of individuals in a population determine the age groups.
Phosphorus is necessary for organisms
DNA & RNA
ATP
Stored mostly in rocks, soil and ocean sediment.
Not in the atmosphere
Plants absorb phosphorus from soil
Phosphorus then moves through the food web
Dead plants and animals decompose, the phosphorus goes back into the soil.

13. Age groups Old people don’t have babies
U.S. Life Expectancy = Men: 75/Women:80
A high % of young people means a greater potential for rapid growth.
Phosphorus is necessary for organisms
DNA & RNA
ATP
Stored mostly in rocks, soil and ocean sediment.
Not in the atmosphere
Plants absorb phosphorus from soil
Phosphorus then moves through the food web
Dead plants and animals decompose, the phosphorus goes back into the soil.

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15. Growth rate Growth rate
is how fast the number of individuals increases or decreases in a population.

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17. Population size Four factors affect population size # of births
# of deaths
Immigration (moving in)
Emigration (moving out)
________________________________________________________________________________________________________
(# of births + immigration #) – (# of deaths + emigration #) = POPULATION GROWTH
Population size the year before + Population growth = CURRENT POPULATION SIZE
Phosphorus is necessary for organisms
DNA & RNA
ATP
Stored mostly in rocks, soil and ocean sediment.
Not in the atmosphere
Plants absorb phosphorus from soil
Phosphorus then moves through the food web
Dead plants and animals decompose, the phosphorus goes back into the soil.

18. Don’t forget to chunk your notes!

19. Exponential growth Exponential Growth
Occurs when a population reproduce at a constant rate.
Creates a J-shaped curve
There has to be unlimited resources.
Food, Water. Shelter

20. Logistical growth
Growth - birth > death
Stationary - birth = death
Decline - birth < death
Logistic growth Accounts for the influence of limiting factors. -it has an S-curve
The carrying capacity is the # of individuals the environment can support.

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