Transcript Population

Chapter 15.1
Populations
Topic 1: What is a Population?
• All the individuals of a species that live together
in one place at one time
– As small as bacteria to as large as elephants
• Populations grow (multiple offspring) and decrease (deaths)
– Limited resources keep populations from growing
too large
Topic 2: Three Key Features of
Populations
•
The future of populations are determined by these
3 factors:
1. Population Size- ability to survive; small
populations more likely to become extinct
1. Natural disasters
2. Population Density- more spaced out, less likely to
reproduce
3. Dispersion- random, even or clumped; interactions
between populations
Random, Even and Clumped
Populations
Topic 3: Population Growth
•
Population Model- predict how populations grow
–
–
Describes the rate of population growth as the
differences between birth rate and death rate
Growth rate
1. Exponential Growth Curve
2. Logistic Growth Model
exponential
growth
Logistic growth
Topic 4: Exponential Growth
• Exponential Growth Curve- rate of population growth stays
the same; population size increases steadily
– Graph Population Size Vs Time
– Not realistic of most populations… limiting factors
Topic 5: Logistic Growth
• Logistic Growth Model- rate of population growth increases
untill it hits the carrying capacity
– Takes into account declining resources
– population growth eventually levels off
Exit Ticket
1. Identify the pattern of dispersion of fans at a
basketball game as random, even or clumped.
EXPLAIN your answer.
2. What is the differences between exponential
growth pattern and a logistic growth pattern?
3. What is a population and what are the three key
features that determine its future?
15.1 Quiz Tomorrow!