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CHAPTER 5
POPULATION ECOLOGY
POPULATION DENSITY
• Measures how crowded a population is
3 types
•
1.
•
2.
•
3.
POPULATION DYNAMICS
•
= number of births over time
•
= deaths over a period of time
•
Life expectancy = how long individuals in pop. are expected to live
– Take a guess: life expectancy for men and women in United States
• Men =
• Women =
POPULATION GROWTH RATE
•
•
Growth rate= change in population size over time
Depends upon the following:
– Birth
–
– Immigration
–
AGE STRUCTURES
 What is a rate?
 What is birth rate?
 What is death rate?
 What are two additional factors that cause a population to increase? Decrease?
 What does per capita or % annual growth rate mean?
CONCEPT MAP FOR POPULATION GROWTH
EXPONENTIAL MODEL
•
•
Says that populations grow rapidly after only a few generations
Bacteria follow this model
DRAW and LABEL THE CURVE
LOGISTIC MODEL
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Populations are limited by their environment
Any factor that limits population growth is called a limiting factor
Limiting factors include things like
DRAW and LABEL THE CURVE
 5–2
Limits to Growth
Limiting Factors
Density-Dependent Factors
1.
Extinction
2.
Competition
3.
Predation
4.
Parasitism and Disease
C.
Density-Independent Factors
A.
B.
DENSITY DEPENDENT FACTORS –
DENSITY INDEPENDENT FACTORS –
EXTINCTION –
Special case: Small populations
COMPETITION AND PREDATION – one organism directly impacts the population
growth of the other EX. Oh Deer!
HUMAN POPULATION
 They have exploded over the last 1000 years
 The death rates have decreased and the birth rates have increased. This makes the
overall growth rate increase.
 Do you think that this current human population is sustainable?
 Do you think that we are way past our carrying capacity and it will go down?