1. Ch. 20.1 Population Ecology pp.379-382
Population = group of the same species, in the same place, at the same time
the place can be defined any way you decide
Pop. size = count
Pop. density = thickness
= 𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒 𝑎𝑟𝑒𝑎
Population #1: 30 people in the gym
Population #2: 20 people in Mr. G’s room
Which has a higher size?
Which has a higher density?

2. Ch. 20.1 Population Ecology pp.379-382
Pop. Size #1 = 30
Pop. Density #1 𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒 𝑎𝑟𝑒𝑎 =
Pop. Size #2 = 20
Pop. Density #2= 𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒 𝑎𝑟𝑒𝑎 =
←80 ft→
←100 ft→
←30 ft→
……….
←20 ft→

3. Ch. 20.1 Population Ecology pp.379-382
Pop. Size #1 = 30
Pop. Density #1 =
𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒 𝑎𝑟𝑒𝑎 = 30 𝑝𝑒𝑒𝑝𝑠 100 𝑓𝑡 𝑥 80 𝑓𝑡
= 30 𝑝𝑒𝑒𝑝𝑠 8000 𝑓𝑡2 = 0.003
Pop. Size #2 = 20
Pop. Density #2= 𝑝𝑜𝑝. 𝑠𝑖𝑧𝑒 𝑎𝑟𝑒𝑎 = 20 𝑝𝑒𝑒𝑝𝑠 30 𝑓𝑡 𝑥 20 𝑓𝑡
= 20 𝑝𝑒𝑒𝑝𝑠 600 𝑓𝑡2 = .03
←80 ft→
←100 ft→
←30 ft→
……….
←20 ft→

4. Ch. 20.1 Population Ecology pp.379-382
Dispersion = spatial distribution of the population
How they are spread out
Clumped
Even
Random
Name a population that might be:
Clumped:
Even:
Random:
:: :::
: : .
. : .

5. Ch. 20.1 Population Ecology pp.379-382
Dispersion = spatial distribution of the population
How they are spread out
Clumped
Even
Random
Name a population that might be:
Clumped:
ducks on a pond
Humans in a city
Even:
Owls in a forest
Random:
Beetles in a forest
:: :::
: : .
. : .

6. Ch. 20.1 Population Ecology pp.379-382
Population Dynamics = how populations change
Dynamic = changing constantly
Birth rate = births/time
Death rate = deaths/time
Life expectancy = how long the average individual is expected to live
Why might the average woman live longer?
Is it because they are healthier or the average man lives shorter?

7. Ch. 20.1 Population Ecology pp.379-382
Age structure = distribution by age of individuals in a population

8. Ch. 20.1 Population Ecology pp.379-382
Survivorship curve = shows when populations die (how they survivor)
Type I: few die early in life, many die late in life (humans, elephants)
Type II: die equally throughout life (prey species, mice, squirrels, rabbits…)
Type III: many die early, few die late (insects, oysters, turtles)

9. Ch. 20.1 Population Ecology pp.379-382
OUT: Table 20-1 p. 380
Predict the Land Size of the countries from Largest to smallest.
Calculate the population of the U.S. in the year 2000 using the information from the table, if the U.S. has an area of 9,620,000 km2